Collect and treat urban wastewater to fight the pandemic disease of COVID-19 effectively

This paper presents multidisciplinary and innovative research concerning fighting against coronavirus through wastewater collection and treatment. Studies suggest that coronavirus exists in the wastewaters. Untreated wastewater is proved to spread the virus. Coronavirus is attacking people globally and shrinking the economy. This paper highlights the idea that the coronavirus shall be defeated with the help of wastewater collection and treatment as well. The question addressed by this paper is will communities defeat the coronavirus without well-collected and treated wastewaters? This research aims to display the role of wastewaters in the spread of coronavirus in cities and to require their collection. The methods to achieve the goals are theoretical surveys, case study strategy, mathematical modeling, statistical procedures, forecasting of future, and dialectical discussions. The findings of this research demonstrate the need for carefully collected and treated wastewaters to overcome the coronavirus. This paper gives suitable techniques to collect and treat wastewater such as wastewater stabilization ponds, bacterial reactors, and anaerobic ponds. The innovative idea of this paper, its suggested indicators to select a certain wastewater treatment technique in every city, and its outcome will assist the global community to fight the coronavirus more effectively.


Introduction
COVID 19 disease is an infectious disease caused by a newly discovered coronavirus [1]. The coronavirus attack on the people of the world came as a surprise. The coronavirus emerged when states that were prioritizing public health care and providing more medical services gave way to governments with policies of austerity and privatization of enterprises [2], [3] and [4]. The coronavirus emerged when the world was proud of its scientific and medical advances in recent decades. The world had controlled some dangerous infectious diseases and thought that it would control any other epidemic easily [5]. Also, the coronavirus emerged when class and income differences between social groups and individuals in societies had become much greater than before [6] and [7]. As a result, many people lost access to health products (such as masks, alcohol, disinfectant solutions, etc.), medical devices (such as ventilators, refrigerants, oxygen capsules, etc.), and medicines that help the patient. Worse, local and regional wars and conflicts in parts of the world have taken over the budgets of some militant countries. The governments of those countries have essentially left the people defenseless against the COVID-19 disease. Worst of all, the results of information communication technological advances in the monopoly of unqualified governments have prevented the publication of real statistics on the casualties of COVID-19 disease. The governments filter information concerning widespread damages caused by the virus to the lives and economy of the people [8]. In this situation, problems such as lack of safe drinking water, unclean living environment, and untreated sewage in the streets and alleys of cities have also increased the arrogance of the coronavirus to attack public health [9]. Therefore, as an essential step in the fight against the coronavirus, the collection of wastewaters from the cities and their treatment should be an important project of local administrations, national governments, and international organizations such as WHO and UNDP [10], [11] and [12].
The question is can we defeat the coronavirus without well-collected and treated municipal and household wastewaters? Another question is that in this economic crisis and the urgency of cleaning the environment, which wastewater treatment technique shall we use?
This study aims to show the role of municipal and household wastewaters in the spread of coronavirus in communities. The purpose is also to emphasize the collection and treatment of wastewaters to protect the health of the people of the community. Therefore, in this article, the most appropriate techniques for wastewater collection and treatment will be proposed and analyzed.
The method of this research is field studies with mathematical modeling to show the capacity of wastewaters in the streets of cities in terms of increasing the number of death tolls due to COVID-19 disease. The statistical technique of the trend line is also used to predict death tolls from this disease in future months.
The findings of this study show that those trying to fight the coronavirus cannot overcome the evil virus just in hospitals. Well-collected and treated wastewaters as important factors are required in achieving this victory as well.

Theoretical exploration
Newly, researchers declared that wastewaters include coronaviruses [13]. Scholars have shown that coronavirus exists in Stockholm's municipal wastewater [14]. In Stockholm's wastewaters, the amount of coronavirus has become doubled in recent weeks. It is now reached to the same amount of May 2020 [14]. New findings confirm that wastewater analyzes can warn concerning future virus outbreaks [14]. Stockholm is one of the most advanced cities in the world in terms of wastewater collection and treatment, clean environment, urban infrastructures, and public healthcare system [15].
In countries with unqualified urban administrations and the majority of impoverished people, wastewaters are discharged from households to the sidewalks. The sewage of such cities flows in open streams in the streets and passages. The wastewater is exposed to touch, inhalation, the breath of people, and penetration into the body of humans and living things in society.
Experiences about the COVID-19 disease show that poor people living in neighborhoods polluted with the wastewaters flowing in the streets are more infected or dead than affluent people in clean A procedure to detect viruses in the water distribution systems had been introduced earlier by Chastain "The COVID-10 pandemic gives us an important stimulus to reevaluate health in the context of a circular system that encompasses human and environment in which we live" [26]. We simulate the idea of Chastain to detect the coronavirus and declare as the following: 'The successful transmission of a coronavirus infection might depend on some factors such excreted volume of the wastewater, the latency of the wastewater on the ground, the persistence of the virus, multiplication of the virus, spatial infectivity, and susceptibility of the individuals'.
Urban wastewater contains a range of organic matter, food, chemicals, human waste, and microorganisms. The city's sewage contains human body waste (feces, urine, nails, and hair) as well as water used to wash the toilet. Domestic sewages contain a wide range of chemicals such as detergents, soaps, fats, and possibly various types of pesticides from home gardens and pots.
Microscopic organisms capable of causing human diseases are also in the wastewaters [27]. An infected person may become diseased, depending on his or her susceptibility to the COVID-19 disease through geohelminths, human cestode and trematode worms, leptospirosis, and coronavirus itself that are included in the wastewaters. Non-treated wastewaters will increase the incidence and prevalence of new cases of COVID-19 disease in a community that occurs in a specified period and a specified point in the time respectively [28]. Figure 1 exhibits that the trend of the number of daily infected people by the coronavirus is additive. and [21]. We may choose one of the following options to collect and treat the wastewater aimed at protecting communities' health against COVID-19 disease and other sicknesses. Wastewater shall be collected in underground pipes (sewers . It is necessary to say that the choice of one or more techniques shall be based on the cognition of the site and the strategic goals of the area. To collect, treat, and even reuse wastewater and to have a healthy and clean environment, the climatic conditions, spatial design, and socioeconomic strategies of every city or region must be carefully analyzed.

Applied methods and case studies
Theoretical studies in the prior section aimed at shaping a guideline for the case studies. Both    Sewage is not eye-catching in appearance and is objectionable. It is not intolerable. It is also dangerous to health. The presence of pathogenic organisms, especially the extremely coronavirus made the wastewater dangerous. Domestic sewage quickly loses its dissolved oxygen and becomes septic. Septic wastewater has an unbearable odor, usually due to hydrogen sulfide. Iranian cities need wastewater management and treatment for three reasons: First, wastewater contains microorganisms that transmit diseases to humans in society.
Second, the impact of sewage on the biology of society, living things, and plants can cause the spread of COVID-19 disease from plants and animals to humans.
Third, it pollutes and degrades the environment, which has detrimental effects on the socioeconomic success of the cities.

Figure8. Trend line exhibits the daily death trolls in coming weeks
As you can see in the picture above, the trend line is, unfortunately, increasing with a steep slope, which is a warning sign of a human catastrophe. Therefore, if all the variables will be left as today, the COVID-19 disease is increasingly spreading and the catastrophe happens. As an essential solution way, wastewaters in the cities shall be managed, controlled, and treated. The risk of the spreading of the COVID-19 disease through the wastewaters shall be eliminated as soon as possible.
In some cities of Iran, the United Nations Urban Development Organization has called for the construction of modern sewage systems with the help of local authorities. However, due to structural corruption in urban management administrations, financial aid has been looted and projects have been left unfinished. The economic and climatic features of the cities shall be considered in every solution of the sewage problem in cities of Iran.
The first stage of wastewater treatment in Iranian cities, regardless of its type and applied technology, is the removal of large floating objects, plastics, pieces of wood, sands, etc. This action is necessary to prevent these materials from the surface of wastewater stabilization pools. Otherwise, floating air conditioners in aeration ponds or any pump in use may be damaged by the wastes. Separation of waste from wastewater in Iranian cities as the first step includes screening wastewater by installing sieves with appropriate sizes on the way to the wastewater treatment plant.
In cities of Iran with mostly hot and dry or temperate climates, domestic wastewater should be injected with oxygen so that the bacteria in it can consume the substances in the wastewater as their food. Equation (4) shows this process. In the process, the combination of oxygen and bacteria with sewage reproduces water as a product.
Wastewater + Oxygen + Bacteria ⇒Treatedwastewater + newbacteria (4) There are three solutions for injecting oxygen into the wastewater. Different amounts of oxygen shall be injected into the wastewater according to the quality and quantity of the wastewater and the purposes of its treatment: 1. Oxygen is required for oxidation of organic wastewater. This method requires some oxygen to oxidize the organic part of the wastewater and convert it completely to carbon dioxide and water. The method works according to Equation (5) Decentralized wastewater treatment plants and water reuse should always be considered when planning urban land-use policies and physical design of cities because it can be an efficient and optimal procedure.

Discussions
As we have seen, having a clean environment, including the collected and treated wastewater, is vital to fight the coronavirus and to keep people healthy. Socioeconomic indicators in Iran show degradation in natural and urban environments, a decrease in the social capital of the government, a structural and institutionalized corruption in governmental institutions, an increase in social poverty and unemployment, and an increase in social revolts [29]. Economic sanctions and international pressures are also catalysts for now day's problems of Iran. For these reasons and widespread thefts with astronomical figures, the sewages in the cities have been abandoned. According to some government officials, a high percentage of Iranians cannot afford to buy masks, disposable gloves, alcohol, and disinfectants, visiting a doctor, and buy medicine [30]. As our field observations have shown, sewages have been dumped in cities, exposing people to a variety of diseases, including COVID-19. According to researchers at the Royal Institute of Technology, KTH, the coronavirus is present in municipal wastewater [14]. Therefore, wastewaters discharged in cities are accelerating the epidemic of this disease. Figure 1 exhibited that the number of daily new infected people in Iran on October 12 th compared to February 15 th increased by 31%. Our concern is that with the polluted environment, this statistic will continue to rise in the coming months. Our mathematical model shows that between August 29 and October 12, 2020, the number of deaths due to this disease was increasing. The death tolls on October 12 were 272. Comparing this statistic with other countries respecting the number of population in every country, Iran ranks first in the world in terms of death tolls due to coronavirus. Note that these statistics are official that many researchers have got doubts about their validity. Many researchers estimate that the death tolls are three to five times higher [31] and [32]. It is also worrying concerning the prediction of the future death tolls that will be caused by the coronavirus. Our prediction through the statistical method of the trend line is alarming. Our forecast shows that the death statistics are going up and unfortunately Iran will experience many more deaths due to this disease in the coming months.
In our opinion, it is necessary to take action to collect, treat, and manage wastewater as soon as possible. Even responsible international organizations, due to the international connections of human beings, it is good to pay attention to this problem in Iran and similar countries.
As has been said, there are different methods of constructing wastewater treatment reactors with wastewater collection lines and infrastructures that create a centralized system for every city.
However, we think that decentralized systems are suitable for cities in Iran and developing countries.
We recommend decentralized systems on the scale of every urban district. Decentralized models such as wastewater stabilization pools can use natural energies. They are also suitable for the economic and climatic conditions of the cities.
In planning and designing for wastewater collection and treatment systems in cities, indicators such as environmental cleanliness, urban landscape, construction and operation costs of reactors, efficiency, and durability of the system and, its economics should be considered.

Conclusion
This article discusses the presence of coronavirus in urban and domestic wastewaters. It was said that domestic wastewaters and sewages in the slums, which unfortunately includes the majority of people, has been left in allays, streets, and squares.
In this article, citing new sources, it was shown that the wastewater in such communities is the source of the spread of COVID-19 disease. The question addressed in this research was: can we stop the increasing spread of this disease without collecting, treating, and managing wastewater?
Our research methods were examining the latest opinions of world scientists, field studies, mathematical modeling, statistical techniques, forecasting of future, and dialectical reasoning. The findings of this study displayed the interconnectedness of the polluted environment, the uncollected, untreated, and unmanaged wastewater, and the increase in the number of COVID-19 diseases.
This article advises governments and city managers that the fight against the coronavirus should not be limited to hospitals and patient beds. Wastewater discharged into the streets and squares of cities must be collected, controlled, managed, and treated as soon as possible. This action destroys one of the centers of life of the coronavirus. The methods of this research and techniques to collect and treat wastewater can be simulated in any city anywhere in the world to fight COVID 19 disease.