Solar Wastewater Treatment (SOWAT) and Reuse for Agricultural Irrigation

Abstract

Solar wastewater treatment (SOWAT) was the subject of experiment between April and September using low cost and mastery equipment: ‘hot‐box’ stills. Using a separate still, treated wastewater (i.e. distillate) production was recorded between 2.4 and 6 l m−2 day−1. Treatment efficiency was comparable to the activated sludge treatment process. Biological oxygen demand (BOD) recorded between 86 and 90% of abatement. Raw wastewater turbidity was reduced by 99%, from 181 nephelometric turbidity units (NTU) to 1.6 NTU. The treatment also allowed wastewater disinfection. The inactivation of total coliforms, faecal coliforms and faecal streptococci was estimated at about 99%. SOWAT offers the advantage of grouping, in a separate piece of equipment, three steps of conventional wastewater treatment: (i) the pre‐treatment, (ii) the biological and (iii) disinfection treatments. Also, this sustainable treatment does not consume electricity and consequently does not emit greenhouse gases (GHGs). Used on a medium and large scale, SOWAT would be promising for safe wastewater reuse in agriculture. This could secure food production of poor and low‐income countries, especially those that are very sunny. Copyright © 2017 John Wiley & Sons, Ltd.

Application of high‐voltage discharges for disinfection and activation of irrigation water*

“…The cost of ultraviolet water treatment, including the cost of energy, installation, and maintenance, is relatively high (Benami et al, 2015; Younis et al, 2019). There are promising developments in the field of water purification from exposure to solar radiation (Igoud et al, 2017) and using nanomaterials (Huo et al, 2020) to ultrasound (Matafonova and Batoev, 2019).…”