Municipal sewage carries degraded and intact viral particles and RNA (ribonucleic acid) of SARS-CoV-2 (severe acute respiratory coronavirus 2), shed by COVID-19 (coronavirus disease 2019) patients, to sewage and eventually to wastewater treatment plants. Proper wastewater treatment can prevent uncontrolled discharges of the virus into the environment. However, the role of different wastewater treatment stages in reducing viral RNA concentrations is, thus far, unknown. Here, we quantified SARS-CoV-2 RNA in raw sewage and during the main stages of the activated sludge process from two wastewater treatment plants in Israel, on three different days during the 2020 COVID-19 outbreak. To reduce the detection limit, samples were concentrated prior to quantification by real-time polymerase chain reaction by a factor of 2–43 using ultrafiltration. On average, ∼1 log RNA removal was attained by each of the primary and secondary treatment steps; however, >100 copies of SARS-CoV-2 RNA/mL remained in the secondary effluents. Following chlorination, SARS-CoV-2 RNA was detected only once, likely due to an insufficient chlorine dose. Our results emphasize the capabilities and limitations of the conventional wastewater treatment process in reducing the SARS-CoV-2 RNA concentration and present preliminary evidence for the importance of tertiary treatment and chlorination in reducing dissemination of the virus to the environment.

The municipal sewage carries the new coronavirus (SARS-CoV-2), shed by COVID-19 patients, to wastewater treatment plants. Proper wastewater treatment can provide an important barrier for preventing uncontrolled discharged of the virus into the environment. However, the role of the different wastewater treatment stages in reducing virus concentrations was, thus far, unknown. In this work, we quantified SARS-CoV-RNA in the raw sewage and along the main stages of the wastewater process from two different plants in Israel during this COVID-19 outbreak. We found that ca. 2 Log removal could be attained after primary and secondary treatment. Despite this removal, significant concentrations of SARS-CoV-RNA (>100 copies per mL) could still be detected in the treated wastewater. However, after treatment by chlorination, SARS-CoV-RNA was detected only once, likely due to insufficient chlorine dose. Our results highlight the need to protect wastewater treatment plants operators, as well as populations living near areas of wastewater discharge, from the risk of infection. In addition, our results emphasize the capabilities and limitations of the conventional wastewater treatment process in reducing SARS-CoV-RNA concentration, and present preliminary evidence for the importance of tertiary treatment and chlorination in reducing SARA-CoV-2 dissemination.

Groundwater resources in many regions of the world are becoming increasingly depleted and salinized. With many aquifers straddling political boundaries, ongoing depletion presents both a flashpoint for conflict and an opportunity for cooperation. A salient example is that of transboundary groundwater resources in the Jordan Valley. These are shared among Israeli, Jordanian and Palestinian residents. Here we describe a collaborative project aiming to develop a desalination system for use by Palestinian farmers in the West Bank. Students have collaborated across borders in a programme of training and research, in which they have constructed desalination prototypes. These are based on a simple but efficient batch-reverse osmosis (RO) technology that incorporates energy recovery and brine recirculation to achieve 70%-76% recovery and specific energy consumption <1.3 kWh/m 3. The technology can be solar powered with minimal PV footprint. Being built almost entirely from offthe-shelf parts, the system is readily implemented with levels of engineering expertise available in many areas of the world. To test and upscale the technology, and to propagate the knowledge about it, it is being trialled at centres in the UK, Israel and soon in Palestine. It is concluded that the project demonstrates a valuable approach in regions facing transboundary groundwater challenges, and that further learning resources should be developed for free access to foster collaboration across borders.