热水解厌氧消化工艺用于污水厂泥区升级改造

Application of Thermal Hydrolysis/Anaerobic Digestion Process to Upgrading of Sludge Treatment Zone

北京某污水处理厂泥区升级改造中面临诸多问题,包括消化池处理能力已达到上限,无扩建用地;污泥出厂的含水率要求不大于50%,现有工艺无法满足要求;已有消化池沼气产量低,运行费用高,不具有可持续性;污泥稳定程度不高,存在安全卫生隐患等。采用热水解作为预处理强化厌氧消化,可解决上述问题。最终采用浓缩→预脱水→热水解→厌氧消化→板框脱水污泥处理工艺,并给出了相应设计参数,指出了可能存在的问题。提出了优化设计建议,包括根据污泥性质分别进行热水解预处理,设置热水解预处理系统除砂、除渣、去纤维,投药强化脱硫,收集不可凝气体管道冷凝液,再利用低温水等,优化了整个系统的设计及运行。

There were many problems in the upgrading of sludge treatment zone in a WWTP in Beijing, including that the digester capacity reached its upper limit, no land for expansion; the final sludge moisture content should be no more than 50%, but the existing technology could not meet the requirements; biogas production of digester was low, with high operating cost, which was not sustainable; sludge was lack of stability, at the risk of security and other healthy problem. The problems described ahove could be solved using thermal hydrolysis as pretreatment to enhance anaerobic digestion. The com- bined process of thickening, pre-dewatering, thermal hydrolysis, an aerobic digester and plate-frame dewatering was adopted, design parameters were given, and the possible problems were indicated. Optimum design recommendations were proposed, including respective pretreatment with thermal hydrolysis according to sludge properties, installing thermal hydrolysis pretreatment system for removing sand, scum and fibers, enhancing desulfurization by dosing chemicals, collecting condensate from non-condensable gas pipeline and reusing low temperature water. The design and operation of the overall system were optimized