Study On Optimal Operation Of Tannery Wastewater Treatment Technologies

Leather industry is a pillar of light industries in our country,is also a serious pollution industry.Tanning wastewater contains high concentrations of protein,fat,and sodium sulfide,chrome tanning agents,dyes,inorganic salts,lime and other raw and auxiliary materials added into the production process,making it a difficult industrial wastewater.Although the specification of HJ2003-2010 "Tanning and fur processing wastewater treatment engineering technical specifications" made it clear to engineering design,construction,acceptance and operation management Since March1,2011.But the standard of GB 30486-2013 "Tanning and fur processing industry water pollutant discharge standards" had clearly increased the emission targets that tannery wastewater discharge should focus on controlling the total nitrogen and other characteristic pollutants indicators.In this paper,2500m3/d tannery wastewater treatment project that an annual production of 850,000 real leather enterprises is taken as an example.On the basis of mastering the parameters of characteristics of various types of wastewater pollution,the design of the load and process design parameters,the main operational problems through on-site commissioning are clarified.Proposed on-site testing program and scientifically to obtain the true causal relationship between the processing unit,then construct a complete portfolio of processing technology that the water indicators to achieve full stability standards.It is of great practical significance to standardize the treatment of tannery waste water and realize the sustainable and healthy development of the industry.The research results show that wastewater pretreatment is the key to guarantee the integrated wastewater biochemical system function and implement overall stable discharging standard.The original sulfur-containing wastewater pretreatment adopted "catalytic oxidation + coagulation sedimentation process" affected by pH,catalyst dosing quantity,catalytic oxidation time,oxygen,temperature,and many other factors.And the engineering construction don't take catalytic oxidation heating measures generally,let the sulfur-containing wastewater pretreatment is not completely when winter is coming along with low temperature and the catalytic oxidation lower efficiency,which cause sulfide content in the comprehensive wastewater more than microbial inhibition concentration.The optimized sulfur-containing wastewater pretreatment is "catalytic oxidation + chemical precipitation process" which also can make that the discharged of the sulfur-containing average effluent after pretreatment is COD_Cr3589mg/L,70.2% of the removal efficiency,S2-41.2mg/L,96.7% of the removal efficiency,fully meet the integrated wastewater biochemical system normal and stable operation condition.The original process for integrated wastewater is "physicochemical + two levels of A/O + aerobic" combined body process and the "two levels of A/O + aerobic" of that composed two aerobic processes are all adopted the activated sludge method,with the quality indicators of the average effluent is COD_Cr270mg/L with 88.5% of the removal efficiency,NH₄⁺-N60mg/L with 82.9% of the removal efficiency,TN180mg/L with 63.6% of the removal efficiency.But it is difficult to reach the TN indirect emissions limits,which is 140mg/L for the new enterprise in the table 2 of GB 30486-2013 "Tanning and fur processing industry water pollutant discharge standards".The optimized process for integrated wastewater is combined main treatment process of "materialized + two levels of A/O +anaerobic/biological contact oxidation + materialized",which converts the original period of aerobic transform anaerobic / biological contact oxidation and forms unique clay film hybrid method.Through efficient microbial carrier,the ability of the biochemical treatment system to removal carbon and nitrogen improved,along with physical and chemical processing units for coagulation precipitation.The quality indicators of the average effluent is COD_Cr175mg/L with 93.5% of the removal efficiency,NH₄⁺-N35mg/L with 90.3 of the removal efficiency,TN80mg/L with86.6% of the removal efficiency,so the effluent water quality indicators of the sewage treatment station can reach the stable discharging standard in an all-round way.