Effect Of Straw Activated Carbon On Phosphorus Recovery From Sewage And Sludge

Phosphorus is not only an indispensable non-metallic element in organism,but also an important raw material for national production and life.At the same time,it has been in a one-way consumption state.However,there are a lot of phosphorus in urban sewage and sludge,but the problem of phosphorus recovery has always been a problem,which attracts much attention.The number of municipal sewage plants in China has been increasing rapidly,the output of excess sludge is huge,and the problem of follow-up treatment is urgent to be solved.Therefore,in this project,the agricultural straw is taken as the research object to prepare straw activated carbon,and to study its effect on phosphorus recovery from sewage and sludge.Firstly,corn straw was used to prepare activated carbon.The effects of straw particle size,activator concentration,impregnation ratio,impregnation time,carbonization temperature and carbonization time on the adsorption properties of activated carbon were investigated.According to the results of orthogonal test,when the particle size of corn straw is between 4.00-3.35 mm,the concentration of zinc chloride is 30 g / L,the ratio of impregnation is 1.0:1,the impregnation time is 16 h,the carbonization temperature is 400 ℃,and the carbonization time is 90 min,the activated carbon with the best phosphorus adsorption capacity can be prepared.When the concentration of phosphorus in water is 60 mg / L,the removal rate of phosphorus in water is 92.81%.Secondly,the effects of initial phosphorus concentration,ammonia nitrogen,organic matter(COD),p H value of solution,amount of activated carbon andadsorption time on phosphorus recovery from straw activated carbon were investigated.The results showed that when the concentration of phosphorus in water was less than 80 mg / L,the removal rate of phosphorus in 50 ml wastewater was more than 75% for every 0.1 g Corn Straw activated carbon.Ammonia nitrogen has an inhibitory effect on phosphorus recovery from corn straw activated carbon.The adsorption of phosphorus and COD in water by corn straw activated carbon is competitive adsorption.Too high or too low p H value of the solution is not conducive to the adsorption of phosphorus by corn straw activated carbon.When the p H value is about 5,the adsorption effect is the best.When the concentration of phosphorus in water is 60 mg / L and the dosage of activated carbon is 0.25 g,the removal rate of phosphorus can reach 99.67%.In a certain adsorption time,the adsorption effect of corn straw activated carbon on phosphorus is more obvious with the increase of adsorption time.When the adsorption time reaches 5 hours,the removal rate of phosphorus is 96.73%.Finally,the prepared corn straw activated carbon was used to recover phosphorus from wastewater and sludge cracking solution.The results showed that the removal rate of TP was 100% when the concentration of TP was 1.03mg/l and every 0.1g corn straw activated carbon acted on 50 ml water sample,and 71.06%when the concentration of TP was 9.95mg/l and every 0.1g corn straw activated carbon acted on 50 ml water sample.