【正文】
污水流進行的大的污染物。而小的處理廠可能采用手動的格柵。收集到的固體將被進行填埋或焚燒處理。 初級處理 在初級沉淀階段,污水流經(jīng)一個大池子,俗稱 “初級澄清池 ”或 “初級沉淀池 ”。在初級沉淀階段的主要目的是提供一個均勻的液態(tài)環(huán)境使微生物和污泥都能被處理。油脂和石油的漂浮物有時會回收進行皂化。大多數(shù)市政都打算采用好氧生物的方法解決污水處理問題。有多種方式來達到這個目的。二級處理系統(tǒng)被分為 生物膜處理法和停止增長生物處理法 。 在停止增長生物處理法如活性污泥系統(tǒng)中,生物質(zhì)可以與與污水充分混合,而且在處理等量污水時可以比膜系統(tǒng)采用更小的空間操作。 粗過濾器是為了處理特別強烈的或可變有機負荷,一般工業(yè),允許它們由傳統(tǒng)的二級處理工藝處理后在進行處理。它們的目的是允許通過高負荷的水力和高速流動的空氣。由此產(chǎn)生的廢水通常在常規(guī)處理工藝的正常范圍內(nèi)。 這個過程中的顆粒物質(zhì)在理想的條件下,可將氨轉(zhuǎn)化為亞硝酸鹽和硝酸鹽,并最終為氮氣(另見反硝化)。表面曝氣池在一到十天的停留時間內(nèi),對生化需氧量的去除可達到 80%至 90%。 在一個曝氣池系統(tǒng)中,曝氣機提供兩個功能:他們轉(zhuǎn)移生物氧化反應所需要的空氣至曝氣池,它們提供空氣的分散和反應物的接觸的所需(即,氧氣,污水和微生物) 。然而,在活性污泥系統(tǒng)中,它們并不能保證提供混合達到預定值,因此活性污泥系統(tǒng)中的曝氣池也不一定能達到預定的水平。 C和 40 176。大多數(shù)表面曝氣池運行溫度為 4 176。 C。這種介質(zhì)必須有足夠的表面積以支持生物膜的形成。擴散的溶液穿過濾池,并在池底通過管道被收集。分布在介質(zhì)表面的細菌,原生動物和真菌生物將以消化或以其他方式使有機質(zhì)含量減少。因為生物膜過厚將會導致介質(zhì)堵塞和濾池上表面積水 。曝氣生物濾池通常包括一個由過濾介質(zhì)填充的反應器。 這個介質(zhì)的兩個目的是支持存在于它上面的微生物的高活性和 過濾懸浮固體。曝氣生物濾池的運作是上流還是下流要取決于設計制造商設計及說明。膜是由 低壓微濾或超濾膜組成的,因此不必再進行澄清或第 三次過濾 。對一個 MBR系統(tǒng)的主要好處之一是,它有效地克服了傳統(tǒng)活性污泥工藝中的污泥的沉降差問題。這一反應過程通常是在 混合液懸浮固體顆粒濃度為 8,00012,000毫克 /升中進行的,而 CAS的允許操作范圍為 20203000毫克 /升。因此,增加污泥滯留時間( SRTs) 通常超過 15天 – 即可確保即使在極其寒冷的天氣里也能完全硝化。 膜過濾器會被油污堵塞或被水流中的沙粒摩擦刮破,且缺乏洪峰流量通過時凈水的靈活性。膜生物反應器系統(tǒng)的體積小,且可以高質(zhì)量的處理污水,使他們在中水回用方面大受歡迎。包括北 Librty,愛荷華,格魯吉亞和加拿大。 生物轉(zhuǎn)盤 主條目:旋轉(zhuǎn)生物接觸池 旋轉(zhuǎn)生物接觸池( RBCs)是機械二級處理系統(tǒng),在承受激增的有機負荷時有強大的應該變能力。轉(zhuǎn)盤為污水中的細菌和微生物提供生長方面的支持,用來破壞與穩(wěn)定有機污染物。 氧氣是轉(zhuǎn)盤旋轉(zhuǎn)過程中從大氣中獲得的。 從旋轉(zhuǎn)生物接觸池流出的污水,將通過最后澄清池在那里懸浮的微生物將沉淀為絮狀物。 與其功能類似的生物過濾系統(tǒng)已成為家庭魚缸受歡迎的過濾和凈化的一部分。紗網(wǎng)轉(zhuǎn)輪將成為一個以水族箱中懸浮飼料廢物為食的微生物形成的生物膜,同時轉(zhuǎn)輪也由于旋轉(zhuǎn)而暴露于大氣。 附錄 2 外文參考文獻(原文) Sewage treatment Abstract: Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff (effluents) and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants. Its objective is to produce a waste stream (or treated effluent) and a solid waste or sludge suitable for discharge or reuse back into the environment. This material is often inadvertently contaminated with many toxic organic and inorganic pounds. Key words: Sewage treatment, fixedfilm and suspendedgrowth, Activated sludge Origins of sewage Sewage is created by residences, institutions, and mercial 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 merce. The separation and draining of household waste into greywater and blackwater is being more mon 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 hardstanding areas. Municipal wastewater therefore includes residential, mercial, and industrial liquid waste discharges, and may include stormwater runoff. Sewage systems capable of handling stormwater are known as bined systems or bined sewers. Such systems are usually avoided since they plicate 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 pounds, 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