两段式系统中自动加热嗜热好氧污泥消化和金属生物浸出。

Autoheated thermophilic aerobic sludge digestion and metal bioleaching in a two-stage reactor system.

机构信息

Department of Biochemical Engineering & Biotechnology Indian Institute of Technology, Hauz Khas, New Delhi-110016, India.

出版信息

J Environ Sci (China). 2010;22(2):230-6. doi: 10.1016/s1001-0742(09)60098-x.

DOI:10.1016/s1001-0742(09)60098-x

PMID:20397411

Abstract

A two-stage process has been developed for stabilization of sludge and removal of heavy metals from the secondary activated sludge with high rate of energy and time conservation. The first stage of the process involves autoheated thermophilic aerobic digestion at 55-60 degrees C inoculated with less-acidophilic thermophilic sulfur-oxidizing microorganisms (ATAD). The results show that it is possible to maintain the autoheated conditions (55-60 degrees C) in the ATAD reactor up to 24 hr, leading to reduction of 21% total solids (TS), 27% volatile solids (VS), 27% suspended solids (SS) and 33% volatile suspended solids (VSS) from the sludge. The sludge pH also decreased from 7 to 4.6 due to the activity of less-acidophilic thermophilic microorganisms. In the second stage operation, the digested sludge (pH 4.6, TS 31.6 g/L) from stage one was subjected to bioleaching in a continuous stirred tank reactor, operated at mean hydraulic retention times (HRTs) of 12, 24 and 36 hr at 30 degrees C. An HRT of 24 hr was found to be sufficient for removal of 70% Cu, 70% Mn, 75% Ni, and 80% Zn from the sludge. In all, 39% VSS, 76% Cu, 78.2% Mn, 79.5% Ni and 84.2% Zn were removed from the sludge in both the stages.

摘要

两段式工艺已被开发出来，用于稳定污泥并去除高能量和时间消耗的高速率活性污泥中的重金属。该工艺的第一阶段涉及在接种了较少嗜酸嗜热硫氧化微生物（ATAD）的 55-60°C 下进行自热高温好氧消化。结果表明，在 ATAD 反应器中维持自热条件（55-60°C）长达 24 小时是可行的，从而使污泥中的总固体（TS）减少 21%、挥发性固体（VS）减少 27%、悬浮固体（SS）减少 27%和挥发性悬浮固体（VSS）减少 33%。由于较少嗜酸嗜热微生物的活性，污泥的 pH 值也从 7 降低到 4.6。在第二阶段操作中，将第一阶段的消化污泥（pH 4.6，TS 31.6 g/L）在连续搅拌槽反应器中进行生物浸出，在 30°C 下操作的平均水力停留时间（HRT）分别为 12、24 和 36 小时。发现 HRT 为 24 小时足以从污泥中去除 70%的 Cu、70%的 Mn、75%的 Ni 和 80%的 Zn。总的来说，在两个阶段中，污泥中的 39%的 VSS、76%的 Cu、78.2%的 Mn、79.5%的 Ni 和 84.2%的 Zn 被去除。