Effect of high-voltage spark discharges on reduction of the concentration of total bacterial count in wastewater

Abstract

The limited supply of fresh water on the planet stimulates the reuse of wastewater in various areas. It is proposed to use disinfected wastewater for irrigation in agriculture. The possibility of reducing the total bacterial count in wastewater by high-voltage spark discharges using a developed experimental setup has been investigated. The total bacterial count was measured by the rapid method using a luminometric mini-laboratory EnSURE Touch and a standard method for counting bacteria, capable of forming colony-forming units on nutrient agar. Wastewater from the Zhulebinsky storm collector with an initial concentration of 1012 CFU ml−1 with a volume of 103 ml is disinfected up to the norm 6 log in 120 s with capacitance 0.1 μF and in 180 s with capacitance 0.05 μF. Wastewater from the Kuryanovsky storm channel with an initial concentration of 109 CFU ml−1 with a volume of 103 ml is disinfected up to the norm 6 log in 100 s with capacitance 0.1 μF and in 160 s with capacitance 0.05 μF. To reduce the concentration of total bacterial count by 1 log, the minimum duration of disinfection of 103 ml of wastewater it took about 30 s at a discharge energy of 5 J ml−1. The advantages of bacterial inactivation in wastewater by high-voltage spark discharges were revealed, such as low operating voltage of 10 kV, high energy efficiency of 600 J l−1 and capacity 30 l h−1, increased service life and operational reliability, portability and environmental friendliness.