氢氧化镁对剩余污泥碱性发酵及脱水性能的影响

剩余污泥厌氧发酵可产出短链脂肪酸(SCFAs)发酵液用作碳源时,可改善污水脱氮除磷效果,但发酵液中的氮磷会增加污水厂的氮磷负荷.此研究分别采用Mg(OH)2和NaOH调节剩余污泥厌氧发酵时的pH值,考察Mg(OH)2能否促进剩余污泥碱性发酵同时去除发酵液中的氨氮和磷,及其对发酵后污泥脱水性能的影响.结果表明:Mg(OH)2可促进剩余污泥碱性发酵,发酵液最大SCFAs含量为2336.3mgCOD/L,同时Mg(OH)2能去除发酵液中的磷,在发酵的第4d,其磷含量接近0;Mg(OH)2调节碱性发酵后的剩余污泥脱水性能优于NaOH调节的,前者剩余污泥毛细吸水时间(CST)较后者短42.3s.

Fermentation and dewaterability of waste activated sludge under alkaline conditions: Effect of Mg(OH)2

Waste activated sludge anaerobic fermentation can produce short chain fatty acids (SCFAs), which can improve nitrogen and phosphate removal efficiency after being used as carbon source. However, the nitrogen and phosphorus in the fermentation liquor can place extra burden on waste water treatment plant. This study used Mg (OH)2 to control the pH of fermentation, by contrast NaOH was also used. Then we tested if the Mg (OH)2 could realize waste activated sludge fermentation and remove the NH4+-N and PO43--P from fermentation liquor at the same time, moreover, the dewaterability of fermented sludge was also investigated. The results showed that Mg (OH)2 could promote waste activated sludge fermentation with 2336.3mgCOD/L SCFAs in fermentation liquor. Also Mg (OH)2 could remove the PO43--P from fermentation liquor ,which reached to nearly zero on fourth day. At last, the dewaterability of waste activated sludge after being fermented in Mg (OH)2 group was better than that in NaOH group. The former waste activated sludge capillary suction time (CST) was shorter of 42.3s than the latter.