污水处理厂再生水回用于农田灌溉的影响与效果

INFLUENCE AND EFFICIENCY OF RECLAIMED WATER FROM WASTEWATER TREATMENT PLANTS(WWTPS)FOR AGRICULTURAL IRRIGATION

我国水资源严重短缺,污水处理厂再生水回用有望缓解用水压力,其中城市绿地和农业灌溉是再生水回用的重要途径。我国作为农业大国,将再生水农业回用有助于确保粮食安全,但由于再生水可能存在微量有毒有害污染物、病原微生物等风险源,应当关注再生水农业回用的安全性。主要讨论了再生水灌溉对土壤物理化学性质、土壤微生物、作物产量、土壤新型污染物含量变化的影响,发现使用再生水灌溉农田时,需要把握灌溉次数和水量,以免产生土壤孔隙率过小、土壤板结等负面影响。再生水灌溉可能会改变土壤pH值和土壤肥力,需要结合再生水水质和土壤类型制定合理的灌溉策略,同时需要特别关注重金属Pb、Cd和Cr的含量变化,进行定期检测和污染评价。再生水灌溉对微生物活性具有促进作用,可提高细菌群落的多样性。适当灌溉再生水可提高作物产量,但是存在灌溉临界点,需要防止灌溉过量对作物产量产生抑制作用。长期灌溉再生水会导致土壤和作物内新型污染物的积累,宜根据其削减特征提出再生水回用于农田灌溉的适用技术和途径。

There is serious shortage of water resources in China,and the reuse of reclaimed water from wastewater treatment plants(WWTPs)is expected to relieve the pressure on water use.Additionally,urban green space and agricultural irrigation are important ways to reuse reclaimed water.As a large agricultural country,the agricultural reuse of reclaimed water in China is helpful to ensure food security,but because of the risk sources such as trace amount of toxic and harmful pollutants,pathogenic microorganisms,more attention should be paid to the safety of agricultural reuse of reclaimed water.In this paper,the effects of irrigation with reclaimed water on soil physical-chemical properties,soil microorganisms,crop yields,and the contents of emerging soil pollutants were discussed,it is necessary to control irrigation frequency and water quantity to avoid negative effects of small soil porosity and soil compaction.Irrigation with reclaimed water may alter soil pH value and soil fertility,and appropriate irrigation strategies should be developed in combination with reclaimed water quality and soil type,with particular attention to the variations of Pb,Cd and Cr,and conduct regular detection and pollution assessment.In addition,irrigation with reclaimed water can promote microbial activity and enrich the diversity of bacterial community.Appropriate irrigation of reclaimed water is conducive to increase crop yield,however,there is a critical point of irrigation and it is necessary to prevent excessive irrigation on crop yield inhibition.Long-term irrigation of reclaimed water will lead to the accumulation of emerging pollutants in soil and crops,therefore,suitable technologies and ways of reusing reclaimed water for farmland irrigation should be put forward according to the reducing characteristics.