| The rapid development of rural economy society and the improvement of farmers’ living standards causing a series of problems in environmental pollution,especially in water pollution.The increasing of domestic sewage and the pollutants and concentration in water,causing serious pollution to the ecological environment in rural areas,threatening the health of the people living in rural areas.Therefore,the increase attention and renovation to the rural domestic sewage are crucial.The rock desertification mountain area has high nude exposure rate,less soil,low water storage capacity,high water leakage,and easy to cause water shortage and drought,heavy rain will lead to serious soil and water loss.Due to serious soil erosion,most of the rocky desertification areas are short of soil,and some areas still lack engineering water.Lingyun,which belongs to the typical rocky desertification area in Northwest of Guangxi,the water resources is limited,therefore the research on agricultural irrigation with domestic sewage is of great significance to agricultural water use in Lingyun county.This research studies the effect of rural domestic sewage treatment process and the effect of sewage irrigation on vegetable quality in Lingyun..The main results are as follows:1.In the detection of the water after the Sewage treatment facilities,the results of pH,chemical oxygen demand(COD),ammonia nitrogen,total nitrogen(N),suspended matter,five day biochemical oxygen demand(BOD5)and total phosphorus(P)etc.are in the standard range of the first grade B standard in the<Discharge Standard of Pollutants for Municipal Waste Water Treatment Plant>(GB18918-2002).The treatment rate of suspended matter in sewage reached 75.81%,the BOD5 reached 86.91%,COD reached 82.52%,total N reached 86.54%,ammonia N reached 91.38%,and total P reached 69.74%.Therefore,the micro power A/O + constructed wetland treatment technology applied in this study has obvious effect on rural domestic sewage in Lingyun.The technology is economical and adaptable,can be applied in rural areas.2.The results of the treatment of soil heavy metals and soil respiration after sewage irrigation showed that the difference of cadmium and lead in the soil irrigated by sewage and water was significant.With the increase of the concentration of irrigation sewage,the content of heavy metals in the soil increased,but the concentration of heavy metals in the sewage was not high,and there was no significant effect on short-term irrigation.The soil respiration was significantly improved by before and after treatment sewage irrigation.The soil respiration of the treated soil after treatment was 46.7%and 69.23%higher than that of untreated sewage irrigation and water irrigation in the soil of coriander,3.6%and 45%in the soil planted with lettuce.Sewage irrigation after treatment has more significant effect on improving soil respiration.3.The results of sewage irrigation on vegetable quality showed that sewage irrigation played a positive role in improving the quality of vegetables.With the increase of sewage concentration,the total sugar and nitrate in vegetables increased.The total sugar content in vegetables increased by 150%and the nitrate content increased by 36.28%after sewage irrigation,and the content of VC and soluble protein in vegetables were higher than the untreated sewage irrigation,which is 10.9%and 11.8%higher in coriander,3.4%and 8.4%in lettuce.Therefore,sewage irrigation improves the quality of vegetables,But there is also a risk of increased nitrate content in vegetables.The water quality of rural domestic sewage treated by microdynamic A/O +artificial wetland has reached the discharge standard and reduces the impact on the ecological environment.At the same time,the treated sewage also contains a small amount of N,P and other nutrient elements needed for the growth of crops,which can improve the quality of vegetables and can solve the problem of water shortage in agricultural irrigation of rocky desertification land. |
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