给水排水工程专业英语论文
Water and Wastewater EngineeringFinal Class ProjectTitle:Applications of municipal wastewater treatment in livesCollege _____C.E__________Major ___ _WWE__________Class ____ _______Number_____ ____Name____ _____Data_____________________Applications of municipal wastewater treatment in livesAbstract:This article describes the following sections:sequential combination ofphotocatalytic oxidation with constructed wetlands is the study and theexperimental evaluation of an alternative and innovative wastewater treatmentsystem, which combines the action of photocatalytic oxidation with the surfaceflow constructed wetlands.A new contact oxidation filtration separationintegrated bioreactor was used to treat municipal wastewater.the syntheticpolymers normally used in the coagulation-flocculation treatment of waste waterrequires sustainable alternatives.Keywords:bioreactor;coagulation;flocculation;photocatalytic oxidation; Combination of photocatalytic oxidation with constructed wetlandsWastewater treatment systems have been designed to minimize the environmental impacts of discharging untreated wastewater.Different options for wastewater treatment have different performance characteristics and also different direct impacts on the environment. During the last decades centralized conventional wastewater treatment systems were typically provided to large cities and secondary towns. They involve large capital investments and operating costs, resulting in systems which are considered as not proper solutions for small villages that cannot afford such expensive treatment facilities.In addition, low water use rates and several operational problems have been encountered with such systems in rural and especially in touristic areas where the population size varies seasonally. The need for alternative methods of wastewater treatment is of interest to regulating authorities everywhere.The so-called advanced oxidation technologies (AOTs) are among the most effective chemical oxidation processes, and are currently gaining significant importance in water treatment applications. Under this term the scientific community refers to the technologies whose effectiveness is based on the production of the •OH radicals, one of the most powerful oxidant reagents.They can easily attack the organic molecules leading to the production of organic peroxide radicals and their final conversion to CO2,H2O and inorganic salts. The increased concern for the use of the AOTs may be explained by the need for seeking of new,alternative to the conventional ones and environmentally friendly technologies.Among these, heterogeneous and homogeneous solar photocatalytic detoxification methods (TiO2/H2O2,Fe3+/H2O2) have shown recently great promise for the treatment of industrial wastewater,groundwater and contaminated air, allowing the contribution of the renewable sources of energy (solar energy) to the process of cleaning and restoring the environment.The system combines the action of photocatalytic oxidation with the surface flow constructed wetlands in order to utilize the high solar irradiation in the Mediterranean region and the ability of the constructed wetlands to improve water quality through natural processes, providing treated wastewater capable of being reused, e.g. for irrigation. More specifically,the method consists of the combination of a common physicochemical precipitation, a solar photocatalytic reduction of the organic content of wastewater by the use of a heterogeneous or homogeneous solar photocatalytic method, and finally passage of the wastewater through a constructed wetland, for the final purification of the wastewater to make its reuse possible.A contact oxidation filtration separation integrated bioreactorTraditional wastewater treatment processes are usually equipped with different treatment units that have a variety of functions to achieve acceptable treatment performance. Conventional processes for municipal wastewater treatment have disadvantages such as complicated operation, high running cost, excessive installation and large land requirement. As a result, wastewater treatment plants normal operation face a number of key challenges in developing countries such as China.In comparison with those traditional wastewater treatment processes, bio-film systems have low land requirement and flexible operation. Bio-film technology systems include trickling filters, biological aerated filter (BAF), rotating biological contactor (RBC), fluidized bed reactor (FBR) and moving-bed reactor (MBR).To help overcome these issues, a new contact oxidation filtration separation integrated bioreactor (CFBR) was developed, which was composed of a Bio-film reactor (the upper part of CFBR) and a gravitational filtration bed prototype and principles of slow and cake filtration .Bio-film configuration coupled with gravitational filtration bed combines the advantages of the Bio-film reactor and the filtration bed in one system. As the use of filtration process, the CFBR can keep its effluent SS at a lower level. Moreover, the low investment cost of CFBR allows a cost-saving advancedtreatment for pollutants from small and medium sized factories as well as separate streams of process wastewater, especially in developing countries such as China.In developing countries such as China, which a trade-off between environmental protection and economical operation has to be made based on the local socioeconomic situation, cost is more important than other factors when choosing a process. Construction and operation cost are two important factors in evaluating a wastewater treatment process. And 60-90 percent of operation cost is electrical power consumption in wastewater treatment. According to Lou’s study on power consumption of municipal wastewater process, irrespective of electrical power consumption of sludge digestion, the electrical power consumption of WWTPs surveyed is 0.21-0.36 kWh/m3 of wastewater treated in China during 2000-2004.As CFBR described, its construction cost is low due to a single reactor of the whole system. And electrical power consumption of CFBR system was 0.13-0.15 kWh/m3 of wastewater treated, and 1.37-1.50 kWh/kg BOD5 removals. Hence, compared with traditional secondary municipal wastewater treatment processes, the cost of CFBR was very low. The results could be explained in two following aspects. On the one hand, there is no sludge return operation in CFBR process. On the other hand, the aspect ratio (i.e. height-to-diameter ratio) of CFBR is 21,which has achieved good DO utilization ratio. Therefore, CFBR is capable of good power consumption.Coagulation-flocculation treatment of municipal wastewaterCoagulation-flocculation treatment is commonly used to reduce the turbidity of municipal and industrial waste water, the coagulants in question typically being divalent or trivalent metallic salts or polymers that have low solubility in the pH range used. Metal salts hydrolyze rapidly in waste water to form cationic species, which are adsorbed by negatively charged dirt particles,resulting in simultaneous surface charge reduction. Polymers have been used in the coagulation-flocculation process for decades to reduce coagulant dosages, the volume of sludge and the ionic load of the waste water (especially the level of aluminum), and to save overall costs.The polymers used in coagulation-flocculation treatment are commonly synthetic poly-acrylamides, poly-acrylic acids and poly-styrene sulphonic acids and their derivatives, which are not readily biodegradable. Moreover, they may also contain un-polymerized monomers and additives that are neurotoxic and carcinogenic. Also, synthetic polymers are produced from oil-based raw materials, which make them non-renewable chemicals. Consequently, there has been a growing interest in replacing oil-based flocculants with more sustainable natural bio-based alternatives.Many natural-based flocculants are environmentally friendly and biodegradable, with good flocculating ability. These include bio polymeric materials such as starch, guar gum, chitin, pectin and algin, and some derivatives of natural carbohydrates such as dextran and pullman have also been investigated for these properties. Derivatives of cellulose, which is the most abundant biopolymer on earth, are nevertheless still scarce. One potential and environmentally sustainable method of producing cellulose flocculants is to introduce reactive aldehyde functionalities into cellulose by aqueous periodate oxidation, as has been reported earlier. The aldehyde groups of 2,3-di-aldehyde cellulose (DAC) can easily be converted further and in a selective manner to various functional groups such as carboxylic acids, sulphonates or imines. Recently Liimatainen et al.have investigated the use of anionic (ADAC) and cationic cellulose (CDAC) derivatives in the flocculation of kaolin suspensions, with promising results, showing that anionic cellulose nanoparticles resulted in better flocculation performance than the corresponding fully water-soluble derivatives. Also Hokkanen et ed modified nanofibrillated celluloses to remove heavy metals from aqueous solutions with promising results.In the present research aldehyde groups of DAC pulp fibres were converted to carboxylic acids and these anionic cellulose derivatives (DCC) were nanofibrillated with a homogenizer. The flocculation performance of five anionic dicarboxylic acid (DCC) nanocelluloses produced in this way with variable charge densities was examined in the context of the coagulation–flocculation treatment of municipal waste water. The effects of DCC dosage and pH on flocculation were studied by measuring residual turbidity and COD of the settled suspension and compared the results with the performance of a commercial coagulant (PIX 105 A) and a commercial combination of a coagulant and a synthetic polymeric flocculant. In addition, the aldehyde and carboxyl content, charge density (CD), size and stability of each DCC were determined in an aqueous solution.References:[1] A. Antoniadis,V. Takavakoglou.Municipal wastewater treatment by sequential combination ofphotocatalytic oxidation with constructed wetlands,Available online 18 April 2010.[2] Z.H.Li, K.Yang,Treatment of municipal wastewater using a contact oxidation filtrationseparation integrated bioreactor,Available online 26 February 2010.[3] Terhi Suopajärvi, Henrikki Liimatainen,Coagulation-flocculation treatment of municipalwastewater based on anionized nanocelluloses,Available online 15 July 201.[4] Weiwei Mo, Qiong Zhang,Can municipal wastewater treatment systems be carbonneutral?Available online 8 September 2012.。
给排水科学与工程英语
给排水科学与工程英语Introduction to Water Supply and Drainage EngineeringWater supply and drainage engineering is a crucial aspect of urban and rural infrastructure development. It involves the design, construction, and management of systems that provide clean and safe water and remove wastewater from homes and commercial buildings.The science and engineering behind water supply and drainage systems are complex and require specialized knowledge in areas such as hydraulics, environmental engineering, and public health. Engineers in this field need to understand the principles of water treatment, distribution, and storage, as well as the collection, treatment, and disposal of wastewater. In recent years, there has been a growing need for sustainable solutions in water supply and drainage engineering. This has led to an increased focus on the use of renewable energy sources, such as solar and wind power, in water treatment and distribution. Additionally, there has been a push for more efficient and cost-effective methods for treating wastewater, such as using natural wetlands to filter pollutants.The importance of water supply and drainage engineering cannot be overstated. Without adequate access to clean waterand proper wastewater management, communities can suffer from a range of health problems, environmental degradation, and economic losses. As such, it is essential that professionals in this field continue to innovate and develop new solutions to meet the needs of a growing global population.In conclusion, water supply and drainage engineering is a crucial component of modern society. As our world continues to grow and evolve, so too must our methods for providing clean and safe water and managing wastewater. By staying at the forefront of scientific and technological advancements, we can ensure a sustainable future for generations to come.。
给水排水专业外语论文
The activated-sludge processAbstract--This paper introduces the composition and principle of activated-sludge process,recent developments and future developments tendency.It also provides a design scheme and a example.Key words--activated-sludge,aeration tank,computer simulation,design scheme1.IntroductionThe activated-sludge process is a biological method of wastewater treatment that is performed by a variable and mixed community of microorganisms in an aerobic aquatic environment. These microorganisms derive energy from carbonaceous organic matter in aerated wastewater for the production of new cells in a process known as synthesis, while simultaneously releasing energy through the conversion of this organic matter into compounds that contain lower energy, such as carbon dioxide and water, in a process called respiration. As well, a variable number of microorganisms in the system obtain energy by converting ammonia nitrogen to nitrate nitrogen in a process termed nitrification. This consortium of microorganisms, the biological component of the process, is known collectively as activated sludge.The overall goal of the activated-sludge process is to remove substances that have a demand for oxygen from the system. This is accomplished by the metabolic reactions (synthesis-respiration and nitrificaction) of the microorganisms, the separation and settling of activated-sludge solids to create an acceptable quality of secondary wastewater effluent, and the collection and recycling of microorganisms back into the system or removal of excess microorganisms from the system.2.The principle of the activated-sludge process2.1The components of the activated-sludge processBefore beginning a discussion of the biological component of the system, an overview of the physical components that comprise the activated-sludge process would seem to be in order. This will help the reader gain a better understanding of the environment in which a mixed community of microorganisms metabolizes organic matter, settles to form a thickened sludge, and is recycled back into or removed from the system.According to Activated Sludge, Manual of Practice(Water Environment Association, 1987),the activated-sludge process contains five essential interrelated equipment components. The first is an aeration tank or tanks in which air or oxygen is introduced into the system to create an aerobic environment that meets the needs of the biological community and that keeps the activated sludge properly mixed. At least seven modifications in the shape and number of tanks exist to produce variations in the pattern of flow.Second, an aeration source is required to ensure that adequate oxygen is fed into the tank(s) and that the appropriate mixing takes place. This source may be provided by pure oxygen, compressed air or mechanical aeration. Just as there are modifications in the shape and number of aeration tanks that can be used in the activated-sludge process, different equipment systems exist to deliver air or oxygen into aeration tanks.Third, in the activated-sludge process, aeration tanks are followed by secondary clarifiers. In secondary clarifiers, activated-sludge solids separate from the surrounding waterwater by the process of flocculation (the formation of large particle aggregates, or flocs, by the adherence of floc-formingorganisms to filamentous organisms) and gravity sedimentation, in which flocs settle toward the bottom of the clarifier in a quiescent environment. This separation leads ideally to the formation of a secondary effluent (wastewater having a low level of activated-sludge solids in suspension) in the upper portion of the clarifier and a thickened sludge comprised of flocs, termed return activated sludge, or RAS, in the bottom portion of the clarifier. Next, return activated sludge must be collected from the secondary clarifiers and pumped back to the aeration tank(s) before dissolved oxygen is depleted. In this way, the biological community needed to metabolize influent organic or inorganic matter in the wastewater stream is replenished.Finally, activated sludge containing an overabundance of microorganisms must be removed, or wasted (waste activated sludge, or WAS), from the system. This is accomplished with the use of pumps and is done in part to control the food-to-microorganism ratio in the aeration tank(s).2.2The basic process of the activated-sludge processThe process involves air or oxygen being introduced into a mixture of primary treated or screened sewage or industrial wastewater (called wastewater from now on) combined with organisms to develop a biological floc which reduces the organic content of the sewage. This material, which in healthy sludge is a brown floc, is largely composed of saprotrophic bacteria but also has an important protozoan flora mainly composed of amoebae,Spirotrichs,Peritrichs including Vorticellids and a range of other filter feeding species. Other important constituents include motile and sedentary Rotifers. In poorly managed activated sludge, a range of mucilaginous filamentous bacteria can develop including Sphaerotilus natans which produces a sludge that is difficult to settle and can result in the sludge blanket decanting over the weirs in the settlement tank to severely contaminate the final effluent quality. This material is often described as sewage fungus but true fungal communities are relatively uncommon.The combination of wastewater and biological mass is commonly known as mixed liquor. In all activated sludge plants, once the wastewater has received sufficient treatment, excess mixed liquor is discharged into settling tanks and the treated supernatant is run off to undergo further treatment before discharge. Part of the settled material, the sludge, is returned to the head of the aeration system to re-seed the new wastewater entering the tank. This fraction of the floc is called return activated sludge (R.A.S.). Excess sludge is called surplus activated sludge(S.A.S.) or waste activated sludge(W.A.S). S.A.S is removed from the treatment process to keep the ratio of biomass to food supplied in the wastewater in balance. S.A.S is stored in sludge tanks and is further treated by digestion, either under anaerobic or aerobic conditions prior to disposal.Many sewage treatment plants use axial flow pumps to transfer nitrified mixed liquor from the aeration zone to the anoxic zone for denitrification. These pumps are often referred to as internal mixed liquor recycle pumps (IMLR pumps). The raw sewage, the RAS, and the nitrified mixed liquor are mixed by submersible mixers in the anoxic zones in order to achieve denitrification.Activated sludge is also the name given to the active biological material produced by activated sludge plants.4.Developments of activated-sludge process4.1Recent developments of activated-sludge processAn innovative activated sludge system without excess sludge production was introduced to thethree existing treatment plants receiving of petrochemical wastewater totally about 17.5ton CODcr/day and 9,600 m3/day in Japan. In the system, simultaneous sludge treatment and wastewater treatment is possible in the same aeration tank. A part of sludge returning from the secondary settling tank is ozonated to change it to more biodegradable compounds and the ozonated sludge is then put into the aeration tank for biological degradation. The degree of excess sludge reduction is controlled by the changing sludge mass to be ozonated. The kinetics and stoichiometrics of ozonated sludge were incorporated into Activated Sludge Model No.1 (ASM1) to predict MLSS concentration and oxygen uptake rate in the each aeration tank. The prediction by the process & hydraulic models matched very reasonably in the dynamic conditions with the changing influent loading rate and the ozonation. The system has been demonstrated successfully by minimal excess sludge withdrawing for more than four years. The water qualities in the effluent also kept at acceptable levels and below the local regulation.4.2Future developments of activated-sludge processTill now,numerous modifications of activated-sludge process have evolved in the last 10 to 20 years.Many new technologies appear,such as MBR,computer modeling.Nearly all of the various modifications are based on the same fundamental principles of biological treatment.Because the design and operation of the activated-sludge process is becoming more complex,a mathematical model of the activated-sludge process has been derived which considers the fate of bacteria which flocculate, bacteria which do not flocculate, and two forms of ciliated protozoa. Computer simulation techniques have been used to study the population dynamics of these organisms in a single completely-mixed and a series of completely-mixed activated-sludge reactor systems; in both cases steady-state solutions were obtained. At steady state, the concentration of soluble substrate in the effluent is determined by the growth rate (fixed by the sludge-wastage rate) of the sludge bacteria. The concentration of dispersed bacteria in the effluent is similarly determined by the growth rate of the ciliated protozoa. The model predicts that the habit of ciliated protozoa would have a considerable effect on effluent quality. A plant containing only free-swimming ciliates would produce a fairly turbid effluent whereas a plant containing attached ciliates would produce a highly clarified effluent. Activated-sludge plants which contain no protozoa would be expected to deliver very turbid effluents although the concentration of soluble substrates would be precisely the same in all three cases. It was possible to simulate successions of organisms which are qualitatively similar to those observed in practice when an activated-sludge plant is set into operation. The results of the model predictions are discussed in the light of full-scale and experimental-scale observations.5.Design of Activated-sludgedesign scheme5.1Activated Sludge Process VariablesThe main variables of activated sludge process are the mixing regime, loading rate, and the flow scheme.5.2Mixing RegimeGenerally two types of mixing regimes are of major interest in activated sludge process: plug flow and complete mixing. In the first one, the regime is characterized by orderly flow of mixed liquor through the aeration tank with no element of mixed liquor overtaking or mixing with any other element. There may be lateral mixing of mixed liquor but there must be no mixing along the path of flow.In complete mixing, the contents of aeration tank are well stirred and uniform throughout. Thus, at steady state, the effluent from the aeration tank has the same composition as the aeration tank contents.The type of mixing regime is very important as it affects (1) oxygen transfer requirements in the aeration tank, (2) susceptibility of biomass to shock loads, (3) local environmental conditions in the aeration tank, and (4) the kinetics governing the treatment process.5.3Loading RateA loading parameter that has been developed over the years is the hydraulic retention time (HRT), q, dq = VQV= volume of aeration tank, m3, and Q= sewage inflow, m3/d5.4Flow Scheme●The flow scheme involves:●the pattern of sewage addition●the pattern of sludge return to the aeration tank and●the pattern of aeration.Sewage addition may be at a single point at the inlet end or it may be at several points along the aeration tank. The sludge return may be directly from the settling tank to the aeration tank or through a sludge reaeration tank. Aeration may be at a uniform rate or it may be varied from the head of the aeration tank to its end.5.6Design ConsiderationThe items for consideration in the design of activated sludge plant are aeration tank capacity and dimensions, aeration facilities, secondary sludge settling and recycle and excess sludge wasting.5.7Aeration TankThe volume of aeration tank is calculated for the selected value ofq c by assuming a suitable value of MLSS concentration, X.VX = YQq c(S O - S)1+ k d q cAlternately, the tank capacity may be designed fromF/M = QS O / XVHence, the first step in designing is to choose a suitable value ofq c(or F/M) which depends on the expected winter temperature of mixed liquor, the type of reactor, expected settlingcharacteristics of the sludge and the nitrification required. The choice generally lies between 5 days in warmer climates to 10 days in temperate ones where nitrification is desired alongwith good BOD removal, and complete mixing systems are employed.The second step is to select two interrelated parameters HRT, t and MLSS concentration. It is seen that economy in reactor volume can be achieved by assuming a large value of X. However, it is seldom taken to be more than 5000 g/m3. For typical domestic sewage, the MLSS value of 2000-3000 mg/l if conventional plug flow type aeration system is provided, or 3000-5000 mg/l for completely mixed types. Considerations which govern the upper limit are: initial and running cost of sludge recirculation system to maintain a high value of MLSS, limitations of oxygen transfer equipment to supply oxygen at required rate in small reactor volume, increased solids loading on secondary clarifier which may necessitate a larger surface area, design criteria for the tank and minimum HRT for the aeration tank.The length of the tank depends upon the type of activated sludge plant. Except in the case of extended aeration plants and completely mixed plants, the aeration tanks are designed as long narrow channels. The width and depth of the aeration tank depends on the type of aeration equipment employed. The depth control the aeration efficiency and usually ranges from 3 to 4.5 m. The width controls the mixing and is usually kept between 5 to 10 m. Width-depth ratio should be adjusted to be between 1.2 to 2.2. The length should not be less than 30 or not ordinarily longer than 100 m.5.8Oxygen RequirementsOxygen is reqiured in the activated sludge process for the oxidation of a part of the influent organic matter and also for the endogenous respiration of the micro-organisms in the system. The total oxygen requirement of the process may be formulated as follows:O2 required (g/d) = Q(S O - S) - 1.42 Q w X rfwhere, f = ratio of BOD5 to ultimate BOD and 1.42 = oxygen demand of biomass (g/g)The formula does not allow for nitrification but allows only for carbonaceous BOD removal.5.9Aeration FacilitiesThe aeration facilities of the activated sludge plant are designed to provide the calculated oxygen demand of the wastewater against a specific level of dissolved oxygen in the wastewater.5.10Sludge RecycleThe MLSS concentration in the aeration tank is controlled by the sludge recirculation rate and the sludge settleability and thickening in the secondary sedimentation tank.Q r = XQ X r-Xwhere Q r = Sludge recirculation rate, m3/dThe sludge settleability is determined by sludge volume index (SVI) defined as volume occupied in mL by one gram of solids in the mixed liquor after settling for 30 min. If it is assumed that sedimentation of suspended solids in the laboratory is similar to that in sedimentation tank, then X r = 106/SVI. Values of SVI between 100 and 150 ml/g indicate good settling of suspended solids. The X r value may not be taken more than 10,000 g/m3unless separate thickeners are provided toconcentrate the settled solids or secondary sedimentation tank is designed to yield a higher value.5.11Excess Sludge WastingThe sludge in the aeration tank has to be wasted to maintain a steady level of MLSS in the system. The excess sludge quantity will increase with increasing F/M and decrease with increasing temperature. Excess sludge may be wasted either from the sludge return line or directly from the aeration tank as mixed liquor. The latter is preferred as the sludge concentration is fairly steady in that case. The excess sludge generated under steady state operation may be estimated byq c = VXQ w X ror Q w X r = YQ (S O - S) - k d XV6.Design exampleDesign of Completely Mixed Activated Sludge SystemDesign a completely mixed activated sludge system to serve 60000 people that will give a final effluent that is nitrified and has 5-day BOD not exceeding 25 mg/l. The following design data is available.Sewage flow = 150 l/person-day = 9000 m3/dayBOD5 = 54 g/person-day = 360 mg/l ; BOD u = 1.47 BOD5Total kjeldahl nitrogen (TKN) = 8 g/person-day = 53 mg/lPhosphorus = 2 g/person-day = 13.3 mg/lWinter temperature in aeration tank = 18°CYield coefficient Y = 0.6 ; Decay constant K d = 0.07 per day ; Specific substrate utilization rate = (0.038 mg/l)-1 (h)-1 at 18°CAssume 30% raw BOD5is removed in primary sedimentation, and BOD5going to aeration is, therefore, 252 mg/l (0.7 x 360 mg/l).Design:(a) Selection of q c, t and MLSS concentration:Considering the operating temperature and the desire to have nitrification and good sludge settling characteristics, adopt q c = 5d. As there is no special fear of toxic inflows, the HRT, t may be kept between 3-4 h, and MLSS = 4000 mg/l.(b) Effluent BOD5:Substrate concentration, S = 1 (1/q c + k d)= 1 (1/5 + 0.07)qY (0.038)(0.6)S = 12 mg/l.Assume suspended solids (SS) in effluent = 20 mg/l and VSS/SS =0.8.If degradable fraction of volatile suspended solids (VSS) =0.7 (check later), BOD5 of VSS in effluent = 0.7(0.8x20) = 11mg/l.Thus, total effluent BOD5 = 12 + 11 = 23 mg/l (acceptable).(c) Aeration Tank:VX = YQq c(S O - S) where X = 0.8(4000) = 3200 mg/l1+ k d q cor 3200 V = (0.6)(5)(9000)(252-12)[1 + (0.07)(5)]V = 1500 m3Detention time, t = 1500 x 24 = 4h9000F/M = (252-12)(9000) = 0.45 kg BOD5 per kg MLSS per day(3200) (1500)Let the aeration tank be in the form of four square shaped compartments operated in two parallel rows, each with two cells measuring 11m x 11m x 3.1m(d) Return Sludge Pumping:If suspended solids concentration of return flow is 1% = 10,000 mg/lR = MLSS = 0.67(10000)-MLSSQ r = 0.67 x 9000 = 6000 m3/d(e) Surplus Sludge Production:Net VSS produced Q w X r = VX = (3200)(1500)(103/106) = 960 kg/dq c (5)or SS produced =960/0.8 = 1200 kg/dIf SS are removed as underflow with solids concentration 1% and assuming specific gravity of sludge as 1.0,Liquid sludge to be removed = 1200 x 100/1 = 120,000 kg/d= 120 m3/d(f) Oxygen Requirement:1For carbonaceous demand,oxygen required = (BOD u removed) - (BOD u of solids leaving)= 1.47 (2160 kg/d) - 1.42 (960 kg/d)= 72.5 kg/h2For nitrification,oxygen required = 4.33 (TKN oxidized, kg/d)Incoming TKN at 8.0 g/ person-day = 480 kg/day. Assume 30% is removed in primary sedimentation and the balance 336 kg/day is oxidized to nitrates. Thus, oxygen required= 4.33 x 336 = 1455 kg/day = 60.6 kg/h3Total oxygen required= 72.5 + 60.6 = 133 kg/h = 1.0 kg/kg of BOD u removed.Oxygen uptake rate per unit tank volume = 133/1500= 90.6 mg/h/l tank volume(g) Power Requirement:Assume oxygenation capacity of aerators at field conditions is only 70% of the capacity at standard conditions and mechanical aerators are capable of giving 2 kg oyxgen per kWh at standard conditions.Power required = 136 = 97 kW (130 hp)0.7 x 2= (97 x 24 x 365) / 60,000 = 14.2 kWh/year/personReferences[1]Benedict, R. G. and Carlson, D. A. (1971) “Aerobic Heterotrophic Bacteria in Activated Sludge,” Water Research, v. 5, pp. 1023-1030.[2]Curds, C. R. and Fey, G. J. (1969) “The Effect of Ciliated Protozoa on the Fate of Escherichia coli in the Activated-Sludge Process,” Water Research, v. 3, pp. 853-867.[3]Water Environment Association. (1987) Activated Sludge, Manual of Practice #9.[4]Jenkins, D., Richard, M. G.and Daigger, G. T. (1993) Manual on the Causes and Control of Activated Sludge Bulking and Foaming, 2nd ed. Boca Raton: Lewis Publishers.[5]Yasui Hidenari.Recent Developments of the Activated Sludge Process.Kuritakogyo Gikaise,2002[6]SCHULZE K. L. (1965) The activated-sludge process as a continuous flow culture.PartII.Wat.Sewage Wks 112, 11-17.[7]MCI(dNNEY R. E. (1962) Mathematics of a completely mixed activated sludge. J. sanit. Engng Div.Am. Soc. cir. Engrs 88, SA3, 87-113.。
给水排水工程专业英语文献翻译原文第一篇
Abbreviations: ADF, Aerobic Dynamic Feeding, also designated as “feast and famine”; CSTR, Continuous Stirred Tank Reactor; C/N, Carbon to nitrogen ratio; HAc, Acetic acid; HB, Hydroxybutyrate; HBut, Butyric acid; HLac, Lactic acid; HProp, Propionic acid; HV, Hydroxyvalerate; HVal, Valeric acid; HRT, Hydraulic Retention Time; OUR, Oxygen Uptake Rate; PHA, Polyhydroxyalkanoate; qP, Maximum specific polymer storage rate; -qS, Maximum specific substrate uptake rate; SBR, Sequencing Batch Reactor; SRT, Sludge Retention Time; TOC, Total Organic Carbon; VFA, Volatile Fatty Acid; VSS, Volatile Suspended Solid; VSSmax, Volatile Suspended Solids at the time of maximum polymer accumulation; X, Active Biomass; Xi, Initial active biomass concentration; YO2/X, Respiration yield, in Cmmol/Cmmol VFA; YP/S, Polymer storage yield, in Cmmol HA/Cmmol VFA; YX/S, Growth yield in Cmmol X/Cmmol VFA
英文文献 给排水专业
Research on Facilitation of Biodegradation for Azo Dye Wastewater by Bioelectrochemical TechnologyZHAO Yuhua，CANG Xiaoyi, JIN Decai, DONG RuijiaoSchool of Municipal and Environment Engineering Shenyang Jianzhu University Shenyang，China 110168 zyh088@, 666xiaoyi@,kingdecai123@, dongruijiao@Abstract—Active brilliant red X-3B is a kind of azo dye which is difficult to biodegrade. The wastewater with azo dye is of chromaticity depth, high content of organic compounds, water quality changing great, and seriously impacts environment. Bioelectrochemical hydrolysis coupled with biological contact oxidation (BEH-BCO) was used to treat azo dye active brilliant red X-3B simulation wastewater. In this experiment, synergy of micro-electrolysis and biological hydrolysis was used to improve the efficiency of hydrolysis reactor, and then improve the biodegradation of azo dye wastewater. In the experiment, the HRT of Hydrolysis reactor kept running 12h, and the HRT of biological contact oxidation reactor 7.95h. The electric current densities used in the experiment were 0.024, 0.048, 0.071mA/cm2. This experiment was compared with the biological hydrolysis and biological contact oxidation (BH-BCO), the single biological treatment. Experiment results showed that, the removal effect of active brilliant red X-3B by bioelectrochemical technology was very good in heavy dye mass concentration in raw water (concentration was 50mg/L); and in the range of current density used in test, the treatment effect was increased with the increase of electric current density; when electric current density was 0.071mA/cm2, the average removal ratio of dye mass concentration, colority, CODCr, and NH3-N reached 98.77%, 91.39%, 69.98%, and 90.41% by bioelectrochemical technology respectively, and 9.65%, 18.21%, 31.32%, and 85.69% respectively by the single biological method. There are some reasons for the results. The first reason is that the dye mass concentration of wastewater in raw water was too high, single biological hydrolysis was difficult [1]. The second reason is that, from the measure results of oxidation reduction potential, the hydrolysis reactor was in anaerobic condition in the experimental process, which produced inhibitory environment to bacteria. The analysis of UV-visible absorption spectrum of the influent and effluent from each reactor indicated that the molecular structure of active brilliant red X-3B was destroyed by bioelectrochemical technology and turned into readily biodegradable small molecular organic compound, but it changed little by biological treatment. The measure results of redox potential showed that, the redox potential of mixed liquor in BEH was about -200mV, which is within the range of azo compound redox required standards (-180mV ～ -430mV); the redox potential of mixed liquor in BH was about -152mV, which is not in the required range, and is also not in the range of hydrolysis reactor working normally (about 0mV). The results of measured azoreductase activity show that the azoreductase activity of the single biological hydrolysis was 1.68 mg/L·h, the azoreductase activity of bioelectrochemical hydrolysis was 55.33 mg/L·h. In a word, bioelectrochemical technology could promote the activity of hydrolysis microbe greatly, and obviously improve the decolorization effect of active brilliant red X-3B wastwater. It plays a great role in promoting biodegradation of azo dye wastewater. Keywords-azo dye wastewater; bioelectrochemical; hydrolysis; contact oxidation; active brilliant red X-3BI.INTRODUCTIONAzo dye is widely used in the trades of printing, food, cosmetics, and so on [2]. Azo dye wastewater with huge volume and extensive distribution, changing water quality greatly, high concentration of toxic organic compounds, heavy colority, and complicated biodegradation, is one of the intractable industrial wastewaters. The routine methods to treat dye wastewater include physical method, chemical method, biological method, electrochemical method, and etc. These methods exist obviously disadvantages when they are used [3]. Bioelectrochemical technology is a method that electrochemical reaction and biochemical reaction are set off in a same reactor. It could make electrochemical reaction and microbial reaction complementary and enhance each other, and improve the efficiency of treating wastewater, and reduce the equipment initial investment [4]. In this test, bioelectrochemical technology was applied to treat active brilliant red X-3B that is in a simulated dye wastewater, researched the strengthening effect of bioelectrochemical technology by the contrast experiments between BEH-BCO process and BH-BCO process, and explored the biodegradation mechanism of active brilliant red X-3B. II. TESTER, MATERIALS AND METHODS A. Tester and methods The schematic of the experiment system was showed in Fig.1. This experiment system was divided into two parts, A and B. Part A was BEH-BCO process. In this process, iron sheet (100cm×50cm) in hydrolysis reactor is as the anode, and graphite column (diameter 4cm, high 100cm) as the cathode. Part B was BH-BCO process.This project is supported by Municipal & Environmental Engineering Key Laboratory Open Foundation of Colleges and Universities in Liaoning Province (No.SZ-200901) and Science and Technology Foundation of Ministry of Housing and Urban-Rural Development (No.2010-K7-14).At the bottom of hydrolysis reactor, pulse current which is provided by air compressor play a part in stir mainly, and shall not exceed the limit of dissolved oxygen (DO) in hydrolysis reactor. Continuous aeration was offered to the contact oxidation reactor. Insides of hydrolysis reactor and contact oxidation reactor placed the combination filling (specific surface area 1400-2500 m2/m3). Both BEH-BCO process and BH-BCO process had the same design parameters. Effective volume of BEH reactor was 24L. The hydraulic residence time of BEH was 12h. Useful volume of BCO reactor was 15.9L. The hydraulic residence time was 7.95h. Flow rate was 2L/h. Because the hydrolysis reactor was cylindrical, electric current density distributed uneven. This paper used average electric current density (center plane interfaced between two electrodes with 50% useful volume each).+solution. A standard curve covered colority from 10° to 100° was drawn. The absorbency of the sample which had been centrifugated was measured at wavelength of 350nm. Colority was obtained by calculation [5]. Azoreductase activity was measured by TTC deoxidation method [6]. III. RESULTS AND DISCUSSION The test device adopted domestic sewage inoculation sludge and hanged membrane for 41 days. After the start-up of the device, the results from the contrastively experiments between BEH-BCO process and BH-BCO process to treat active brilliant red X-3B wastewater in electric current density 0.071, 0.048, 0.020 mA/cm2 were showed in figure 2- figure 5. A. Azo dye concentration variety Figure 2 shows the variety of azo dye mass concentration of inflow and effluent to and from every reactor in different electric current density. It depicts that, comparing to the single biological method, treating active brilliant red X-3B by BEH-BCO process has better efficiency. The azo dye concentration of effluent from BEH-BCO process increased with the electric current density declined. When the electric current density was 0.071mA/cm2, the average removal ratio of dye concentration by BEH-BCO process was 98.77%. In BH-BCO process, because of the dye concentration of inflow was too high and the DO in hydrolysis reactor was lower, the bacteria in hydrolysis reactor were restrained. As a result, the average removal ratio of dye concentration was 9.65%.A.BEH-BCO B.BH-BCO 1.Wastewater tank 2..Dosing pump 3.Power 4. BEH reactor 5. Graphite electrode 6 .Packing 7. Iron electrode 8. BCO reactor 9. Aerated conduit 10. Effluent 11. Air compressor 12. Air distributor 13. Time controller 14. Disposed sludge 15. BH reactorFigure 1. Schematic of the experiment apparatusB. Azo dye wastewater Component of simulated azo dye wastewater for experiment is showed in Table I.TABLE ICODCr (mg/L)EXPERIMENTAL WASTEWATER COMPONENTNH3-N/ (mg/L) active brilliant red X-3B/(mg/L) colority pHFigure 2.Variety of Azo dye concentration 122.84-206.41 6.3-7.145.5-128.62.06-6.6240.88-66.26B. Colority varietyC. Analysis method CODCr was measured by fast digestion spectrophotometric method. NH3-N was measured by Nessler's reagent spectrophotometric method. The azo dye concentration was measured at wavelength of 540nm by spectrophotometric method. The sample of the wastewater was centrifugated by a centrifuge at a speed of 4000 revolutions per minute about 10 min. Colority was measured by spectrophotometric method. The dilute H2SO4 solution (ca. 0.02 mol/L) made up of K2Cr2O7 and CoSO4 was used as standard solution for colority measurement. The wavelength of measurement was defined at 350 nm, which was the maximum absorbency of the standardFigure 3. Variety of colorityFigure 3 was the variety of colority of inflow and effluent to and from every reactor in different electric current density. It showed that when electric current density was 0.048 and 0.071mA/cm2, bioelectrochemical technology had a good effect on decolorization to active brilliant red X-3B wastewater. When the electric current density was 0.071mA/cm2, the average decolorization rate reached 91.39%. Biological method had a low decolorization effect to active brilliant red X-3B wastewater. The average decolorization rate was only 18.21%. When the electric current density was 0.020mA/cm2, the colority of the effluent from BCH reactor was higher than the inflow to BCH reactor. The reasons were as follows: on the one hand, when the electric current density was lower, the loose biofilm and the free bacterium in reactor made colority increase; on the other hand, because of the lower electric current density, the OH—produced in cathode was too less, but the Fe3+ produced in anode was excessive, the color of Fe3+ made colority increase. C. Organics varietywhich indicated that hydrolysis process was more efficiency. When electric current density was 0.071mA/cm2, the average removal ratio of NH3-N was 90.41% by bioelectrochemical technology, the average removal ratio of NH3-N was 85.69% by biological method.Figure 5. Variety of ammonia nitrogenousIV.RESEARCH OF PRINCIPLEA. UV-visible absorption spectrum Analysis Azo dye’s active brilliant red X-3B has absorption peaks in the wavelength of 280 nm, 320 nm and 540 nm respectively. The absorption peaks 540 nm in visible light was caused by the n→π system which connected benzene ring to naphthalene ring by azo double-bond. In ultraviolet, the absorption peaks in 280nm, 320nm wavelengths were caused by benzene ring, naphthalene ring, dichloro-methoxy-triazine and so on [7]. When electric current density was 0.071mA/cm2， The analysis of UV-visible absorption spectrum for the influent and the effluent is shown in figure 7.4.0Figure 4. Variety of organics3.5Absorbance(AU)Raw water By BEH By BCO(BEH-BCO) By BH By BCOFigure 4 shows the variety of organics of inflow and effluent to and from every reactor in different electric current density. It depicts that along with the electric current density decreased, the CODCr of effluent from BEH increased. When electric current densities were 0.071, 0.048, 0.020mA/cm2, the average removal ratio of CODCr was 50.08%, 30.11%, 24.71%, respectively. When electric current density was 0.071mA/cm2, the average removal ratio of CODCr was 69.98% by bioelectrochemical technology, and the average total removal ratio of CODCr was 31.32% by biological method. D. Ammonia nitrogenous variety Figure 5 shows the variety of ammonia nitrogenous of inflow and effluent to and from every reactor in different electric current density. As shown in Figure 5, the NH3-N of the effluents from BEH reactor and BH reactor are all higher than raw water. It was because azo double bonds of dye molecule was broken in hydrolysis process, became small molecule organics. Benzenering, naphthalene nucleus or dichlotriazine active group of the dye molecule was broken and ammonia nitrogenous was liberated. So ammonia nitrogenous concentration in the effluent was more than that in the influent,3.0 2.5 2.0 1.5 1.0 0.5 0.0 200 250 300 350 400 450 500Wavelength(nm)550 600650 700Figure 7. UV-visible absorption spectrum of azo dye wastewaterAs shown in figure 7. After the treatment of biological method, the absorption peaks were not changed obviously. It showed that the structure of active brilliant red X-3B was not changed. But, after the treatment by BEH-BCO process, the absorption peaks decreased obviously, and the absorption peaks at 540nm was almost zero. Consider the molecular structure of active brilliant red X-3B, the absorption peaks nearby at 280nm and 320nm are decreased, which explained that benzene ring, naphthalene ring, dichloro methoxy triazine were degraded, unsaturated ring was opened. The absorptionpeaks at the wavelength of 540nm declined obviously, it explained that azo double-bond was opened. But at 215nm, the absorption peaks rose, It explained that there were some aromatic ring compounds in the wastewater [8]. B. Redox potential analysis In order to research the redox potential of BEH and BH, we got some mixed liquors from BEH and BH respectively, then measured the redox potential by potentiometric titrator. The reaction between azo dyes and reduced electronic carrier is nonspecific reduction process. The occurrence of reaction was decided on the redox potential of redox intermediates and azo compound, namely determined by the redox potential (-180mV ~ -430mV) of cell redox cofactor, the NAD(P)H, and the potential of azo compound[9].TABLE II Rector BEH BH REDOX POTENTIAL Electric Current Density (mA/cm2) 0.024 0.048 0.071 Redox Potential (mV) -217 -185 -202 -152V. CONCLUSIONS • Compared with the single biological method, electrochemical function of DC micro-electric field and biological function produced synergy for the degradation processes of active brilliant red X-3B by bioelectrochemical technology. This method improved the activity of microorganism, and promoted the dye biodegradation. In the biodegradation process of azo dye active red X-3B by bioelectrochemical technology, the treatment effect increased with the increase of current density. The treatment efficiency of active brilliant red X-3B was increased with the increase of electric current density. The structure of active brilliant red X-3B was destroyed in bioelectrochemical hydrolysis reactor and turned into readily biodegradable small molecular organic compound. But in biological method, because the concentration of dye wastewater was too high, and the dissolved oxygen in hydrolysis reactor was lower, the bacteria in hydrolysis reactor were restrained. It made the structure of active brilliant red X-3B changed smaller.•••Table II was the redox potential of BEH and BH. Table II showed that, the redox potential of mixed liquor in BEH was about -200mV. It was in the range of azo compound redox requirement (-180mV ～ -430mV). The redox potential of mixed liquor in BH was about -152mV. It was not in the range of azo compound redox requirement, and also not in the range of hydrolysis reactor running normally (about 0mV). C. Azoreductase analysisThe first step of azo dyes biodegradation was the key to open azo double-bond, and produce aromatic ammonia. This step was finished by catalysis of azoreductase[10]. The decolorization ability of bacteria to the dyes mainly depended on the effect of azoreductase. This experiment analyzed azoreductase activity of the bacterium from each reactor. Measured each water sample in the same reactor three times, the average results were in table III.TABLE III BEH (mg/L·h) 55.33 AZOREDUCTASE ACTIVITY IN EACH REACTOR BCO （BEH-BCO） (mg/L·h) 3.17 BH (mg/L·h) 1.68 BCO (mg/L·h) 1.68As shown in table III, azoreductase activity in BEH-BCO system was higher than in BH-BCO system. The azoreductase activity in BEH reactor was 55.33 mg/L·h. It explained that due to the effect of direct current field, the rate of biochemical reactions was enhanced, microbial activity was better. It also explained that except for the electrochemical function and biodegradation function, the electric field could stimulate the activity of microbe and enhance the efficiency of dye degradation.Mi Yilei, Fan Jinhong, Ma Luming. Research on removal of azo dye by bioelectrochem ical technology [J]. Chinese Journal of Environmental Engineering, 2009, 3(8): 1457-1461. [2] Wang Hui. Recent Advance in Biological Treatment of Dyeing Wastewater [J]. Journal of Xia Men University (Natural Science), 2008, 12: 286-290. [3] Liang Hong, Zeng Kangmei. Progress in the Dyes Wastewater Treatment Processes [J]. Journal of Sichuan University of Science & Engineering, 2003, 6: 20-24. [4] Zhang Changsheng, Xue An, Zhao Huazhang. Progress in the studies of electrical bio-technology in environmental engineering[J]. Industrial Water Treatment, 2008, 28(3): 1-5. [5] Yao Guo, Wang Jian wei.Determination of Colority of Sewage Water[J]. PTCA (PART B: CHEM. ANAL.), 2008, 44:61-64. [6] Zhou Chunsheng,Yin Jun, Meng Lin. Study of Method for Determing TTC-Dehydrogenase [J].Journal of Jilin Architectural Civil Engineering Institute, 1995, 3 (1) [7] Brewster M, Fuss F, Tebbens J, et al. Spectrophotometer analysis of electrochemically treated simulated disperse dye bath effluent [M].AATCC, Book of papas, 1992: 17-19· [8] Zhao Yuhua ， Dong Ruijiao. Hydrolyzing Mechanism on Azo Dye Wastewater Treatment by Anaerobic Bioreactor [J]. Journal of Shenyang Jianzhu University (Natural Science), 2009, 25(2):325-328. [9] Liu Guangfei, Zhou Jiti, Wang Jing. Progress on Degradation of Azo Dyes by Bacteria and Azoreductase [J]. Environmental Science & Technology, 2006, 29(4): 112-114 [10] Ftrojt L， Strasak L， Vetted V， et a1． Comparison of the low—frequency magnetic field effects on bacteria Escherichia coli ， Leclercia adecarboxylata and Staphylococcus aureus[J] ．Bioelectrochemistry， 2004，63(12) ：337~341 [11] Chang Y H D， Grodzinsky A J ， Wang D I C ． Augmentation of masstransfer through electrical means for hydrogel-entrapped Escherichia colicultivation[J]．Biotechnol Bioeng， 1995， 48(2) ： 149~157 [12] Laleh Loghavi，B.S．electric field on growth kinetics，cellmembrane permeabilization，and frequencyresponse of microorganisms．The Ohio State University，2008[1]。
给排水专业英语_英文1
Sewage treatmentSewage treatment, or domestic wastewatertreatment, is the process of removing contaminantsfrom wastewater and household sewage, bothrunoff (effluents) and domestic. It includesphysical, chemical, and biological processes toremove physical, chemical and biologicalcontaminants. Its objective is to produce a wastestream (or treated effluent) and a solid waste orsludge suitable for discharge or reuse back into theenvironment. This material is often inadvertentlycontaminated with many toxic organic andinorganic compounds.Origins of sewageSewage is created by residences, institutions, and commercial and industrial establishments. Raw influent (sewage) includes household waste liquid from toilets, baths, showers, kitchens, sinks, and so forth that is disposed of via sewers. In many areas, sewage also includes liquid waste from industry and commerce. The separation and draining of household waste into greywater and blackwater is becoming more common in the developed world, with greywater being permitted to be used for watering plants or recycled for flushing toilets. A lot of sewage also includes some surface water from roofs or hard-standing areas. Municipal wastewater therefore includes residential, commercial, and industrial liquid waste discharges, and may include stormwater runoff. Sewage systems capable of handling stormwater are known as combined systems or combined sewers. Such systems are usually avoided since they complicate and thereby reduce the efficiency of sewage treatment plants owing to their seasonality. The variability in flow also leads to often larger than necessary, and subsequently more expensive, treatment facilities. In addition, heavy storms that contribute more flows than the treatment plant can handle may overwhelm the sewage treatment system, causing a spill or overflow. It is preferable to have a separate storm drain system for stormwater in areas that are developed with sewer systems.As rainfall runs over the surface of roofs and the ground, it may pick up various contaminants including soil particles and other sediment, heavy metals, organic compounds, animal waste, and oil and grease. Some jurisdictions require stormwater to receive some level of treatment before being discharged directly into waterways. Examples of treatment processes used for stormwater include sedimentation basins, wetlands, buried concrete vaults with various kinds of filters, and vortex separators (to remove coarse solids).Process overviewSewage can be treated close to where it is created (in septic tanks, biofilters or aerobic treatment systems), or collected and transported via a network of pipes and pump stations to a municipal treatment plant (see sewerage and pipes and infrastructure). Sewage collection and treatment istypically subject to local, state and federal regulations and standards. Industrial sources of wastewater often require specialized treatment processes (see Industrial wastewater treatment).Conventional sewage treatment may involve three stages, called primary, secondary and tertiary treatment. Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment. Secondary treatment removes dissolved and suspended biological matter. Secondary treatment is typically performed by indigenous, water-bornemicro-organisms in a managed habitat. Secondary treatment may require a separation process to remove the micro-organisms from the treated water prior to discharge or tertiary treatment. Tertiary treatment is sometimes defined as anything more than primary and secondary treatment. Treated water is sometimes disinfected chemically or physically (for example by lagoons and microfiltration) prior to discharge into a stream, river, bay, lagoon or wetland, or it can be used for the irrigation of a golf course, green way or park. If it is sufficiently clean, it can also be used for groundwater recharge or agricultural purposes.Process Flow Diagram for a typical large-scale treatment plantPre-treatmentPre-treatment removes materials that can be easily collected from the raw wastewater before they damage or clog the pumps and skimmers of primary treatment clarifiers (trash, tree limbs, leaves, etc).ScreeningThe influent sewage water is strained to remove all large objects carried in the sewage stream. This is most commonly done with an automated mechanically raked bar screen in modern plants serving large populations, whilst in smaller or less modern plants a manually cleaned screen may be used. The raking action of a mechanical bar screen is typically paced according to the accumulation on the bar screens and/or flow rate. The solids are collected and later disposed in a landfill or incinerated.Grit removalPre-treatment may include a sand or grit channel or chamber where the velocity of the incoming wastewater is carefully controlled to allow sand, grit and stones to settle.Primary treatmentIn the primary sedimentation stage,sewage flows through large tanks,commonly called "primary clarifiers" or"primary sedimentation tanks". The tanksare large enough that sludge can settle andfloating material such as grease and oilscan rise to the surface and be skimmed off.The main purpose of the primarysedimentation stage is to produce both agenerally homogeneous liquid capable ofbeing treated biologically and a sludgethat can be separately treated or processed.Primary settling tanks are usuallyequipped with mechanically drivenscrapers that continually drive the collected sludge towards a hopper in the base of the tank from where it can be pumped to further sludge treatment stages. Grease and oil from the floating material can sometimes be recovered for saponification.Secondary treatmentSecondary treatment is designed to substantially degrade the biological content of the sewage which are derived from human waste, food waste, soaps and detergent. The majority of municipal plants treat the settled sewage liquor using aerobic biological processes. For this to be effective, the biota require both oxygen and a substrate on which to live. There are a number of ways in which this is done. In all these methods, the bacteria and protozoa consume biodegradable soluble organic contaminants (e.g. sugars, fats, organic short-chain carbon molecules, etc.) and bind much of the less soluble fractions into floc. Secondary treatment systems are classified as∙fixed-film or∙suspended-growth.Fixed-film OR attached growth system treatment process including trickling filter and rotating biological contactors where the biomass grows on media and the sewage passes over its surface.In suspended-growth systems, such as activated sludge, the biomass is well mixed with the sewage and can be operated in a smaller space than fixed-film systems that treat the same amount of water. However, fixed-film systems are more able to cope with drastic changes in the amount of biological material and can provide higher removal rates for organic material and suspended solids than suspended growth systems.Roughing filters are intended to treat particularly strong or variable organic loads, typically industrial, to allow them to then be treated by conventional secondary treatment processes. Characteristics include typically tall, circular filters filled with open synthetic filter media to which wastewater is applied at a relatively high rate. They are designed to allow high hydraulic loading and a high flow-through of air. On larger installations, air is forced through the media using blowers. The resultant wastewater is usually within the normal range for conventional treatment processes.Activated sludgeMain article: Activated sludgeIn general, activated sludge plantsencompass a variety of mechanisms andprocesses that use dissolved oxygen topromote the growth of biological floc thatsubstantially removes organic material.The process traps particulate material andcan, under ideal conditions, convertammonia to nitrite and nitrate and ultimatelyto nitrogen gas, (see also denitrification).Surface-aerated basinsMost biological oxidation processesfor treating industrial wastewatershave in common the use of oxygen (orair) and microbial action.Surface-aerated basins achieve 80 to90% removal of Biochemical OxygenDemand with retention times of 1 to10 days. The basins may range indepth from 1.5 to 5.0 metres and usemotor-driven aerators floating on thesurface of the wastewater.In an aerated basin system, theaerators provide two functions: they transfer air into the basins required by the biological oxidation reactions, and they provide the mixing required for dispersing the air and for contacting the reactants (that is, oxygen, wastewater and microbes). Typically, the floating surface aerators are rated to deliver the amount of air equivalent to 1.8 to 2.7 kg O2/kW·h. However, they do not provide as good mixing as is normally achieved in activated sludge systems and therefore aerated basins do not achieve the same performance level as activated sludge units.Biological oxidation processes are sensitive to temperature and, between 0 °C and 40 °C, the rate of biological reactions increase with temperature. Most surface aerated vessels operate at between 4 °C and 32 °C.Filter beds (oxidizing beds)Main article: Trickling filterIn older plants and plants receiving more variable loads, trickling filter beds are used where the settled sewage liquor is spread onto the surface of a deep bed made up of coke (carbonized coal), limestone chips or specially fabricated plastic media. Such media must have high surface areas to support the biofilms that form. The liquor is distributed through perforated rotating arms radiating from a central pivot. The distributed liquor trickles through this bed and is collected in drains at the base. These drains also provide a source of air which percolates up through the bed, keeping it aerobic. Biologica l films of bacteria, protozoa and fungi form on the media’s surfaces and eat or otherwise reduce the organic content. This biofilm is grazed by insect larvae and worms which help maintain an optimal thickness. Overloading of beds increases the thickness of the film leading to clogging of the filter media and ponding on the surface.Biological aerated filtersBiological Aerated (or Anoxic) Filter (BAF) or Biofilters combine filtration with biological carbon reduction, nitrification or denitrification. BAF usually includes a reactor filled with a filter media. The media is either in suspension or supported by a gravel layer at the foot of the filter. The dual purpose of this media is to support highly active biomass that is attached to it and to filter suspended solids. Carbon reduction and ammonia conversion occurs in aerobic mode and sometime achieved in a single reactor while nitrate conversion occurs in anoxic mode. BAF is operated either in upflow or downflow configuration depending on design specified by manufacturer.Membrane bioreactorsMembrane bioreactors (MBR) combine activated sludge treatment with a membrane liquid-solid separation process. The membrane component uses low pressure microfiltration or ultra filtration membranes and eliminates the need for clarification and tertiary filtration. The membranes are typically immersed in the aeration tank; however, some applications utilize a separate membrane tank. One of the key benefits of an MBR system is that it effectively overcomes the limitations associated with poor settling of sludge in conventional activated sludge (CAS) processes. The technology permits bioreactor operation with considerably higher mixed liquor suspended solids (MLSS) concentration than CAS systems, which are limited by sludge settling. The process is typically operated at MLSS in the range of 8,000–12,000 mg/L, while CAS are operated in the range of 2,000–3,000 mg/L. The elevated biomass concentration in the MBR process allows for very effective removal of both soluble and particulate biodegradable materials at higher loading rates. Thus increased Sludge Retention Times (SRTs) — usually exceeding 15 days — ensure complete nitrification even in extremely cold weather.The cost of building and operating an MBR is usually higher than conventional wastewater treatment. Membrane filters can be blinded with grease or abraded by suspended grit and lack a clarifier's flexibility to pass peak flows. The technology has become increasingly popular for reliably pretreated waste streams and has gainedwider acceptance where infiltration and inflowhave been controlled, however, and the life-cyclecosts have been steadily decreasing. The smallfootprint of MBR systems, and the high qualityeffluent produced, make them particularly usefulfor water reuse applications.There are MBR plants being built throughout theworld, including North Librty, Iowa, Georgia, andCanada.Secondary sedimentationThe final step in the secondary treatment stage is to settle out the biological floc or filter material and produce sewage water containing very low levels of organic material and suspended matter.Rotating biological contactorsMain article: Rotating biological contactorRotating biological contactors(RBCs) are mechanical secondarytreatment systems, which arerobust and capable ofwithstanding surges in organicload. RBCs were first installed inGermany in 1960 and have sincebeen developed and refined into areliable operating unit. Therotating disks support the growthof bacteria and micro-organismspresent in the sewage, whichbreakdown and stabilise organicpollutants. To be successful, micro-organisms need both oxygen to live and food to grow. Oxygen is obtained from the atmosphere as the disks rotate. As the micro-organisms grow, they build up on the media until they are sloughed off due to shear forces provided by the rotating discs in the sewage. Effluent from the RBC is then passed through final clarifiers where the micro-organisms in suspension settle as a sludge. The sludge is withdrawn from the clarifier for further treatment.A functionally similar biological filtering system has become popular as part of home aquarium filtration and purification. The aquarium water is drawn up out of the tank and then cascaded over a freely spinning corrugated fiber-mesh wheel before passing through a media filter and back into the aquarium. The spinning mesh wheel develops a biofilm coating of microorganisms that feed on the suspended wastes in the aquarium water and are also exposed to the atmosphere as the wheel rotates. This is especially good at removing waste urea and ammonia urinated into the aquarium water by the fish and other animals.。
给水排水工程专业英语文献翻译译文第五篇
CO2与零价铁有压系统处理硝酸盐废水研究Chi-Wang Li*, Yi-Ming Chen, Wei-Shuen Yen摘要：本文提出一种新的反应装置进行硝酸盐的去除，反应器中的Fe0（ZVI）成流化状态，并通过加压CO2来控制系统的PH值。
所采用的CO2有压系统比传统CO2曝气系统的CO2用量少且能更快的使PH稳定下来。
但由于碳酸盐是弱酸性，系统的PH会随着ZVI的氧化和硝酸盐的降解逐渐上升。
随着反应过程中溶液PH的增加，硝酸盐的降解效率不断的下降。
实验结果表明硝酸盐的去除效率随着ZVI的用量和硝酸盐的初始浓度的增加而不断上升，但当ZVI用量超过8.25g/l，或硝酸盐的初始浓度达到100mg/l以后，硝酸盐的去除效率不会发生较大的变化。
与我们曾经研究的通过强酸来控制溶液PH的流化系统不同的是，在本实验中，硝酸盐的去除率接近100%，这说明通过ZVI在不同的PH条件下去除硝酸盐有不同的反应途径。
关键词：加压系统；CO2；硝酸盐降解；化学平衡方程式1.导言用ZVI来处理硝酸盐废水已有不少研究者做了这方面的研究，如： Choe（2000）、 Alowitz and cherer（2002）、Westerhoff（2003）、Westerhoff and James（2003）、Choe 2004）、Su and Puls（2004）、Chen（2005）、Liou（2005） Zhang and Huang（2005）、Ruangchainikom （2006）等等。
在他们发表的论文中，提到了在ZVI反应墙(Furukawa et al., 2002; Wilkin et al., 2003)和滤柱(Westerhoff, 2003; Westerhoff and James, 2003)中硝酸盐降解比较慢的反应动力学以及金属表面的金属氧化膜的阻碍反应进行等问题。
由于硝酸盐在酸性PH下具有较高的去除效率(Alowitz and Scherer, 2002; Choe et al.,2004; Zhang and Huang, 2005),我们在以前的研究中提出了一种地上渗透墙系统来处理水体中的硝酸盐，这种系统与PH控制装置合成一体，系统中的ZVI成流化状态(Chen 2005).在这种流化状态的ZVI系统装置中，通过PH控制装置自动的投加强酸性物质（盐酸），系统的PH可以精确控制在适合硝酸盐降解的水平上。
给水排水工程专业英语文献翻译译文第一篇
一种利用蜜糖废水产生PHA的侧流工艺的建立方法摘要试验建立了一种利用蜜糖废水生产聚羟基烷酸脂（PHA）的三阶段过程。
该过程包括（1）糖蜜废水酸酵解，（2）PHA富集菌的筛选，（3）利用富集完毕的污泥和酵解之后的糖蜜废水批次累积PHA。
在发酵阶段，试验评估了PH（5~7）对有机酸型体分布以及产率的影响。
PH较高时乙酸和丙酸为主要产物，然而较低的PH值有利于丙酸和戊酸的产生。
试验评估了利用乙酸盐和发酵糖蜜废水为基质筛选的两类菌群的PHA积累能力。
考察了有机酸型体分布对利用醋酸盐筛选菌群产生的多聚体的组成以及产率的影响。
PHA富集产率在0.37到0.50CmmolHA/Cmmol VFA之间变化。
试验观察到了被利用有机酸的类型和多聚物成分的一种直接关系。
在糖蜜废水中，低氨氮浓度（0.1Nmmol/l）促进了PHA 的储存（0.59 Cmmol HA/Cmmol VFA）。
此外，试验建立了一种控制反应器运行利用发酵糖蜜废水筛选PHA富集菌群的方法。
利用高有机负荷以及低氨氮浓度选择了一种具有稳定储存PHA能力的菌群，富集产率达到0.59Cmmol HA/Cmmol VFA)，这一能力与醋酸盐筛选菌相似。
前言聚羟基烷酸脂被认为是优良的可生物降解塑料的候选者。
这类含有多种单体组分具有热塑性的多聚物是被细菌作为能量和碳储存物质的。
它们的结构特性与聚丙烯的结构性质一致，同时又具有诸多优势：可生物降解、可生物相容、能进一步由可再生碳源产生从而使可持续生产过程成为可能。
然而，PHAs与石化工业衍生的塑料制品在成本上相当大的差异成了这类高聚物部分替代后者的阻碍。
目前，商业可行的PHAs是由纯菌（野生的和基因重组的菌种）和纯底物（通常很昂贵）工业化生产而来。
PHAs的价格主要取决于底物成本，约占总成本的40%（Choi和Lee，1997）。
最近十年来，一系列低成本的碳源基质（例如淀粉、木薯粉水解物、乳清和蜜糖）在纯菌生产PHA过程中得到检验。
给水排水工程专业英语论文
Water and Wastewater EngineeringFinal Class ProjectTitle：Applications of municipal wastewater treatment in livesCollege _____C。
E__________ Major ___ _WWE__________Class ____ _______Number_____ ____Name____ _____Data_____________________Applications of municipal wastewater treatment in livesAbstract：This article describes the following sections：sequential combinationof photocatalytic oxidation with constructed wetlands is the study and theexperimental evaluation of an alternative and innovative wastewater treatmentsystem， which combines the action of photocatalytic oxidation with the surfaceflow constructed wetlands。
A new contact oxidation filtration separationintegrated bioreactor was used to treat municipal wastewater。
the syntheticpolymers normally used in the coagulation—flocculation treatment of wastewater requires sustainable alternatives.Keywords:bioreactor;coagulation;flocculation;photocatalytic oxidation; Combination of photocatalytic oxidation with constructed wetlandsWastewater treatment systems have been designed to minimize the environmental impacts of discharging untreated wastewater。
关于给排水的专业英语作文
关于给排水的专业英语作文As a professional in the field of drainage and plumbing, it is essential to have a deep understanding of the principles and practices involved in this industry. From designing efficient drainage systems to installing and maintaining plumbing fixtures, there is a wide range ofskills and knowledge required to ensure the proper functioning of water supply and waste disposal systems.In the realm of drainage and plumbing, it is crucial to stay updated with the latest technologies and innovations. With the continuous advancements in materials and equipment, professionals in this field must be adaptable and open to learning new techniques to improve efficiency and sustainability in their work.One of the key aspects of drainage and plumbing is ensuring the proper disposal of wastewater. This involves designing and implementing effective sewage systems thatcan safely and efficiently remove waste from residential,commercial, and industrial buildings. It is important to consider environmental impact and public health when dealing with wastewater management.In addition to wastewater disposal, another important aspect of drainage and plumbing is the installation and maintenance of water supply systems. This includes ensuring a consistent and safe supply of clean water to buildings, as well as maintaining and repairing water distribution networks to prevent leaks and contamination.In the field of drainage and plumbing, it is essential to prioritize safety and compliance with regulations. Professionals must adhere to building codes and standards to ensure that their work meets legal requirements and is safe for public use. This includes proper installation of fixtures, use of appropriate materials, and adherence to best practices for drainage and plumbing systems.Effective communication and collaboration are also crucial in the field of drainage and plumbing. Professionals must be able to work closely with architects,engineers, and other construction professionals to ensure that drainage and plumbing systems are integrated seamlessly into building designs and construction plans.In conclusion, the field of drainage and plumbing requires a diverse set of skills and knowledge, from understanding technical principles to staying updated with the latest technologies. It is a dynamic and essential industry that plays a critical role in ensuring the safety, health, and efficiency of water supply and waste disposal systems.。
给排水专业毕业设计翻译中英文对照(20页)
Oxidize ditch craft in dirty water handle of application and development Summary: This text expatiated primarily the Carrousel oxidizes the construction, craft mechanism of the ditch and circulate the problem exsited in the process with the homologous the method of solution.Finally, introduce the Carrousel oxidize the latest research progress of the ditch and pointed out the future and main research direction.Key phrase: The Carrousel oxidizes ditch divideds by the phosphor takes off the nitrogen construction mechanism Application and Development of Carrousel Oxidation Ditch Process on Wastewater TreatmentAbstract: The structure and the techniques of carrousel oxidation ditch process on nitrogen and phosphor removal are introduced in this paper. The problems inrunning and their corresponding resolvent are also pointed. At last, The authorshowed the up to date research improvement and the mainly future research dire-ction.Key words: Carrousel; oxidation ditch; nitrogen and phosphor removal; structure;techniques1. ForewordOxidize the ditch( oxidation ditch) again a continuous circulation spirit pond( Continuous loop reactor), is a live and dirty mire method a kind of to transform.Oxidizing the dirty water in ditch handles the craft be researched to manufacture by the hygiene engineering graduate school of Holland in the 50's of 20 centuries success.Since in 1954 at Dutch throw in the usage for the very first time.Because its a water fluid matter good, circulate the stability and manage convenience etc. technique characteristics, already at domestic andinternational and extensive application in live the dirty water to is dirty to manage aqueously with the industry[1].Current application than oxidize extensively the ditch type include:The ( Pasveer) oxidizes the ditch, the ( Carrousel) oxidizes the ditch, ( Orbal) oxidizes the ditch, the type of T oxidizes the ditch( three ditch types oxidize the ditch), the type of DE oxidizes the ditch to turn to oxidize the ditch with the integral whole.These oxidize the ditch because of the difference of esse in construction with circulating, therefore each characteristics[2].This text will introduce construction, mechanism, existent problem and its latest developments that Carrousel oxidize ditches primarily.2. The Carrousel oxidizes the construction of the ditchThe Carrousel oxidize the ditch to be researched to manufacture by Dutch DHV company development in 1967.Oxidize the last the company of DHV in foundation of the ditch in the original Carrousel to permited specially the company EIMCO to invent again with its patent in the United States Carrousel 2000 system( see the figure ), realizes the living creature of the higher request takes off the nitrogen with divided by the function of .There has been in the world up to now more than 850 Carrousels oxidize the ditch with the Carrousel 2000 system are circulating[3].From diagram therefore, the Carrousel oxidizes the ditch the usage the spirit of that definite direction control with shake up the device, face to mix with the liquid deliver the level speed, from but make drive the liquid of admixture that shake up is in oxidize ditch shut match outlet circulate flow.Therefore oxidize the ditch have the special hydraulics flows the , current complete mix with the characteristics of the type reactor, have the characteristics that push the flow type reactor again, the ditch inside exsits obviously of deliquescence oxygen density steps degree.Oxidizing the ditch crosssection is rectangle or trapezoids, the flat surface shape is many for oval, the ditch internal water is deep general for 2.5 ～4.5 ｍ, the breadth is deep compare for 2:1, also have the deep water amount to 7 ms of, ditch inside average speed in water current is 0.3 ms/ s.Oxidize ditch spirit admixture equipments contain surface spirit machine, the spirit of turn to brush or turn the dish and shoot to flow the spirit machine, pipe type spirit machine with promote take care of type spirit machine etc., match with in recent years usage still contain underwater push machine[4~6].3. The Carrousel oxidizes the mechanism of the ditch3.1 The Carrousel oxidizes the ditch handles dirty and aqueous principleThe at the beginning common Carrousel oxidizes the dirty water in inside in craft of the ditch direct with dirty mire in reflux together enter oxidize the ditch system.The surface spirit machine makes fuse in the liquid of admixture the density of the oxygen DO increases about 2 the 3 mgs/ L.Under this kind of well the term of the oxygen , the microorganism gets the enough deliquescence oxygen comes and go to divided by the BOD;At the same time, the ammonia were too oxidized nitrate with second nitrate, this time, mix with the liquid be placed in the oxygen appearance.In the spirit machine downstream, after water current be become by the swift flow appearance of the spirit District of even flow the appearance, the water current maintains in the minimum current velocity, guaranteeing the live and dirty mire be placed in the floats the appearance.( average current velocity>0.3 ms/ s)Oxidize microbially the process consumed to fuse the oxygen in the water, until the value of DO declines for zero, mixing with the liquid report the anoxia appearance.Versa nitric that turn the function through anoxia area, mix with the liquid enter to have the oxygen area, completing once circulating.That system inside, theBOD declines the solution is a continuous process, the nitric turns the function to turn with the versa nitric the function take place in same pond.Because of structural restrict, this kind of oxidize the ditch although can then valid whereabouts BOD, divided by the phosphorus take off the nitrogenous ability limited[7].For the sake of the acquisition better divided by the phosphorus take off the nitrogenous result, Carrousel 2000 systems increased a oxygen District before common Carrousel oxidize ditch with the unique oxygen area.( call again that the versa nitric in front turns the area)The dirty mire in all refluxes enters the anaerobic District with 10-30% dirty water, can under the anoxia with 10-30% carbon source term complete remaining of dirty mire in reflux inside nitric acid nitrogen to versa nitric to turn, creates for the unique oxygen pond of hereafter unique oxygen term.At the same time, anaerobic District inside of concurrently the sex germs convert the dissolubility BOD VFA, the germ acquire the VFA its assimilation PHB, the energy source needed solves in the phosphoric water and cause phosphatic releasing.The anaerobic District a water enters the inner part installs the unique oxygen area that have the mixer, the so-called unique oxygen is a pond inside to mix with liquid since have no the numerator oxygen, also have no the compound oxygen( nitric acid root), the here unique oxygen environment is next,70-90% dirty water can provide the enough carbon source, can make the germ of released the phosphorus well.The unique oxygen area connects behind the common Carrousel oxidizes the ditch system, further completing to do away with the BOD and take off the nitrogen with divided by the phosphorus .Finally, mix with the liquid transfer the dirty mire inside in oxidize ditch enrich oxygen area eject, while enriching the oxygen environment germ surfeit, phosphorus from the water, ejecting the system with the dirty mire in surplus.Like this, in Carrousel 2000systems, than completed to do away with the BOD, COD with take off at the same time goodly the nitrogen divided by the phosphorus .Synthesizing and dirty water in the river City , long sand City decontamination center[s of the dirty the factory of water in the first in Kunming of adoption that crafts handles the movement result of the factory therefore:Through Carrousel 2000 system after handling, the BOD, COD, SS does away with the rate to all come to a 90% above, the TN does away with the rate comes to a 80%, the TP does away with the rate to also come to a 90%.3.2 The Carrousel oxidizes the ditch divideds by the phosphorus takes off the nitrogenous influence factor.Affecting the Carrousel oxidizes the ditch divideds by the phosphoric factor is dirty mire , nitrate density and quality densities primarily.The research expresses, being total and dirty mire as 11% that a hour biggest phosphorus 4% with deal is its fuck dirty mire deal within live and dirty mire, keep for the the germ physical endowment measures, but when dirty mire over 15 d hour dirty mire the inside is biggest to contain the obvious descent in deal in phosphorus , canning not reach the biggest divideding by the result of phosphorus on the contrary.Therefore, prolong persistently the dirty mire ( for example 20ds,25ds,30ds) is to have no necessary, proper choose to use within the scope of 8~15 d.At the same time, high nitrate density with low quality density disadvantage in divided by the process of phosphorus .Affecting the Carrousel oxidizes the ditch takes off the nitrogenous and main factor is DO, nitrate density and carbon source densities.The research expresses, oxidizing the ditch inside exsits deliquescence oxygen density steps degree namely the good oxygen area DO attains 3~3.5 mgs/ L, the anoxia area DO attains 0~0.5 mgs/ L is a prior condition to take place nitric turn reaction and versa nitricsturn the reaction.At the same time, ample carbon source and higher C/ the N ratio benefits to take off to complete nitrogenously[7].4. The Carrousel oxidizes problem and solution methods of the ditch esse.Though the Carrousel oxidizes the ditch has a water fluid matter good, the anti- pounds at the burthen ability strong, divided by the phosphorus take off the nitrogen efficiency. But, in physically of movement process, still exsits a series of problem.4.1 Dirty mire inflation problemWhen discard the aquatic carbohydrate more, the N, P contains the unbalance of deal, the pH value is low, oxidizing the dirty mire in inside in ditch carries high, fuse the oxygen density the shortage, line up the mire not etc. causes easily dirty mire in germ in form in silk inflation;Not the dirty mire in germ in form in silk inflation takes place primarily at the waste water water temperature is lower but the dirty mire carries higher hour.The microbial burthen is high, the germs absorbed the large quantity nourishment material, is low because of the temperature, metabolism the speed is slower, accumulating the rises large quantity is high to glue sexual and many sugar materials, making the surface of the live and dirty mire adhere to the water to increase consumedly, SVI the value is very high, becoming the dirty mire inflation.Cause that aim at the dirty mire inflation, can adopt the different counterplan:From the anoxia, water temperature high result in of, can enlargement tolerance or lower into the water measures to alleviate burthen, or the adequacy lowers the MLSS( control dirty mire reflux measure), making need the oxygen measures decrease;If the dirty mire carries high, can increase MLSS, to adjust the burthen, necessity the hour can stop into the water, stuffy a period of time;Can pass the hurl add the nitrogen fertilizer, phosphorus fatty, adjust the admixturenourishment in the liquid material equilibrium( BOD5:N:P=100:5:1);The value of pH over low, can throw to add the lime regulate;Bleach the powder with the liquid chlorin( press to fuck 0.3% of the dirty mire~0.6% the hurl adds), can repress the silk form germ breed, controling the dirty mire in combinative water inflation[11].4.2 Foam problemBecause entering to take the grease of large quantity in the water, handling system can't completely and availably its obviation, parts of greases enriches to gather in in the dirty mire, through turn to brush the oxygen agitation, creation large quantity foam;The mire is partial to long, the dirty mire is aging, and also easy creation foam.Spray to pour the water or divided by with the surface the of do away with the foam, in common use divided by the an organism oil, kerosene, the oil of silicon, throw deal as 0.5~1.5 mgs/ L.Pass to increase dirty mire in pond in spirit in density or adequacies let up the tolerance of , also can control the foam creation effectively.When contain the live material in surface in the waste water more, separate with the foam easily and in advance method or other methods do away with.Also can consider to increase to establish a set of divideding by the oil device moreover.But enhance most importantly the headwaters manage, reducing to contain the oil over the high waste water and other poisonous waste water of into[12].4.3 Float the problem on the dirty mireWhen contain in the waste water the oil measures big, whole system mire quality become light, can't like to control very much in operate process its at two sink the pond stop over time, resulting in the anoxia easily, producing the corrupt and dirty mire ascend to float;When spirit time over long, take place in pond the high degree nitric turn the function, making nitrate density high, at two sink theversa nitric in easy occurrence in pond turn the function, creation nitrogen spirit, make dirty mire ascend float;Moreover, contain the oil in the waste water?Take place the dirty mire ascend after floating should pause enter water, broke off or dirty mire in clearance, judge the clear reason, adjust the operation.The dirty mire sinks to decline the sex bad, can throw to add of oagulate or sloth materials, the improvement precipitates the sex;Such as enter the water carries big let up into the water measures or the enlargement reflux measures;Such as the dirty mire grain small lower the spirit machine turn soon;If discovers versa nitric turning, should let up the toerance , enlarge the reflux or row the mire measures;If discover the dirty mire is corrupt, should enlargement tolerance, the clearance accumulates the mire, and try the ameliorative pond internal water dint term[12].4.4 Current velocity is not all and the dirty mire sinks to accumulate the problemIn Carrousel oxidize ditch, for acquiring its special admixture with handles result, mix with liquid must with certain current velocity is in ditch circulate flow.Think generally, the lowest current velocity should should attain for an average current velocity for, doing not take place sinking accumulating 0.3~0.5 ms/ s.The spirit equipments that oxidize the ditch is general to turn to brush for the spirit of to turn the dish with the spirit of , turning to brush of immerse to have no depth for 250~300 mms, turn the dish immerse to have no depth for 480~530 mms.With oxidize the ditch water the deep(3.0~3.6 ms) comparing, turn to brush occupied the deep 1/10~ in water 1/12, turned the dish to also occupy the 1/6~ only 1/7, therefore result in to oxidize the ditch upper part current velocity bigger( roughly 0.8~1.2 ms, even larger), but the bottom current velocity is very small( especially at the water is deep 2/3 or 3/4 below, mix with theliquid has no current velocity almost), causing ditch bottom large quantity accumulate the mire( sometimes accumulate the mire thickness amount to a 1.0 ms), the valid capacity that reduced to oxidize the ditch consumedly, lowered to handle result, affected a water fluid matter.Adding the top, downstream leads to flow the plank is a valid method that ameliorative current velocity distribute, increases the oxygen ability with the most convenient measure.The upper stream leads to flow the plank installs at be apart from to turn the 4.0 places( upper stream) ：dish( turn to brush) axis, lead to flow plank high degree as the deep 1/5~ in water 1/6, combine the perpendicularity install in the surface;The downstream leads to flow the plank installs at be apart from to turn dish( turn to brush) axis 3.0 ms.Leading to flow knothole material can use metals or glass steels, but regard glass steel as good.Lead to flow the plank compares with other ameliorative measure, can't not only increase the motive consumes with revolves cost, but also can still than significantly exaltation 充oxygen ability with theories motive efficiency[13].Moreover, pass in the spirit on board swim to establish the underwater push machine can also turn to the spirit of the liquid of admixture that brush the bottom low speed area circulates to flow to rise positive push function, from but the solution oxidizes the problem that low and dirty mire in current velocity in bottom in ditch sink accumulates.Establish the underwater push machine useds for exclusively the push mixs with the liquid can make movement method that oxidize the ditch much more vivid, this for economy energy, lift the high-efficiency having the very important meaning[14].5. The Carrousel oxidizes the development of the ditchBecause the dirty water handles standard inside to divided by the phosphorus take off the nitrogenous request more and more strict,the development that Carrousel further oxidized the ditch to also get.Current, the research and application includes morely below two category type:Tiny bore spirit type Carrousel 2000 systems, Carrousel 3000 system.5.1 Tiny bore spirit type Carrousel 2000 systemTiny bore spirit type Carrousel 2000 tiny bore in adoption in system spirit( provide oxygen equipments as the drum breeze machine), the tiny bore spirit machine can produce the diameter of large quantity as a surface for or so and small spirit steeping, this consumedly increases spirit bubble accumulates, undering the certain circumstance in capacity in pond make the oxygen transfer the gross measures aggrandizement.( if deep increment in pond, its spread the quality efficiency will be higher)Produce the technique ability of the factory house according to the current drum breeze machine, the valid water of the pond is deep biggest amounting to a 8 ms, therefore can select by examinations according to the different craft request the fit water is deep.The tradition oxidizes the ditch pushes to flow is to make use of to turn to brush, turn a disc or pour the umbrella type form machine realizes of, its equipments utilization is low, the motive consumes big.Tiny bore spirit type Carrousel 2000 systems then adopted the underwater pushes the way that flow, rises to dive the propeller the leaf the motivation that round creation the direct function namely in the of water, at push to flow the function to can keep dirty mire from sinking to decline effectively again at the same time.As a result, the adoption dives the propeller since lower the motive consume, making mire water got again to mixs with adequately.Seeing from water power characteristic, tiny bore spirit type Carrousel 2000 systems are wreaths form the fold flows the pond type, concurrently pushing the flow type with complete mix with the typeflows .In regard to whole oxidize ditch, can think that oxidize the ditch is a complete mix with spirit pond, its density variety coefficient smallest even can neglect to do not account, enter the water will get the dilution quickly, therefore it have the very strong anti- pounds at the burthen ability.But have oxidize ditch inside of a certain very much the some pushing the characteristic of the flow type, in the nearby district in downstream in machine in spirit inDO density higher, but along with increase with spirit machine distance continuously then the density of DO lowers continuously.( appear the anoxia area)This kind of structure method makes friendly oxygen in area in anoxia area exsited to build the thing inside , making use of its water power characteristic well, coming to an efficiently the living creature takes off the nitrogenous purpose.Tiny bore spirit type Carrousel 2000 system though have the oxygen ability strong, divided by the phosphorus take off the nitrogen effective, cover the area little with can consume low etc. advantage, it also exsits at the same time the problem that tiny bore spirit equipments maintain.Current, the service life of the local and tiny bore spirit machine is 5 years in 4~, can amount to 10 years in 8~ goodly, but with import the tiny bore spirit machine compare to still have the certain margin.The spirit machine maintains unlike the form equipments is so convenient, it need to fuck the pond talent fixs, and also is to say once the tiny bore spirit machine appears the problem to need the adoption parallel two inconvenience for or third sets to solving problem, or adopting promoting device waiting to resolving, this too will giving production with managing bringing biggest[15 16].5.2 Carrousel 3000 systemCarrousel 3000 systems are in the Carrousel 2000 systems are ex- to plus a living creature the choice the area.That living creaturechoice area is a craft to make use of high organism carries to sieve germ grow, repress silk form germ increase, increase each pollutant do away with the rate, afterward principle together Carrousel 2000 system.Carrousel 3000 system of bigger increases to express at:An is to increased the pond deep, can amount to 7.5~8 ms, united at heart circle type, the pond wall uses totally, reducing to cover the area, lowering to build the price to increases to bear the low temperature ability at the same time;( can amount to 7 ℃ )Two is the liquid of admixture that spirit equipments that skillful design, the form machine descends to install to lead to flow , the anoxia of take out , adopt the underwater propeller solution current velocity problem;Three is to used the advanced spirit controller QUTE.( it adopt the much aer kind of changing the deal control mode)Four is to adopt the integral whole turn the design, starting from the center, including below wreath form consecution craft unit:Enter the well of water with the cent water machine that used for the live and dirty mire in reflux;Difference from four-part the choice pond that cent constitute with 厌oxygen pond.This outside is a Carrousel to have three spirit machine with a prepare versa nitric turn the pond 2000 system.( such as figure 2 show)Five is tube line that the design that the circular integral whole turn to make oxidize the ditch do not need additionally, can immediately realize dirty mire in reflux allotment in different craft unit[17].6. ConclusionThe Carrousel oxidizes the ditch because of having the good a phosphorus takes off the nitrogen ability, anti- pounds at the burthen ability with circulate to manage the convenience etc. the advantage, having got the extensive application.But because of technological development with social advance, that craft is necessarily willexaltation getting further.The author thinks:The Carrousel oxidizes the future research direction of the ditch will now of main below several aspects.1 Combination living creature method, research with develop the living creature model Carrousel oxidize the ditch.Like this can not only increases the microorganism gross of the unit reactor measures, from but increases the organism carries, but also living creature oneself the inside that have places the A/ the system of O enhances to take off the nitrogen result[18].2 Increases continuously the Carrousel oxidize the microbial activity in inside in ditch.For example throw to add the EM in oxidize ditch with single mind the germ grow, throws in that the salt of iron make the microorganism tame the live char in iron, devotion in living creature to become the formation to strengthen the germ gum regiment and increases to bear the toxicity pound at etc..3 Increasing the Carrousel oxidizes the ditch equipments function with supervise and control the technique.Function that increases form machine, underwater propeller, reduce to maintain the workload;Making use of DO, etc. of ORP many targets supervises and control the technique and changes the technique of is from now on the Carrousel oxidizes ditch science circulate necessarily from it road.4 Increasing the Carrousel oxidizes the ditch resistant to cold and bear toxicity can, reduce to cover the area to build the price with the engineering.Theoretical application, deep pond in water power term with the research of the craft function is to lowers the engineering builds the price and increases resistant to cold bear the toxicity can wait to provide the possible direction.氧化沟工艺在污水处理中的应用与发展摘要：本文主要阐述了Carrousel氧化沟的结构、工艺机理、运行过程中存在的问题和相应的解决方法。