Treatment Of Pentavalent Arsenic In Surface Water By Subsurface Infiltration System

In recent years, surface water and groundwater have been polluted by arsenic because of many artificial reasons, so treatments of arsenic pollution become the urgent environmental problems. Currently processing methods for arsenic in water are including precipitation, flocculation, filtration, adsorption, oxidation, membrane separation and biological methods which in recent years are the fastest growing arsenic wastewater treatment. Subsurface infiltration system is an artificially intensified sewage ecological treatment, and its advantages are low operating cost and convenient. Therefore, the subject will take the improved subsurface infiltration system as the new removing arsenic device, in order to examine removal efficiency of the new processing device for arsenic and explore new ways for the biological treatment of arsenic.In the paper, quartz sand and bioceramic reactor were used as reaction district of subsurface infiltration system and the pollution load, hydraulic loading and dry/wet ratio were adjusted to inspect the removal efficiency of the systems for pollutant removal in different working conditions. And adsorption role of three fillers of the soil, quartz sand and bio ceramic reactor on As(V), ammonia nitrogen and phosphorus were investigated.When initial concentration of As(V) was 0.1 mg/L, the adsorption quantity of three fillers on As(V) were minor witch was between 0.5-2.5μg/g and adsorption rate of three kinds of fillers on As(V) were all fast to reach saturated in a very short period of time. These two points were indicated in the absorption experiments.The System l's best hydraulic loading was 20cm/d which was much higher than traditional subsurface infiltration system in the dry/wet ratio 1:1. The test showed that the effect of Set 1 was significantly improved on removal of As(V) and the As(V) concentration of the effluent water was below the Environmental quality standards for surface water of Level I in the hydraulic loading of 20cm/d. Relatively speaking, the removal rate of Set 2 is all lower than Set 1's in three hydraulic loads and the best hydraulic loading is at least higher than 20cm/d. The As(V) concentrations of the effluent water in Set 2 were below the Environmental quality standards for surface water of Level I in three hydraulic loadings. It was showed that the performance of Set 2 was comparatively steady. Compared with dry/wet ratio 1:1, the working law of Set 1 and Set 2 on dry/wet 1:2 and 1:3 was similar, the removal rate of As(V) was just a little rise. On the actual operation cost, practical use of space of wet/dry 1:2 and 1:3 is not large.To sum up, in this experiment condition, the effect of the improved subsurface infiltration system was good on low concentration of As(V) (0.05-0.5 mg/L) and it has a good application prospect for As(V) removing.