A New Concept Of Reversed Capillary Filtration System For Domestic Wastewater Treatment And Its Laboratory Verification

Treatment of domestic wastewater is of importance in bettering environment and easing water shortage problem. A new method was advanced to use capillary phenomenon existing in porous medium to filtrate domestic wastewater. Sand and sandy loam were used as filtration media for the laboratory experimental trials with four specially made prototypes of Reversed Capillary Filtration Reactor (RCFR). The purposes of the experiments were: i). to verify the feasibility of the method, and ii) to quantify the effects of the water potential difference in the media (WPDM) and the relative dimensional ratio of the outer cylinder diameters to that of the inner cylinder, the wastewater tank (ROI) on the performance of the RCFR. Four WPDMs (0.11, 0.26, 0.41, 0.56, 071, 0.86m) and 3 ROIs (14/6, 12/6, 10/6) were used in the experiments. The experimental data showed very good logarithmic relationships of the filtration discharge rates and the removal efficiency with WPDM values. The filtration discharge rates increased with the increase of WPDM. The ROIs had clearly inversed influence on the filtration discharge rate, the higher the ROI, the lower the discharge rate.Percentages of COD, NH/-N, TN and TP removed from the effluent in the filtration process were used as indicators to evaluate the filtration effectiveness of the RCFR. As far as COD and NH4+-N removal efficiency is concerned, sand system had a better removal ability than sandy loam system. However, sandy loam system had a higher TN removal efficiency than sand system. With RCFR, wastewater was under cover of the filtration media, which diminished the emission of bad odor from wastewater to the air environment as well as the swarms of flies. The characteristics of CRFR make itself have a sound application prospects in wastewater reutilization and other fields.