Emerging contaminants in drinking water and wastewater treatment

Contaminants in Drinking Water and Wastewater and Effects on Environment

Drinking water and wastewater contamination pose a significant threat to the public health sector. The contaminants affect the society in various ways, including causing diseases, developmental and growth problems. The causes of the problem are identifiable and can be managed by using the most applicable strategies. As such, necessities for the adoption of strategies that will help identify the contributing factors, results and adopt effective strategies that will prevent and reduce waterway pollution. Therefore, the research provides analysis on the effects, studies, and recommendations appropriate in reducing drinking water and wastewater contamination.

Introduction

A number of chemicals play a significant role in influencing human activities of the daily living. They enable the development of new technologies and improve the standards and quality of life. Because of the widespread use of technology, chemicals enter the environment. Although, it is unintentional in most cases, some chemicals like pesticides are released deliberately into the environment. Water forms a major and significant means by which these chemicals reach the living organisms in the environment, which exert their effects upon consumption, or accumulate in the water bodies. Therefore, water carries the imprint of all the activities performed by human beings. The chemicals in the water can be either macro pollutants or micro-pollutants depending on the concentration of a chemical in the water body. Micro-pollutants and macro-pollutants have significant impacts on the environment, which varies depending on the concentration of the chemicals. The increasing amounts of pollutants have raised concerns among different agencies globally to embrace the adoption of strategies will help reduce the postulated consequences associated with the high levels of pollutants in the environment (Altaf, Masood, and Malik, 2008).

Structure of this research paper

This researcher analyzes in detail the different emerging wastewater and drinking water treatment. The analysis begins by discussing some of the emerging contaminants of wastewater and drinking water alongside their effects on health and the environment. The paper also analyzes the fate and the assessment of the emerging contaminants alongside providing an analysis of the different methods of treating contaminants of wastewater and drinking water. It ends by providing recommendations aiming at minimizing the contaminants and strengthening the treatment methods used for minimizing the contaminants in the society.

Fate of the emerging contaminants of the drinking water and wastewater

The fate of the contaminants of drinking water and wastewater varies depending on the source of the contamination. Empirical studies show that contaminants bind to different particles and compounds as they are transported to the sewage plants. Richardson (2003) explains that, the ability of a contaminant to remain unchanged in a treatment plant depends on the medium it attaches itself while under transportation to the plant. For example, he found that, particles such as those of sand and quartz retain and stops the release of the contaminants outside the treatment plan. This implies that, the absorption strength of a transporting medium determines the fate of a drinking water and wastewater contaminant. Srinivasa, Ramakrishna, and Govil (2010) added that, the nature of the lining of a treatment plant influences the rate of escape of wastes into the environment. The material used as the lining of the treatment plant form a barrier to transport of contaminants and its ultimate release to the atmosphere.

Biological degradation contributes to the elimination of wastewater and drinking water contaminants. A study conducted by Richardson and Ternes (2005) found that biological degradation contributes to the removal of pharmaceutical and personal care products in the wastewater treatment. Triclosan and tribocraban are some of the drinking water and wastewater contaminants eliminated by biological degradation. Mitch et al. (2003) added that aerobic reactions that occur during the loading of the contaminants contribute a larger percentage of the degradation of these products. However, it is appreciable that, not all the pharmaceutical and personal care products are eliminated from the treatment plant. According to Richardson and Ternes (2005), pharmaceutical products such as the beta-blockers exit the plant effluent without its removal. This contributes to the contaminants found in the drinking water and wastewater.

As stated by Srinivasa, Ramakrishna, and Govil (2010), the environmental fate of the contaminants of drinking water and wastewater depends on the physical and chemical characteristics of the media that transport the contaminant. Biodegradation plays a key role in eliminating the endocrine disrupting compounds as in the case of the pharmaceutical and personal products. Apart from this, volatilization contributes to the elimination of the endocrine disruptors and the pharmaceutical care products. Leaching into the ground water contributes to the elimination of some of the contaminants having low vaporization abilities. Atmospheric fate contributes to the elimination of the Nona toms, which occurs through a reaction between the particles of the contaminant with the hydroxyl radicals in the atmosphere (Richardson, 2009).

According to Richardson (2003), chlorination and reductive de-chlorination contributes to the fate of the organic waste contaminants. The fate of persistent organic pollutants (POPs) varies depending on the geographical location of a place. For example, the fate of POPs in the arctic regions is different from that of the desert environment. It is appreciable that, POPs are non-biodegradable in nature. As such, moving water transports the contaminant into different compartments of the earth system. It also carries the contaminant into remote regions that might be minimally proximal to animal access (Richardson and Ternes, 2005).

Assessing the emerging contaminants of wastewater and drinking water

Assessing the emerging contaminants of drinking water and wastewater takes into consideration the sources, effects and severity of the effects of contaminants to the environment, plants, and animals. The assessment aims at determining the amount of the contaminants released to the environment and the adoption of strategies that aim at minimizing the release and effects of the emerging contaminants. Petrovi?, Gonzalez, and Barcelo (2003) stated that, risk assessment of the emerging contaminants helps in the formulation of goals that help in protecting the public and the environment. Assessment enables the involve parties to determine the effectiveness of the planned goals for reducing the impacts of the emerging contaminants in the environment. Successful assessment of the emerging contaminants involves evaluating the occurrence of the emerging contaminant, evaluating the exposure of the contaminant and compliance choices for the regulatory alternatives. In addition, it entails the assessment the alternatives available for preventing and reducing incidences of the emergence of contaminants. Epidemiological studies facilitate the success of the assessment process (Pruden et al. 2006).

Treatment and Removal Methods of the Emerging Contaminants of the Drinking water and Wastewater

There are different methods of treating drinking water and wastewater alongside removing the emerging contaminants. These techniques as stated by Mitch et al. (2003) include advanced oxidation processes (AOPs), adsorption, Reverse Osmosis Membrane (RO), and Nano-filtration (NF). However, most organizations face the challenges of using these methods efficiently due to the high investment and maintenance costs associated with the methods. Complicated procedure in treating the contaminants and massive generation of toxic wastes compounds to the challenges associated with the effectiveness and adoption of these methods. Apart from this, physicochemical treatments are considered effective in cases that do not involve the elimination of the endocrine disrupting compounds and pharmaceuticals and personal care products (Peabody, Taguiwalo, and Robalino, 2006). Empirical evidence shows that, the adsorption method of treating and eliminating emerging contaminant is more superior as compared to the other methods. The adsorption method does not add undesired by-products to the water under treatment and has a simple design that makes it easy to operate. Adsorption process is easy to operate and the insensitivity of the toxic substances it uses and/or eliminate (Levine and Asano, 2004).

The adsorption method uses a mass transfer mechanism that involves the accumulation of contaminants in two phases that promote their elimination. Physisorption and chemisorption are the two key interactions that promote the elimination of the contaminant and water treatment. The adsorption method incorporates the principles of Wastewater Treatment Plants (WWTPs) in the partial removal of the micro pollutants through biological degradation, stripping, and sorption. Activated carbon, clays, minerals, and agricultural wastes as some of the adsorbent agents used to facilitate the process. The agents provide a sorption medium for many emerging contaminants (Jones, Lester, and Voulvoulis, 2005).

Reverse osmosis membrane uses a semi-permeable membrane to treat drinking water and wastewater alongside eliminating the emerging contaminants (Focazio et al. 2008). Pressure is applied to overcome the osmotic pressure, which is driven by a positive chemical potential. This removes different types of ions and molecules from the water solution. In the end, a solute is retained on the membrane side while the pure solvent passes to the opposite side. The method use straining and size-exclusion processes to eliminate the contaminants in the solution. However, this method is less effective as compared to the adsorption method since it does not eliminate endocrine disrupting compounds, pharmaceuticals, and personal care products (Chen et al. 2006). In addition, Bolong et al. (2009) added that, the process uses much water as it relies on low backpressure for its effectiveness and enhanced functioning. Thus, there is a significant wastage of water used for treating the water. This is because of a significant wastage of water (85%) used for treating and eliminating the contaminants.

On the other hand, advanced oxidation process uses hydroxyl radicals that remove contaminants in water through oxidation. The method proves effective in the elimination of non-biodegradable emerging contaminants. Altaf, Masood, Malik, (2008) states that, advanced oxidation processes are more effective in treating water contaminated with persistent organic pollutants. The method operates on different chemical principles such as the formation of the hydroxyl ions and reaction with the oxide ions of the contaminant promoting its elimination. On the other hand, Nano-Filtration (NF) removes contaminants as in the case of reverse osmosis. The method helps in the elimination endocrine disrupting compounds, pharmaceuticals, and personal care products.

Conclusion

Contaminants of drinking water and wastewater have numerous risks to the environment. The effects of the contaminants range from developmental, growth, and reproductive effects. The causes of these effects can be identified. Adopting the most effective strategies will contribute to the reduction of the incidences of adverse environmental effects brought by drinking water and wastewater contaminants. Therefore, it is highly recommended that interventions aiming at determining the source of contamination, and responding to the challenges should be adopted to ensure environmental safety and sustainability.