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Emerging Techniques for Treatment of Wastewater

Naseema A. Wani1, Nazir A. Malik2, Younas R. Tantary3, Ishrat Jan4, Tawseef Ahmad5, and Mohammad S. Wani6

1 Department of Botany, Punjabi University, Patiala, Punjab, India

2 Department of Botany, Dolphin PG College of Science and Agriculture, Chandigarh, Punjab, India

3 Department of Botany, Government Degree College, Tangdhar, Jammu and Kashmir, India

4 Department of Zoology, University of Kashmir, Srinagar, Jammu and Kashmir, India

5 Department of Biotechnology, Punjabi University, Patiala, Punjab, India

6 Department of Agriculture, Government Mohindra College, Patiala, Punjab, India

1.1 Introduction

Water is exceptionally a prerequisite for sustaining earthly existence. While 70% of the earth is made up of water, it is surprisingly accessible to only less than 1%. The world population will increase by up to nine million by 2050 with the current population growth rate that may trigger serious freshwater shortages in the immediate future. It is predicted that access to clean water for human needs will be challenging around the globe by 2030, as natural freshwater resources may be under great strain (Wichelns et al. 2015). Regrettably, 97% of the world's surface water is saltwater; two-thirds of the remaining 3% have frozen because 1% of the world's water source is not equally dispersed, and this scarcity is a major trouble in developing nations (Smith 2009). The most important prerequisite of each and every human being is the clean and potable water, but at the same time, usage of this is the utmost responsibility and concern of today's world. Some areas are supplied with water for this purpose despite constant rainfall. There is a shortage in this regard in some areas. In all regions across the globe, this creates a major obstacle in managing water distribution. Water is a predominant factor in the environment which influences human health and other living organisms. The physical and chemical facets of water quality have become a problem with the rise in population, as wastewater from various sources poses a serious threat. Globally, billions of people face the big issue of proper sanitation and clean water supply (WHO 2013). The rapid development of human society throughout the globe in the form of population growth, urbanization, and industrial development has led to an increase in the need for clean and safe drinking water on the one hand and the formation of wastewater on the other. In both the developed world and the developing world, human actions have contributed to water resource pollution by discharging harmful chemical substances from factories, industrial waste, agricultural land, etc., raising some additional load on accessible water supplies and generating large amounts of wastewater (Li et al. 2013). This wastewater approaching from various anthropogenic places is released in a very identical manner into distinct water bodies, which include streams, seas, oceans, and estuaries where it pollutes and significantly damages the aquatic vegetation and fauna. Over the years, various regulations, protocols, and procedures associated with the treatment and release of wastewater into water bodies have been developed and applied around the world and reused to address the continuing challenge of drinking water. But, alternatively, apart from all the rules and regulations, there is another sad truth that a substantial quantity of wastewater has been abandoned untreated or dealt with using strategies that are ineffective and discharged into the environment which subsequently ends in the degradation of the environment. These inadequate sanitation services result in many waterborne diseases (Bixio et al. 2006). According to the WHO, about 80% of the diseases in the developing world are water-related, due to low water quality and lack of sanitation, and this is worse in rural areas (WHO 2013). Lack of sanitation contaminates watercourses around the world and is one of the most important sources of water contamination. Every year there are three million deaths from diarrheal diseases due to Escherichia coli, Salmonella and Cholera bacterial infections, as well as parasites and viruses. The number of children dying of diarrhea in the 1990s was much greater than the number of conflict-ridden victims after World War II (Smith 2009). Furthermore, it is reported that approximately four million humans around the globe have little or no accessibility to safe and sanitized water sources and every year huge numbers of people die from waterborne diseases (Montgomery and Elimelech 2007; Malato et al. 2009).

In order to solve these issues, wastewater treatment is needed to reprocess wastewater in a useful way from distinctive sources. Wastewater treatment approaches that are currently in use have been validated to be effective in the past, but there is a desperate need to reconsider and develop current policies and procedures and create new wastewater management systems if you want to lessen the environmental risk. Another prime advantage of wastewater treatment is that it can be utilized for consuming purposes that will significantly reduce the burden on natural freshwater supplies from increasing water requirements. The World Health Organization reported that 1.1 billion people did not have access to safe drinking water in 2015. So, purifying wastewater and keeping it safe to drink can help reduce the need for drinking water.

1.2 Composition of Untreated Wastewater and Its Effect on Water Bodies

Defining wastewater really is difficult. Water consideration in its natural state, i.e. water from streams, lakes, and rivers, contains a wide range of minerals, nutrients, and suspended and dispersed substances. The water that is employed for one reason may not be suitable for another. Therefore, to explain the purity of water, there is a list of criteria set by various countries for different water groups. In order to make sure of the availability of clean water, changes are made regularly on the basis of the databases accessible across the planet from certain water and health regulatory authorities. Any degradation in water quality due to the involvement of human activities is water pollution. Anthropogenic and ecological waste both together contribute with regard to the switch in the natural constitution of water. Wastes discharged into water bodies of one country do not remain restricted to specific limits, and this leads to an increase in conflict between bordering nations. Therefore, it is an international concern and that is why it needs global support. Every segment of society has been experiencing an increasing need for sustainable use of resources. Wastewater is any water that has been influenced by human consumption. Wastewater is used water from any mechanical, residential, or arming exercises, stormwater, surface overflow, or any sewer inflow or sewer penetration (Almuktar et al. 2018). Because of the water global scarcity issues, the situation is fundamental to consider nonconventional sources of water for satisfying the increase in the need for freshwater. Wastewater is considered an acceptable solution suitable for addressing the scarcity of water resources caused by multiple factors such as population progression (Bichai et al. 2012; Almuktar and Scholz 2016). However, the unbelievable diversity in wastewater sources intrusive of organic and inorganic elements generates the recycling of that water condition to ordered checking to evaluate incoming hazards affecting the overall environment (FAO 2003). Only 20% of the total wastewater produced is treated before it is delivered into the environment (UNESCO 2012). Satisfactory recycling of wastewater is important to look after the health of the community, the environment, and water resources.

Wastewater normally originates from various anthropogenic places that lead to various forms of contaminants and pollutants present in it counting organic, inorganic, and biological origin (Das et al. 2014). Inorganic contaminants and heavy metal pollutants, viz. copper, cadmium, nickel, and zinc, other chemical toxins and pollutants, such as colorants, detergents, hydrocarbons, and biodegradable substances, are contained in drinking water. Also contained in wastewater are biological pollutants, such as bacteria, microorganisms (pathogenic and nonpathogenic), fungi, and viruses (UN Water 2015). All of the three wide variety of contaminants and pollutants discussed if left untreated or not properly handled affects and impacts the environment in a dangerous way that leads to the degradation of the environment and its related problems. The level of impact depends on the contaminant and pollutant type, form, and concentration.

As discussed earlier, wastewater is a complex mixture of many contaminants and pollutants discharged from domestic, industrial, and agricultural places and, when left untreated, these contaminants and pollutants will pollute the water bodies and produce a significant hazard to the water's natural environment.

Biological pollutants of wastewater by pathogenic or nonpathogenic sources from various sources directly or indirectly contaminate groundwater, which can contribute to infection outbreaks. Untreated wastewater from various places is of major concern due to the long-term effect of water resources on the aquatic environment.

1.2.1 Effect on River Water

Globally, river water is the main source of freshwater for humans, and any pollution of any sort...