Study On Control Of Black Mud Odor And Nitrogen And Phosphorus Release By In-situ Combined Remediation Technique

The resuspension effect of sediment contaminant is the major sources of internal pollution of water pollution.Controlling sediment pollution is an essential work for water treatment.It's crucial and complicated for us to solve the water of black odor and eutrophication which have perplexed us.In view of the problem of black odor from sediment in rivers or lakes and nitrogen and phosphorus released from the overlying water.In this project in-situ chemical remediation,in-situ physical remediation and in-situ bioremediation were combined,exploring the effect of the control of black odor from sediment and nitrogen and phosphorus release.The combined remediation technique used in this paper to lay three layers of material on the surface of contaminated sediment,respectively are chemical oxide layer,physical adsorption layer and plant absorption layer.Calcium peroxide powder was used as an oxide agent,and exploring the scope of action and additional influence on overlying water of black and odorous sediment by adding calcium peroxide powder were investigated,comparing the method to select calcium peroxide for application in oxide layer.The results showed that the addition of calcium peroxide in the three ways all could significantly increase ORP and decrease AVS content in the sediment;adding the calcium peroxide capsule will increase the concentration of ammonia nitrogen and COD in the overlying water;the action range of calcium peroxide powder in sediment is limited.In this experiment,it is optimized to use the method of tiling the surface of the sediment with calcium peroxide mixed with clay to apply calcium peroxide to the oxide layer of combined repair technology.Secondly,exploring the adsorption effect of zeolite,iron oxide coated zeolite and phenolic resin on ammonia nitrogen and phosphate,a material applied to the adsorption layer was selected by comparison;exploring the nitrogen and phosphorus absorption and removal effects of goldfish algae,black algae and bitter grass,a material applied in absorption layer was selected relatively.The results showed that zeolite have better adsorption effect on ammonia nitrogen than phenolic resin.The goldfish algae had better absorption and removal effect on nitrogen and phosphorus,and is obviously better than black algae and bitter grass.Considering the cost and efficiency,zeolite and goldfish algae were selected as the adsorption layer and absorbing layer materials.By contrast experiments,exploring different combinations of the control effect of chemical oxide layer,physical adsorption layer and plant absorption layer on the black odor from sediment and nitrogen and phosphorus release,we got the following conclusions: Under experimental conditions,calcium peroxide + zeolite + hornwort,calcium peroxide + zeolite,calcium peroxide + hornwort,calcium peroxide,the total nitrogen concentration in the overlying water of the calcium peroxide group decreased respectively 36.4 mg,31.0 mg,24.6 mg,22.3 mg;the total phosphorus concentration in the overlying water of the calcium peroxide group decreased respectively 4.1 mg,2.5 mg,3.9 mg,2.5 mg;the AVS removal rate of the surface sediment was respectively 98%,97%,83%,99%.The effect of controlling nitrogen and phosphorus release from sediment by calcium peroxide + zeolite + hornwort group was apparently better than that of other groups,and calcium peroxide mixed clay had a good control effect on AVS.