餐厨垃圾水解液与传统碳源的脱氮效果比较

Comparison of Denitrification Efficiency between Kitchen Waste Hydrolysate and Conventional External Carbon Source

采用自配餐厨垃圾在pH值为6、温度为35℃、TS为100 g/L的条件下进行厌氧消化,并利用其水解产生的酸化液作为外加碳源进行反硝化脱氮试验,考察了水解酸化液、甲醇、乙酸钠等三种碳源在相同COD/NO-3-N值下的脱氮效果。在COD/NO-3-N值约为5、NO-3-N初始浓度约为35 mg/L及常温条件下,甲醇、乙酸钠和水解酸化液的反硝化速率分别为7.4、13.8及16.3 mgNO-3-N/(gVSS·h)。水解酸化液作外加碳源的反硝化过程经历了两个不同NO-3-N去除速率的反应阶段,且反应过程中存在NO-2-N积累。利用基于Monod方程的动态模型对反硝化过程进行模拟,并与零级反应的反硝化速率进行比较。结果表明,以甲醇、乙酸钠、水解酸化液作碳源的反硝化速率分别为8.50、14.14、18.67 mgNO-3-N/(gVSS·h),其对甲醇和乙酸钠的模拟效果较好,而水解酸化液中由于存在多种物质同时进行反应,故模拟结果与试验结果的拟合度不高。

Anaerobic digestion of the self-prepared kitchen waste was carried out under the condi- tions of pH of 6, 35 ℃ and TS of 100 g/L, and the hydrolysate produced from the kitchen waste was used as external carbon source for wastewater denitr[fication. The denitrifieation effects with methanol, sodium acetate and kitchen waste hydrolysate as carbon sources were investigated under the same COD/ NO-3 - N ratio. The denitrification rates of methanol, sodium acetate and kitchen waste hydrolysate were 7.4, 13.8 and 16.3 mgNO-3 -N/（ gVSS · h） respectively under the conditions of the COD/N0-3 -N ratio of about 5, the initial nitrate concentration of about 35 mg/L and the normal temperature. In the denitrification process with kitchen waste hydrolysate as carbon source, the removal of nitrate went through 2 stages with different removal rates. Nitrite accumulation appeared during the denitrification process. Monod model was applied in the denitrification process, and in comparison with zero-grade reac- tion, the denitrification rates with Monod model for methanol, sodium acetate and kitchen waste hydroly-sate as carbon source were 8.50, 14.14 and 18.67 mgN0-3 -N/（gVSS · h） respectively. Monod model applied in methanol and sodium acetate showed good fit of the linear relation. However, the simulation effect was not so good for kitchen waste hydrolysate due to the simultaneous reaction of different sub stances existing in it.