Study On Cellar Water For Quality Maintenance And Purification

The crisis of water resources or inadequate access to water treatment infrastructure is a big problem in some arid areas or remote rural areas of China.It is a great threaten to Residents' health because they can only use and drink water directly storaged in rainwatercollecting cellars,cells or natural water bodies without any treatment.It was clearly reported on the Work of the Government at the Second Session of the 13 th NPC on March 5,2019 that it was necessary to solve the problem of drinking water safety in rural areas,projects would be consctructed to consolidate and promote drinking water quality and improve the security level of water supply.Based on the characteristics of decentralized water supply system and storaged water quality in rural areas,a water purification process of disinfection in place and terminal treatment of ultrafiltration combined with activated carbon adsorption was integrated and a practical device suitable for single household was designed.Performance of ultrafiltration membrane,activated carbon and the disinfectant under different conditions,effects of integrated process and the design of the integrated devices were focused in this study.Among the several kinds of ultrafiltration membranes,the membrane made of PTFE with larger pore size showed a high flux under lower pressure,and it was easier to clean.Ultrafiltration of the several ultrafiltration membranes had a good effect on the removal of turbidity and total numbers of colony with the effluent turbidity below 1 NTU and the total numbers of colony up to 29 CFU/mL.But it didn't perform well in the removal of organic matters and ammonia nitrogen.Activated carbon was used to make up for the lack of ultrafiltration.The static experiment determined that the optimal dosage of activated carbon was 2.0 g/L,and the adsorption equilibrium time was 12 h.The increase of temperature and and decline of pH were beneficial to the adsorption of organic pollutants.Value of the effluent pollutants is about 80% of the influent after 25 hours' operation under the optimal choice of the filtration rate 6.07m/h.Considering the water deterioration during long-term storage,a slow release disinfectant named Trichloroisocyanuricacid(TCCA)was added to the cellar water to study the chlorine decay and the changes of microorganisms in the bulk water.The residual chlorine in the bulk water gradually rised at the initial reaction,reached a maximum value at about 3 h,and then began to decay which was fitted to the first-order reaction kinetics.The decay was henced with the decrease of the added chlorine and the pH,also with the increase of the compounds in water and the temperature.The amount of microorganisms is significantly reduced compared with the raw water after chlorination.It exhibited better disinfection effect with higher dosage of TCCA and reaction temperature but lower pH and less ammonia nitrogen.After adding chlorine of 2.5mg/L at a time,the concentration of free residual chlorine was still above 0.05 mg/L after 30 days,which effectively inhibited the growth of microorganisms in the cellar.The integrated process can effectively maintain the water quality of the artificial catchment such cellar water.Several quality indexes of the effluent from ultrafiltration can meet the hygienic standard of decentralized drinking water and keep stable.The designed integrated device can be adapted to many circumstances and effectively solve the problem of “human drinking safety” in rural areas.It is not only economical and practical,but also easy to operate and manage.So it has a broad application market and prospects.