本文選題：城市污泥 + 水熱處理��； 參考：《北京交通大學(xué)》2017年碩士論文

【摘要】：城市污水廠的不斷建設(shè),使污泥的產(chǎn)量逐漸增加,如何合理的處置這些污泥是城市發(fā)展急需解決的重要問題。從長遠看,污泥土地利用是實現(xiàn)污泥資源化的有效途徑之一。但在土地利用前,必須對污泥中的重金屬進行處理,降低其生態(tài)風(fēng)險。水熱處理技術(shù)可以有效實現(xiàn)污泥的穩(wěn)定化,特別是低溫條件下的水熱處理發(fā)展前景廣闊,如果配合適當(dāng)?shù)拟g化劑,可以有效控制其中重金屬的生態(tài)風(fēng)險,有助于實現(xiàn)污泥的土地利用。本論文從重金屬濃度、賦存形態(tài)和生態(tài)風(fēng)險評價三個方面探討低溫(150℃)條件下水熱處理對污泥中重金屬行為的影響。同時對影響重金屬行為的因素,如反應(yīng)溫度、反應(yīng)時間和鈍化劑類型及用量等進行研究。結(jié)果表明:(1)水熱處理能夠很好的降低污泥的含水率,實現(xiàn)污泥的減量化。同時,污泥中的重金屬呈現(xiàn)富集現(xiàn)象,在140℃、8h條件下,富集率最高達130%,這對重金屬的穩(wěn)定化處理增加了 一定的難度。(2)水熱處理后,進入液相部分的重金屬比例保持在2%以下。固相部分中重金屬的賦存形態(tài)發(fā)生了一定的變化,特別是在140℃、8h條件下,Cu、Cd和Cr的殘渣態(tài)(T5)比例分別上升了 5.12%、2.64%和3.36%。Pb和Hg的T5態(tài)所占比例有所下降,主要是由于直接風(fēng)險態(tài)(T1+T2)和無風(fēng)險態(tài)(T5)向潛在風(fēng)險態(tài)(T3+T4)的遷移轉(zhuǎn)化。污泥含水率降低而導(dǎo)致的重金屬富集使地累積指數(shù)和潛在生態(tài)危害指數(shù)的數(shù)值略有增加,其中Cd和Hg的危險程度最高。(3)添加鈍化劑后,進入液相部分的重金屬比例下降了到1.5%以內(nèi),更多的重金屬殘留在固相部分中。鈍化劑對重金屬賦存形態(tài)的影響很大,Cu和Zn的可還原態(tài)(T4)比例及Cd、Pb、Cr和Hg的殘渣態(tài)(T5)比例均有明顯上升。添加羥基磷灰石會增加Cr的直接生態(tài)風(fēng)險,而添加尿素可以降低所有六種重金屬的直接生態(tài)風(fēng)險。對于Cd、Pb、Cr和Hg,兩種鈍化劑均可降低其間接生態(tài)風(fēng)險,使污泥在環(huán)境中的穩(wěn)定性增強。通過生態(tài)風(fēng)險評價結(jié)果可以看出,鈍化劑對Cd和Hg有良好的穩(wěn)定化效果,能有效降低其在環(huán)境中的危險等級,從而使污泥更加穩(wěn)定。整體而言,羥基磷灰石的穩(wěn)定化效果稍好于尿素�？傊�,添加鈍化劑后的水熱處理能明顯降低污泥中重金屬的生物可利用性和環(huán)境遷移性,使污泥更加穩(wěn)定。而這種穩(wěn)定化作用與反應(yīng)時間、反應(yīng)溫度、鈍化劑類型和用量有密切關(guān)系。
[Abstract]:With the continuous construction of municipal wastewater treatment plant, the output of sludge is increasing gradually. How to dispose the sludge rationally is an important problem that needs to be solved urgently in the development of city.In the long run, sludge land use is one of the effective ways to realize sludge resource utilization.But before land use, the heavy metals in sludge must be treated to reduce the ecological risk.The technology of hydrothermal treatment can effectively realize the stabilization of sludge, especially the hydrothermal treatment at low temperature has a bright future. If the proper passivating agent is used, the ecological risk of heavy metals in the sludge can be effectively controlled.It is helpful to realize the land use of sludge.In this paper, the effects of hydrothermal treatment on the behavior of heavy metals in sludge were studied from three aspects: concentration of heavy metals, occurrence forms and ecological risk assessment.The factors influencing heavy metal behavior, such as reaction temperature, reaction time, type and amount of passivator, were also studied.The results show that hydrothermal treatment can reduce sludge moisture content and realize sludge reduction.At the same time, the heavy metals in sludge showed enrichment phenomenon. At 140 鈩，

本文編號：1738506