Emergency Detectation Of Nitrobenzenes In Songhua River And Treatment Technology For Meeting With The Demand Of Water Quality Standards

There are Mopanshan reservoir and Songhua River in Harbin which are used asthe supply of drinking water. Currently, Mopanshan reservoir is the main watersupply, Mopanshan waterworks can provide90million m3/d of water, SonghuaRiver is a backup source of water supply in Harbin, it has three waterworks and canprovide60million m3/d of water. Because the water quality in Songhua River ofHarbin suffered different degrees of pollutions, the water quality of waterworks inconventional water treatment technology could not meet with the state drinkingwater health standards which is just lauched and forced to implement in2012.Therefore, when use Songhua River water, The development of emergencydetection for organic pollutants in Songhua River water, typical organic emergencytreatment and treatment technology could make water meat with the demand of106indexes of drinking water health standard, it has important and long-termsignificance.With regard to both GB5749-2006and GB3838-2002, the organic pollutantstesting results of GC-MS on Songhua River water source water and the third waterfactory are165kinds of organic compounds and137respectively. In the detectionof organic matter, there are benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene, nitrobenzene, naphthalene, dibutyl phthalate, dioctyl phthalate and other10kinds of priority control in China pollutants and halogenated hydrocarbons, phenol,all kinds of cyclohexane, polycyclic aromatic hydrocarbons and other potentiallyhazardous substances.Based on the fact that Songhua river suffered nitrobenzene pollution in2005, agas chromatography method for rapid testing nitrobenzene concentration isdeveloped. Through research, benzene was replaced by n-hexane as extractant innational standard method, extraction time decreases significantly, which can meetwith the technical requirement of the emergency detection. The lowest detectionlimit is0.1μg/L, the measured concentrations is (25~250μg/L) of nitrobenzenestandard deviation (RD) is1.0~5.5μg/L, the relative deviation (RSD) are lessthan6.5%. Being practical in Songhua River water samples with the recovery being100~108%. Compared with several laboratory results, it showed that this methodwith other laboratory results the determined maximum deviations being less6%. The method has been successfully used in the work of nitrobenzene pollution eventin water quality testing, and plays an important role for restoring the water supplyof Harbin.Study on gas chromatography method and technical process for thedetermination of nitrobenzene, in special chromatographic conditions, the detectionlimit is superior to the national standard method for the determination a series ofconcentrations (20~200μg/L) of nitrobenzene, the standard deviation (RD) is0.15~3.4μg/L, the relative deviation (RSD) are less than2.0%, the result isbetter than that achieved with the national standard method. In the same time,although research founds that liquid chromatographic method can achieve10kindsof nitrobenzenes effectively separated compounds, if emergency detection is need,first using gas chromatography method to determine and then classify appropriatelynitrobenzenes for rapid detection. The standard deviation (RD) of nitrobenzenes is6.06~12.4μg/L, the relative deviation (RSD) are less than2.0%(n=7). Therecovery of the method is94.7~104.3%. In addition to the detection limit ofnitrobenzenes, all other compounds are superior to the method achieved by thenational standard.Based on the organic pollutants for water source, the selected target compoundsare nitrochlorobenzene and2,4-dinitrochlorobenzene for powdered activatedcarbon absorption test, the results indicate that when nitrochlorobenzene and2,4-dinitrochlorobenzene are5times the superscalar, the addition of powdered activatedcarbon are20and30mg/L respectively, the water quality could reach the controlstandard. The adsorption of nitrochlorobenzene and2,4-dinitrochlorobenzene isphysical absorption, and the absorption characteristics the follows Freundlichisotherm, the adsorption kinetic constants are1.6849(g/mg·min)(5℃),1.7742(g/mg·min)(15℃),1.8286(g/mg·min)(25℃) for Nitrochlorobenzene, and21.537(g/mg·min)(5℃),19.596(g/mg·min)(15℃),20.39(g/mg·min)(25℃) for2,4-dinitrochlorobenzene. It indicates that low temperature is favour the adsorption ofnitrochlorobenzene and2,4-dinitrochlorobenzene by powdered activated carbon.This paper introduces the engineering example of emergency treatment duringSonghua River polluted by nitrochlorobenzene, it points out that in the process ofcoping with nitrochlorobenzene pollution, using powdered activated carbon toadsorb the nitrochlorobenzene and combining activated carbon and sand layersfilter could remove nitrochlorobenzene from water effectively, and ensure water supply security.Two sets of5.0t/h pilot plant are operated, and lasting one year time to studythe ozone pre-oxidation and ozone activated carbon technology systematically, theresults indicate that pre-ozonation could improve the characteristic coagulation ofwater quality, it can save about12%of coagulant agents. Ozone/activated carbontechnology is proposed as an advanced treatment technology, it could meet with thetechnology requirement of Songhua River source water on advanced treatment. Theresults of pilot show that ozone-activated carbon technology could improvebiological stability of drinking water to meat with the demand of GB5749-2006’s106index standard.The research results include several key research issues of water supply inHarbin, there are important values for the use of method for improving the level ofwater supply in Harbin.