Water is very important for the survival of living organisms, which include both plants and animals. Sources of water available include rivers, oceans, seas, springs, groundwater, and rainwater. Increase in population, expanded urbanization, and establishment of industries put pressure on sources, quality, and quantity of available water; hence, demand for water increases. As water utilization increases, generation of wastewater increases. The wastewater treatments are described under the followings sub-heading, namely sources and types of wastewater, properties of wastewater, methods of treatment, and challenges of wastewater treatment methods. Information is sourced from the internet through Google search engine. The objective of this chapter is to compile information on emerging contaminants in wastewater, methods that can be adopted in the process of wastewater treatment that will minimize energy use and ensure safety of environment. Green methods of wastewater treatment and disposal are suggested.
TopIntroduction
Good quality water is needed for cooking, drinking, bathing and industries. Polluted water is not suitable for human and animal consumption as it can lead to adverse health effect. Wastewater composition depends on human activities around the sources and the system that generated it. The presence of several emerging contaminants, such as plastics, pharmaceuticals, pathogenic organisms, personal care products and endocrine disruptor compounds in wastewaters is a source of concern (Gogate and Pandit, 2004). The wastewater industry is in a state of transition due to the recent wastewater effluent standards and complexity of the emerging contaminants in water bodies (Moji and Bashir, 2022; Soares, 2020).
These compounds have been identified but the severity of adverse effect associated with some of them is yet to be fully unraveled. The final destination of these compounds is a source of concern as it ends-up in food chain which may initiates adverse health condition and aggravates it in predisposed individuals. Plants, animals and human beings are mostly affected with devastating consequences.
Several factors affect wastewater treatment namely, heterogeneity of influents composition (Wang et al., 2017). Different water pollutant requires different technology for treatment. Nanosilver and microplastic in wastewater portend danger to human health, hence, cannot be treated in the same way as other pollutants. Such pollutants lack a well-defined quality standard that can be tolerated in water environment (Heiss and Kuster, 2015). The temperature at a particular climatic region may affect the activity of microorganisms required for degradation in cases of microbial treatment of wastewater. Other factors are space and energy demand. The increasing level of pollutants from cities and industries compel the need for treatment for appropriate technologies for wastewater treatment (Agyemang et al., 2013).
Sewage sludge that are produced from wastewater treatment contains pathogenic organisms, heavy metals and partially degraded organic matter need to be treated before disposal (European Commission, 2018). The appropriate steps to take is to dewatered, incinerate, disposed professionally as land fill or used for soil amendment. However, nutrients such as phosphorus can be recovered from sludge ash to concentrate in large quantities, elements of interest useful for agricultural purposes. Organics and nutrients in wastewater from agricultural activities has been removed using membrane and biological methods (Gutu et al., 2021) while different types of membrane techniques were found to be useful for the treatment of poultry slaughterhouse wastewater (Fatima et al, 2021).
The increase in uncontrolled peri – urban development, unapproved extension, creation of slums has been making people live in housing structures without facilities like sewerage, electricity, water or paved roads (Harremoes, 1997). Social amenities such as water supply, communication network, access road, transport, energy, health care services and schools are often inadequately provided. In such a situation, people will rely on stream, wells and boreholes for their water sources. There will be no channel for erosion, the wastewater generated will flow freely into the available streams, contaminate the soil and groundwater, exposing people to different types of health related diseases. Mojiri et al. (2020), reported that conventional wastewater treatments have failed to remove emerging contaminants from water bodies. Therefore, researchers have tried to propose new systems with maximum performance in removing emerging pollutants.