污泥堆肥过程中三氯生的降解转化规律及其环境风险研究

Triclosan is commonly found in antibacterial personal-care products such as hand soaps as well as deodorants, mouthwashes, toothpaste. Now some findings provide strong evidence that the chemical is of concern to both human and environmental health. One part of triclosan in waste water is absorbed by sludge after the waste water treatment. Now, land application after composting is the most popular treatment and disposal method for sludge from municipal waste water treatment plant. There is little study about the microbial degradation of triclosan during the sludge composting process, and the environmental risk is not clear for sludge land application either. This study is focus on the dynamic of triclosan during the sludge composting process. We will study the effect of the composting regulation and control method, such as C/N of the material, the temperature of composting pile, and the supplying of oxygen. Through these experiments, we can observed the degradation rate of triclosan during the sludge composting process, and find the appropriate composting conditions for triclosan degrades rapidly. And we can make clear the law of the triclosan degradation during sludge composting. Rely on the degradation rate of triclosan and the degradation products, we can judge the changes of environmental risk about the triclosan and the effect of composting for sludge. Through determined the triclosan in sludge from municipal waste water treatment plants in China, the environmental risk of the sludge land application can be judged by us. The results also can be an important proof for Chinese government to formulate the technology route and policy about the sludge treatment and disposal.

吸附和富集有较高含量三氯生的城市污泥的最终环境归宿是需要关注的重点。目前对污泥堆肥过程中三氯生的降解机理及其土地利用的环境风险尚未有研究。 本项目在开展全国范围的城市污泥中三氯生调查基础上，选取典型城市污水处理厂的污泥，通过堆肥实验，研究污泥中有机污染物三氯生的降解动态过程。并通过调控堆肥过程中影响污泥降解腐熟的C/N、温度、氧气等条件，研究污泥中三氯生降解率的变化，确定污泥堆肥过程中能够促进三氯生降解的适宜条件，阐明污泥堆肥过程中三氯生的降解规律，提出促进污泥中三氯生降解的堆肥调控措施。根据好氧堆肥处理后三氯生的降解率及降解产物的生态风险，阐明堆肥处理对污泥土地利用时三氯生环境风险的影响。研究成果为避免污泥土地利用的二次污染、制订科学合理的污泥处理处置技术路线提供依据。

目前对城市污水处理厂污泥堆肥过程中三氯生的降解特点及其土地利用的环境风险尚未有研究。本项目在开展全国范围的城市污泥中三氯生调查基础上，选取了上海市松江污水处理厂的污泥，通过堆肥实验，研究污泥中有机污染物三氯生的降解动态过程。并通过调控堆肥过程中影响污泥降解腐熟的C/N、温度、通风供氧等条件下，研究污泥中三氯生降解率的变化，确定了污泥堆肥过程中能够促进三氯生降解的适宜通风条件，阐明污泥堆肥过程中三氯生的降解规律，提出促进污泥中三氯生降解的堆肥调控措施。根据好氧堆肥处理后三氯生的降解率及降解产物的生态风险，阐明堆肥处理对污泥土地利用时三氯生环境风险的影响。本项目研究了城镇污水处理厂污泥堆肥过程中三氯生的降解特点，发现通过堆肥处理，城市污泥中三氯生从堆肥前期至下堆整个堆肥过程中，含量下降了56.9%，升温阶段TCS下降的量占总下降量的58.2%，后期降解趋于稳定。堆肥处理使污泥中三氯生的含量显著降低。改变堆肥过程中的通风措施，高通风主要在升温阶段和高温阶段提高了三氯生的降解率，三氯生降解率分别为56.9%。高通风组比比低通风组的降解率提高了10.4%。而没有进行堆肥处理的污泥在堆置了和堆肥处理相同的时间后，三氯生的含量几乎没有变化。表明城市污泥通过堆肥处理可以显著降低污泥中三氯生的含量。通过堆肥处理可以显著降低城市污泥土地利用过程中三氯生的环境风险。