工艺参数对蚯蚓生态滤池净化养殖污水的影响

[目的]探讨蚯蚓添加量、布料强度和布料方式等工艺参数对蚯蚓生物滤池净化养殖污水的影响特征,确定滤池规模化处理畜禽养殖污水的最佳条件,为养殖污水处理提供技术支撑.[方法]采用蚯蚓生态滤池技术净化养殖污水,测定水样中的总氮(TN)、氨氮(NH4+-N)、硝氮(NO3--N)、总磷(TP)、磷酸盐(PO43-)、化学需氧量(COD)、pH和电导率(EC)等指标.[结果]在相同蚯蚓添加量和滤料总量下,单层生态滤池去除养殖污水中TN、NH4+-N、NO3--N和COD的效果优于双层,但去除PO43-的效果劣于双层;布料强度为2.25~4.50 m3/m2·d时,最有利于养殖污水中NH4+-N、TN、TP和COD的去除,但对NO3--N含量、pH和EC变化无明显影响;蚯蚓添加量为0.5 kg/箱的处理对进水TN、NO3--N、NH4+-N、TP、PO43-和COD的平均去除率明显小于投入量1.0~2.0 kg/箱的处理,但蚯蚓添加量过大会导致出水EC增加.[结论]蚯蚓生态滤池能够持续高效并相对稳定地去除养殖污水中氮、磷和碳等污染物质.综合成本和效率因素,蚯蚓生态滤池净化养殖污水工艺建议采用单层布料,布料强度4.50 m3/m2·d,蚯蚓添加量1.0 kg/箱.

Effects of technical parameters on purification of breeding wastewater by earthworm ecofilter

[Objective]This paper studied effects of technical parameters such as earthworm adding amount, filter ma-terial adding intensity and filter material adding mode on purification of breeding wastewater by earthworm biofilter, deter-mined the optimal condition for scale purification of breeding wastewater by earthworm biofilter, so as to provide technical support for breeding wastewater purification. [Method]Earthworm ecofilter technology was used to purificate breeding wastewater. Total nitrogen(TN), ammonia nitrogen(NH4+-N), nitrate nitrogen(NO3--N), total phosphorus(TP), phosphate (PO43-), chemical oxygen demand(COD), pH value and electrical conductivity(EC) in water were measured. [Result]Under the same amount of earthworms and filter material, removal effects of single layer earthworm ecofilter on TN、NH4+-N、NO3--N and COD was better than those of double layer earthworm ecofilter; but the removal effects of double layer earthworm ecofilter on PO43- was better. When the material adding intensity was 2.25-4.50 m3/m2·d, the removal effects on NH4+-N,TN,TP and COD in earthworm ecofilter was the best, but there was no obvious influence on NO3--N content, pH value and EC value. When earthworm adding amount was 0.5 kg/box, the average removal rates of TN,NO3--N,NH4+-N,TP, PO43- and COD for inlet water were lower than those in treatment with 1.0-2.0 kg/box earthworm. Excess addition of earth-worm could lead to increase of EC value in outlet water. [Conclusion]Earthworm ecofilter can continue to remove nitrogen, phosphorus, carbon and other pollutants efficiently and steadily in breeding wastewater. Considering comprehensive cost and efficiency, the suggested technical parameters are as follows:sigle layer material addition with intensity of 4.50 m3/m2·d, and earthworm addition is 1.0 kg/box.