铁基污泥水热炭强化印染废水生物脱氮除碳的效能与机制

The wastewater pollution loading from dyeing and finishing process accounts for approximately 80% in textile industry. It is a great challenge how to efficiently remove refractory dyestuff and nitrogen from wastewater up to date. Meanwhile, waste sludge produced from wastewater treatment is also difficult to dispose and utilize as resource. To solve this problem, a novel way was presented as reusing sludge to enhance wastewater treatment, meaning that refractory organics and nitrogen removal in printing and dyeing wastewater can be facilitated by hydrochar derived from ferric sludge and biosolid. However, it is not well-known to form hydrochar favorable for refractory organics and nitrogen removal by co-hydrothermal carbonization of ferric sludge and biosolid, especially mechanism on impoving these pollutants removal efficiency by hydrochar. Moreover, nitrogen removal depends on whether hydrochar derived from ferric sludge and biosolid can convert refractory organics to bioavailable carbon source due to its catalysis, and incomplete carbonization products from hydrochar can also slowly release into water and act as bioavailable carbon source. It is necessary to make this mechanism clear for removing nitrogen from wastewater. Notably, hydrolysate rich in nitrogen, phosphorus and organics can be produced during hydrothermal process. The impact of recycling hydrolysate as nutrients on aerobic process should be investigated in detail. Consequently, it will be demonstrated in this study about structure-function relationship between hydrochar and its promotion on removing refractory organics and nitrogen. Base on hydrothermal conditions, hydrochar structure, functional reinforcement and internal mechanism, the reason why hydrochar can enhance refractory organics and nitrogen removal will be found, which can support simultaneous governing wastewater and sludge for sustainability of low-profit printing and dyeing industry.

印染废水及污染物排放量占纺织工业80%左右，是废水及污染物的主要来源。印染废水治理不仅存在难降解染料、助剂、总氮的高效去除问题，还面临印染污泥难于处理处置及资源化的问题。基于“来自于废水处理，用之于废水处理”的理念，提出将混凝含铁污泥及生物污泥共水热碳化制备铁基污泥水热炭，并循环于好氧生化以强化废水脱氮除碳的资源化思路。结合前期研究，拟开展含铁污泥与生物污泥共水热条件下铁基污泥水热炭形成过程及机制、对印染废水生物处理脱氮除碳强化效能及作用机制、对印染废水有效碳源转化及原位缓释碳源强化机制、水热过程中物质组分特性变化规律及转化机制、铁基污泥水热炭与印染废水生物处理脱氮除碳功能强化的构效关系系列研究。本项目旨在从水热条件—产物结构—功能强化—内在机理四个层面，发现铁基污泥水热炭强化印染废水生物脱氮除碳内在规律，为实现适用于低利润率的印染行业“泥水共治”的思路提供理论基石。

纺织工业是废水及污染物排放量最大的工业行业之一，位居全国工业行业第3~4位，其中印染废水及污染物的排放量占全行业的80%左右，是废水及污染物的主要来源。当前，新型染料、助剂的使用及废水排放标准日渐提升，使废水中有机物去除难度日益增大；同时，印花过程中尿素的使用，导致废水中总氮浓度增高，脱氮亦成为近年印染废水治理难点。印染废水处理过程中还伴随大量的污泥产生，目前面临填埋无地可施、焚烧能耗及二次污染大的问题；限于印染污泥含有难降解染料、助剂，厌氧产甲烷资源化难以获得较高效率，从而无法在纺织印染行业推广应用。废水治理中的脱氮除碳、污泥处理处置及资源化问题直接制约着利润率较低的印染行业的可持续发展。. 为破解这一难题，本项目基于“取之于废水处理，用之于废水处理”的理念，提出污泥内循环减量并同时强化废水处理效果的“泥水共治、以泥治水”创新思路。开展了混凝污泥与剩余污泥共水热碳化减量及制备铁基污泥水热炭的研究，并探究了铁基污泥水热炭资源化循环至生物处理强化印染废水生物脱氮、除碳及重金属去除效果，并深入研究了其强化脱氮的电子介导作用及重金属去除机制，建立了铁基污泥水热炭强化印染废水脱氮及苯胺、Cr(VI)和Sb(III)的去除构效关系。发表SCI论文13篇，核心期刊论文5篇。获授权发明专利11项。获中国环境保护产业协会环境技术进步一等奖、《工业水处理》优秀论文一等奖各1项。在国内国际重要学术会议受邀作报告8次。培养硕士研究生5名，博士研究生3名。. 项目成果已应用于印染综合废水集中处理厂及提标改造示范工程；主持制定新疆《印染废水排放标准》、《印染废水治理工程技术规范》、《棉浆粕和粘胶纤维行业水污染物排放标准》及《棉浆粕和粘胶纤维工业废水治理工程技术规范》4项地方生态环保标准。成果可为纺织印染行业“碳达峰、碳中和”目标的实现提供废水及污泥低碳治理技术支撑。