基于物质流分析餐厨垃圾厌氧消化工艺的问题与对策

Problems of Anaerobic Digestion Process to Deal with Food Waste and its Countermeasures through Material Flow Analysis

采用物质流分析方法,评估了我国现有餐饮垃圾和厨余垃圾厌氧消化的9种典型工艺模式,估算了气、液、固三相产物和残余物产生量,计算了物料在预处理、厌氧消化、固液分离、污水处理等主要技术单元的物流分配,分析了这些工艺模式的特点和局限性。物质流分析结果表明,厌氧消化和沼液处理成为调控物流分配的核心单元;改善干式厌氧消化技术和高稳定沼液资源利用技术的整合水平,是化解废物流通量随处理流程持续增加的关键;而干式厌氧消化技术的应用受到沼渣和沼液处理脱水污泥的消纳出路限制;预处理和液体回流等单元环节均有优化空间。因此,应从城市固体废物全系统管理(包括与污水处理的衔接)的角度,综合应用物质流分析等决策工具,认识餐厨垃圾处理厂在环境管理和生态保护中的作用。

We used the tool of material flow analysis （MFA） to estimate the generation of gas, liquid and solid materials from nine types of typical anaerobic digestion processes for food waste from restaurants or kitchens. The mass flows along pre- treatment, anaerobic digestion, solid-liquid separation, and wastewater treatment were calculated. The characteristics and the limitations of these processes were then critically reviewed. Results demonstrated that anaerobic digestion and the treatment of liquid digestate were the two core units regulating the mass flow. In order to prevent the expansion of waste flow along process, it was important to develop the technology of dry anaerobic digestion and the technology for the beneficial utilization of liquid digestate. Furthermore, the sustainable development of dry anaerobic digestion depended on appropriate utilization of solid di- gestate and dewatered wastewater sludge from the treatment of liquid digestate. Meanwhile, the units of pretreatment and liquid recirculation can be further optimized. Therefore, from the viewpoint of an integrated management of municipal solid waste which is also associated with the treatment of municipal wastewater, we should made an integrated application on decision tools such as MFA and realized the function of food waste treatment plant in the context of environmental management and ecological protection.