To alleviate the fouling of the flocculant and polymer coagulant on the membrane treatment system and strengthen the clarification and coagulation effect in treatment of the circulating water drainage

a thermal power plant in northern China adopted the electrocoagulation-efficient clarifying basin combined technology to pretreat the circulating waste water. Through the system commissioning

the changes of the effluent turbidity

total hardness and total alkalinity of the clarifier were investigated under conditions with different current densities

pH values of the pool and sodium carbonate dosages. The results show that

under condition with current density of5.96 A/m2

pH value of 11.0

and the sodium carbonate dosage of 170 mg/L in the electroflocculation-efficient clarifying basin system

the turbidity

total hardness and total alkalinity removal rates were approximately 90%

60% and 66%

the average effluent turbidity

total hardness and total alkalinity were 0.9 NTU

9.7 mmol/L and1.2 mmol/L

respectively. The effluent water quality was stable

which satisfied the requirements for subsequent membrane treatment process

and reduced the risk of fouling of the membrane system.