城市餐厨垃圾前处理的工艺优化

Improvement of municipal food waste pre-treatment process

为提高餐厨垃圾资源化,利用自动化分选设备组合处理餐厨垃圾,考察餐厨垃圾快速减量化和资源化的可行性,对自动化分选前后餐厨垃圾成分进行分析,发现分选前其总量为243.05 t·d^(-1),TS为12.69%,VS为93.26%,分选后总量为242.00 t·d^(-1),TS为10.97%,VS为91.93%,其有机物含量稳定,利于厌氧发酵处理的工艺控制;对分选后餐厨垃圾进行厌氧发酵处理,考察其pH和NH_4^+-N变化,发现反应初期pH值出现弱酸性,NH_4^+-N浓度较低;随着反应进行,pH稳定在7.6~7.8,NH_4^+-N浓度约为1 200 mg·L^(-1)左右。最后对厌氧发酵产气量进行考察发现,反应前期受到pH、NH_4^+-N以及温度等反应条件影响,产气量和甲烷含量较低;随着实验趋于稳定,产气量为22 000 m3·d^(-1)左右,甲烷含量范围在65%~72%。结果表明,使用新型餐厨垃圾预处理设备,其分选效率较高,能提高后续厌氧发酵产气量和甲烷含量,较大程度实现餐厨垃圾资源化。

The aim of study is to make food waste reduced and reuse and recycle by compensating for the shortage of traditional pretreatment,improving process efficiency and food waste treatment industrialization.The feasibility of food waste treatment reduction and resourcezation is tested by pilot scale.First,The analysis on the food waste content before and after treatment finds out that total quantity becomes 242.00 t·d^-1 from 243.05 t·d^-1,TS 10.97% from 12.69%,VS 91.93% from 93.26%; second the review on the change of pH and NH_4~＋-N in the process of anaerobic digestion turns out that pH becomes stable on 7.6 to 7.8 from weakly acidic,NH_4~＋-N becomes 1 200 mg·L^-1 from low concentration.Third,the evaluation on gas quantity generated by anaerobic digestion comes out that the gas quantity and methane content becomes stable on 22 000 m3·d^-1,methane 65%to 72% from less quantity and low concentration.The result of experiment demonstrates that the segregation efficiency is higher and the quantity of generated gas is much more than before,the methane content is increased by using new type food waste pre-treatment equipments.