Study On Removal And Recovery Of Algae By Pre-ozonation In Xinlicheng Reservoir

Algae blooms can do a lot of harm to the drinking water production, coagulation andprecipitation and also can increase the amount of coagulant, shorten filter filtration cycle. Itcan cause a stink and produce toxic algal pigment, and chlorine role to the formation ofchlorinated disinfection product so that reduce the safety of drinking water. Thepre-ozonation is an advanced oxidation technology, it is a conventional treatment which canuse as an effective way to deal with the problem of eutrophication of water algae. Advancedoxidation processes (AOPs) has been widely used. In this study, the characteristics of thenorthern drinking water source Xinlicheng Reservoir are conducted. In order to evaluate thequality of the source of drinking water and study the ozone dosage and temperature to removealgae, the study use ozone oxidation pretreatment process and indoor simulation experiments.Different ozone dosage effective, temperature and light are all studied to determine theoptimal conditions for algae recovery.The experimental results are listed as follows:(1) In the ozone algaecide experiment, pH,turbidity, algae concentration and chlorophyll show a downward trend and good removalefficiency with ozone oxidation treatment time increasing. By ozonation, the algal cellshave been damaged and some intermediate product precipitated generated, so as to achievethe purpose of reducing turbidity, and also to oxidative cleavage of the algal cells, release thedissolved substance, change the pH value of the environment. According to change ofpermanganate index and DOC curve, the ozone oxidation time may not last too long; algaeconcentration and chlorophyll a is an important indicator of ozone algaecide, presented aslow downward trend with increasing ozonation time and ozone oxidation time. The mostsignificant downward trend for2.5min.②Investigated in the liquid phase reactiontemperature experiments on Algae Removal Efficiency in the ozone into the time of2.5min,ozone inlet concentration of20mg/L, the higher the temperature, the better the ozoneremoval efficiency of algae,25℃>20℃>15℃>10℃, and temperature changes in the algaeconcentration of chlorophyll a change of less impact.③Algaecide effect experiments, the investigated concentrations of ozone in the ozone access for2.5min, the liquid phase reactionat room temperature, the greater the concentration of ozone into the flow, the higher theremoval efficiency of algae, but when the ozone concentration reaches2.0mg/L, and thenincrease, its concentration did not significantly improve the removal efficiency of algae.④According to the the ozone algaecide experiments to determine the subsequent algae recoveryexperiments under the conditions of inlet ozone concentration of20mg/L, and ozoneoxidation time is2.5min.⑤Under the condition of suitable temperature and illuminationadequate, a small amount of ozone treatment can effectively inhibit the growth of algae water,when the ozone oxidation time reacher2.5min, algae recovery trend show weak, with theincrease of ozonation time, algae growth and reproduction slowed.⑥Comparison growthcurve of algae at different5℃,15℃,25℃, the result show that the temperature can impacton algal recovery in the temperature range of15-25℃, the algae concentration andchlorophyll a were not significant increase in the state, and in5℃, algae recoveryslow down,low temperature inhibits the growth and reproduction of algae.⑦In the appropriatetemperature conditions and strong light (3000lux), algae revival significantly, and chlorophylla changes significantly; If the ambient temperature is appropriate, algae become a recoveryphenomenon, a phenomenon also consistent with an annual summer season of the sunillumination is sufficient.