Study On Combined Pollution Toxicity Of Cu²⁺ And Chlorophene In Wastewater Treatment Sludge From Typical Chemical Plants

Chemical industry is a high pollution,high energy consumption industry.The wastewater discharged from chemical production process has caused serious pollution to the water environment in our country.In particular,heavy metals in chemical wastewater such as mercury,chromium,cadmium,lead,molybdenum,copper,manganese and other chemical pollutants as well as arsenic,cyanide,sulfide,polycyclic aromatic hydrocarbons,phenols,chlorobenzene compounds caused great risks on the ecological environment.Heavy metals in chemical wastewater were transferred into sludge in the form of chemical precipitation during physical,chemical,and biological treatment process,and some organic compounds with poor biodegradability may be enriched in activated sludge in biological treatment process.This paper focuses on the study of pollution characteristics of wastewater treatment sludge from typical chemical industries which containing heavy metals and toxic refractory organic pollutants and the risk assessemnt method to evaluate the ecological risk of sludge.Chlorophene is a broad-spectrum fungicide used in personal care products and household cleaning products.It has been reported that the concentration of chlorophene in sewage treatment system is as high as 50 ?g/l,and the amount of it in river water is about 10?g/L.Copper ion is a kind of heavy metal necessary for plant growth.Copper ion is prevalent in the environment,especially in chemical wastewater treatment sludge.USEPA stipulates that MCL of copper ion in water is 0.05mg/L.Many studies are focused on the single pollution,tending to underestimate the effect of combined pollution of various pollutants coexisted in sludge.In this paper,we study on the effect of copper ion and clorophene in case of single pollution and combined pollution on seed germination of wheat,and explore toxic mechanism.In addition,the removal of heavy metal ions from aqueous solution by a new type of hollow fiber adsorption material was studied,including the optimization of conditions,adsorption kinetics and desorption kinetics.The inhibition of single copper exposure on the root length of wheat seed germination is stronger than that of chlorophene exposure.The joint toxicity action mechanism of copper and chlorophene is synergistic.SPE + LC-MS method was used to determine the content of endogenous hormones gibberellin(GA3),abscisic acid(ABA),and indole-3-acetic acid(IAA)in wheat roots and shoots.The results showed that the levels of GA3,ABA,and IAA in the roots and shoots of wheat were in proportion to the exposure dosage of copper and chlorophene,which indicated that copper and chlorophene affected the growth of wheat roots and shoots by regulating the contents of endogenous hormones in the germination process.Heavy metals are the main pollution factors in titanium gypsum which was the wastewater treatment sludge from production of titanium pigment.Among the surveyed titanium pigment factories the major pollution element were zinc,nickel,and chromium in Annada titanium gypsum,Ningbo Xin Fu titanium gypsum,and Jinzhou titanium industry,respectively.These elements may cause some damage to the ecological environment,and therefore it's necessary to strengthen the control of heavy metal content in titanium gypsum.Moreover,the lixivium from the sludge of Jinzhou titanium industry has significant inhibitory effect on the seed germination of wheat.Copper ions could be effectively removed from water by hollow fiber adsorption.The adsorption kinetics is in accordance with the pseudo second order kinetics model.The maximum adsorption capcity of hollow fiber to copper ion is 39.66 mg/g calculated from the Langmuir adsorption equation.Chemical adsorption was the main adsorption mechanism.