Study On Chemical Phosphorus Removal Agent And Application For Sewage

The traditional process of chemical phosphorus removal has the disadvantages of high cost of phosphorus removal agent,and need to add agent frequently.Slow-release phosphorus removal agents has a long release duration and can reduce the times of addition of agent.The existing slow-release phosphorus removal agents only can be put into use after being processed by compounding and,and the cost of the agents is high.Finding slow-release phosphorus removal agent with low price and good slow-release effect can reduce labor and time costs,which is of great significance for the phosphorus removal of dispersed and intermittent phosphorus-containing wastewater.In this experiment,calcium aluminate,sponge iron and the iron powder produced during mechanical processing were used as phosphorus removal agents,and the reactors were designed.Phosphorus removal experiments were carried out on simulated phosphorus-containing wastewater and domestic wastewater respectively.It is determined that the iron powder produced during mechanical processing is the best agent for phosphorus removal.Combining it with biological method to form a combined process for domestic wastewater treatment,and good results have been achieved.(1)The performance of phosphorus removal by calcium aluminate increases gradually with the increase of dosage,and the rater of phosphorus removal reached 97.76%when the dosage is 25 g/L.Prolonging the time of reaction is beneficial to the removal of phosphorus.The results is best when the pH of raw water is 5.0.The capacity of continuous removal of phosphorus from simulated phosphorus-containing wastewater and domestic wastewater by calcium aluminate was 9.39 mg/g and 3.44 mg/g,respectively.Calcium aluminate is easy to agglomerate,and has a great influence on the pH of water and the pH can reach 9.5.It is limited in combination with biological method.(2)The performance of phosphorus removal by sponge iron increases gradually with the increase of dosage and the time of reaction.95%of phosphorus can be removed when the time of reaction is 75 minutes.The results is best when the pH of raw water is 4.0.During the process,sponge iron needs to be pickled regularly and secondary wastewater was produced.(3)The performance of phosphorus removal by the iron powder produced during mechanical processing increases firstly and then decreases with the increase of dosage.When the dosage was 20 g/L,the phosphorus concentration can be reduced to 0.15 mg/L.The results is best when the pH of raw water is 4.0.The capacity of continuous removal of phosphorus from simulated phosphorus-containing wastewater and domestic wastewater by the iron powder produced during mechanical processing was 1.96 mg/g and 0.75 mg/g,respectively.The optimum parameters of phosphorus removal by the iron powder produced during mechanical processing is:the dosage is 20 g,the reaction time is 3.0 h,and the pH of raw water is 4.0.The order of influence of each factor on phosphorus removal is:pH of raw water>time of reaction>dosage.(4)The combined process of the iron powder produced during mechanical processing and biological method can remove phosphorus stably.The phosphorus concentration can be reduced to below 0.50 mg/L in each cycle.The removal of COD was enhanced by adding the iron powder produced during mechanical processing.