餐厨废弃物预处理及厌氧处理工程的运行效果及设计优化

Optimization Design and Operation of Kitchen Waste Pretreatment and Anaerobic Digestion Project

江苏省某200 t/d的餐厨废弃物处理工程采用自动分选+加热搅拌+固液分离+除杂除砂+油水分离+CSTR湿式厌氧工艺。餐厨废弃物通过预处理后形成粗油脂、有机浆料、残渣三股物料,粗油脂和预处理后的废弃食用油脂一并制取生物柴油;残渣外运填埋处置;有机浆料进行厌氧发酵,厌氧发酵产生的沼气在厂内净化后部分用作锅炉燃料,部分发电上网。该项目投产后1年多的实际运行表明,运行效果良好;预处理提油效果好、杂质去除率高、有机质损失率低;CSTR湿式厌氧消化运行稳定、固相全量厌氧时产沼率高、出水水质好。但是,提油的波动性对厌氧产沼有一定影响,餐厨废弃物的品质对预处理运行的稳定性影响较大,全物料厌氧时系统稳定性不强,仅液相厌氧时系统稳定性强,但产气量下降较多。

A 200 t/d kitchen waste treatment project in Jiangsu Province adopted ＂automatic sor- ting ＋ heating and stirring ＋ solid-liquid separation ＋ impurity and sand removal ＋ oil-water separa- tion ＋ CSTR wet anaerobic＂ process. After the kitchen waste was pretreated, crude oil, organic slurry and residue emerge. The crude oil was used to make biodiesel together with the pretreated waste edible oil and fat; the pretreated residue was disposed by landfill; the organic slurry was treated by anaerobic fermentation. Biogas produced from anaerobic fermentation was partially used as boiler fuel after purifica- tion in the plant, and the rest part was used as power generation for the internet. The actual operation for more than one year showed that the process performed well： the pretreatment had good oil extraction effect, high impurity removal rate and low loss rate of organic matter; CSTR wet anaerobic digestion process showed stable operation performance, high production rate of biogas, and high quality of effluent water; while, it was found that the fluctuation of oil extraction had a certain impact on biogas production rate and the quality of kitchen waste had a great influence on the stability of the pretreatment. The stabili- ty of the whole material anaerobic system was not strong enough, while liquid phase anaerobic system was much more stable except the gas production decreases more.