In order to realize zero liquid discharge

a power plant treated circulating wastewater by the combination process of two stage softening and clarification

media filtration

ultrafiltration

nanofiltration(NF) and reverse osmosis(RO)

and treated terminal wastewater by the combination process of chemical softening

tubular microfiltration(MF)

NF

seawater desalination reverse osmosis

electrodialysis(ED) and evaporative crystallization. After the above measures were taken for 1 year

insufficient NF output was found in the circulating wastewater treatment system

and serious MF membrane organic fouling and ED silicon scaling was observed in the terminal wastewater treatment system. Thus

the causes of the membrane fouling was analyzed and the desulfurization process water was optimized to reduce the chemical oxygen demand(COD) of desulfurization wastewater from the source. Moreover

the MF operation mode was optimized

so as to slow down the MF organic pollution phenomenon. In addition

the RO concentrated water of circulating water treatment mode was adjusted

and the total silicon mass concentration was reduced to less than 1 mg/L before being fed into the ED equipment

to solve the problem of the ED silicon scaling.