| At present,there are still some problems in the treatment of rural domestic sewage in China.Classified treatment is not accessible to the gray water and black water produced in life in most rural areas,leading to poor effect of sewage treatment and low efficiency of sewage utilization.Even if there is classified treatment,it’s hard to maintain due to high treatment cost and poor matching.Achieving classified treatment of sewage in rural areas can not only effectively improve the living environment of rural residents,but also form a classified treatment system in accordance with the characteristics of rural areas.In this paper,we got the data of rural domestic water consumption,sewage production and sewage quality through the investigation into some typical rural areas.On the basis of previous studies,two kinds of aquatic plants,water hyacinth and calamus,which are better at removing sewage,were proposed as the research objects,and the research focuses on the relationship between the effect and time of removing major pollutants COD,NH4+-N,TN,TP in gray water and black water.On this basis,a prediction and management system of aquatic plants was designed and developed with the help of computer programming language.Through the investigation and experimental research in this paper,the following conclusions are drawn:1.According to the typical survey of Touzha Village,the total water consumption per capita is 55-73 L/d,of which the water consumption for toilets,clothes and washing vegetables and pans is the largest,accounting for 72.33%of the total water consumption.The sewage production per capita is 42.4 L/d,of which the per capita production of gray water and black water are 27.62 L/d and 14.78 L/d,respectively.The generated grey water is directly sprinkled on the ground to make it evaporate and percolate,which causes potential pollution to the environment.The removal rates of COD,NH4+-N and TN in black water in rural three-cell septic tanks,which is low,are mostly below 30%,in addition,black water can not be treated in a timely and effective manner.2.Aquatic plants can not only grow normally,but also do well to remove the main pollutants in sewage after using water hyacinth and calamus to purify the gray water and black water generated in the survey area.Water hyacinth is better to remove COD and TP,and the removal rates in gray water and black water are 74.3%,77.8%and 71.7%,64.2%,respectively.Acorus calamus does better to remove NH4+-N and TN,with the removal rates of 78.9%and 62.9%in grey water and 55.8%and 53%in black water,respectively.3.The effect of removing main pollutants in gray water and black water by aquatic plants is related to time,showing the changing law of straight line or curve.Combined with mathematical means to deduce and fitting,the equation of relationship between the rate of removing main pollutants in gray water and black water by a certain plant and time can be obtained,and with this relationship we can get the rate of removing main pollutants by aquatic plants in a specific time.4.According to the equation of relationship between rate of removing pollutants and time,a prediction and management system of removing pollutants by aquatic plants is developed by applying Python language,which can quickly tell us how much aquatic plants do we need and predict the removal efficiency according to actual quality of sewage.This study aims to provide theoretical basis and practical value for the use of aquatic plants to remove the main pollutants in gray water and black water in the study area. |
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