Study On The Water Environment Situation Of Surface Water Source And Pollution Controll Countermeasure

With the progress and the economic development of human society,the scale of industry, agriculture and city is increasingly enlarging and thepopulation is increasing rapidly, resulting in environmental degradation,water pollution, water resources waste and serious water shortage in theworld. The relating materials show that more than a billion people can notdrink clean water and 2.1 billon people have no good sanitary facilitiesglobally at present. The bad water quality gives a rise to poverty life andbad sanitary conditions, and 3.1 million people died from diarrhea andmalaria in 2002.According to the assessment results of National Water ResourcesComprehensive Plan, one fourth of the water source quality do not meetthe standard requirements for the central surface drinking water sourcequality among 1073 central surface drinking water source. Nowwastewater of 3620 billion tons is discharged, in which 80% are nottreated. 850 rivers are polluted among 1200 rivers in China and the figureindicates the serious situation of water source pollution.Qitahe Municipality is an important old industry base in the southeastpart of Heilongjiang Province. The city is not rich in surface water andgroundwater. The Taoshan Reservoir is the only surface water supplysource and takes charge of water supply for more than 65% populationin the city. On the basis of water monitoring data over the years, waterpollution is aggravating in the reservoir year by year. Therefore it is themost important matter that bears upon people's life to study the existingenvironmental conditions, put forward reasonable and effectivecountermeasures for controlling pollution in the reservoir.There are many problems for existing environmental conditions inthe reservoir, such as many pollution sources in upstream, bad raw waterquality that can not meet the requirements of national standard, seriouseutrophication, incomplete urban drainage system, unreasonabledischarge outlet locating, poor management for the water sourceprotection area and lack of protecting engineering. All problems aboveresult in wastewater entering the reservoir directly and large amount ofpollutants from surface pollution source is discharged into the watersource protection area and contaminate the water quality in the reservoir.At the moment water quality in the reservoir has become class Ⅴ orworse than class Ⅴ.In light of above problems and combining the second phaseconstruction of the reservoir, the paper carries out a comprehensive studyon reservoir water environment, deeply analyzes the pollution situation,main receipting tributary ,water quality , eutrophication condition andwater environment capacity in the reservoir area from various respectiveand angles, presents the relevant countermeasures for controlling pollutionin order to protect drinking water source, further improve water qualityand provide scientific foundation for optimizing water resourcesmanagement.The main contents and technological method of the paper are asfollows:Feeling out the basic conditions of the catchments. The type, quantity,distribution and discharging ways of pollution source are investigatedthoroughly, and discharged quantity of wastewater and pollutants areestimated in the study area. By the method of pollutant loading inequivalent standard, the equivalent standard discharge of thepollutants is calculated and we find out the main pollution source andpollutants.Collecting the water quality data in recent years in the area. By meansof single factor assessment, standard index assessment andcomprehensive pollution index assessment, water quality situation ofmain receiving tributaries and reservoir is understood, temporal andspatial variation characteristic of the water quality, dynamic variationtendency of the main water parameters are analyzed and the mainpollutants exceeding the standard are founded comprehensiveconclusion for water body is derived.On the basis of pollution source assessment and water qualityassessment and according to the index of nutrition and the standard ofeutrophication, eutrophication degree of the reservoir is studied.In the light of above study results and combing water function zoning,water environmental capacity of the reservoir is determined and basedon existing pollutant discharge and water environmental capacity, thequantity of pollutant reduced is calculated for each area.By the pollution source assessment, water quality assessment,eutrophication study and environmental capacity study, the paper putsforward the countermeasures for controlling water pollution andprovides the scientific foundation for reservoir management andpollution control.The main results of the study are as follows:1. The point sources are more than no-point source. Since there aremany factories and coal mines, large population located at the upstream ofthe reservoir, large amount of wastewater is discharged into the reservoir,resulting in a large amount discharge of pollutant.The pollutant discharge in equivalent standard for no-point source islarger than that of point source and no-point source is main affectingfactor for the water environment of Taoshan Reservoir. The reason is thatthere are a large population, fowls and farmland in upstream catchmentsand no-point source has a high TN,TP concentration.2.CODcr takes the first place among the pollutants. The reason is thatthe wastewater from factories and mines contains large amount of CODcr.TN takes the first place among the pollutant discharge in equivalentstandard, accounting for 55.2%;TP next, accounting for 28.0%. Thereason is that the no-point pollutants from the countryside contains largeamount of TN and TP, therefore the environmental quality of the researcharea is controlled by TN and TP.3. Water quality for Qiezhihe River, which is main receiving tributaryof Wokenhe River, is worse than class Ⅴ and comprehensive pollutionindex for the water body is >2.0(2.33),belonging to serious pollutedwater body. Variation tendency of water quality is that it exceeds standardseriously at normal period and slightly better at high water season. Thereason is that water quality in the river has a close relation withprecipitation, precipitation is ample and pollutants are less in the season,pollutants are diluted to some extent. Therefore the concentration of mostpollutants at high water season is lower than that at normal season. Butlarge amount of no-point pollutants enter water body with surface runoffand eroded soils and make the concentration increase for minority ofpollutant at high water season. Since inflow decreases from upstream atnormal season and river receives wastewater, so the concentration ofpollutants increases.4.Water quality in Taoshan Reservoir is worse than class Ⅴ andcomprehensive pollution index for the water body is > 2.0(2.26),belonging to serious polluted water body. Main pollutants are TP,Tfe,TN,CODmn,CODcr,NH3-N。Variation tendency of water qualityis that it exceeds standard seriously at normal period, slightly better athigh water season and comparatively it is better at dry season. The reasonis that large amount of no-point pollutants enter reservoir with runoff athigh water season and normal water season, water flows slowly and waterbody does not exchange frequently in the reservoir, therefore theconditions are helpful for pollutants accumulation, resulting inconcentration increase for most of poll tents. At dry season no-pointpollutants decrease, inflow ware dilutes the water body and it purifiesitself, so water quality at dry season is better comparatively.5. The eutrophication degree of the reservoir is higher and the heeutrophication value reaches 71, belonging to serious eutrophication. Proportion ofN/P is 7.85>7, being P controlling type eutrophication. Ecosystem reflectsdistinctly to P concentration variation and easy to form water bloom whencondition is suitable. It is necessary to forbid using phosphorus in WokenCatchments.6.The reservoir has no water environmental capacity now and receivedwastewater exceeds 1.12～10.80 times of water environmental capacity, farsurpassing capacity loading. Quantity of pollutants reduced for TP,TN,CODmn,CODcr,NH3-N is 90.7%,75.6%,55.5%,42.1% and 10.3% respectively.7.In terms of environmental condition in Taoshan Reservoir, controllingmeasures for water environment to reduce the inner and exterior pollution source,total amount control and pollutants reduction measure, ecological protection andremediation measure and law, regulation and scientific management measureshould be taken. By means of the measures pollution source will be cut down, watersource retention function will be restored and water quality of Taoshan Reservoir andits tributaries will become better year by year.