Integrated chemical coagulation with natural base coagulant – electro-proxone process and ultrafiltration membrane for treatment of compost leachate

Guilan Province compost leachate was treated utilizing a hybrid process including chemical treatment followed by electro-proxone and ultra filtration (UF). The effects of different parameters including ratio of natural / chemical coagulant (1:5, 1:15, 1:25), pH (5-8), time (10-90 min), ozone dose (10-90 mg L-1), current intensity (50-500 mA), TMP (0.5-3.5 bar) and temperature (20-50 °C) on COD and turbidity removal were investigated. At optimum conditions of the coagulation process (Salvia hispanica mucilage/FeCl3 = 1:15 and pH = 6.5), 36.19 % and 56.9 % removal efficiencies were obtained for COD and turbidity, respectively. Effluent from the chemical treatment went through. Results from the electro-proxone process showed that by increasing the current intensity from 50 to 350 mA, COD removal efficiency reaches form 14 % to  79 %. By changing O3 concentration from 10 mg L-1 to 90 mg L-1, COD reduction increased and reached from 29 % to 84 %. UF reactor was used for final polishment of the treated wastewater at the optimum TMP of about 1.5 bar and pH = 7.5. By increasing the temperature from 20 °C to 40 °C, permeation flux increased from 76.7 Lm-2 h-1 to 104.1 Lm-2 h-1. However, following the increase of the permeation flux, the removal efficiency of COD and turbidity decreased slightly to 54 % and 90 %, respectively. This study showed that the employed hybrid method is capable of treating the hardly biodegradable compost leachate and obtaining the environmental standards.