高氨氮难降解渗滤液电解氧化处理的特性

Study on Characteristics of Refractory Leachate with High NH_3—N Concentration by Electrolytic Oxidation

在实验得到的优化电解氧化工况下,对不同初始氨氮质量浓度的渗滤液进行处理,并分析了电解过程中渗滤液循环回灌出水的可生化性变化.另外,还从出水溶解性有机物分子量分布变化和腐殖酸、富里酸和亲水性部分的变化两方面,来讨论电解氧化对渗滤液循环回灌出水中有机物的去除特性.研究表明:进水氨氮质量浓度越低,氨氮的去除速率越慢,电解中氨氮先于化学需氧量被完全去除;电解后渗滤液中溶解性有机物的分子量分布向小分子量方向转变,使得电解出水中分子量在10×103u以上的有机物占总量比例由18.4%降到6.7%,分子量在1×103u以下的有机物占总量比例由30.5%增至56.3%;电解后腐殖酸部分基本上都被降解,而电解对富里酸和亲水性部分的去除率相对较低;电解90 min时,出水腐殖酸、富里酸和亲水性部分的比紫外吸收值较电解前减少了75%左右,难降解物质含量大幅度下降,使得出水ρBOD5/ρCOD由0.06上升到0.27.

The leachates with different ammonia concentrations were electrolyzed under the optimal conditions and the biodegradability in the whole process was analyzed. The removal characteristics of the recirculated leachate were studied based on the changes of the molecular weight distribution and the humic acid, fulvic acid and hydrophilic fractions of dissolved organic matter from the recirculated leachate through electrolytic oxidation. The results show that the removal rate of ammonia is lower for leachates with lower ammonia concentration; The molecular weight distribution of recirculated leachate is changed toward the low molecular weight through electrolysis： The content of organic matter with molecular weight 〉 10 × 10^3 is reduced from 18.4 % to 6.7% and the content d organic matter with molecular weight 〈 1 × 10^3 increases from 30.5% to 56.3% after electrolysis; Almost all humic add is degraded while the removal ratio of fulvic add and hydrophilic fractions is relatively lower; The specific ultraviolet absorption at 254 nm of humic add, fulvic add and hydrophilic fractions decreases by 75 % or so and the ratio of ρBOD2/ρCOD increases from 0.06 to 0.27 through 90 minutes of electrolytic oxidation.