Removal of turbidity and suspended solids by electro-coagulation to improve feed water quality of reverse osmosis plant

Electro-coagulation EC is a simple and efficient method for water treatment. It was not widely applied because of high capital cost compared to other treatment technologies. In recent years, many investigations have focused on the use of EC owing to the increase in environmental restrictions on effluent wastewater.Removal of total suspended solids TSS and turbidity from feed water of a reverse osmosis unit by EC using iron electrodes is investigated. The effect of current density and residence time were studied in an attempt to achieve a higher removal efficiency. Water samples from well water with initial suspended solids TSS of 300 mg L−1 and turbidity of 150 NTU were prepared.The results show that feed water treated by EC was very clear and its quality exceeded the standard of feed water quality of reverse osmosis units. Removal efficiencies of total suspended solids TSS and turbidity were more than 99% and 98%. The results presented in this paper on two water reverse units operated for 6 months showed that total treatment of feed water by addition of EC reduced all fouling factors indicators such as water flow, pressure drop and silt density index SDI.

Research Highlights
► Electro-coagulation improves pretreatment of feed water to RO plants.
► This is achieved by removing turbidity & suspended solids.
► The efficiency of EC increases by increasing the electric current up to 2.5 A and increasing residence time.
► Tests on reverse osmosis units indicate that all fouling factors such as flow, pressure drop, silt density index improves by the addition of EC treatment to the traditional pre treatment of feed water.