Demonstration and performance analysis of on-beach public toilet with a decentralised modified French vertical flow constructed wetland and ex situ electrochlorination integrated treatment system

Abstract

Abstract This study demonstrated an on-beach public toilet equipped with a sustainable decentralised treatment system in Goa, India. The number of toilet users, freshwater demand, and wastewater (WW) generated per day were documented. The treatment system consisted of a modified French-type vertical flow constructed wetland (MVFCW) and electrochlorinator. The first and second stage MVFCW were an unsaturated and saturated type, respectively. The onsite beach bore well water with a chloride concentration of 8464 ± 415.18 mg/L was electrolysed for 1 h at 40.49 Am−2. Then MVFCW effluent was disinfected by dosing 2412.50 + 278.61 mg/L of chlorine (Cl2) generated at a disinfectant dilution ratio of 1:300 (Cl2:WW). The average daily toilet users, freshwater usage, and WW generated were 96 ± 17.02, 1381.38 ± 380.35 L, and 1407.98 ± 611.8 L, respectively. The integrated treatment system treated 1,400 L/day. The integrated treatment system achieved an average percentage removal of 93.38 ± 0.38% chemical oxygen demand, 79.18 ± 1.55% NO3−, 98.45 ± 0.22% total ammoniacal nitrogen, 93.13 ± 1.19% PO4−3, 87.28 ± 0.2% total suspended solids, 83.09 ± 1.16% total organic carbon, 80.22 ± 0.87% total carbon, 80.05 ± 0.12% inorganic carbon, and 100% coliform. The power consumption cost was 0.17 INR m−3.