Research On The State Of Stain And The Decolourization Of The Outflow In A₁-A₂-O-M Craft

Coking wastewater is a kind of difficult biodegradation industrial wastewater.At present most processing factories most adopt A-O and A₁-A₂-O craft etc.But these crafts have the problems that COD and NH₃-N do not reach the discharge standards at the same time.The craft of A₁-A₂-O-M is adopted to treat with the coking wastewater in the experiment.In the optium control conditions,the active stain is reseached in detail,and the results indicate that nutrition needs to be added every half amonth,the new stain needs to be added every six months.The changes happen for the components of the coking wastewater before and after being disposed through the A₁-A₂-O-M craft(not feeding carbon source and alkali source in this system,the total HRT of the system is 25 hours),and the changes is studied with the absorbed spectrum of the UV and the analyzed spectrum of the GC-MS.The results prove:a majority of aromaticity may be wiped off almost completely,and all of the hydroxybenzenes may be reduced,and the furans,the aniline and the quinolines in a great measure also may be wiped off.The things explain the A₁-A₂-O-M craft is very successful to deal with the coking wastewater. Because the national standard requests the outflow chroma should be under 50,the chroma of the effluent of A₁-A₂-O-M craft is much higher than the national standard.In the experiment it is adopted by the two decolourization methods(the one of the scrap iron electroanalysis and the one of the effect by FeSO₄ and CaO),which may decolor to the waste water desposed by the measure of A₁-A₂-O-M.In the method of the scrap iron electroanalysis the optium control conditions may be:the value of pH is 5.0～6.0,the temperature of the water is about 25℃,the diameter of the scrap iron is 1.0～1.2mm.Under the condition,if the experiment will react about 20min,the chroma of the waste water may decrease and be thereinafter 15,and the value of NH₃-N may decrease and get to 5mg/L,and the value of COD may increase and get to 3000mg/L.In the method of the effect by FeSO₄ and CaO,the optium control conditions may be:the value of pH is 5.0～7.0,and the temperature of the reaction is room temperature,and the time of the reaction is 45min,and the separate quantity of FeSO₄ and CaO is 20g/L and 40g/L.Under the condition,if the reaction happens,the chroma of the waste water may decrease and be thereinafter 15,and the value of NH₃-N may decrease and get to 5mg/L,and the value of COD may increase and get to 2000mg/L.By the two methods the value of the chroma of the waste water has achieved the primary national standard about wastewater discharge (GB8978-1996)respectively.