Essay on Water and Sewage Treatment

Introduction

Water and sewage treatment is described as the removal of contaminants from the effluent. There are different sewage treatment approaches which form the comprehensive process. This process entails the physical, biological and chemical approaches which are all aimed at removing the pollutants. The central objective of the treatment is to ensure that the sewage is environmentally safe for release while the solid wastes which are referred as sludge are suitable for reuse or disposal (Pronk et al. 209). Notably, the reuse is usually for the agricultural purposes. Recent developments have focused on the converting the sludge to fuel. Essential to note is that the source of this wastewater and sewage include houses, farming, and manufacturing processes. In these wastes, some of the elements that have to be removed include the organic matter, bacteria, nitrates, and phosphates among other pollutants.

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To ensure that the wastewater is safe for reuse and return to the environment, it is imperative to ensure that the contaminants concentrations are reduced to safe levels which are usually outlined by the Environment Agency (Xu et al. 1380). Important to note is that the sewage can be treated near where it is produced or stored. The wastewater is usually transported by the pipes to the treatment area. In water and sewage treatment, factors that determine the systems include the nature of wastes conveyed and the amount of treatment that is required to ensure that the effluent and sludge are safe for release to the environment. While the effluent is directed to the rivers and lakes, the sludge is used in agricultural lands and as fuel. Ensuring the high safety levels is centered on protecting aquatic life.

There are two primary treatment processes which include aerobic and anaerobic. In the anaerobic treatment, the decomposition is initiated by the anaerobic bacteria which is found in the tank and does not use air and in particular oxygen. This is associated with the reduction of the organic matter being converted to various elements including methane, carbon dioxide, and hydrogen sulphide (Bengtsson-Palme et al. 698). This process is used widely based on its merit of mass reduction of sewage quantity. In large-scale treatments, there is the production of methane gas which is currently being examined how it can be used in homes and industries. A common example of a treatment system that adopts the anaerobic system is the septic tank. Essential to note is that since the process is anaerobic, only the sludge that is settled at the tank's bottom produces the methane.

In the aerobic treatment, digestion of the pollutants is aided by the aerobic bacteria. Here, air is imperative for the bacteria to survive and decompose the matter. There are different ways of supplying the air which include direct surface aeration or submerged diffused aeration. In these processes, the air is forced through impellers or bellows. In modern aerobic systems, they do not require electricity and make use of natural air currents. One of the main merits of aerobic digestion is that as a result of the bacterial colony established, digestion and oxidation of the organic compounds and mater to water, nitrogen, and water eliminates odor (Xu et al. 1383). The effluent produced here is safe for release to the watercourse.

In the water treatment systems, there are different stages. In the primary treatment, it is mainly centered on an anaerobic process where the solids and sewage are separated and settle in the tank's basement. The sludge is then continuously reduced in quantity by the anaerobic process. In the secondary treatment, it entails also entails aerobic process where the liquid from the initial treatment that contains particulate and dissolved biological treatment is taken through the next step. Here the obtained waste is transformed into clean water through the use of aerobic bacteria and microorganisms which are responsible for digesting the pollutants. This effluent is in most cases clean for safe discharge to the water bodies. In the tertiary treatment, it is centered on situations that the effluent from the secondary process is not safe for discharge. The main processes involved here include the removal of nitrogen or phosphorus (Bengtsson-Palme et al. 699). For phosphorus, the process involves dosing system while for nitrogen, the nitrification and de-nitrification approaches are used to ensure that safe nitrogen gas enters the atmosphere. In the final treatment, it entails the formation of sludge at the tank's bottom based on the bacterial action settling. This sludge is collected for further treatment. The water, on the other hand, is allowed to flow through sand and other filtration material for further removal of solid particles. The filtered water is in this case safe for release in the river and other water bodies.

Conclusion

In wastewater and sewage treatment, the marine environment is considered a critical aspect. This surrounding is characterized by smaller temperature variability, oxygen concentration, pH, and high salinity. Important to note is that as the depth of these environments increase so does the pressure and a decrease in the sunlight penetration. It is the marine environments that microorganisms from various main taxonomic groups are found. For the photosynthesis organisms, they are located closer to the surface. The categorization of the organisms includes heterotrophs in the lower strata and surface and the decomposers at the base sediments.

Works Cited

Bengtsson-Palme, J., Hammaren, R., Pal, C., Ostman, M., Bjorlenius, B., Flach, C. F., ... & Larsson, D. J. (2016). Elucidating selection processes for antibiotic resistance in sewage treatment plants using metagenomics. Science of the Total Environment, 572, 697-712.

Pronk, M., et al. "Full scale performance of the aerobic granular sludge process for sewage treatment." Water research 84 (2015): 207-217.

Xu, Jian, et al. "Occurrence of antibiotics and antibiotic resistance genes in a sewage treatment plant and its effluent-receiving river." Chemosphere 119 (2015): 1379-1385.