Biotoxicity Detection Of Wastewater And Recycling Water And The Origin Analysis

The water quality has been evaluated by conventional chemical and biological analysis.Aquatic biotoxicity indicators show the comprehensive biotoxicity of water that can improve the evaluation of environment samples.Therefore,biotoxicity of environmental water have been attention of more and more researchers.So biotoxicity of contaminated water were not only detected,but also the origin of bitoxicity must be discussed in order to provide the theoretical basis of selecting control program.However,biotoxicity of industrial wastewater with high toxicity and complex the components of contamination were detected to need diluting the samples,and biotoxicity and the origin of industrial wastewater are unclear;domestic wastewater and recycled water toxicity testing are often needed to concentrate the contaminants from samples and the origin analysis of biotoxicity is also not clear;from the biotoxicity test of wastewater treatment plant,the biotoxicity of effluent were tended to increase,so it's significant woke for the cause on the biotoxicity of effluent with chlorine.In response to these problems,so we can use the responses of a variety of organisms on pollution water to express the biotoxicity level.The microalgae-Chlorella vulgaris and luminescent bacteria – vibrio qinghaiensis sp.-Q67 were used to detect the phytotoxicity and microtoxicity of water and a various detection using instruments conducted a series of research about analysis the cause of biotoxicity.This study is part of the project of National Natural Science Foundation of China.Firstly,the phytotoxicity and microtoxicity of typical organic substances and heavy metals were detected by microalgae and luminescent bacteria,and the origins of biotoxicity about industrial wastewaters were analyzed by physical,chemical combing bitoxicity indictors;Secondly,in the wastewater treatment and recycle system,dissolved organic substances in samples were concentrated and fractionated by reverse osmosis(RO)and resin columns,the characteristics of dissolved organic substances were analyzed though three dimensions excitation-emission matrix(3DEEM),TOC and SUVA detection and so on,and phtotoxicity and microtoxicity of samples were tested and analysis the origin of biotoxicity from the characteristics and biotoxicity of six fractions of dissolved organic substances;Lastly,in the domestic wastewater treatment plant(WWTP),solid phase extraction(SPE)technology extracted the organic matters then detected phytotoxicity and microtoxicty from the technological process on WWTP and explain the cause of bitoxicity raise of effluent after chlorination.The main work and achievements are as follows:(1)In order to explicit the biotoxicity of common organic matters and inorganic substances,phytotoxicity and microtoxicity of six organic matters and seven heavy metals were tested.For the six organic compounds,bactericidal organic matters have the highest biotoxicity,then naphthalene amine,surfactants and antibiotics,and phenolic compounds had the lowest bitoxicity to organisms.Compared with organic matters of wildly biotoxicity distribution,all of heavy metals belong to “very toxic”(EC50 <1mg/L)and “toxic”(1mg/L<EC50 <10mg/L)to plant and microorganism.For finding out the origin of industrial wastewater,we detected phytotoxicity and microtoxicity by Chlorella vulgaris and vibrio qinghaiensis sp.-Q67 and combing phytotoxicity and microtoxicity of single organic matter and heavy metal.Effective concentration with 50% inhibition(EC50)values with single organic matter were converted into the values of EC50,TOC with effective carbon content and EC50 values with heavy metal compounds were converted into the values of EC50,metal with heavy metal ions content.So we compared EC50,TOC values of industrial wastewater with EC50,TOC values of single organic matter and compared the content of heavy metal in diluted industrial wastewater following EC50,% values with EC50,metal values of single heavy metal,then the origin of biotoxicity was determined from the values proximity after comparing.The origin of brewery biotoxicity come from the high concentration and low toxic or nontoxic organic matters(EC50,TOC = 274mg/L)and the origin of coking wastewater biotoxicity come from the high toxic organic matters(EC50,TOC = 32.93mg/L).(2)In the wastewater treatment and recycle system,the biggest of TOC percent of samples were hydrophobic acid and hydrophilic neutral components,the sum of which were exceed 50% of TOC percent.Lots of humic-like substances(including humic-like substances with microbial activity,humic-like substances)existed in the two compounds.Besides,aromatic proteins in influent were used by microorganism and humic-like substances in effluent were produced.However,sample from lake about recycled water presented aromatic proteins because of opened system with lakes,the content of humic-like substances were declined in lake maybe due to absorption of microorganism in lake.Sample from wastewater treatment and recycling system have shown biotoxicity that reduced following the concentration of dissolved organic matters(TOC values)decline in technological process.The relationship between TOC values of sample and biotoxicity were linear,so organic matters in samples were removed and biotoxicity were removed effectively at the same time.Besides,organic matters in samples were classified into 6 components by resins,the origin of biotoxicity of samples in wastewater treatment and recycle was determined by analysis organic matters in 6 components combining biotoxicity.Then the source of biotoxicity was from the neutral substance and aromatic proteins and humic-like organic compounds may be related to biotoxicity.(3)In domestic wastewater treatment plant(WWTP),phytotoxicity and microtoxicity of dissolved organic matters were detected and evaluated though solid phase extraction with HLB column combing algae and luminescent bacteria.Influent had shown the highest phytotoxicity and microtoxicity that were not removed obviously in aeration tank and primary sedimentation tank.In aerobic tank,phytotoxicity and microtoxicity were removed 90%,however,biotoxicity of effluent after chlorination was increased.Three dimensions excitation-emission matrix(3DEEM)combined water quality testing were used to be judged the differences of organic component between influent and secondary effluent.Comparing influent,the proportion of humic-like substances in secondary effluent was increase because of the new humic-like with microorganisms' activity.Dissolved organic matters in secondary effluent were classified by reverse osmosis(RO)and resins which used to be researched the origin of disinfection by products(DBPs),hydrophobic acid and hydrophilic neutral component produced more thihalomethane formation potential(THMFP)than other components,humic-like substances(including humic-like with microorganisms activity and humic-like substances)was the main precursors of DBPs combing 3DEEM and fulvic-like substances were shown the high THMFP.The effective trihalomethanes(THMs)concentration corresponding to a 50% inhibition was 318?g/L at a chlorine dose of 19.6mg/L as Cl2.THMs formation may be the direct reason for the increase of toxicity in the secondary effluent when chlorine was used as disinfectant.This paper based on detecting and evaluating the biotoxicity of wastewater and recycling water and exploring the origin of biotoxicity using a variety of analytical methods,which not only provided the reference of analytical methods of the origin of biotoxicity but also furnished the theoretical basis for the wastewater treatment solution of contorting biotoxicity.