A Study Of Rainwater Pollutant Load In The Migration And Transformation Of The Cellar Water

On Loess Plateau in northwest China, one of China’s severe water shortage areas,groundwater and surface water resources are very limited, and many villages in remote areasbuild water cellars to solve the problem of drinking water, which cover about three millionpeople in Gansu Province. In order to solve the drinking water problem in these regions, thenational and provincial governments invest a lot of material and financial resources andconsume a lot of manpower, launching the "121Rainwater Harvesting Project"," WaterCellar for Mothers Project" and other rainwater harvesting projects, which basically solvedthis problem for the local people in these areas. However, many cellar water pollutants exceedstandard, and the quality security of cellar water can not be effectively ensured, which greatlyaffect the local residents’ health in northwest arid rural areas. Based on these factors, thisthesis studies the rainwater pollutant load in the migration and transformation of cellar water,offers some cellar water quality evaluation methods based on principal component analysis bygrasping the molecular features of the organic matters in cellar water, and provides scientificevidence for the small water treatment equipment—inexpensive and easy to operate, takingcellar water as resource, and applying to the local residents in the northwest arid rural areas,which was to be developed by the research team in their subsequent work.In the first part of this thesis, we studied the load change of turbidity, ammonia nitrogen,total phosphorus, CODMn, total bacteria, coliform group in the conveyance of cellar water,due to suspended solids, microorganisms and many organic pollutants existing in therainwater in the savings process, and worked out the rules of migration and transformation ofpollutants that ammonia nitrogen, CODMn, nitrite nitrogen, nitrate nitrogen, microorganismsin the conveyance of rainwater will increase in varying degrees, but in the storage process, theabove indicators decrease gradually, with ammonia nitrogen, CODMn, nitrite nitrogen, nitratenitrogen falling within the range of the national drinking water standards, but microorganismexceeded the standard considerably.In the second part we tested turbidity, ammonia nitrogen, total phosphorus, CODMn, totalbacteria, coliform, nitrite nitrogen and nitrate nitrogen in the cellar water after addingsediment into the simulated cellar, and worked out the sediment’s impact on cellar waterquality. We found that CODMn, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, andmicroorganisms increased significantly after adding sediment to the cellar water, while in thesubsequent storage process, the above indicators decreased gradually to the national drinkingwater standard, but microorganism exceeded the standard significantly.In the third part, by measuring the molecular weight of the organic matter in cellar water,we worked out the distribution and variation of organic molecules in cellar water, namely organic matter in rain water and CODMnand UV254mainly consist of organic substances <3kDalton molecular weight and>100k dalton molecular weight in northwest China. In thecourse of the water storage, organic matters are mainly low molecular weight organiccompounds, while CODMnand UV254are in organic substances <3k Dalton molecular weight.In the last part of this thesis, we still used principal component analysis to evaluate thecellar water quality, and found out ammonia nitrogen, CODMn, UV254, total coliform bacteriaare major factors affecting the cellar water quality, and assessment results are consistent withthe actual test results, which proved that the principal component analysis is a suitable andimportant method to evaluate cellar water quality in northwest China.