| Sediment dredging is possible to effectively prevent secondary pollution of the lake,but at the same time,it will produce large amounts of dredged sediment.The dredged sediment particles are small,the water content is high and it is not easy to be separated in the natural state.How to speed up mud separation of sediment is a prerequisite for its comprehensive utilization.This paper mainly explored the effects of different chemical flocculant on the dewatering performance of lake sediments.The experiment was divided into three parts:The first part is the scheme of screening test.This study taked the sediment of Sha Lake as the research object,and selected AlCl3?FeCl3?FeSO4·7H2O?Fenton reagent(FeSO4·7H2O+H2O2)?PAM and other different chemical flocculant.In the study,different dewatering schemes were formed by the way of individually adding and combined adding,and the effective dewatering time and mud cake moisture rate were used as evaluation indexes.Had the Sediment dewatering experiments conducted to select the best plan dehydration.The second part is the comparison and verification experiment:it is to test the effectiveness and applicability of the best plan dehydration by comparing with Dong lake sediments Nan lake sediments Tangxun lake sediments.Third part is Pot experiment:use dewatering sludge which was obtained by the optimum adding amount of the above chemical dewatering agent Conduct Pot experiment of annual ryegrass.The results are as follows:1.Scheme select experiment:Use dewatering time as the reference index.The results are as follows:In the Separate adding scheme,When the amount of AlCl3 was added to 0.2g/100mL,the dewatering time of the sludge was reduced from 152s to 42s;When the amount of FeCl3 was added to 0.3g/100mL,the dewatering time of the sludge was 36s;When the amount of FeSO4·7H2O was added to 0.15g/100mL,the dewatering time of the sludge was 57s;When the strength of PAM was added to 0.15‰,the amount of additives is 1mL/100mL,the dewatering time of the sludge was 65s.In the Joint adding scheme:When the amount of AlCl3+PAM was added to 0.1gAlCl3+1mL2.5‰PAM,the dewatering time of the sludge was reduced from 152s to 25s;When the amount of FeCl3+PAM was added to 0.1gFeCl3+1mL2‰PAM,the dewatering time of the sludge was 29s;When the amount of FeSO4·7H2O+PAM was added to 0.15gFeSO4·7H2O+1mL2‰PAM,the dewatering time of the sludge was 19s;When the amount of Fenton was added to 0.3gFeSO4·7H2O+150?LH2O,the dewatering time of the sludge was 35s;When the amount of FeCl3+ Fenton was added to 0.3gFeCl3+0.05gFeSO4·7H2O+25gLH2O,the dewatering time of the sludge was 33s.Use Cake moisture content as refrence index:In the Separate adding scheme,When the amount of AICl3 was added to 0.2g/100mL,the Cake moisture content is 58.8%;When the amount of FeC13 was added to 0.3g/100mL,the Cake moisture content is 58.1%;When the amount of FeSO4·7H2O was added to 0.15g/100mL,the cake moisture content is 58.9%;When the e strength of PAM was added to 0.15‰,the amount of additives is 1mL/100mL,the Cake moisture content is 58%.In the Joint adding scheme:When the amount of AICl3+PAM was added to 0.1gAlCl3+1mL2.5‰PAM,the Mud Cake moisture content is 55.5%;When the amount of FeCl3+PAM was added to 0.1gFeCl3+1mL2‰PAM,the Mud Cake moisture content is 56.8%;When the amount of FeSO4·7H2O+PAM was added to 0.15gFeSO4·7H2O+1mL2‰PAM,the Mud Cake moisture contentis 56%;When the amount of Fenton was added to 0.3gFeSO4·7H2O+150?H2O,the Mud Cake moisture content is 59.9%;When the amount of FeCl3+Fenton was added to 0.3gFeCl3+0.05gFeSO4·7H2O+25?LH2O,the Mud Cake moisture content is 57.2%.Comparison of the best mud cake water content of different adding scheme is known.There is no obvious difference between the lowest water content.In summary:The dewatering schemes of 0.15gFeSO4 · 7H2O+1mL2‰PAM is the best schemes for improvement of dewatering performance of sludge2.Verification experiment of different lakes:The scheme consists of 0.15gFeSO4·7H2O+1ml2‰PAM can effectively improve the dewatering performance of the sediment of South Lake,and the East Lake Tangxun Lake.The dewatering time of the South Lake sludge was reduced from 162s to 36s;The dewatering time of the East Lake sludge was reduced from 1380s to 165s;The dewatering time of the Tangxun Lake sludge was reduced from 213s to 42s.3.Pot experiment:Plant height and fresh weight were used as the index to measure the growth characteristics of plants.plant height of Ryegrass in soil is 15.6 cm,Rhizome length of Ryegrass in soil is 8.6 cm,fresh weight of Ryegrass in soil is 0.25g;plant height of Ryegrass in Sediment that after conditioning of 0.15gFeSO4·7H2O+1mL2‰PAM is 22.1cm,Rhizome length of Ryegrass in Sediment that after conditioning of 0.15gFeSO4·7H2O+mL2‰PAM is 9.3cm,fresh weight of Ryegrass in Sediment that after conditioning of 0.15gFeSO4·7H2O+1mL2%PAM is 0.53g.Sediment that after conditioning of 0.15gFeSO4·7H2O+1mL2‰PAMcan Promote the growth of Ryegrass. |
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