Yang Yan-ling

Removal of Microcystis aeruginosa and Microcystic Toxins by Four Algaecides

In this study, static tests were conducted using high algae-laden simulated water sample under laboratory conditions. Microcystis aeruginosa biomass was characterized by Chlorophyll a, and Microcystic toxins LR was detected by solid phase extraction- high performance liquid chromatography. The removal effect of Microcystis aeruginosa and Microcystic toxins LR of Copper sulfate, Zeolite, Potassium Permanganate and Potassium Permanganate supported zeolite(Mn-Zeolite) algaecide had been investigated. The results showed that five day after dosing, copper sulfate and Mn-Zeolite had the optimal removal rate over 80% of Chlorophyll a. Removal rate of Chlorophyll a by potassium permanganate reached 60%~80%. While zeolite was the least effective to remove Chlorophyll a, with a removal rate of only 30% Zeolite alone and Mn-Zeolite both had an effective removal rate of MC-LR, over 50%. MC-LR could be removed by 30% after dosing 0.09mg/L of potassium permanganate, but MC-LR in water increased to different extent when the dosage of potassium permanganate increased. As to copper sulfate, MC-LR in water all increased sharply under different dosages. Potassium Permanganate supported zeolite(Mn- Zeolite) algaecide had an optimal removal effect not only of Microcystis aeruginosa but also of Microcystic toxins compared to other three algaecides.

Effect of Different Phosphorus Conditions on the Growth of Microcystis aeruginosa

Static tests were conducted to study and analyse the growing situation of M. aeruginosa and variation of dissolved total phosphorus in medium under laboratory condition. The results shows that the higher is the concentration of exogenous phosphorus, the longer log phase does M. aeruginosa have. The limiting concentration of phosphorus for growth of M.aeruginosa is 0.1mg/L. As cultured with different phosphorus source, the specific growth rate of M. aeruginosa decreased in the following order K2HPO4> NaH2PO4>Na3PO4. K2HPO4 is easily used for M. aeruginosa growing.