| The contaminated water pollution is more extrusive environment problem currently.A variety of hazardous and toxic pollutants in the sediment will release to aquatic environment through exchange,which will result secondary pollution of the overlying water.It has became a key question and to select economic and ecological effective technology for management of water pollution.The study used in-situ repair technique,target the contamination in the sediment and was carried out in reactors which studied the effect of chemical deactivator on the sediment.Utilization of aquatic plants to control the malodorous water of Hobbing pond,the purification effect of aquatic plants combined with Daphnia magna for treatment of campus lakes was studied Simultaneously.Some conclusions were summed up through a large number of indoor and outdoor experiments as following:(1)the new composite passivator for TN,NH4+-N,TP had a good removal rates,and the better effect can get with the increase of the new composite passivator dose.The highest removal rate of TN,NH4+-N,TP was 23.52%,21.79%,81.5%,respectively.In the overlying water body the removal rate of COD was first increased and then decreased with the increase of the dosage of the reagent,the highest removal rate(dosage of 600mg/L)reached 57.6%.Adding the new composite passivator can increase the concentration of TP in the sediment and can promote the conversion of unstable phosphorus to steady state.Adding the new composite passivator can increase the steady state of Zinc,which Mainly is residual state.The residue of zinc in the 1#-5# treatment group was increased 41.3%,52.7%,49.8%,54.7%,54.2%,but there was no significant difference among different treatments.From the economic costs and remediation effect,the optimum dosage of the new composite passivator was600mg/L.(2)The influence of pollutant release characteristic from sediment of Lake Nanfei was discussed.Four kinds of passivator were used.The results showed that with the add of Fe0 and calcium nitrate,the p H value raised from 6.7 to 8.5,while Eh value descended.With the add of new composite agent,the p H value stabled at around 7.5,while Eh value descended slowly.Meanwhile,the effect on overlying water COD by adding calcium nitrate was bigger than that by Fe0 adding,and will had a greater impact on the water quality at early stages.The removal rate in new composite agent minder system was most significant,the COD of overlying water stabled at around 5mg/L,while the inhibitory effect of aluminum sulfate was second only to new composite agent.Adding four kinds of inactivation agent has inhibitory effect on TP of sediment,and new composite passivatort>calcium nitrate>aluminum sulfate>Fe0,while adding new composite agent had some inhibitory effect on TN、NH4+-N of sediment,however,with the add of calcium nitrate,the TN、NH4+-N value increased.So,the inhibitory effect of new composite passivator was better than other single passivator for river sediment pollution.(3)The restoration model of Daphnia magna collaborative Vallisneria had a good effect on the Hobbing pond,through Water quality analysis of Hobbing pond in recent three months,and water quality had been greatly improved.TN、TP、NH4+-N、COD removal rate were reached 76.7%、85%、83.6%、67.5%.(4)The ecological management of Hobbing bond enhanced the selfpurification ability of water,and Water transparency reached 0.5 meters,the best time could reach about 1 meters,water color returned to normal,which no debris、no algae and other floating objects,Black odor was eliminated,Landscape effect was enhanced. |
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