不同pH值及碱性物质对短程硝化的影响

为了探究污水生物处理短程硝化过程中最佳pH值范围及适宜的碱性物质,采用序批式活性污泥法(SBR)研究模拟污水不同pH值及碱性物质对短程硝化的影响.结果表明,短程硝化反应的最适pH值为8.0,当pH值低于6.6时,短程硝化反应几乎停止.调节反应器初始pH值为8.0时,添加氢氧化物和碳酸类物质的反应器因pH值下降速度快而先后停止反应.KHCO3的酸碱缓冲能力最强,pH值降低最慢,短程硝化速率最快,平均亚硝积累速率达0.155 g/(g·d)(以可挥发性固体计算).通过添加不同碱性物质维持反应过程恒定pH=8.0时,KHCO3调节的反应器反应速率最快,最适合短程硝化反应.因此,在工程应用中,从可行高效等方面考虑,建议选择用KHCO3调节至pH=8.0促进短程硝化反应的进行.

Influence of pH and Alkaline Substances on Shortcut Nitrification

The effect of pH on shortcut nitrification is not uniform and the effect of different alkaline substances on shortcut nitrification has not been reported so far. The influence of pH and alkaline substances on shortcut nitrification was studied in sequencing batch reactors ( SBR ) fed with artificial wastewater. The test showed that the best pH for shortcut nitrification was 8. 0 and shortcut nitrification almost stopped when the pH was less than 6. 6 . When the initial pH was 8. 0 regulated by adding different alkaline substances, the reactor regulated by hydroxide and Na2 CO3 stopped reacting due to pH reducing. The acid buffer action of KHCO3 was the strongest among them. Therefore, the pH of the reactor regulated by KHCO3 reduced most slowly, thus the rate of shortcut nitrification reaction increased. The average of nitrate accumulation rate was 0. 155 g/( g·d) . When the pH was 8. 0 in the whole process of reactions regulated by adding different alkaline substances appropriately, the KHCO3 was the most suitable substrates. The results indicate that it is necessary to maintain the pH greater than 6. 6 by adding KHCO3 both in the engineering application feasibility and efficiency considered.