人工土配比的土柱试验研究

Study of soil column experiment on the composition ratio of artificial soil

为了减小天然土壤的堵塞程度,提高污水上地处理系统对污染物质的去除效率,向天然土壤——耕层土中加入粉煤灰、草炭、冲击砂和煤渣配制成人工土,研究不同质量配比下污染物质的去除率和污水的渗透系数。污染物质去除率、渗透系数的正交试验及最优质量配比试验结果表明,各因素的最优质量分数为粉煤灰8%、草炭10%、冲击砂10%、炉渣12%。在此条件下,污水的出水水质为NH_4^+-N12.92mg/L、TP0.19mg/L、COD_(Cr)53.90mg/L,其中NH_4^+- N和COD_(Cr)达到污水综合排放标准(GB 8978—1996)一级标准的限值,TP达到二级标准的限值;污染物质去除率为NH_4^+-N42.30%、TP 93.20%、COD_(Cr)70.66%,渗透系数为1.41mm/min。以人工土为填料的污水土地处理系统的渗透速率、抗堵塞性能及污水处理能力都得到了有效提高。

Selection of the soil is a key of chamber underground infiltration system. Soil is a combination of soil-plant-microbial ecosystem which contains rich microorganisms and acts as a natural wastewater treatment plant. The combination ecosystem plays an important role in the purification of sewage through physical interception, chemical precipitation, adsorption, redox, complexation and ion exchange. Natural soil easily causes the clogging for wastewater treatment and affects the operating costs as well as the service life of system. Therefore, the land treatment technology of wastewater using artificial com- bination ecosystem has been proposed. In this study, an artificial combination ecosystem consisting of fly ash, slag, impact sand, peat and natural soil was created and applied in the experiment of sewage treatment. The effect of different combination of mass ratio on the removal efficiency of pollutants and permeability coefficient of wastewater was studied. This new artificial soil can reduce the clogging of natural soil and increase the removal efficiency of the pollutants. By integrating the orthogonal experimental results of pollutant removal rate, permeability coefficient and the optimization test of weight ratio, the best weight ratio of various factors is obtained as follows： fly ash is 8% , peat is 10% , impact sand is 10% and slag is 12%. Under this condition, the effluent qualities are as follows： NH4＋ - N is 12.92 mg/L, TP is 0.19 mg/L, CODcr is 53.90 mg/L where the NH4＋ - N and CODcr are able to meet the primary standard limit of integrated wastewater discharge standard （ GB 8978--1996 ） and TP is able to meet the secondary standard limit. The removal efficiencies of pollutants are as follows： NH4＋ - N is 42.30% , TP is 93.20% , CODcr is 70.66%. Finally, the obtained permeability coefficient is 1.41 mm/min. The sewage land treatment system be filled with artificial soil, permeation rate, anti-blocking performance of soil and ca- pacity treatment of system have been effectively improved.