The Research On Zero-emission Technology Of High Salt Wastewater From Ningxia Energy Chemical Industry

Ningdong industrial park in Ningxia is in a semi-arid area,with a perennial shortage of water,and the annual average precipitation is 191.4 mm,which is a severe shortage of water resources and has no sewage storage body.Therefore,the local government requires new enterprises to achieve zero discharge of wastewater.In the initial stage of project construction,SINOPEC Great Wall Energy and Chemical(Ningxia)CO.,LRD.maximizes the recycling of wastewater which including the industrial wastewater,domestic sewage,uncontaminated water,storm-water drainage and so on.However,after swage treatment,water from reuse water system to reverse osmosis device which will produce 45011m3/h high-salt wastewater,and how to handle these high-salt wastewaters can be one of the restricted factor.High-salt wastewater is characterized by high salinity,alkalinity,hardness and chloride,and the pollutant becomes poorly biodegradable wastewater after concentrated.At the moment,there are many techniques of handling high salinity wastewater,which including advanced oxidation processes,ion exchange,vibrating membrane,forward osmosis,evaporation,crystallization and so on.However,problems like instability operation,high cost of operation,and secondary pollution also exist in the above techniques.That is why enterprises are difficult to achieve zero discharge.Therefore,it is high necessary to build up a stable operation,great value and high operability of high-salt wastewater treatment,to achieve zero effluent discharge.To against above problems and based on the demand of SINOPEC Great Wall Energy and Chemical(Ningxia)CO.,LRD.,this paper carried on a research in analysis of the sample water quality,measure of water balance,comparison and selection of routing,model selection of equipment,to design a suitable routing for SINOPEC Great Wall Energy and Chemical(Ningxia)CO.,LRD.and also will go through an assessment in the later stage to figure out its insufficiency and diversity.The study shows,the technology of pretreatment + mesohigh membrane filtrating + mechanical falling film evaporation + stable crystallographic routing,which has the advantages of high shock resistance and low cost at treatment.The data presents that the recovery rate reaches 99%,salt rejection rate achieves 98%,treatment cost is only 1 6.48 RMB perton.On the other hand,this paper also analyses the existing problems in production operating,based on the transform of evaporator air inflow heat source and water distributor,to carry out the analysis and research.Hopefully this paper can provide reference and value for other units.