投碱种类和氨吹脱对污泥碱性发酵产酸的影响

采用完全混合式厌氧反应器,比较了NaOH和Ca(OH)2 2种碱试剂对污泥厌氧发酵产酸的作用效果,结合氨吹脱作用考察了NH4+浓度的降低对各有机物水解酸化程度的影响.结果表明在pH值为10的条件下,以NaOH调节的体系中各种有机物尤其是挥发性脂肪酸(VFAs)的量明显高于以Ca(OH)2调节的体系.Ca(OH)2调节的体系中释放出的蛋白质有部分沉淀,磷酸盐含量也较低,小于40mg/L;氨吹脱的体系发酵液中氨氮含量减少了43%,增大了VFAs的积累量;在NaOH和氨吹脱的组合条件下,污泥水解酸化程度最好,SCOD为6732mg/L,蛋白质为2029mg/L,碳水化合物374mg/L,VFAs总量2545mg/L,且氨氮含量低于200mg/L;分析认为氨吹脱作用增大VFAs积累量的原因主要是NH4+浓度的减小,促进了产酸菌对于碳水化合物的发酵.

The effect of alkali types and ammonia stripping on volatile fatty acids accumulation in sludge alkaline fermentation

A series of completely mixed anaerobic reactors were operated to investigate different alkalis (NaOH and Ca (OH)2) performance on sludge disintegration and organics hydrolysis and acidification in sludge alkaline fermentation systems. In addition, ammonia stripping was combined with alkali adjustment to observe the effect of NH4+ concentration on the hydrolysis and acidification effective of released organics. Results showed that at pH10, sludge disintegration as well as organics release, especially, volatile fatty acids (VFAs) was much higher in NaOH systems than that in Ca(OH)2 systems. However, part of soluble protein and PO43- were precipitated with Ca2+ in Ca(OH)2 systems. The PO43- concentration was less than 40mg/L in Ca(OH)2 systems. 43% of NH4+ was removed by ammonia stripping. The maximum hydrolysis and acidification performance was achieved in the NaOH adjustment and ammonia stripping system. The SCOD, protein, carbohydrate as well as total VFAs concentrations were 6732, 2029, 374 and 2545mg/L, respectively, and the NH4+ concentration was as low as 200mg/L. Analysis results also found that ammonia stripping could increase VFAs production by relieving the inhibition of NH4+ on acid-forming bacteria, and enhancing the fermentation of carbohydrate.