A simple and effective treatment for the safe discharge of concentrated disinfectant solutions

LUCILA DOUMIC; GUADALUPE RODRIGUEZ; ALAN CAPANO; A. MICAELA FERRO OROZCO; M. ALEJANDRA AYUDE

Congreso; WCCE11 - 11th WORLD CONGRESS OF CHEMICAL ENGINEERING; 2023

The use of disinfectants containing Benzalkonium Chlorides (BAC) is widespread and increasingly being released into the environment. BAC concentrations used in hospitals can be as high as 0.1%w/v [1]. This study analyzes the feasibility of treating concentrated BAC solutions by homogeneous Fenton oxidation with subsequent storage. Fenton tests were conducted using BAC 0.1%w/v (1000 mgBAC/L, 2176 mgCOD/L, and 743mgDOC/L) in a batch reactor at pH0=3and 30°C for 180 min. The storage of Fenton-treated liquids was in the dark, at room temperature, and without stirring. The effect of initial catalyst load ([Fe+2]0=0.36, 1.70 mmol/L), oxidant concentration ([H2O2]0=15, 50, 75, 150 mmol/L) and storage time on the evolution of BAC, oxidant, total dissolved iron (TDI), dissolved organic carbon (DOC), and carboxylic acids concentrations was analyzed. When oxidant was depleted, the chemical oxygen demand (COD) was also measured. The effectiveness of the treatment was evaluated in terms of the impact of the treated solutions on a non-acclimated activated sludge (NAS). In particular, biodegradability, toxicity and susceptibility to antibiotics (Ampicillin, Cephalexin, and Ciprofloxacin) were evaluated and taken as criteria for safe wastewater discharge. The minimum inhibitory concentration (MIC) was recorded as the lowest antimicrobial concentration that prevented any measurable growth.