酸碱联合调节剩余污泥过程中氮、磷和有机质的释放

实现城市污泥的减量化和资源化是污水厂面临的难题之一。通过采用(1)先酸性(pH=3)后碱性(pH=10)、(2)先碱性(pH=10)后酸性(pH=3)的两段控制方式(每段反应8 d),同时做pH不调的对比实验,研究剩余污泥水解酸化过程中氨氮、磷酸盐和溶解性COD(SCOD)、碳水化合物、蛋白质和挥发性脂肪酸(VFAs)等有机质组分的释放。结果表明,酸碱联合调节有利于各组分的释放;氮和磷在酸性条件下的释放量大于碱性,有机质在碱性条件下的释放量大于酸性;采用(2)方式,调为酸性后反应1 d,氨氮的释放量即达到最大(17.28 mg/g TS);采用(1)的调节方式反应7 d,磷酸盐能达到最佳释放量(14.16 mg/g TS);总VFAs的产生受反应时间的影响较大,其余有机质组分在(2)的调节方式下,6 d左右即可达到较大释放量。

Release of ammonia, phosphate and organic matter during process of co-controlling excess sludge with acid and alkaline

Municipal sludge reduction and reutilization is one of the problems in WWTPs. Two kinds of co-control methods were taken to study the release of such soluble items as ammonia, phosphate, chemical oxygen demand, carbonhydrate, protein, and volatile fatty acids during the hydrolysis and acidification of excess sludge. One was acid-alkali, acidity control (pH=3) for 8 days and then alkalinity (pH=10) for 8 days, the other was alkali-acid, alkalinity control (pH=10) for 8 days and then acidity (pH=3) for 8 days, meanwhile with pH uncontrolled as contrast. The results show that more release amounts of all matters mentioned above are achieved with the co-control methods than those with the contrast. Besides, compared with alkaline condition, the release amounts of ammonia and phosphate are greater under acidic condition, but those of the organic matters are greater under alkaline condition. Ammonia arrives at the maximum release amount of 17.28 mg/g TS through 1 day after acidity is converted to with the alkali-acid method. And, the optimal release amount of phosphate, 14.16 mg/g TS, is attained after 7 days with the acid-alkali method. The release amounts of those organic matters, except volatile fatty acids, get to the top through 6 days or so. The production of total volatile fatty acids is seriously influenced by reaction time.