Papers by Keyword: Hydraulic Loading

Abstract: For unstable high water ammonia shortcomings of soil infiltration system for rural sewage, one kind of new soil infiltration systems-two-stages soil aquifer treatment (SAT) system with pre-denitrification process was designed. The results show that when the hydraulic loading is within 0.06-0.08 m³/(m²·d), the effluent COD_Cr and NH₄⁺-N concentration reach GB18918-2002 level A standard, the removal rate is 91%-94% for COD_Cr and 95%-98% for NH₄⁺-N. The TN concentration is below 20 mg/L, meeting GB18918-2002 level B standard, and the removal rate is 71%-75%. The TN removal is dramatically affected by reflux ratio.

Abstract: Based on the main factor of hydraulic loading, removal of nitrogen and phosphorus and effluent quality of rural domestic wastewater were studied in subsurface constructed wetlands-ponds system in Jiangxi Province. The results showed that there had good processing results on nitrogen and phosphorusremoval by subsurface constructed wetlands-ponds system,especially on removal of phosphorus.In the combined system removal influence of nitrogen and phosphorus were affected by hydraulic loading,it was influenced more significantly for nitrogen removal and had less influence on removal effect of phosphorus relatively.When the hydraulic loading was 72 m³·m^-2·d^-1, removal rate of TNNH₃-NTP were 75.3%76.08%86.77% respectively,which was very good for the combined system;removal rate of TNNH₃-NTP were 42.67%33.62%61.72% in the subsurface constructed wetlands; removal rate of TNNH₃-NTP were 32.63%42.46%25.05% in the ponds.While hydraulic loading was lower,the subsurface constructed wetlands was the control factor for the combined system.With the increasing of hydraulic loading,the ponds was the control factor gradually. In the combined system, effluent quality of TN was superior to the first class B criteria specified in GB 18918-2002(15mg·L^-1),effluent quality of NH₃-N was superior to the first class B criteria (8mg·L^-1), effluent quality of TP was superior to the case-Vwaters of surface water quality (GB3838-2002) standard (0.4 mg·L^-1) .Research results could be the basis of combined system in Jiangxi Province.

Abstract: At present the majority of studies on constructed wetlands reports are limited to a single wetland and hence the results lack broad representation. In order to study the general effect of treatment of sewage using a horizontal subsurface-flow constructed wetland, a more detailed wetland regression equation needs to be established to guide the design of constructed wetlands. In this study, we used the main pollutant index COD as the indicator and classified 1500 groups of collected data in accordance with the season, hydraulic loading, planting vegetation type and climate type classification in accordance with the "black box model". We analyses different factors affecting pollutant removal by constructed wetlands, using the impact of season and hydraulic loading as the main classification criteria. On this basis, in accordance with the linear regression method, 12 groups of regression equations for COD removal were established. The goodness of fit R² values ranged from 0.65 to 0.95, showing the accuracy had been greatly improved. Using the regression equation in the design process can better estimate the removal effect.

Abstract: Three folds stable surface flow wetlands (FSSFWs) were operated at different hydraulic loadings of 0.80, 0.53 and 0.27m³/ (m²•d) to treat the decentralized domestic sewage. And we investigated the effect of the hydraulic loading rate (HLR) on the removal efficiency of FSSFWs by measuring five indicators of chemical oxygen demand (COD), total nitrogen (TN), ammonium (NH₃-N), total phosphorus (TP) and suspended substance (SS). The research results indicated that the hydraulic loading had great impact on the removal efficiency of FSSFWs, and was looked upon as one crucial factor for FSSFWs design. The removal efficiency of FSSFWs presented a downward trend in various degrees along with the increase of hydraulic loading. Also the hydraulic loading had greater influences on the removal rate of NH3-N and TN than COD, TP and SS. Considering the operation costs, the treatment capacity and the purification effect in this experiment, we could ensure the efficient and stable operation of FSSFWs with HLR at 0.53 m³/ (m²•d) and HRT at 0.4 m³•d^-1, which were the most appropriate options.

Abstract: This paper adopts the indoor artificial rapid infiltration system of simulated soil columns to deal with several water-quality indexes of wastewater from Dongfeng Ditch. The test indicates the change of several indexes, such as COD, ammonia nitrogen, total phosphorus, Cr6+ after the treatment, analyzes the influential factors and display the wastewater treatment effects of the simulation method in laboratory with different soil components and different wet- dry ratios.

Abstract: On the up-flow biological aerated filter to remove COD and NH₃-N were studied the effect and contrast in various stages of finding the optimal operating conditions, so as to achieve energy conservation, the purpose of reducing operating costs. Through experiment studied that the variation of air-water ratio, hydraulic loading, organic concentration in the removal of COD and NH₃-N effects, observe and analyse the change of COD and NH₃-N removal and the characteristics of microorganisms of filter’s different height. The results showed that COD and NH₃-N removal are high under the condition of air-water ratio 4:1~5:1, hydraulic loading 1~2 m³/ (m²●h), organic concentration 300~400 mg/L. The concentration of COD and NH₃-N of effluent which are treated by biological aerated filter can meet with second degree discharging standards.