Recycling Solid Waste Of The Wastewater Containing Sulfuric Acid Treatment

Solid waste is by-produced of the wastewater treatment containing sulfuric acid.It consists of a large number of activated carbon and neutralization gypsum and a small amount of COD and Fe(OH)3,etc.At present,most of the solid waste generated from sulfate wastewater treatment mixed with sludge hasn't cyclically used,mainly is dumped,which not only occupy the land resources and destroy the ecological environment,but also caused the waste of sulfur resources and if solid waste generated from sulfate wastewater treatment is hazardous waste,it is extremely expensive to professionally deal with it.Therefore,recycling wastewater gypsum has great significanct.In this paper,the source of wastewater gypsum,application of PAC in water treatment,the deactivation and regeneration of PAC,the mechanism of gypsum decomposition and the technology of sulfur recovery are mainly discussed,and recycling of solid waste are put forward.HSC chemistry6.0 was used to investigate the decomposition temperature and phase composition in different molar ratio of carbon to sulfur.The kinetic parameters of the decomposition are calculated by Kissinger method,Ozawa method,FWO method,KAS method with TG techniques and the kinetic mechanism of wastewater gypsum decomposition with PAC is analyzed by Coast-Redfern method.The results was demonstrated that the apparent activation energy E is 351.83KJ·mol-1 and the pre-exponential factor A is 6.68 × 10-11s-1.The most probable mechanism functions are F(a)=(1-2a/3)-(1-a)2/3 and the kinetic equation is da/dT = 6.68 × 1011 ×e-369690/RT(1-2?/3)-(1-?)2/3.According to the thermodynamics and dynamics calculation results,the experiment is designed to study the effects of reactiong temperature,reaction time,the molar ration of C to S,the mixing way and the different impurities on the reduction of solid waste with PAC.Based on these investigation,orthogonal experiments were conducted to find out the best conditions,which are as follows:the reaction temperature is 900?,the ratio of the activated carbon with the sulfur is 3:1 and reaction time is 50 minutes.Under this condition,the reduction rate of wastewater gypsum from solid waste could be above 99%.The cycle decomposition experiment is conducted.After seven times the reduction rate of wastewater gypsum is more than 98%.Sulphur manufacture by H2S gas are proved by sulfur recovery experiment.Though tech-economic analysis the cycle process has a certain feasibility because it can save about 2.44 million every year for the enterprise which has capacity of 1000t for a year.Five carbon used in this study could all promote the solid waste decomposition,but the promotion effect deffered among those five carbon which may be attributed to the difference in ash.In order of most reduction rate,it goes:straw carbon carbon,petroleum coke,activated carbon,sludge and coke.