| Total Load control of Land-sourced pollutant is the basic content of achieving aresource-saving and environment-friendly socio-economic sustainable development.And it’s also an effective means to solve the atmosphere, surface water, soil andmarine pollution problems. Since the beginning of total pollutant load control researchin the middle of1980s, particularly the implementation of “Targeted Total LoadControl” plan in2006, in which COD reduction is the restricted index, the waterquality of Bohai Sea has not been improved to an extent satisfied, even after theimplementation of “Bohai Comprehensive Improvement Plan” and “Bohai Blue SeaAction plan”, due to the defects of “Targeted Total Load Control”. The areaexceeding the water quality standard of Bohai Sea increased by approximately50%in2010comparing with that in2005. According to the experience on total pollutant loadcontrol from U.S., EU and Japan, etc, it is more necessary to execute the “TotalPollutant Load Control based on Environment Capacity” instead of the “TargetedTotal Pollutant Load Control” for China. However, due to the reason that thedevelopment of calculation method of marine environment capacity usingthree-dimensional numerical models lags and etc., in many repots, not only theconcept of environmental capacity and allocated capacity is often mixed up, but alsothe calculation results are often limited to some area of the Bohai Sea or land aroundit. Particularly, up to now, Bohai pollutant discharge region has not been scientificallyand accurately divided. Therefore, the purpose of this research is to get the allocatedcapacities of pollutant discharge region around Bohai Sea based on the more accuratecalculation results of environment capacity of Bohai Sea, and to provide a scientificand theoretical basis for the scientific, accurate and quantitative management indicator system to achieve the implementation of “Total Discharge Control based onenvironment capacity”.The main contents of this research include:(1) According to the general principles of environment capacity’s calculation,establishing a method of calculating environment capacities, which is adapted to theocean three-dimensional numerical model.(2) Calculating the environmentalcapacities of pollutants of COD, nitrogen and phosphorus of the Bohai Sea using themethod established above.(3) According to the general principles of dividingcatchments and pollutant collecting areas and the actual land range whose pollutantentering into Bohai Sea, reasonably dividing the Bohai pollutant discharge regionBased on scientifically defining the range of Bohai discharge management belt.(4)Based on the results obtained in the (2), calculating the allocated capacities of COD,nitrogen and phosphorus of Bohai pollutant discharge regions with the method ofmulti-objective linear programming.(5) According to the estimated results ofdischarge rates of COD, nitrogen and phosphorus, preliminary proposing aquantitative and administration-leveled management system of total load control onBohai pollutant discharge region.Major results of this research are as follows:1. Calculation Environmental capacities of Pollutants of COD, Nitrogen andPhosphorus of Bohai SeaCurrently, the general principles of the method of calculating environment capacitiesbased on pollutants’ self-purification can only be applied to the box-type numericalmodel, and cannot meet the demand of establishing three-dimensional numericalmodels. Therefore, considering the hydrodynamic space and biogeochemicaltime-varying characteristics, the method of calculating pollutants’ environmentcapacities (EC) can be established, which is adapted to the three-dimensionalnumerical model, and the results can be called “Concentration Gradient IntegralMethod”. According to the characteristics of the numerical model in terms of time,space, indicators and standards, environmental capacity calculation process includeseight sessions including from identifying waters the pollutant entering into to assessing the calculation results of environmental capacity. In this research, the Bohaithree-dimensional hydrodynamic (HAMSOM)-biogeochemical coupled model isapplied to numerical simulations of state variables of COD, nitrogen and phosphorus.The results show that the simulation results basically coincide with the monitoringresults, for nitrogen, the average relative deviation (RSD) and the similarity index (SI)is51%and0.42respectively, which illustrates that the model basically could be usedto calculate the environment capacities of pollutants of Bohai Sea. The results showthat the environment capacities of COD, nitrogen (ammonia) and phosphorus of theBohai Sea, were respectively about9.80,0.93and0.13million tons per year, and theenvironmental capacity density (t/a/km~2) of nitrogen and phosphorus wereapproximately1/3of Jiaozhou Bay of the Yellow Sea and Luoyuan Bay of the EastChina Sea under the conditions of water quality standards of the national functionalareas.2. Calculation of allocated capacities of land-sourced COD, Nitrogen and Phosphorusof Bohai Pollutant Discharge Regions.The calculation of land-sourced pollutants allocated capacities of Pollutant DischargeRegion includes three main components: First, considering the145points locatedaround the three provinces and two cities in the Bohai economic region wherepollutant enters into Bohai, of which there are115catchment area Zone,19pollutant collection area and17enterprise whose pollutants are discharged into theBohai sea directly, and confirming that the Bohai Sea pollutant management zonecovers343county-level administrative regions belonged to37prefecture-levelcities and105county-level administrative regions belonged to19prefecture-levelcities are outside this range. On this basis, the county-level Administrative Region issetted as the minimum Administrative Region of Bohai Sea pollutant managementzone. According to the main path of pollutants entering into sea. catchments andpollutant collection areas in the same administrative district, are merged. So, Bohaipollutant management zone can be divided into42pollutant management regions and3closely related pollutant management areas outside the region, which is the middleand upper reaches of the Yellow River and theupstream of Haihe River and Liaohe River (see above), of which the former can be further divided into Yellow Riverpollutant discharge management district, Haihe pollutant discharge managementdistrict and Liaohe pollutant discharge management district respectively. Secondly,allocated capacities (AC) of COD, nitrogen and phosphorus of the42pollutantmanagement regions are calculated with the method of multi-objective (non-) linearprogramming. and of which the maximum of allocated capacity of pollutantmanagement regions is set as the objective function and the the total pollutant load,water quality and non-negative as constraints, and the former takes Bohai’senvironmental capacity as land allocated capacity’s threshold. Finally, allocatedcapacities of pollutants of the pollutant management regions can be calculated usingthe simplex method. The results show that, as for pollutants of COD, nitrogen andphosphorus, the allocated capacities within the Bohai Sea pollutant management zoneaccounts for about95%, and that outside thezone accounts for only about5%, ofwhich Yellow River pollutant discharge management district, Haihe pollutantdischarge management district and Liaohe pollutant discharge management districtaccounted for27%,30%and43%respectively. The analysis shows that the density ofCOD allocated capacity (DA) is an average of3.9, of which16%area of the BohaiSea pollutant management zone, mainly located at the29pollutant managementregions including Beidaihe District and so on, is higher than the mean value.3. The preliminary research on a quantitative and leveled management system of totalload control on Bohai Pollutant Discharge zone.According to the five level quantitative management model of the land-sourcedpollutants total load control, it could implement the level quantitative managementusing the COD, nitrogen and phosphorus pollutants superovulated%for the Bohaipollutant discharge region, of which: Super ovulation rate%=(Pollutant dischargenumber density-Allocated capacity density of Administrative Region)/Allocatedcapacity density of Administrative Region. However, in the same multi-objective(non-) linear programming method that calculates the allocated capacity ofAdministrative Region is still not possible to determine the demand for additionaleconomic development, population development, pollutant discharge intensity, project discharge reductions and other constraints of the function or parametric form. In thiscase, assuming that the ratio result of Allocated capacity density of the AdministrativeRegion/Allocated capacity density of Pollutant Discharge Region of the Bohai Sea isbasically the same with the result of Qingdao City which is about0.3, the ratioexceeding the allocated capacity can be estimated through the density of allocatedcapacities of Bohai pollutant management regions. The results showed that accordingto the COD ratio exceeding the allocated capacity (see above), within the Bohai Seapollutant management zone, the area needed to be managed with the level of red andorange together takes a proportion of approximately53%, and the area needed to bemanaged with the level of green and blue together takes a proportion ofapproximately46%.In short, in this research, according to the demand of quantitative indicators in theprocess of the “Targeted Total Load Control” converted to the “Total Pollutant LoadControl based on Environment Capacity” the method of calculating environmentcapacities and integral concentration gradient are established, which is adapted tothe ocean three-dimensional numerical model. And with the method, theenvironmental capacities of COD, nitrogen and phosphorus in Bohai are calculated.Considering the actual situation of the catchment, pollutant collection area and the seapoints, it is identified with the scope of the Bohai pollutant management and rationaldivision of42Bohai pollutant management district. Based on above two results, thisresearch use multi-objective (non-) linear programming method to get a more detailedcalculation of COD, nitrogen and phosphorus pollutants distribution capacities of42pollutant management area. And this research provides a theoretical basis for thequantitative management system of total load control on Bohai pollutant dischargeregion.The innovation of this research is, aimed at the demand of more accurate calculationresults of environmental capacity, establishing the concentration gradient integralmethod that adapted to the ocean three-dimensional numerical model. on this basis,more detailed allocated capacities of COD, nitrogen and phosphorus of42Bohai Sea pollutant management regions is obtained, which provides a scientific basis for thequantitative indicators management system of total load control on343county withinthe Bohai pollutant discharge zone during the12th Five-Year plan. |
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