Microorganisms in AAO-biofilter after denitrification enhanced by composite carbon source

To reuse the agricultural wastes and develop the economic solid carbon source enhancing the nitrogen removal of domestic wastewater with low C/N ratio, the polyvinyl alcohol-sodium alginate (PVA-SA) is used as a carrier and combined with agricultural waste corncob powder to prepare a new composite carbon source in this study. The new composite carbon source filler should have the stronger mechanical strength compared to agricultural waste, and not be easily broken or microbial clogged when applied in the anoxic tanks of AAO process or in the denitrification filter. It has the characteristics of low cost, non-toxic and harmless, and easy dosage control.The new composite carbon source fillers are added into the anoxic tank of the traditional AAO lab-scale reactor and packed in the lab-scale denitrification biofilter to evaluate the enhanced nitrogen removal efficiency for treatment of the low C/N domestic wastewater. The result of the experiment is: the removal of nitrogen in domestic sewage was successfully strengthened, and the TN was reduced to below 2mg/L, provided that the effluent COD did not exceed 35mg/L. In order to clarify the effect of the addition of composite carbon sources on the microorganisms in AAO and denitrification filters, four different microbial samples were taken before and after the addition of composite carbon sources, namely: AAO anoxic tank activated sludge without carbon source filler : Q1, activated sludge of AAO anoxic tank after adding carbon source filler: Q2, biofilm attached to AAO carbon source filler: T, sludge in biofilter: L.

为实现农业废弃物资源化利用，并开发经济高效的固体碳源以强化低C/N比生活污水的脱氮效果，本研究以聚乙烯醇-海藻酸钠（polyvinyl alcohol-sodium alginate，PVA-SA）为载体，复配农业废弃物玉米芯粉制备新型复合碳源。相较于单一农业废弃物基填料，该新型复合碳源填料具备更优异的机械强度，应用于AAO工艺缺氧池或反硝化滤池时不易破碎、不易发生微生物堵塞。其具有成本低廉、无毒无害、投加量易于调控的特点。
将该新型复合碳源填料投加至传统AAO实验室规模反应器的缺氧池，并装填于实验室规模反硝化生物滤池中，以评估其对低C/N比生活污水的强化脱氮效能。实验结果显示，生活污水的脱氮效果得以有效强化，在出水化学需氧量（Chemical Oxygen Demand，COD）不超过35mg/L的条件下，总氮（Total Nitrogen，TN）可降至2mg/L以下。
为明确复合碳源投加对AAO系统及反硝化滤池中微生物的影响，本研究在复合碳源投加前后共采集4组微生物样本，分别为：未投加碳源填料的AAO缺氧池活性污泥（Q1）、投加碳源填料后的AAO缺氧池活性污泥（Q2）、附着于AAO碳源填料表面的生物膜（T）以及生物滤池内污泥（L）。