Photochemical oxidation model of organic pollutants in greywater from a small household

Abstract

The treatment of coagulated greywater from a small household was investigated. The processes of oxidation of organic compounds with hydrogen peroxide combined with ultraviolet radiation (H 2 O 2 /UV) was described. Greywater with various initial COD and TOC concentrations was used in the H 2 O 2 /UV process. The process parameters were hydrogen peroxide doses 0.5–4.0 kg H 2 O 2 /m 3 , UV (254 nm) light intensity 75.5 W/m 2 and irradiation time – 1 h. The oxidation efficiency varied broadly from 15 to 98% and higher COD values corresponded to lower oxidation efficiencies. The average hydrogen peroxide consumption per kg of COD w was = 12.2 g H 2 O 2 /g O 2 COD, while per TOC it was w ′ = 69.0 g H 2 O 2 /g C. The experiments enabled one to developed mathematical models for coagulation and oxidation kinetics. The models showed that at the initial COD = 859 g O 2 /m 3 , the coagulant dose of 100 g Al 3+ /m 3 , the hydrogen peroxide dose of 4 kg H 2 O 2 /m 3 and the UV irradiation time of 3 h it is possible to decrease the COD by 98.4%.