某啤酒廠啤酒廢水處理工程初步設(shè)計(jì)-UASB-CASS工藝含開(kāi)題及8張CAD圖,啤酒廠,啤酒,廢水處理,工程,初步設(shè)計(jì),UASB,CASS,工藝,開(kāi)題,CAD Abstract With the rapid development of brewery industry in China, more brewery wastewater is discharged, which endangers enviroment.This design is one beer waste water treatment. The degree of the design is in a preliminary phase. The main distinguishing feature of the beer waste water is that it contains the massive organic matters, so it belongs to the high concentration organic waste water, therefore its biochemical oxygen demand is also high. The water which needs to treatment in the beer waste water treatment plant is 2100, regardless of the specified future development. Various target in the raw waste water is: the concentration of BOD is 1100 mg/L , the concentration of COD is 2100 mg/L , the concentration of SS is 310 mg/L . For the beer waste water's BOD is high, it could pollute the environment if drained before treatment, so it request the beer waste water which drained must be strictly treated to the two effluence standard in the country, which is as following: BOD ≤ 20 mg/L , COD ≤ 100 mg/L , SS ≤ 70 mg/L . This paper analyzes the generation processes of wastewater, the major contaminats and their major sources in beer production. It also introduces the primary biological processing techniques of aerobic and anaerobic treatment. According to the product scale of beer brewery, the main standard of draining water\natural materials, and so on, the main process technology of the beer waste water disposal station is defined as UASB + CASS .Practice of project indicate, when COD of wastewater reduces from 2200mg/l to 50~100mg/l, BOD reduces from 1100mg/l to 20mg/l, SS reduces from 400mg/l to 70mg/l, so that drains out can reaches the Standard. The technological process of this design is: Beer waste water → Screens → The sewage lift pump house → Regulates tank → Reaction tank of UASB → Tank of CASS → Treatment water This technology of wastewater treatment has many traits. Such as, well-knit structure, pithy quick control, lasting attacked, less sledge capacity. Practice indicates that the composed craft has reliable function, its investment is little, and its running and management is uncomplicated. Key words: beer waste water UASB CASS Ⅱ 設(shè)計(jì)任務(wù)書(shū) 一、 設(shè)計(jì)題目： 某啤酒廠啤酒廢水處理工程初步設(shè)計(jì) 二、 設(shè)計(jì)目的 本設(shè)計(jì)是在學(xué)生經(jīng)過(guò)給水排水專(zhuān)業(yè)課程學(xué)習(xí)后，在初步掌握污水和廢水處理理論，處理工藝、處理方法和構(gòu)筑物設(shè)計(jì)計(jì)算的基礎(chǔ)上進(jìn)行，是對(duì)學(xué)生的基本理論、基本知識(shí)、基本技能的一次綜合性訓(xùn)練。通過(guò)畢業(yè)設(shè)計(jì)使學(xué)生掌握一下知識(shí)： 1.了解啤酒生產(chǎn)工藝、廢水的來(lái)源、特點(diǎn)。 2．掌握啤酒廢水處理工程設(shè)計(jì)的方法和步驟； 3．學(xué)習(xí)利用各種資料確定設(shè)計(jì)方案的方法； 4．熟悉構(gòu)筑物工藝設(shè)計(jì)計(jì)算方法； 5．熟悉啤酒廢水處理廠（站）總體布置方法和原則； 6．加強(qiáng)工程制圖能力。 三、設(shè)計(jì)任務(wù) 1．確定啤酒廢水處理程度，選擇污水處理流程。 2．選擇啤酒廢水和污泥處理構(gòu)筑物。 3．進(jìn)行啤酒廢水和污泥處理構(gòu)筑物工藝設(shè)計(jì)計(jì)算，確定主要尺寸。 4．進(jìn)行啤酒廢水處理廠（站）總體布置。 5．整理計(jì)算書(shū)，編制說(shuō)明書(shū)。 三、設(shè)計(jì)原始資料 1．設(shè)計(jì)平均日水量2100m3/d。 2．廢水經(jīng)24h逐時(shí)取樣混合后的水質(zhì)指標(biāo)： 水質(zhì)指標(biāo) BOD5（mg/L） COD（mg/ L） SS（mg/ L） pH 原水 1100 2100 310 6-10 排放標(biāo)準(zhǔn) 20 100 70 6-9 設(shè)計(jì)要求 20 90 60 6-9 3．氣象資料： 溫度： 多年平均氣溫14.5℃。月均最冷氣溫-12℃，最熱氣溫26.8℃,最高氣溫40.1℃,極端最低氣溫-18.9℃，最大溫差26.6℃。 降雨量：年降雨量637.5mm,小時(shí)最大降雨量41.7mm，地區(qū)最大時(shí)降雨量Q=1807.0m3/h。 日照：平均日照率65%， 你按照時(shí)間2451h，冬日照率56.7%，消極照率66.0%。 風(fēng)速：夏季平局風(fēng)速2.6m/s,冬季3.4m/s,夏季為南風(fēng)向，冬季為北風(fēng)。 4.地質(zhì)條件 該地區(qū)地下含水層的透水性好，多為粗沙、粉細(xì)沙和加油粗沙的松散土層。地下水位埋深已超過(guò)50m.基本處于疏干狀態(tài)。 5.地形地勢(shì) 處理站地勢(shì)較低，自西北向東南方向有緩坡，坡度為0.5%。300m內(nèi)沒(méi)有生活區(qū)和辦公樓。處理站面積為200m×200m。南北向方形。 四、設(shè)計(jì)成果 1 開(kāi)題報(bào)告 1 2 中英文摘要 1 3.設(shè)計(jì)說(shuō)明書(shū) 1 4.設(shè)計(jì)計(jì)算書(shū) 1 5.設(shè)計(jì)圖紙 8 五、時(shí)間安排 1.畢業(yè)設(shè)計(jì)準(zhǔn)備、收集資料、翻譯外文、擬框架、寫(xiě)出開(kāi)題報(bào)告2周； 2.畢業(yè)設(shè)計(jì)實(shí)習(xí) 2周 3.工藝設(shè)計(jì)計(jì)算 4周 4.主要構(gòu)筑物設(shè)計(jì)繪圖 4周 5.寫(xiě)作設(shè)計(jì)說(shuō)明 1周 6.畢業(yè)答辯 1周 第 2 頁(yè) 共 2 頁(yè) 附錄Ⅰ： Wastewater Biological Treatment Processes The objective of wastewater treatment is to reduce the concentration of specific pollutants to the level at which the discharge of the effluent will not adversely affect the environment or pose a health threat. Moreover , reduction of these constituents need only be to some required level. For any given wastewater in a specific location , the degree and type of treatment are variables that require engineering decisions . often the degree of treatment depends on the assimilative capacity of the receiving water . DO sag curves can indicate how much BOD must be removed from wastewater so that the DO of receiving water is not depressed too far . The amount of BOD that must be removed is an effluent standard and dictates in large part the type of wastewater treatment required . To facilitate the discussion of wastewater , assume a “ typical wastewater ”and assume further that the effluent from this wastewater treatment must meet the following effluent standards : BOD≤15mg/L SS≤15mg/L P≤1mg/L Additional effluent standard could have been established , but for illustrative purposes we consider only these three . The treatment system selected to achieve these effluent standards includes 1. Primary treatment : physical processes that nonhomogenizable solids and homogenize the remaining effluent . 2. Secondary treatment : biological process that remove most of the biochemical demand for oxyen . 3. Tertiary treatment : physical , biological , and chemical processes to remove nutrients like phosphorus and inorganic pollutants , to deodorize and decolorize effluent water , and to carry out further oxidation . Primary treatment The most objectionable aspect of discharging raw sewage into watercourses is the floating material . Thus screen were the first form of wastewater treatment used by communities , and they are used today as the first step in treatment plants .Typical screens consist of a series bars that might be about 2.5 cm apart . A screen in a modern treatment plant removes might damage equipment or hinder further treatment . in some older treatment plants are cleaned by hand , but mechanical cleaning equipment is used in almost all new plants . The cleaning rakes are activated when screens get sufficiently clogged to raise the water level in front of the bars . In many plants , the second treatment step is a comminutor , a circular grinder designed to grind the solids coming through the screen into pieces about 0.3 cm or less in diameter . The third treatment step is the removal of grit or sand from the wastewater . Grit and sand can damage equipment like pumps and flow meters and must be removed . The most common grit chamber is a wide place in the channel where the flow is slowed enough to allow the dense grit to settle out . Sand is about 2.5 times dense than most organic solids and thus settles much faster . The objective of a grit chamber is to remove sang and grit without removing organic material .Organic material must be treated further in the plant , but the separated sand may be used as fill without additional treatment . Most wastewater treatment plants have a settling tank after the grit chamber , to settle out as much material as possible . Accordingly , the retention time is long and turbulence is kept to a minimum . The solids settle to the bottom of the tank and are removed though a pipe , while the clarified liquid escapes over a V-notch weir that distributes the liquid discharge equally all the way around a tank . Settling tanks are also called sedimentation tank or clarifiers . The settling tank that immediately follows screening and grit removal is called the primary clarifier . The solids that drop to the bottom of a primary clarifier are removed as raw sludge . Raw sludge generally has a powerfully unpleasant odor , is full of pathogenic , and is wet , three characteristics that make its disposal difficult . It must be stabilized to retard further decomposition and dewatered for ease of disposal . The objective of primary treatment is the removal of solids , although some BOD is removed as a consequence of the removal of decomposable solids . A substantial fraction of the solids has been removed , as well as some BOD is a little P , as a consequence of the removal of raw sludge . After primary treatment the wastewater may move on to secondary treatment . Secondary Treatment Water leaving the primary clarifier has not lose much of the solid organic matter but still contains high-energy molecules that decompose by microbial action , creating BOD . The demand for oxygen must be reduce (energy wasted ) or else the discharge may create unacceptable condition in the receiving waters . The objective of secondary treatment is to remove BOD , where the objective of primary treatment is to remove solids . The trickling filter consists of a filter bed of fist-sized rocks or corrugated plastic blocks over which the waste is trickled . The name is something of a misnomer since no filtration takes place . A very active biological growth forms on the rocks , and these organisms obtain their food from the waste stream dipping through the rock bed . Air either is forced through the rocks or circulates automatically because of the difference between the air temperature in the bed and ambient temperatures . Trickling filters use a rotating arm that moves under its own power , like a lawn sprinkler , distributing the waste evenly over the entire bed . often the flow is recirculated and a higher degree of treatment attained . Trickling filtration was a well-established treatment system at the beginning of the twentieth century . in 1914 , a pilot plant was built for a different system that bubbled air through free-floating aerobic microorganisms , a process which became known as the activated sludge system . The activated sludge process differs from trickling filtration in that the microorganisms are suspended in the liquid . An activated sludge system includes a tank full of waste liquid from the primary clarifier and a mass of microorganisms . Air bubbled into this aeration tank provides the necessary oxygen for survival of the aerobic organisms . The microorganisms come in contact with dissolved organic matter in the wastewater . adsorb this material , and ultimately decompose the organic material to CO2 , HO2 ,some stable compounds , and more microorganisms . When most of the organic material , that is , food for the microorganisms , has been used up , the microorganisms are separated from the liquid in a settling tank , sometimes called a secondary or clarifier . The microorganisms remaining in the settling tank have no food available , become hungry , and are thus activated-hence the term activated sludge . The clarified liquid escapes over a weir and may be discharged into the receiving water . The settle microorganisms , now called return activated sludge , are pumped back to the head of the aeration tank , where they find more food in the organic compounds in the liquid entering the aeration tank from the primary clarifier , and the process starts over again . Activated sludge treatment is a continuous process ,with continuous sludge pumping and clean-water discharge . Activated sludge treatment produces more microorganisms than necessary and if the microorganisms are not removed , their concentration will soon increase and clog the system with solids . Some of the microorganisms must therefore be wasted and the disposal of such waste activated sludge in one of the most difficult aspects of wastewater treatment . Activated sludge system are designed on the basis of loading , or the amount of organic matter , or food , added relative to the microorganisms available . The food-to-microorganisms (F/M) ratio is major design parameter . Both F and M are difficult to measure accurately , but may be approximated by influent BOD and SS in the aeration tank , respectively . The combination of liquid and microorganisms undergoing aeration is known as mixed liquor , and the SS in the aeration tank are mixed liquid suspended solids (MLSS) . The ratio of influent BOD to MLSS , the F/M ratio , is the loading on the system , calculated as pounds (or kg ) of BOD per day per pound or kg of MLSS . Relatively small F/M ,or little food for many microorganisms , and a long aeration period (long retention time in the tank ) result in a high degree of treatment because the microorganisms can make maximum use of available food . Systems with these features are called extended aeration systems and are widely used to treat isolated wastewater source , like small developments or resort hotels . Extended aeration systems create little excess biomass and little excess activated sludge to dispose of . The success of the activated sludge system also depends on the separation of the microorganisms in the final clarifier . when the microorganisms do not settle out as anticipated , the sludge is said to be a bulking sludge , Bulking is often characterized by a biomass composed almost totally of filamentous organisms that from a king of lattice structure within the sludge floes which prevents settling . A trend toward poor settling may be the forerunner of a badly upset and ineffective system . The settle ability of activated sludge is most often described by the sludge volume index (SVI) , which is reasoned by allowing the sludge to settle for minutes in a 1-Lcyliner . If the SVI is 100 or lower , the sludge solids settle rapidly and the sludge returned to the final clarifier can be expected at a high solids concentration . SVI is about 200 , however , indicate bulking sludge and can lead to poor treatment . Tertiary Treatment The effluent from secondary treatment meets the previously established effluent standards for BOD and SS . only phosphorus content remains high . The removal of inorganic compounds , including inorganic phosphorus and nitrogen compounds , requires advanced or tertiary wastewater treatment . Primary and secondary (biological) treatment are a part of conventional wastewater treatment plants . However , secondary treatment plant effluents are still significantly polluted . some BOD and suspended solids remain , and neither primary nor secondary treatment is effective in removing phosphorus and other nutrients or toxic substances . A popular advanced treatment for BOD removal is the polishing pond , or oxidation pond , commonly a large lagoon into which the secondary effluent flows . such ponds have a long retention time , often measured in weeks . BOD may also be removed by activated carbon adsorption , which has the added advantage of removing some is a completely enclosed tube , which dirty water is pumped into bottom and clear water exits at the top . microscopic crevices in the carbon catch and hold colloidal and smaller particles . As the carbon column becomes saturated , the pollutants must be removed from the carbon and the carbon reactivated , usually by heating it in the absence of oxygen . Reactivated or regenerated carbon is somewhat less efficient than using virgin carbon , some of which must always be added to ensure effective performance . 附錄Ⅱ： 污水的生物處理過(guò)程 物水處理的目的是降解特定污染物的濃度使其達(dá)到污水排放不影響環(huán)境或形成健康威脅的程度，而且降低這些成分僅僅需要達(dá)到要求大的水平即可。 應(yīng)為任何給定的污水在來(lái)源，處理程度和類(lèi)型方面是變化的，而這種變化是由工業(yè)決定的，而且處理程度往往依賴(lài)接納水體的同化能力。氧垂曲線能顯示多少BOD必須從污水中去除以致于使接納水體的溶解氧不致降低太多。在大部分的污水處理要求的類(lèi)型中，必須被去除的BOD數(shù)量是污水的一個(gè)標(biāo)準(zhǔn)和指標(biāo)。 為了便于討論污水，假定一種“典型的污水”而且假定這種污水通過(guò)處理必須達(dá)到以下的污水標(biāo)準(zhǔn)： BOD ≤ 15 mg/L SS ≤ 15 mg/L P ≤ 1 mg/L 增加的污水標(biāo)準(zhǔn)應(yīng)該被列出，但是為了說(shuō)明目的我們僅僅考慮這三項(xiàng)。能達(dá)到這些污水標(biāo)準(zhǔn)的處理系統(tǒng)包括： 1. 初級(jí)處理：固體物質(zhì)非均勻化和污水排放均勻化的物理過(guò)程。 2. 二級(jí)處理：依靠氧去除大部分生化物質(zhì)的生物處理過(guò)程。 3. 三級(jí)處理：物理，生物和化學(xué)過(guò)程的目的就是去除營(yíng)養(yǎng)物質(zhì)，像磷和有機(jī)物等，而且去除污水的臭味，色度和更多的氧化物。 初級(jí)處理 排放原污水到水域中最厭惡的一個(gè)方面是其中的漂浮物，因此，格柵被用在社區(qū)污水處理的首要位置，現(xiàn)在它們被作為處理方案的第一步，典型的格柵由一系列的鋼條組成，這些鋼條之間大約相距2.5cm，在現(xiàn)代的處理方案中，格柵攔截了那些可能對(duì)設(shè)備造成破壞或者影響后續(xù)處理的物質(zhì)，在過(guò)去的一些舊的處理方案中，格柵通過(guò)人工清洗；但是現(xiàn)在幾乎所有的方案中都用機(jī)械清洗設(shè)備。當(dāng)格柵被阻塞使水位上升到柵條以上時(shí)，清洗設(shè)備被啟動(dòng)。 在許多方案中，第二步是粉碎，循環(huán)擠壓固體物質(zhì)通過(guò)格柵形成大約3.0cm或更小直徑的小塊。 第三步處理是去處污水中的沙粒和石子，沙粒和石子會(huì)損壞設(shè)備，像水泵和流量計(jì)，因此必須被去除。大部分沉沙池是個(gè)很寬的空間，在這個(gè)渠道內(nèi)水流慢到足夠大密度的沙粒沉淀下來(lái)，沙粒的密度是大部分有機(jī)物密度的2.5倍，因此沉淀的比較快。沉沙池的目的就是去除沙粒和石子，而不去除有機(jī)顆粒，在處理過(guò)程中有機(jī)物必須被進(jìn)一步處理而分離除的出的沙粒可以被用作填充物而無(wú)需額外處理。 大部分污水處理方案中在沉沙池后面都有一個(gè)沉淀池，目的就是盡可能的去除固體顆粒，因此，停留時(shí)間比較長(zhǎng)，水流速度保持比較慢。 固體沉淀到池子底部，然后通過(guò)管道被清除，而被澄清的液體則通過(guò)均勻布置在池子周?chē)腣型溢流堰排放，沉淀池也被稱(chēng)為沉積池或澄清池，緊隨在清渣和除沙之后的沉淀池也被叫作初次澄清池，沉淀在初次澄清池底部而被排放的固體稱(chēng)為原污泥。 原污泥通常有很強(qiáng)的令人不快的氣味，含有病原有機(jī)體，而且含水率高，這三個(gè)特點(diǎn)增加了它處理的困難，它必須被穩(wěn)定為了防止它進(jìn)一步腐化，也為了容易脫水處理。 初級(jí)處理的目的就是去除固體顆粒，然而一些BOD也在分離固體物質(zhì)的一系列過(guò)程中 被去除了。相當(dāng)?shù)囊徊糠止腆w物質(zhì)，還有一部分BOD和少量的P作為原污泥的產(chǎn)物而被去除了，被初級(jí)處理之后污水可能繼續(xù)進(jìn)行二級(jí)處理。 二級(jí)處理 水離開(kāi)初次澄清池并沒(méi)有去除多少固體有機(jī)物，而且仍含有能通過(guò)微生物作用分解的高能量分子，成為BOD。要求氧必須減少，否則，在接納的水體中排放可能出現(xiàn)不能接受的情況。二級(jí)處理的目的就是去除BOD，而初級(jí)處理的目的則是去除固體顆粒。 慮池由拳頭大小的礫石或波紋塑料板的慮床組成，通過(guò)它污物被慮掉，命名可能有錯(cuò)誤，因?yàn)楦緵](méi)有過(guò)濾發(fā)生?；钚晕⑸锔街诘[石上，空氣被強(qiáng)制通過(guò)礫石或自動(dòng)循環(huán)，因?yàn)閼]床空氣溫度和周?chē)鷾囟鹊牟町悾瑧]池用一個(gè)循環(huán)調(diào)節(jié)系統(tǒng)降低它的能耗，像一個(gè)均勻布水裝置，能均勻的在整個(gè)慮床上分布污水，而通常水流是循環(huán)的，因而更高程度的處理被實(shí)現(xiàn)。 在20世紀(jì)初，滴慮是一種被證實(shí)了的處理系統(tǒng)。1914年，一個(gè)試驗(yàn)方案確立了一個(gè)不同系統(tǒng)，空氣泡通過(guò)自由漂浮的好氧微生物，一種變的出名的活性污泥系統(tǒng)的處理方案?；钚晕勰嗵幚聿煌诘螒]在于滴慮過(guò)程中微生物是懸浮在液體中的。 一個(gè)活性污泥處理系統(tǒng)包括一個(gè)充滿(mǎn)來(lái)自初次澄清池的污染液體的池子和一團(tuán)微生物, 空氣泡進(jìn)入曝氣池提供存活好氧有機(jī)物所必須的氧氣，微生物進(jìn)入與在污水中的溶解性有 機(jī)物混合，吸附這些物質(zhì)，最終將有機(jī)物分解成，等一些穩(wěn)定的化合物和更多的微生物。 當(dāng)大部分作為微生物食物的有機(jī)物被消耗掉，在一個(gè)沉淀池里微生物被從液體中分離，有時(shí)叫二次澄清池，在沉淀池里微生物仍舊沒(méi)有食物可利用，變得饑餓，變成失去活性的活性污泥，澄清的液體從溢流堰流出而排入接納水體。沉淀的微生物現(xiàn)在叫回流污泥，被抽送至曝氣池前端，在那里它們從初次澄清池進(jìn)入曝氣池的液體的有化合物中找到更多的食物，處理再一次開(kāi)始。活性污泥處理是一個(gè)連續(xù)的過(guò)程，連續(xù)的污泥回流和連續(xù)的清水排放。 活性污泥處理產(chǎn)生的微生物多于需要的，如果微生物不被清除，它們的濃度將很快增加而形成固體物阻塞系統(tǒng)，因此，一部分微生物必須被去除，而處理這樣多余的活性污泥也是污水處理中一個(gè)最困難的方面。 活性污泥處理系統(tǒng)設(shè)計(jì)依據(jù)負(fù)荷，有機(jī)物數(shù)量或營(yíng)養(yǎng)物，而且聯(lián)系到微生物的易變性，營(yíng)養(yǎng)物與微生物（F/M）之比是一個(gè)主要的設(shè)計(jì)參數(shù)，F(xiàn)和M難于精確測(cè)定的，但是可以通過(guò)曝氣池中的BOD和SS分別被估算，液體和微生物的混合物被稱(chēng)為混合液。在曝氣池內(nèi)SS是混合液懸浮固體（MLSS），BOD/MLSS，F(xiàn)/M是系統(tǒng)負(fù)荷，以計(jì)。 相對(duì)小的F/M，或者少的營(yíng)養(yǎng)物，而且一個(gè)長(zhǎng)的曝氣周期（長(zhǎng)的停留時(shí)間在池中）產(chǎn)生一個(gè)高的處理效果，因?yàn)槲⑸锬茏畲笙薅鹊睦脿I(yíng)養(yǎng)物，有這些特點(diǎn)的系統(tǒng)被稱(chēng)為延時(shí)曝氣系統(tǒng)，而且被用于單獨(dú)的污水處理工藝，像小的工業(yè)部門(mén)或用于應(yīng)急處理的旅館。延時(shí)曝氣系統(tǒng)產(chǎn)生少的剩余生物團(tuán)，而且只有少的剩余活性污泥需要處理。 活性污泥處理系統(tǒng)的成功也依賴(lài)微生物最終在澄清池里的分離。當(dāng)微生物沒(méi)有像預(yù)期中的沉淀去除，則污泥被稱(chēng)為膨脹污泥，膨脹被描述為生物團(tuán)有大量的絲狀菌組成，形成了一個(gè)由污泥附著其上的空架結(jié)構(gòu)而阻止了沉淀，低的沉淀率可能是一個(gè)低效率系統(tǒng)的先兆?；钚晕勰喑恋砟芰?jīng)常用污泥容積指數(shù)描述（SVI），SVI值的測(cè)定是通過(guò)在一個(gè)1L的圓筒內(nèi)讓污泥沉淀數(shù)分鐘，如果SVI值是100或更低，則污泥固體沉淀快而且最終從澄清池流出的污泥可能被保持在一個(gè)高的固體濃度，然而，SVI值大約是200時(shí)，顯示污泥膨脹而導(dǎo)致低的處理效果。 三級(jí)處理 來(lái)自二級(jí)處理的污水能達(dá)到前續(xù)要求的BOD和SS排放標(biāo)準(zhǔn)，僅僅磷含量仍舊是高的，去除無(wú)機(jī)化合物，包括無(wú)機(jī)磷和氮化合物，就要求先進(jìn)的或廢水三級(jí)處理系統(tǒng)。 初級(jí)和二級(jí)處理是傳統(tǒng)廢水處理方案的一部分，而且二級(jí)處理后污水被污染的程度仍然很高，一定程度的BOD和懸浮固體仍然存在，既不是初級(jí)也不是二級(jí)處理是有效的去除磷，氮或者碳的化合物的方法。一種流行的先進(jìn)的BOD去除處理是人工塘或氧化塘，通常是二級(jí)污水流入一個(gè)大的環(huán)礁湖，像這樣的塘有一個(gè)長(zhǎng)的停留時(shí)間，經(jīng)常保持在一周。 BOD也可能被去除通過(guò)活性炭的吸附，它增加的去除的有點(diǎn)是被完全封閉在導(dǎo)管中，污水被從底部抽送進(jìn)去，而清水則從上部流出，在活性炭中微小的入口能捕捉和吸附病毒和更小的顆粒，當(dāng)炭柱變的飽和后，污物必須從炭中清除，使炭恢復(fù)活性，通常是通過(guò)在缺氧條件下加熱?；謴?fù)活性或再生的炭效率仍較低，經(jīng)常一些新的活性炭必須被添加進(jìn)去以確保其工作效率。