| In order to solve the problem of algal blooms in the reclaimed water recharge section of Xi’an moat,Microcystis flos,the dominant algal species identified,was taken as the research object,the control effects of aluminum sludge,lactic acid and their combination on Microcystis Flos were studied.Aluminum sludge can reduce the concentration of phosphorus in water,and then inhibit the growth of algae,lactic acid as an allelochemical can inhibit the growth of algae through allelopathy.However,when aluminum sludge is used alone,it takes a long time and a large amount to control algae.The amount of lactic acid used to control algae is relatively large,but although the large amount can kill algae,it will also endanger the safety of fish and other aquatic organisms in the water.Therefore,on the basis of the research on algae control by aluminum sludge and lactic acid alone,this paper carries out the experimental research on algae control by aluminum sludge and lactic acid together,and the research results can provide a feasible method for algae control,it has certain theoretical significance and application value.The main findings of the study are as follows:(1)The optimum conditions of algae control by aluminum sludge were clarified.When the particle size of aluminum sludge was 80 mesh and the dosage was 5 g/L,the concentration of total phosphorus in water decreased from 0.5 mg/L to 0.08 mg/L on the 10th day,the algal density of Microcystis Flos decreased from 1.0 × 106 cells/mL to 4.22 × 105 cells/mL.The results of SEM and elemental composition analysis before and after adsorption showed that the weight percentage of P increased by 2.1%.The results of Flow cytometry analysis showed that adding aluminum sludge for 10 days or so significantly reduced the activity of Microcystis flos-aquae cells.(2)The optimal conditions for the control of algae by lactic acid alone were obtained.When the concentration of lactic acid was 20 μL/L,the density of Microcystis Flos increased within 4 days,and decreased after 4 days When the concentration of lactic acid was 40,60,80,100 μL/L,the density of algae decreased compared with the control group,especially when the concentration of lactic acid was 100 μL/L,the inhibition effect was obvious,the inhibition rate was over 90%.When the concentration of lactic acid was 100 μL/L,the concentration of malondialdehyde(MDA)increased by 2.42 times as compared with that of the control group.(1)The treatment conditions and influencing factors of aluminum sludge combined with lactic acid for algae control were discussed.The combined use of aluminum sludge and lactic acid reduced the amount of aluminum sludge and lactic acid under the condition of stable algae control effect.The inhibition rate of microcystis algal bloom was 91.2%when 3g/L aluminum sludge was used in combination with 60 μL/L lactic acid.The growth cycle of Microcystis Flos has some influence on the control of algae by aluminum sludge combined with lactic acid.It is difficult to control the algae cells in the decaying period,but the algae cells in the logarithmic growth period are easy to be inhibited.At the same time,the initial cell density had little effect on the effect of combined treatment. |
