尚志市污水处理厂工程工艺设计 中英文翻译.docx

1、尚志市污水处理厂工程工艺设计 中英文翻译尚志市污水处理厂工程工艺设计 本设计为尚志市污水处理厂工程工艺设计，污水处理厂处理规模为一期40000m3/d，二期60000 m3/d。污水主要来源为生活污水和工业废水，主要污染物质为NH3-N、BOD、COD，适宜采用生化处理方法。经过方案比较，确定采用三槽式氧化沟工艺。NH3-N、BOD、COD的去除率分别达到92%、93%、89%，污水处理厂处理后的出水达到污水综合排放标准（GB8978-1996）中的二级标准。污水和活性污泥的混合液在氧化沟中进行不断的循环运动，具有良好的去除BOD、COD及脱氮除磷的功能。另外，工艺流程简单，构筑物少，构造形式

2、多样，运行较为灵活，运行稳定性好，基建投资省，运行费用低，操作管理方便，出水水质好也是氧化沟优于其他处理工艺的地方。活性污泥或任何生物废水处理法的目的是花费最少的时间和资金，将有机物质尽可能彻底地从原废水中除去。原废水的性质及其流动特征确定了，便必须根据它们进行处理法的设计。仅在少数情况下，工业废水可排放到调节池以平衡有机物浓度和流量。常规活性污泥的基本问题之一是微生物的优势种群易于变化。原废水中的有机物促进曝气池中某些菌种的生长。当除去有机物质，微生物进人内源期时，原有的用于稳定有机物的微生物群衰减以致死亡。第二批细菌利用原来的微生物死亡的产物并在曝气池的终端占据优势。当污泥回流到曝气池的首

3、端时，原来的细菌群又必须重新生长起来。只有长的曝气时间，原来的细菌数量才能减少到某一水平，故需要较长的恢复期，来处理流量或浓度突然增加的废水。在以活性污泥处理不同的工业废水中，这是很重要的，并且也是活性污泥对冲击负荷反应缓慢的原因之一。保持菌种均匀的唯一方法是保持有机物浓度的均匀。对于处理多变的废水来说，这是不可能的，但这种变化可保持在最小的限度。食料微生物比(F：M)是细菌生长的关键。业已证明，高的食料微生物比使细菌迅速生长，而低食料微生物比便细菌生长不显著。在常规活性污泥法中，食料(F)和微生物(M)都在不断地变化，随着每一次循环，食料微生物比(F：M)从最大值变为最小值。如果在完全混合的

4、情况下，原废水由曝气池全部池水所稀释，该曝气池就成了一个巨大的调节池，减小食料(F)的波动范围。由于曝气池处于完全混合，食料(F)值变得最低，波动也最小，池中任何一点的微生物活动与任何其他点相同。微生物在整个正常生长期内的变化趋近一点，而不像在常规活性污泥法中那样是一条宽阔的生长带。因而，从微生物的观点看，完全混合系统的优点最多，缺点最少。在任何废水处理问题申，有机物负荷都是固定的，因此只有通过调整微生物数量才能改变食料微生物比。通过调整食料微生物比，在细菌生长曲线的任何一点上进行处理都是可能的。现已清楚，就废水处理而论，在生长曲线上的某些段，并不能满意地进行工作。对于完全混合系统来说，其处理

5、范围将处在生长下降阶段的某一点上。最近的改革之一是让完全混合系统在生长下降阶段的较低端进行工作，此处污泥增加最小。剩余的污泥随出水排放，不致引起公害。出水中的活性与非活性固体之比必须与混合液中的相同。如果不能定期地除去悬浮固体（因为不能将这些悬浮固体随出水排放），那么完全氧化是否会大量用于处理生活污水，是值得怀疑的。另一方面，含有可溶物质的工业废水形成惰性固体缓慢，其生物处理接近完全氧化。出水中剩余的固体与所处理的有机物质成正比，约有10%-13%的有机物质作为惰性固体存在于出水中。在多数情况下，活性污泥必须有固体分离和排除装置。对于活性污泥法来说，仍须解决的主要问题之一乃是如何从液体中有效地

6、除去和浓缩污泥。现行的方法则依靠重力分离，但浓缩污泥的能力有限。如果污泥主要是活性的，就需要进一步稳定，才能最后进行处置。在正常情况下，厌氧消化用于污泥稳定，但近来在小系统中好氧消化也已达到相同的目的。决定采用何种方法，由经济因素决定，因为两种方法都会产生可以经过过滤除去其水分的稳定物质。如果污泥主要是非活性的，就不需要进一步稳定，污泥可以直接脱水。目前城市污水生化处理技术发展很快，工艺类型较多。除广泛采用的传统活性污泥法外，近年来国内外应用较多的有氧化沟法、A/A/O法、A/O法、A-B法、SBR法等。为了使污水处理厂能够选择到最合适的处理工艺，按照因地制宜的原则，先排除不适用的处理工艺后，

7、再对可以采取的处理工艺方案进行对比和优选。生物处理法是目前研究得较多、新技术层出不穷的方法， 无论是好氧生物处理技术，还是厌氧生物处理技术都引起了研究人员的极大兴趣。因为用生物法利用的是微生物的新陈代谢作用， 以污染物质为食料， 将其代谢成诸如CO2、H2O、NH3、SO2等稳定的小分子，它的二次污染小，对处理生活污水及与之性质相近的有机污水有其独特的优势。本课题选择典型的工艺流程，有两种可供选择的工艺：分别为普通的A/A/O法处理工艺及氧化沟处理工艺。 普通的A/A/O法处理工艺优点：该工艺为最简单的同步脱氮除磷工艺 ，总的水力停留时间，总产占地面积少于其它的工艺 。在厌氧的好氧交替运行条件

8、下，丝状菌得不到大量增殖，无污泥膨胀之虞，SVI值一般均小于100。污泥中含磷浓度高，具有很高的肥效。运行中勿需投药，两个A段只用轻缓搅拌，以不啬溶解氧浓度，运行费低。缺点：除磷效果难于再行提高，污泥增长有一定的限度，不易提高，特别是当P/BOD值高时更是如此 。脱氮效果也难于进一步提高，内循环量一般以2Q为限，不宜太高，否则增加运行费用。对沉淀池要保持一定的浓度的溶解氧，减少停留时间，防止产生厌氧状态和污泥释放磷的现象出现，但溶解 浓度也不宜过高。以防止循环混合液对缺反应器的干扰。氧化沟（oxidation ditch）又称循环曝气池，是一种改良的活性污泥法，其曝气池呈封闭的渠形，污水和活性

9、污泥混合液在其中循环流动。采用氧化沟处理污水时，可以不设置初沉池，二次沉淀池可以和曝气部分分开设置，此时需要设置污泥回流系统。如果二次沉淀池与曝气部分合建在同一沟渠中，则可以省去二次沉淀池和污泥回流系统。氧化沟的出水质好，一般情况下，BOD5去除率可达到 95%99%，脱氮率可达到90%，除磷效率在50%左右，如在处理过程中，适量的投加铁盐，则除磷效率可达到95%。工艺处理流程简单，构造形式多样，运行较为灵活，运行稳定性好，具有脱氮功能，基建投资省，运行费用低，操作管理比较方便。因此，氧化沟工艺使用与我国大部分地区。氧化沟的工艺流程工作特点：在液态上，介于完全混合与推流之间，有利于活性污泥的适

10、于生物凝聚作用。对水量水温的变化有较强的适应性，处理水量较大。污泥龄较长，一般长达1530天，到以存活时间较长的微生物，如果运行得当，可进行除磷脱氮反应。污泥产量低，且多已达到稳定。自动化程度较高，使于管理。占地面积较大，运行费用低。脱氮效果还可以进一步提高，因为脱氮效果的好坏很大一部分决定于内循环，要提高脱氮效果势必要增加内循环量，而氧化沟的内循环量从政论上说可以不受限制，因而具有更大的脱氮能力。氧化沟法自问世以来，应用普遍，技术资料丰富。两种工艺经过比较，氧化沟除了具有A/A/O的效果外，还具有如下特点：不设初沉池，有机性悬浮物在氧化沟内能达到好氧稳定的程度。BOD负荷低，使氧化沟具有对水

11、温、水质、水量的变动有较强的适应性，污泥产率低，勿需进行硝化处理。电耗较小，运行费用低。所以本课题选择氧化沟处理工艺。污泥浓缩方法的选择：污泥浓缩的主要目的就是减少污泥体积，从而降低后续处理构筑物和设备的负荷，减少处理费用。常用的浓缩方法有重力浓缩法、气浮浓缩法和离心浓缩法。各种方法的优点为：重力浓缩法：浓缩池构造简单，操作方便；动力消耗小，运行费用低；贮存污泥能力强。气浮浓缩法：浓缩效果好，出泥含水率低；占地面积小，只为重力法的1/10；运行效果稳定，不受季节影响；产生臭气小，能去除油类。离心浓缩法：浓缩效果好，工作效率高；占地面积小，几乎不散发臭气，工作环境好。本设计选择重力浓缩法翻译译文

12、The design of a sewage treatment plant of the city of Shang Zhi for the process design project, a sewage treatment plant to deal with a size of 40000m3 / d, 2 60000 m3 / d. The main source of water for domestic sewage and industrial wastewater, the main pollutants for the NH3-N, BOD, COD, appropriat

13、e use of biological and chemical treatment. After comparing the program to determine the three-trough oxidation ditch process. NH3-N, BOD, COD removal rate reached 92%, 93%, 89%, a sewage treatment plant effluent treated to achieve Integrated Wastewater Discharge Standard (GB8978-1996) in the two st

14、andards. Sewage and activated sludge in the oxidation ditch of the mixture in the cycle of continuous movement, has a good removal of BOD, COD and nitrogen and phosphorus removal functions. In addition, the process is simple, small structure, constructed in various forms, more flexible operation, op

15、eration stability, infrastructure investment and low operating costs, easy operation and management, water quality is also good oxidation ditch treatment process is superior to other places. The purpose of activated sludge or any biological waste treatment process is to remove the organic matter as

16、completely as possible from the raw wastes with the least expenditure of time and funds. The nature of the raw wastes and their flow characteristics are set and the treatment process must be designed around them. Only in a few industrial situations can the wastes be discharged to a surge tank for le

17、veling out the organic strength and flow. One of the basic problems with conventional activated sludge has been the variable predomination of the microorganisms. The organic matter in the raw wastes stimulates certain bacteria species in the aeration tank. As the organic matter is removed and the mi

18、croorganisms pass into the endogenous phase the primary group of microorganisms which were responsible for stabilizing the organic matter die off and lyse. A second group of bacteria utilize the lysed products of the primary group and predominate at the end of the aeration tank. When the sludge is r

19、eturned to the head end of the aeration tank, the primary group of bacteria have to grow all over again. With a long aeration period the number of primary bacteria can drop off to a level that requires a long recovery period to handle sudden increases in waste flow or strength. This is very importan

20、t in activated sludges treating strange industrial wastes, and it is one of the reasons activated sludge is slow in responding to shock loadings.The only way to keep the bacteria species uniform is to keep the organic level uniform. This is impossible to do with a variable waste, but the variations

21、can be kept to a minimum. The F:M ratio is the key to bacterial growth. A high F: M ratio has been shown to yield rapid growth while a low F: M ratio depresses the apparent growth. In conventional activated sludge, both F and M are constantly changing, with the F M ratio going from a maximum to a mi

22、nimum with each cycle. If the raw wastes were diluted with the entire contents of the aeration tank as in complete mixing, the aeration tank would become a large surge tank, damping out wide fluctuations in F. With complete mixing in the aeration tank, F becomes a minimum value with minimum fluctuat

23、ions and the microbial activity at any point in the tank is the same as at any other point. The microbial variation over the normal growth cycle tends to approach a point function rather than a wide band as in conventional activated sludge. Thus it is that the complete mixing system offers the most

24、advantages from a microbiological standpoint and the least disadvantages. In any v/aste disposal problem the organic load is fixed so that the F:M ratio can be varied only by adjusting M. It is possible to operate at any point on the bacterial growth curve by adjusting the F:M ratio. It has already

25、been pointed out that certain phases of the growth curve do not yield satisfactory operations as far as waste treatment is concerned. With complete mixing systems the operations will range at some point in the declining growth phase. One of the most recent innovations has been the operation of compl

26、ete mixing systemsat the lower end of the declining growth phase where sludge increase is minimal. The excess sludge is allowed to be discharged with the effluent without causing nuisance conditions. The ratio of act-ive solids to inactive solids in the effluent would have to be the same as it is in

27、 the mixed liquor. It is doubtful if total oxidation will have much application to the disposal of domestic sewage unless the solids are removed at periodic intervals, as they cannot be discharged with the effluent.On the other hand, a soluble industrial waste can be operated close to total oxidatio

28、n with only a slow build-up of inert solids. The excess solids in the effluent would be in direct proportion to the organic matter being treated with approximately 10 to 13 percent of the organic matter appearing in the effluent as inert solids.In most instances activated sludge must have a means of

29、 solids separation and wasting. One of the major problems still to be solved with activated sludge is the efficient removal and concentration of the sludge from the liquid. Current methods depend upon gravity separation and are limited in their ability to concentrate the sludge.If the sludge is pred

30、ominantly active, it will require further stabilization before it can be ultimately disposed of. Normally, anaerobic digestion is used for sludge stabilization but recently in small systems aerobic digestion has accomplished the same purpose. Once again economics determines which process should be u

31、sed since both will produce a stable material which can be dewatered by filtration. If the sludge is predominantly inactive, there is no need for further stabilization and the sludge can be dewatered directly. At present, municipal wastewater biological treatment technology developed rapidly, more t

32、ypes of technology. Widely used in addition to the traditional activated sludge process, the application of more recent years, both at home and abroad have oxidation ditch, A / A / O method, A / O method, AB Law, SBR law. Sewage treatment plant in order to be able to choose the most suitable treatment process, in accordance with the principle of suiting measures to local conditions, to rule out the possibility of the treatment process does not apply, and then on the process that can be taken for comparison and optimization program. Biological treatm