热碱预处理对剩余污泥发酵产酸效能提升的影响

Improvement of acidification performance of waste activated sludge by thermal alkaline pretreatment

为提高污泥的有机物溶出率,以利于后续生物处理,采用热碱技术对剩余污泥进行预处理,并利用响应曲面法对预处理工艺条件进行优化,在最佳试验条件下处理剩余污泥,进行中温厌氧发酵试验,探讨预处理对发酵过程中污泥水解、挥发性脂肪酸产生量和组成比例的影响.得到的最优预处理条件为:在pH12.0、88.8℃条件下处理73.79 min,能获得理论最大溶胞率48.1%.剩余污泥经热碱处理后能够提高厌氧发酵期间的溶胞率、溶解性蛋白质和溶解性总糖质量浓度,挥发性脂肪酸积累量在发酵第3天达到最大值,最高挥发酸质量浓度(以COD计)为3 269.20 mg/L,是对照组的3.22倍,且热碱预处理对挥发酸组成分布也有一定影响,各种挥发酸积累量顺序为:乙酸>正丁酸>异戊酸>丙酸.

To increase the dissolution ratio of waste activated sludge（WAS）,which contributes to the post bio-treatment,the thermal alkaline pretreatment was applied and the optimization of operational parameters for enhanced acidification performance of WAS by thermal alkaline pretreatment was studied using response surface methodology.Mesophilic anaerobic fermentation experiment of pretreated WAS was conducted.Experimental results showed that temperature,pH and treatment time had significant influence on lysis rate of WAS and the maximum lysis rate of 48.10% was predicted when the operational parameters were temperature 88.83 ℃,pH 12.0 and treatment time 73.79 min,respectively.After thermal alkaline pretreatment,the lysis rate,solute protein and carbohydrate concentrations were all apparently higher than those of untreated sludge（blank test）.The maximum amount of volatile fatty acids（VFAs） was 3 269.20 mg/L in the thermal alkaline pretreated test on day 3,which was 3.22-fold of that in the blank test.VFAs composition analysis revealed that acetic acid was consistently most abundant,followed by n-butyric acid and iso-valeric acid in the pretreated test,while the order was changed to n-butyric acid〉 acetic acid〉 propionic acid in the blank test.