Reduction in energy for electrochemical disinfection of E. coli in urine simulant

Abstract

We report the development of novel modes of operation for electrochemical disinfection of E. coli in human urine simulant with an aim to minimize the energy required for disinfection. The system employs boron-doped diamond electrodes and will be part of an energy neutral, water and additive free outdoor toilet being developed for use in developing countries. Disinfection had been previously demonstrated with voltage being continuously applied to the electrode until disinfection was achieved. In the present study, a new pulsed mode of operation is investigated. This includes a continuous on mode, where oxidants are generated until disinfection is achieved, a single cycle mode, where oxidants are generated for a fixed time and the water is circulated so allow already generated oxidants to disinfect, and a pulsed mode with different duty cycles, which is like the single cycle mode but with multiple cycles. Disinfection was achieved with pulsed mode operation with a 68% energy reduction compared to the continuous on mode. Energy saving was most likely achieved by lengthening the contact time of the disinfectant with the bacteria and increased generation of non-chlorine disinfecting oxidants. Graphical abstract

Electrochemical Disinfection in Water and Wastewater Treatment: Identifying Impacts of Water Quality and Operating Conditions on Performance

“… 103 Likewise, BDD electrodes have been widely used in electrochemical disinfection. 37 , 44 , 49 , 60 , 100 Because BDD electrodes lack binding sites to facilitate water decomposition, they can be readily operated at higher cell voltages that are favorable for OH • generation. 104 However, operating at higher voltages corresponds to increased energy consumption as seen in reported systems using BDD electrodes ( Figure 5 ).…”

“… 12 , 37 − 42 In electrochemical disinfection, an oxidant is generated in situ via redox reactions on the surface of an electrode. 12 , 43 − 47 Just as with traditional disinfection techniques, numerous electrochemically generated oxidants can be used in disinfection including Cl 2 , 37 , 40 , 47 − 49 O 3 , 44 , 50 , 51 SO 4 •– , 52 , 53 and OH • . 54 − 56 Due to modular cell design, electrochemical oxidation can potentially be scaled across centralized and distributed treatment contexts.…”

“…A promising approach to disinfection which could be leveraged in both centralized and distributed treatment contexts is electrochemical oxidation. ,− In electrochemical disinfection, an oxidant is generated in situ via redox reactions on the surface of an electrode. ,− Just as with traditional disinfection techniques, numerous electrochemically generated oxidants can be used in disinfection including Cl 2 , ,,− O 3 , ,, SO 4 •– , , and OH • . − Due to modular cell design, electrochemical oxidation can potentially be scaled across centralized and distributed treatment contexts. − Likewise, electrochemical oxidant generation can operated in resource limited settings that often lack transportation and electrical power distribution infrastructure by using electricity generated onsite through renewable energy sources such as photovoltaic cells with minimal external chemical additions. ,, While there are an increasing number of studies investigating electrochemical oxidation/disinfection, there has been inconsistent reporting of disinfectant dose generation, energy consumption, and pathogen inactivation. Likewise, little focus has been devoted to contextualizing the potential challenges of applying electrochemical disinfection systems in both water and wastewater treatment.…”

An Amphiphilic Carbonaceous/Nanosilver Composite-Incorporated Urinary Catheter for Long-Term Combating Bacteria and Biofilms

“…Release Profile of UC/ACPs@AgNPs in a Urine Simulant and DMEM. To examine the silver ion release property of UC/ACPs@ AgNPs in a urine simulant (the composition of the urine simulant is shown in Table S1), 29 2 cm of a UC/ACPs@AgNPs segment was immersed in 4 mL of the urine simulant and stirred at 180 rpm in a water bath at 37 °C. At scheduled time intervals, catheter segments were removed and immersed in a fresh urine simulant medium under stirring.…”

Electrochemical Technologies to Decrease the Chemical Risk of Hospital Wastewater and Urine

“…These microorganisms can be eliminated under milder conditions than PhCs by chlorination, ultraviolet, ozone, Fenton process, photocatalysis, etc. [27][28][29], or by in situ generation of oxidizing species (advanced electrochemical oxidation processes) [30][31][32].…”