Study On Water Quality Characteristics And Reuse Safety Of Reclaimed Water From Different Sources

As an unconventional water resource,reclaimed water plays an important role in alleviating the pressure of water supply.With the shortage of water resources and the serious environmental pollution,separated treatment models with the advantages of low energy consumption,low pollutant discharge and high degree of resource utilization have be emerged.Therefore,source of reclaimed water has become more diverse,including the tertiary effluent of municipal sewage treatment plant,black water and grey water effluent of small-scale separated treatment system,etc.At present,reclaimed water focuses on the optimization of its treatment technology and the research of treatment effect of micro-pollutants,while there are few reports on the micro-differences and the key pollution factors of reclaimed water from different sources.Reclaimed black water,reclaimed grey water and reclaimed synthetic wastewater were selected as the research object in this paper in order to make up for these deficiencies,find out the differences of reclaimed water from different sources and identify the characteristic pollutants in reclaimed water.From the point of view of inorganic component content,DOM characteristics and biological toxicity characteristics,microcosmic difference of reclaimed water from three different sources were analyzed,key pollution factors of different reclaimed water were identified,and corresponding suggestions were proposed.The results of this study can provide theoretical support for improving the treatment effect and ensuring the safety of reclaimed water.The results showed that:?A?The results of the standard index method showed that the quality of reclaimed grey water was the best.The comprehensive standard index of reclaimed grey water was the lowest in all kinds of reuse modes.From the view of the content of inorganic components in water,chloride ion and manganese were the key limiting factors to limit the reuse modes in three kinds of reclaimed waters from different sources.The Larson index of three kinds of reclaimed waters from different sources were greater than 1,which indicated that the three kinds of reclaimed waters were very corrosive to iron pipelines.At the same time,Larson index of three kinds of reclaimed waters from different sources followed the following rule:reclaimed synthetic wastewater>reclaimed black water>reclaimed grey water.?B?Through the analysis of dissolved organic matter content and characteristics in three kinds of reclaimed waters,it was found that the order of DOC content was:reclaimed synthetic wastewater>reclaimed black water>reclaimed grey water.The order of the values of UV₂₅₄54 and SUVA were:reclaimed black water>reclaimed synthesis wastewater>reclaimed grey water.It showed that the reclaimed black water contained more unsaturated organic matter,and the potential of trihalomethane formation potential?THMFP?was the largest in chlorine disinfection process,while the THMFP of reclaimed grey water was lowest.The molecular weight of organic matter in the three kinds of reclaimed waters were mainly concentrated in MW<10k Da,and the proportion of small molecular organic matter?MW<1k Da?in the reclaimed grey water was the highest,which was77.05%.It was easy to cause secondary polluted by biological utilization.There were obvious characteristic peaks of humic acid in the three kinds of reclaimed waters,and humic acid was one of the main pollution factors in three reclaimed waters.And the reclaimed black water contained more humus,accounting for 87.51%of the total amount.?C?Through the analysis of the biotoxicity of three kinds of reclaimed waters,there were found that the acute toxicity of reclaimed synthesis wastewater was the highest,with the inhibition rate of luminescence as high as 90%.The residual chlorine in the water was the main reason to significantly enhance the acute toxicity of the reclaimed water.The acute toxicity of the reclaimed black water and reclaimed grey water was very low,with little inhibition on luminescent bacteria.The degree of genetic toxicity pollution of reclaimed water from different sources was:reclaimed black water>reclaimed synthetic wastewater>reclaimed grey water.The effect of three reclaimed waters on germination rate of different crops were different.