Study On Sewage Treatment By Biomass Ash

For a long time, sewage treatment is the weak link of the construction of the rural environment, for the dispersed living environment and low population density, it could not be treated centralized, and restricted the construction of large sewage treatment equipment. Thus, the sewage discharges directly into the farmlands, rivers and lakes nearby without treatment. This makes a threat to the rural ecological environment, and restricts the ecological construction seriously in rural areas. With the speeding construction and rapid development of economic and society, more and more attention is payed to the treatment of sewage. And we start to concentrate to some treatment technology of dispersive sewage. It becomes the core of current rural sewage treatment increasingly.Combined with the characteristics of hilly mountainous terrain and scattered living conditions in rural areas of chongqin. This article discussed the treatment effect of biomass on sewage. We choosed biomass ash as experimental material, used biomass ash with a loose and porous structure and powerful adsorption, to purify the sewage via soil infiltration system. The paper studied the influence of different factors of water hydraulic load, packing density and biomass ash particle size, explored the best operation parameters, and provided theoretical guidance of efficient utilization on biomass ash. The mean conclusions were as following.1. The removal efficiency of Chemical oxygen demand(COD) decreaseed with the increase of hydraulic loading, and showed W1(5cm3/(cm2·d))<W5(7.5cm3/(cm2·d))<W4(10cm3/(cm2·d))<W3(12.5cm3/(cm2·d))<W2(15cm3/(cm2·d) of the five different treatments. The removal efficiency between7.5and12.5cm3/(cm2·d) was the best. The removal efficiency of total nitrogen (TN) decreased at the early stage, and then increased with the hydraulic loading. The effluent concentrations of TN were14.54mg/L,12.65mg/L,6.89mg/L,5.61mg/L and3.46mg/L respectively, the removal rate were46.6%,52.2%,81.0%,84.8%and88.4%, respectively. The effluent concentrations of total phosphorus (TP) were increased gradually with processing. The hydraulic loading had a negative impact on removal efficiency of W4<W3<W5<W2<W1. It showed fine removal efficiency of ammonia nitrogen, the removal rate reached more than98%of each management.2. The removal rate of COD showed reducing at the earlier stage, then rose at last with the increase of packing density. The average removal rate was R2(0.35g/cm3)> R1(0.3g/cm3)> R3(0.4g/cm3). The multiple comparisons found that R3was the worst removal efficiency, and had a significant differences with R1and R2. The TN removal rate of three types of packing density was R2(84.8%)> R3(43.3%)> R1(26.1%). The average effluent TP concentrations were0.406mg/L,0.249mg/L and0.406mg/L, the average removal rate was R2(91.3%)> R1(85.8%)> R3(85.6%). This all showed high removal efficiency and did not exist significant differences by variance analysis. The ammonia nitrogen removal effect was fine at above97%, it had no difference between three managements.3. The COD removal efficiency increased with the increase of particle size. The effluent concentration was29.9mg/L and removal rate was79.2%, it was the best at the scope of0.25mm to0.5mm. During the earlier course, the TN removal rate keep high, and increased with inflow. L6showed the best removal efficiency of all. On the contrary, the TP effluent concentration keep rising during the process. The effluent concentration showed L4(0.1～0.25mm)<L1(0.25～0.5mm)<L3(0.25～0.5mm and below0.1mm)<L2(0.25～0.5mm and0.1-0.25mm)<L5(0.1～0.25mm and below0.1mm)<L6(below0.1mm), it indicated that biomass ash had the worst removal efficiency below the particle size of0.1mm. With the increase of inflow, the effluent concentration of ammonia nitrogen increased below the particle size of0.1mm. But the size of0.25mm to0.5mm reflected an advantage removal efficiency.4. The comprehensive study of hydraulic loading and packing density indicated that, the removal efficiency of COD was better during0.3～0.35g/cm3and7.5～12.5cm3/(cm2·d). It had a better removal efficiency under high packing density of low hydraulic loading than secondary packing density of high hydraulic loading. R2W5had the best treatment effect of all. The removal efficiency of TP was better at low hydraulic loading and secondary packing density. Ammonia nitrogen removal efficiency was good in each management and unlimited with control elements.