The Inhibition Of Microcystis Recruitment In Lake Poyang Nanchang Area By IN-SITU Passivation Technology

The research was showed that Microcystis would sink into sediments by envirommental factors,and the Microcystis could survive in sediments for a long time because of the unique physiological characteristics.The Microcystis would recruit from sediments into the water in spring,providing the"seeds"for the blooms of Microcystis.IN-SITU passivation technology is to add artificial or natural materials that have passivating effect on pollutants,increasing the binding capacity of sediments to nutrients through precipitation,adsorption and other physical and chemical effects,and reduce the pollution from sediments into water.The IN-SITU passivation technology is used to control sediments,pollution and soil heavy metal pollution currently.This research was going on through the simulation experiments in laboratory,had studied the threshold of the biomass of Microcystis recruitment in different sediments in the Lake Poyang Nanchang District,and investigated the influence of IN-SITU passivation technology on Microcystis recruitment,explored in-depth the mechanism of IN-SITU passivation technology on microcystis in sediments.This research could help us to understand the threshold of the biomass that needed by Microcystis recruitment and the influence of IN-SITU passivation technology on the the migration ability of Microcystis from sediments to water in the Lake Poyang Nanchang District,providing a new way to control the Microcystis blooms and a new theoretical basis.The main conclusions were as follows:（1）Selected the 4 lakes as the study object,by the way of laboratory simulation experiments of Microcystis recruitment,the threshold of the biomass that needed by Microcystis recruitment in different sediments was explored,the threshold of the biomass in Lake Qingshan,Lake Junshan,Lake Jinxi and Lake Yao respectively was:（1）The resuspension group:0.09×10³cells.g^-1、0.09×10³cells.g^-1、0.06×10³cells.g^-1、0.06×10³cells.g^-1;（2）The static simulation group:0.07×10³cells.g^-1、0.06×10³cells.g^-1、0.06×10³cells.g^-1、0.05×10³cells.g^-1.The analysis of variance had showed that the environmental factors in the sediments had a very significant effect on the survival of microcystis（P<0.01）.Related analysis had found that the TN,TP and OMS of the sediments had a significant effect on the survivability of microcystis（P<0.05）.（2）Selected the Lake Qingshan sediments as the study object,This research was studied the influence of IN-SITU passivation technology on the microcystis recruitment in the sediments when the microcystis biomass in the sediments reached the threshold.The study was suggested that the experimental materials can increase the content of intracellular MCs and carbohydrate and protein of Microcystis,so that materials could inhibit the recovery of microcystis.It was found that sepiolite and montmorillonite had no inhibiton on Microcystis recruitment,while other materials had an inhibitory effect on Microcystis recruitment under the resuspension.All the materials were useful for inhibiting the Microcystis recruitment under no resuspension condition.Among them,kaolin and diatomaceous earth had the best inhibition effects under the resuspension,which inhibition rates respectively was 31.56%and 32.78%.Diatomite was the best inhibition material under no resuspension condition,which inhibition rate was 50.56%.Diatomite was more cost-effective than kaolin in terms of price.（3）Selected the Lake Qingshan sediments as the research object,this research was aimed to study the influence of IN-SITU passivation technology on the second recovery of Microcystis that sank into sediments during bloom.Kaolin and diatomaceous earth had the best inhibition effects under the resuspension,which inhibition rates respectively was 33.48%and 32.62%.Diatomite was the best inhibition material under no resuspension condition,which inhibition rate was 37.52%.Diatomite was more cost-effective than kaolin in terms of price.