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Renewable Energy: For a Safer Future

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he Global demand for energy is increasing rapidly, as the world’s population continues to grow. Nonrenewable energy sources are scarce and unsustainable. On the other hand, Renewable energy (RE) sources are environmentally friendly and, unlike fossil fuels, will not deplete.

RE can be sensed in our daily lives. Solar energy can be felt in bright sunlight and the warmth that we feel when the sun’s light shines on our skin. Wind energy can be felt by the movement of tree branches and leaves. Geothermal energy can be felt through hot water pools.

RE is generated from natural sources that are abundant in most parts of the world, which implies that it does not deplete with high consumption. It has a negligible environmental impact when compared to fossil fuels. RE has become an essential component and duty for businesses seeking to achieve sustainable development. Also, the usage of RE is expanding day by day. In 2017, 8% of the world’s electricity was produced using RE; China received a quarter of this amount, and the United States of America, India, and Japan shared a sixth.

RE sources include solar, wind, hydropower, geothermal, biomass, tidal, and wave energy. The sun generates solar irradiation, which is captured by photovoltaic solar panels. These panels contain cells that absorb sun rays and convert them into consumable energy such as electricity.

The energy that reaches the globe in one hour is higher than the energy utilized by the world in a year, demonstrating the vastness of solar energy (SE). SE is reliable because it depends on the sun, does not contaminate the environment, and provides enough electricity for the location where it is built, and sometimes more.

Wind energy has been used by humans since ancient times. Five thousand years ago, the ancient Egyptians made boats driven by the wind. In 200 BC, humans used windmills to grind grain and pump water. Nowadays, Wind turbines are used to generate electricity from the wind. These turbines contain a very tall tower with two or three fan-like blades rotated by the wind. The blades drive the generator located inside the tower and produce electricity. A group of wind turbines is known as wind farms and is found near farmland in narrow mountain passes. Also, in oceans where there is stronger and more steady wind.

Geothermal energy, which is obtained from the heat of the Earth’s interior, is another source of RE. The Earth’s core is located deep beneath the Earth’s surface and has a temperature over 6000°C. Some of the heat from the Earth’s interior can be seen as it floats to the surface. The Earth’s internal heat melts surrounding rocks, and the molten materials seep to the Earth’s surface from volcanoes in the form of lava. It also heats groundwater and transports it to the surface. These water streams are known as hot springs.

Geothermal heat can be acquired in a variety of ways. One of these ways is to employ geothermal heat pumps, in which water pipelines are extended to the building and heated by geothermal energy located beneath the ground. Steam is another application of geothermal energy. Underground steam exists in several parts of the earth and naturally comes to the surface. This steam is directly transmitted to the power plant, but because the soil in some regions of the planet is dry, water is injected underground to make steam.

Biomass energy is also regarded as a RE source. Any substance produced by plants or microbes is referred to as biomass. Plants obtain energy from the sun through photosynthesis. This energy is stored in plants even after they die. As biomass feedstock, manure, trash, and crops such as corn, soybeans, and sugarcane can all be used. This energy is obtained by burning biomasses, which consist of drying wood, compost, and litter, and then burning them to generate heat or electricity. Biofuels can also be made from biomass. This biofuel is blended with gasoline and can be used to power automobiles and trucks. As a result, blended biofuel emits fewer dangerous contaminants than gasoline.

Hydropower is a type of energy that is generated from water sources such as dams, reservoirs, and flowing river water. The turbines move and rotate in response to the passage of water, converting mechanical energy into electrical energy. It is also thought to be one of the oldest RE sources used by humans. Initially in grain mills, when hydropower was used to power the mills. It is also one of the most used and vital kinds of RE, accounting for 17% of the total electricity production. It is abundant in China, Brazil, and Canada.

Scientists and engineers are continually attempting to discover new forms of RE, the most important are tidal energy and wave energy. The energy generated by ocean tides is sufficient to generate electricity. The movement of the tides is used to rotate the blades of turbines in projects that profit from this energy. Other projects employ small dams to constantly fill reservoirs at high tide, slowly release water, and spin turbines at low tide.

Wave energy is generated by ocean waves, lakes, or rivers. In wave energy projects, turbines are used. The constant flow of water through these floating pieces of equipment powers turbines and creates electricity.

The primary goal of employing RE is to achieve more environmentally friendly and sustainable development. RE provides various benefits for both individuals and the environment. It remains with the human being on earth. It cannot be drained, the water is continually flowing, the sun shines every day, the mild wind never stops, and the powerful wind is permanent in some locations, providing the planet with an infinite source of energy.

RE is friendly to the environment. They are non-flammable, unlike fossil fuels, and their use helps the globe reduce greenhouse gases produced by fossil fuels. These greenhouse gases have contributed to climate catastrophe, forest fires, and accelerated ice melting at the earth’s poles. RE is also safe for humans because it does not produce dangerous pollutants into the environment, lowering the number of diseases spread among people.

The RE advancement, increased efficiency, and dissemination among individuals have led to a low cost of installing and maintaining some of them. For instance, wind and solar power energy generation are less expensive than petroleum gas generation. It also boosts the country’s economy by reducing energy imports or purchases from producing countries.

On the other hand, people in industries have relied on fossil fuels for hundreds of years. The switch to alternative energies is costly and requires major changes to existing systems. So, the transition to RE requires large-scale changes by governments and companies and the provision of support and assistance in providing funds for alternative technologies. Also, some alternative energy technologies are still relatively new and in their early stages and require further research and development, and these sources may be vital for saving energy while using other resources.

As a result, several actions must be taken to ensure the efficient use of renewable energy, including shifting subsidies from fossil fuels to renewable energy, increasing investments in renewable energy, improving global access to components and raw materials for RE technologies, and making RE technology a global public good. To make RE technology a worldwide public good and available to all, barriers to knowledge exchange and technology transfer, such as intellectual property constraints, must be removed.

References

  1. https://www.un.org/en/climatechange/raising-ambition/renewable-energy
  2. https://youmatter.world/en/definition/definitions-renewable-energy-definition
  3. https://myenergi.com/guides/the-10-advantages-of-using-renewable-energy-in-2021
  4. https://blogs.worldbank.org/es/voices/que-se-necesita-para-profundizar-la-transformacion-de-las-energias-renovables
  5. https://www.conserve-energy-future.com/advantages-and-disadvantages-of-renewable-energy.php
  6. https://www.sciencedirect.com/science/article/pii/S1364032111004497
  7. https://www.ucsusa.org/resources/benefits-renewable-energy-use
  8. https://education.nationalgeographic.org/resource/tidal-energy
  9. https://www.eia.gov/energyexplained/geothermal/
  10. https://www.usgs.gov/special-topics/water-science-school/science/hydroelectric-power-water-use?qt-science_center_objects=0#qt-science_center_objects
  11. https://www.irena.org/wind
  12. https://www.energy.gov/eere/bioenergy/bioenergy-basics
  13. https://www.remoteenergy.org/blog/what-is-solar-energy

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The danger of climate change

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limate change (CC), which are changes that occur in the global atmosphere, shows a clear variation in either the state of the climate or its fluctuations. The CC that occurs on Earth usually continues for long periods of decades or more. CCs have begun since the formation of the earth, as the earth has gone through many climatic changes such as ice ages and heat waves that have taken over the earth for millions of years, as ice caps and forests spread, and sea levels rose and decreased, and all of this is mainly due to climatic changes. It is worth noting that it must differentiate between climatic changes and weather diversity, as climatic changes last for very long periods, while weather changes last for relatively short periods 1,2.

CC has a serious effect on the environment include effects on Global warming, crops, water resources, the strength of hurricanes, increasing drought, and human health. CC is one of the most important reasons that affect the environment, as droughts and changing global rainfall patterns can destroy livelihoods. In addition to the spread of dangerous diseases such as malaria and dengue fever. It is worth noting that climatic changes affect the natural wild habitats. As well as it creates crises that are difficult to recover from 3.

CC contribute to the increase in the average temperature of the Earth’s surface by more than 0.9 degrees Celsius since 1906. Human activities are the basis of increasing Global warming, which contributes to the addition of greenhouse gas to the atmosphere leading to a rise in the global temperature. This rise led to melting of glaciers and sea ice, change in rainfall patterns, rising Sea levels, destruction of some wild habitats, and migration of animals to cooler regions 4.

CCs such as changes in temperature, weather intensity, and the proportion of carbon dioxide in the atmosphere affect agricultural crops significantly, as these changes can affect the increase or decrease in the number of crops planted according to the type grown and the conditions required for them to grow. The most important effects of CC on crops involve the increase in the level of carbon dioxide, which is good for crops, as it can help increase the growth of plants. However, Extreme temperatures and increased rainfall inhibit crop growth. Also, both floods and droughts prevent the growth of crops. Also, CCs can encourage the growth of weeds, fungi, and pests, which will prevent the growth of crops 5.

 Further, CC greatly affects water supplies and food production in various parts of the world, and as a result, the lack of drinking water can lead to very great damage to all different sectors. The most prominent effect of CC on water resources includes increased water evaporation, which affects the absorption of water from oceans, lakes, soil, and plants. Heavy rainfall on the land leads to floods, which can cause the death of large numbers of people and animals. Also, the temperature change leads to a change in the main ocean currents 6.

CC is a key factor in increasing drought on Earth, as rising temperatures can accelerate the transfer of water from the Earth’s surface to the atmosphere, which will increase drought, and thus drought can cause great damage to water resources in the future. It can also affect population growth, increase pollution, raise living standards, change eating habits, change agricultural practices, increase industrial activities, change economic activities, increase demand for water and energy, and changes land use and urbanization 7.

Additionally, CC affects in some way on hurricanes. The stronger the hurricanes, the greater the destruction caused by them. As it is believed that hurricanes appear as a result of a state of instability in the atmosphere, and thunderstorms resulting from CC may be the main reason for the emergence of Hurricanes 8.

In addition to the impact of CC on the environment, it also affects human health significantly, as a change in climate can change the basic factors that affect human health, as CC can result in air pollution, availability and quality of food and drinking water. Therefore, the safety of these factors is important to maintain human health. Researchers at the World Health Organization expect that CC will contribute to an increase in deaths by 250,000 annually between 2030 and 2050. The most prominent effects of CC on human health includes the effects on the spread of insects that carry infectious diseases, increasing human fears causing anxiety and despair, the increase in temperature which affects the action of some types of medications, such as those used to treat schizophrenia. Also, human exposure to high temperatures leads to many health problems such as Heatstroke, heat exhaustion, muscle spasms, and respiratory diseases.

Also, CC causes an increase the migration from drought-ridden rural areas to urban cities, where these migrations will overcrowd urban cities, and thus raise the risk of disease. There are a set of studies and statistics that have been recorded for cases that have suffered from the effects of CC, which have led to major health problems in humans and even reached death. According to the Centers for Disease Control and Prevention, suicide rates increase with higher temperatures, the nutritional value of foods can decrease due to CC, and about 98 people die each year due to floods in the United States. Researchers say that natural disasters greatly affect people’s mental health, and these disasters can also cause post-traumatic stress disorder (PTSD) 9,10.

Therefore, several actions must be taken by individuals and governments to reduce the effect of CC. These actions involve Increasing energy efficiency and using renewable energy, applying climate-smart farming practices and forest expansion, reducing the use of fossil fuel, and reducing the use of plastic, which is highly contribute to the generation of greenhouse gases.

References

  1. “What is Climate?” WMO, www.wmo.int,
  2. Climate Change”, Encyclopedia, https://www.encyclopedia.com/earth-and-environment/atmosphere-and-weather/weather-and-climate-terms-and-concepts/climate-change
  3. Environment and climate change”, UNICEF, https://www.unicef.org/environment-and-climate-change
  4. Effects of global warming”, National Geographic, https://www.nationalgeographic.com/environment/article/global-warming-effects
  5. Climate Change Impacts”, EPA, https://19january2017snapshot.epa.gov/climate-impacts/climate-impacts-agriculture-and-food-supply_.html
  6. How Climate Change Impacts Our Water”, Columbia, https://news.climate.columbia.edu/2019/09/23/climate-change-impacts-water/
  7.  “Climate Change and Its Impact on Water Resources”, Researchgate, https://www.researchgate.net/publication/314210788_Climate_Change_and_Its_Impact_on_Water_Resources
  8. Tornadoes and Climate Change”, National Geographic, https://www.nationalgeographic.org/article/tornadoes-and-climate-change/#:~:text=Some%20studies%20predict%20that%20climate,of%20supercell%20thunderstorms%20produce%20tornadoes
  9. “Climate change and health: Impacts and risks”, Medical News Today, https://www.medicalnewstoday.com/articles/climate-change-and-health#food-security
  10. At the Crossroads of Climate Change and Global Security”, UN, https://www.un.org/en/chronicle/article/crossroads-climate-change-and-global-security
Brine entering the Mediterranean, 300 metres off the coast of Israel. (Image: Hagai Nativ / Alamy) Blog

Environmental Impacts of brine discharge from Desalination plant on…

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owadays, the lack of freshwater is expanding with increasing the world population, urbanization, contamination, and environmental change. To keep up the equilibrium between water supply and demand; some strategies should be implemented. The best system to treat saline water is desalination. Desalination is a process of removing dissolved minerals and pollutants from seawater, brackish water, and treated wastewater Different desalination technology has been developed based on evaporation and membrane technology Table 1. 1 2

    

       Table 1 Desalination technology and mechanism 2

Most of the desalination plants are built on the coastline, where seawater is used to produce fresh water. The brine water (BW) is the byproduct of the desalination process and is discharged into the sea again by channels or pipelines. It has a high concentration of dissolved minerals, salts, and temperature compared to seawater. The brine characteristic depends usually on the type of feed water and desalination process, recovery percentage, and chemical used in the desalination process 2 3.

The BW has two different behaviors when it is dumped into seawater. The first behavior is near the discharge point, and it is called the near field region behavior. The second behavior is far from the discharge point, and it’s called the far-field region behavior. The Near-field region depends on the design of the brine discharge system, which is intended to increase the dilution rate at this region. The Far-field region is located far from the discharge point, where the brine is flowing down the seabed due to gravity current. In far regions, the brine mixing with seawater depends on ambient conditions and density differences between the Hypersaline brine and the receiving seawaters.

Figure 1 shows the near and far-field region 1.

BW discharge to seawater can cause a change to seawater salinity, alkalinity averages temperature, and can cause a change in the marine environment. The BW characteristic usually depends on the type of feed water, desalination process, recovery percentage, and chemicals used in the desalination process. Also, Brine discharge into seawater has several environmental impacts on marine life.4

The List of the environmental Impacts of a desalination plant on the seawater environment includes salinity, Temperature, Dissolved Oxygen, Chlorine Concentration, unionized ammonia, and Seawater Intake.

BW Salinity can lead to an increase in the seawater salinity level near the discharge point.  The negative effect of brine discharge occurs with the sensitive marine ecosystems 3 4. According to the Medeazza study, changes in the salinity of seawater have a potential to heavily affect marine biota. Changes in Seawater salinity affect the propagation activity of the marine species, their development, and growth rate. “Larval stages are very crucial transition periods for marine species and increasing salinity disrupts that period significantly”  5 6.

Also, some of the desalination plants are combined with power plants. Power plants produce water effluent at high temperatures. These water effluents are mixed with BW from the desalination plant and discharged into seawater causing an increasing the seawater temperature between 7 °C to 8 °C. The raises in the seawater temperature leading to a change in species composition and abundance in the discharge region. 4 6

Seawater dissolved oxygen level is a very important factor and depends on the temperature. By increasing the temperature of the seawater near the discharge point, the amount of dissolved oxygen will decrease. That causes Hypoxia, which is resulting from the low level of dissolved oxygen concentration in water, and it can cause serious damage for the marine life 6 4

Moreover, the presence of high chlorine concentration in BW can lead to the formation of hypochlorite and hypobromite in seawater, which affect seawater quality and the ecological system. Chlorine affects the fish and marine invertebrates can cause burns in both of them and resulting in serious damage to the marine organisms (Boumis). 4

Ammonia substances and un-ionized ammonia are very toxic to marine life. The ratio of ammonia substance and un-ionized ammonia are PH dependence. With increasing the PH, the concentration of both ammonia substance and un-ionized ammonia increases. The concentration of both ammonia substance and un-ionized ammonia in the discharge region depends on the size of the plant and the ambient seawater conditions. Usually, the concentration of ammonia substance and un-ionized ammonia should meet the water quality standard because they are very toxic and harmful for marine life 4 (Mohamed 2009).

Seawater Intake has the most impact on marine life.  Substantial Seawater intake can be very harmful to marine life, by causing Entrainment & impingement. Impingement happens when large organisms such as fish are pulled into the water intake pipe and looked in intake pipe mesh, causing death or injury of these organisms. Entrainment happens when small organisms pulled into the water intake pipe and pass the intake pipe mesh to feed the water tank, causing the death of these organisms in a pre-Chlorination process 6

Nowadays, the continuous increase of water desalination plant numbers led to the development of methods and processes to minimize the negative impact of BW discharge. There are many strategies for decreasing the negative impact of brine discharge. The main strategies include BW treatment before discharge and redesigning the desalination plant.6

Desalination plant brine can be treated before discharging into seawater to reduce the impact on the marine environments. In brine discharge into the seawater surface, outfall diffusion devices such as diffusion nozzles can be used to dilute the brine with the surface seawater. Also, the brine can be diluted with treated wastewater before the discharge into seawater. Further, the brine can be evaporated naturally by spreading it in pools and reused the solids lefts. These strategies are suitable for small and medium-sized desalination plants. It reduces the salinity of the brine and decreases the negative impact on the marine environment 6 7 8

The environmental impact for desalination plants can also decrease by designing them in a sustainable way and by installation mechanisms reduces their negative impact. Beach wells or infiltration galleries are one of the mechanisms that are used to reduce the negative impact. Beach wells or infiltration galleries work as a natural filter for feed seawater. It keeps out the marine organism, increases the quality of feed water, reduces the cost of pretreatment and Impingement, and entrainment. Jet brine release is another mechanism that can be added, where the brine released at an angle of 30-45⁰ can enhance brine mixing and offshore transport in coastal water. This leads to a decrease in the intensity of brine plumes resulting in a decrease in the salinity level 8 9.

However, BW management is on from the biggest challenge economically and environmentally. But Still, BW monitoring and quality standards should be applied in the desalination plant. More research and development in the field of brine impact on the environment and processes to reduce this impact should be further investigated. Research and comprehensive studies to minimize the negative impact of desalination plants should be carried out in water research centers and water authorities.

References

1.      Palomar P, J. I. Impacts of Brine Discharge on the Marine Environment. Modelling as a Predictive Tool. In: Desalination, Trends and Technologies. ; 2011. doi:10.5772/14880

2.      Danoun R. Desalination Plants: Potential impacts of brine discharge on marine life. Final Proj Ocean Technol Gr. 2007.

3.      Panagopoulos A, Haralambous KJ. Environmental impacts of desalination and brine treatment – Challenges and mitigation measures. Mar Pollut Bull. 2020. doi:10.1016/j.marpolbul.2020.111773

4.      Dawoud MA. Environmental Impacts of Seawater Desalination: Arabian Gulf Case Study. Int J Environ Sustain. 2012. doi:10.24102/ijes.v1i3.96

5.      Meerganz von Medeazza GL. “Direct” and socially-induced environmental impacts of desalination. Desalination. 2005. doi:10.1016/j.desal.2005.03.071

6.      Ahmed M, Anwar R. An Assesment of the Environmental Impact of Brine Disposal in Marine Envirnmento. Int J Mod Eng Res. 2012;2(4):2756-2761.

7.      Castillo RS, Maria J, Sanchez S, Castillo NS. Brine Discharge Procedures to Minimize the Environmental Impact and Energy Consumption. October.

8.      Salt HITS. Desalination: is it worth its salt? A Primer on Brackish and Seawater Desalination. 2013;(November).

9.      Laspidou C, Hadjibiros K, Gialis S. Minimizing the environmental impact of sea brine disposal by coupling desalination plants with solar saltworks: A case study for Greece. Water (Switzerland). 2010. doi:10.3390/w2010075

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Covid-19: Potential Wastewater Risks

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he coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread widely, becoming a global pandemic. COVID-19 symptoms include cough, fever, difficulty breathing, and diarrhoea. Genetic material from SARS-CoV-2 ribonucleic acid (RNA) has been detected in the faeces of both symptomatic and asymptomatic people who have been infected 1.

This pandemic has become one of the most significant international public health challenges of this century; globally, nearly 53 million cases and more than 1.3 million deaths have been counted to date 2. Tools for rapidly identifying, containing, and mitigating the spread of SARS-CoV-2 are crucial for managing community transmission, particularly until a vaccine or effective pharmaceutical intervention is developed and becomes widely available 3.

Considering recent epidemics that have emerged around the world, there has been increasing awareness regarding the risk of exposure to pathogens during wastewater collection and treatment. Emerging pathogens may enter wastewater systems through several pathways, including viral shedding in human waste, animal farming, hospital effluent, or surface water runoff following biological incidents. Sewage and wastewater systems transport water to wastewater treatment plants (WWTPs), and the water is then discharged into the environment. SARS-CoV-2 viral material poses a significant threat to human health, and their transmission in wastewater systems may lead to increased exposure, potentially causing serious health consequences. This virus is primarily transmitted through person-to-person and aerosol/droplet transmission via the respiratory system, with fomite and touch-based contamination comprising a lesser proportion of cases. Potential exposure and transmission through sanitation systems have not been sufficiently studied and require further evaluation 4 5.

Environmental surveillance has commonly been implanted in public health management, and methods such as testing wastewater for evidence of pathogens can indicate the severity and scope of pathogenic spread in communities. In the context of the ongoing COVID-19 pandemic, environmental surveillance methods are being used to evaluate SARS-CoV-2 shed in wastewater via human waste 6. Wastewater monitoring exhibits significant promise as an early detection approach. However, available data indicate that the role of wastewater as a potential source of pathogens and as a risk factor for public health must be further explored 4.

Further, genetic material from SARS-CoV-2 in untreated wastewater and/or sludge has been detected in many regions, such as Milan, Italy; Murcia, Spain; Brisbane, Australia; multiple locations in the Netherlands; New Haven and eastern Massachusetts, United States of America; Paris, France; and existing poliovirus surveillance sites across Pakistan. Researchers in the Netherlands, France, and United States of America have reported a correlation between wastewater SARS-CoV-2 RNA concentrations and COVID-19 clinical case reports; research from the latter two countries further suggests that wastewater virus RNA concentrations can provide a 4- to 7-day advanced indication of incoming COVID-19 confirmed case data 6.

Recently observations of viral material in wastewater have intensified the need for the acquisition of more information on the transmission pathways of SARS-CoV-2 through various environmental exposure pathways, including that of wastewater. Wastewater is known to be a major pathogen transmission pathway, and contaminated water should be treated carefully to reduce the risk of human exposure 7. Moreover, contamination risk is extremely high in densely populated regions with minimally developed sewage and wastewater treatment facilities. This is particularly critical for SARS-CoVs, as they can survive for several days in untreated sewage and longer in colder regions 8.

Conventional sewage treatment methods that include disinfection are expected to effectively eradicate SARS-CoV-2 8. Despite ongoing treatment strategies, recent studies have shown that SARS-CoV-2 RNA has been found in the outlet of WWTPs as well as in water bodies receiving treated wastewater, indicating a serious public health risk via the faecal–oral or faecal–aerosol infection routes 9. Covid-19 transmission through wastewater poses a major concern in areas without adequate sanitation and water treatment facilities, as discharge of wastewater without appropriate treatment would expose the public for infection 7. Globally, approximately 1.8 billion people access faecal-contaminated water sources as drinking water, which significantly increases the risk of COVID-19 transmission by several magnitudes when proper precautions are not taken8. Therefore, the risk of infection through various forms of contact with conventionally treated wastewater cannot be dismissed.

Owing to the lack of clean natural water resources in many countries, treated and untreated wastewater is increasingly used for irrigation. In addition, sludge from treated wastewater has been applied as fertilizer, and it is increasingly used as an agricultural amendment. The viruses contained in this wastewater and sludge are thus deposited on crops and soil where they are likely to survive for a short period. This can facilitate further spread into ground and agricultural water sources, further increasing the risk of exposure. It is therefore important to understand the survivability of and exposure risk to these viruses, specifically on crops and soil. Studies on viral survivability in such conditions can only be conducted with enteric viruses that can multiply in cell cultures. Complex methods are required as the presence of the viral genome alone does not indicate the presence of infectious viral particles 4.

Wastewater Use in Irrigation Higher Than Thought | Fluence

 Although the extent of infectivity associated with SARS-CoV-2 RNA in treated wastewater is not yet clear, the potential risk can be minimized by ensuring complete viral RNA removal in wastewater treatment plants 9. It may be beneficial to add an additional disinfection step, or ‘tertiary treatment’, to further reduce the risk posed by viral pathogens. Disinfection methods for wastewater effluents and water include physical and chemical techniques, such as ultraviolet light and heat treatments as well as chlorine and ozone treatments, respectively. Ozonation and UV irradiation are reported to be more effective than chlorine-induced reactive oxygen species formation; however, the latter induces residual disinfection, which ozonation and irradiation cannot facilitate 10. Moreover, chlorine addition to create a residue after ozonation can be performed to produce water free of toxic residues. Despite existing disinfection techniques, further investigation is required to determine dose and contact time for SARS-CoV-2 inactivation 4 8. In addition to conventional treatment methods, household disinfection techniques such as boiling, nanofiltration, UV irradiation, and bleaching powder addition in appropriate doses are also effective and should be evaluated for regions without safe piped water supplies and centralized water treatment facilities.

References

1.      Ahmed W, Angel N, Edson J, et al. First confirmed detection of SARS-CoV-2 in untreated wastewater in Australia: A proof of concept for the wastewater surveillance of COVID-19 in the community. Sci Total Environ. 2020. doi:10.1016/j.scitotenv.2020.138764

2.       WHO Coronavirus Disease (COVID-19) Dashboard. Covid19.who.int. https://covid19.who.int/. Published 2020. Accessed November 14, 2020.

3.      Hassard F, Lundy L, Singer AC, Grimsley J, Cesare M Di. Comment Innovation in wastewater near-source tracking for rapid identification of COVID-19 in schools. The Lancet Microbe. 2020;5247(20):19-20. doi:10.1016/S2666-5247(20)30193-2

4.      Lahrich S, Laghrib F, Farahi A, Bakasse M, Saqrane S, El Mhammedi MA. Review on the contamination of wastewater by COVID-19 virus: Impact and treatment. Sci Total Environ. 2021. doi:10.1016/j.scitotenv.2020.142325

5.      Mohapatra S, Menon NG, Mohapatra G, et al. The novel SARS-CoV-2 pandemic: Possible environmental transmission, detection, persistence and fate during wastewater and water treatment. Sci Total Environ. 2020. doi:10.1016/j.scitotenv.2020.142746

6.      WHO. Status of environmental surveillance for SARS-CoV-2 virus. 2020;(August):1-4.

7.      Kataki S, Chatterjee S, Vairale MG, Sharma S, Dwivedi SK. Concerns and strategies for wastewater treatment during COVID-19 pandemic to stop plausible transmission. Resour Conserv Recycl. 2021. doi:10.1016/j.resconrec.2020.105156

8.      Bhowmick GD, Dhar D, Nath D, et al. Coronavirus disease 2019 (COVID-19) outbreak: some serious consequences with urban and rural water cycle. npj Clean Water. 2020. doi:10.1038/s41545-020-0079-1

9.      Abu Ali H, Yaniv K, Bar-Zeev E, et al. Tracking SARS-CoV-2 RNA through the wastewater treatment process. medRxiv. 2020:2020.10.14.20212837.

10.    Zhang CM, Xu LM, Xu PC, Wang XC. Elimination of viruses from domestic wastewater: requirements and technologies. World J Microbiol Biotechnol. 2016. doi:10.1007/s11274-016-2018-3

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