Bioremediation of Waste Water Treatment

This article discusses the process of bioremediation of waste water treatment, including the introduction of microorganisms to remove contaminants. It also covers the advantages and disadvantages of this method, as well as future research needed to improve it. The subject is relevant to environmental science and engineering courses. No specific course code or college/university is mentioned.

Bioremediation of waste water treatment
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Bioremediation of waste water treatment
Water pollution continues to be a nagging environmental problem which is accompanied with
the ever increasing population as well as economic advancement. According to research, the
leading cause of water pollution is the organic compounds that mostly include phosphorous and
nitrogen. The two substances are usually released through run off and this contributes to what is
known as eutrophication. Eutrophication negatively affect the health of human beings as well as
creating imbalance in the ecological environment. Therefore, it is necessary for scientists to
design environmental friendly and cheap measures that can be used to keep this pollutants under
check. Currently, there is significant progress using different waste water treatment options that
include adsorption, photocatalytic oxidation and bioremediation. Each of the above methods has
its own pros and cons. In this assignment however, focus will be on the bioremediation process
of waste water treatment.
Bioremediation is the process through which clean drinking water is produced from waste water.
This is a process that involves introducing certain micro-organisms to the pre-treated waste water
storage vessels such as tanks and dams and they work on the waste water until all the
contaminants have been removed.
The source of waste water is from homes and industries where they run through plastic pipes or
ditches to the waste water treatment plants. This pipes and ditches are placed at certain angles to
facilitate the flow of water through gravity (Abinandan & Shanthakumar, 2015, p. 126). Waste
water can also come from car parks and drainage from roads and they usually contain harmful
compounds such as tar, hydrocarbons, salt and finally grit. Once the waste water is at the
treatment plant, they are thoroughly screened to remove large and visible particles such as paper,

trees, grit and cloth which would damage the pumps. The waste water is then treated using the
three main processes.
During primary treatment, the waste water is stored in tanks and metal salts are added to enable
solid particles stick together. This process is known as flocculation and it results to sludge that
settles at the base of the tanks. The second process is known as secondary treatment and this is
where the remaining effluent is pumped to erected tanks (Anastasi et al., 2012, p. 108). Air is
then constantly introduced as well as different microorganisms to breakdown the other remaining
solid particles. The next step is tertiary treatment and this is where nitrogen is removed through
denitrification and phosphates by precipitating the effluent (Vincenzo Naddeo, 2013, p. 2). At
this stage of tertiary treatment, the water is now safe to be discarded to the sea or the river.
However, if the water is to be used for drinking purposes, then there will be subsequent
processing.
Waste water can be used as drinking water after being treated successfully by the three stages of
treatment and subsequent removal of suspended solids, algae, fungi and viruses. Other harmful
substances such as fertilizers, run off pollutants, minerals and metals like iron, Sulphur and
manganese should also be removed (Vaiopoulou & Gikas, 2012, p. 1).There are different natural
microorganisms that are used during waste water treatment. Scientists established that any
organic molecule can be treated by using an organism. This achieved by the microorganism
extracting energy from the bonds of the organic molecule (Bai et al., 2013, p. 352). This is
believed to be the most effective treatment. However, the microorganism do not accomplish this
task alone. They need the contribution of substances known as bioremediators.
During the process of waste water treatment, it is usually necessary to differentiate the different
types of microorganisms present in water and the type of the contaminants or pollutants that are

to be removed and where they can be located in the process of the waste water treatment (Bhuta,
2014, p. 199). This process is accomplished by specialized companies who analyses samples and
make the necessary recommendations.
During bioremediation to produce drinking water, the initial three treatment phases (Primary
treatment, secondary treatment and tertiary treatment) are carried out followed by introduction of
the microorganisms that breakdown the sludge which settles down at the base of the tank during
secondary treatment (Drury, Rosi-Marshall, & Kelly, 2013, p. 1901). The type of microbes used
in this case are anaerobic and the anaerobic breakdown of the sludge produces methane gas
which is in turn used as fuel at the site or the water treatment plant. Since micro-organisms
cannot act on non-organic matter, flocculation is necessary to remove this non-organic matter.
Addition of microorganisms
After the primary treatment phase, the effluent moves to the secondary treatment phase where it
is oxidized biologically. This is where air and the microorganisms are introduced into the waste
water. Any remaining suspended matter such as feces are also removed at this stage .It is also at
this stage that the Biological Oxygen Demand of the effluent is reduced (Egede, Jones, Cook,
Purchase, & Mouradov, 2016, p. 162). However, microorganisms act at an optimal level when
subjected to certain favorable conditions. This conditions include constant temperature, dissolved
oxygen content, PH and adequate levels of nutrients. After this process, the water is conducive
for irrigation. To make the water meet the World Health Organization standards for drinking,
more processes are required.
The processes needed to make waste water safe for drinking include disinfection, filtration,
reverse osmosis and irradiation. During filtration, the effluent is passed through polypropylene

microfiltration membranes embedded filters to remove any solid matter (Gurunathan,
Selvakumari, Aiswarya, & Renganthan, 2017, p. 340) .Reverse osmosis is on the other hand
done to process the effluents through membranes. Irradiation involves the use of UV light and
addition of hydrogen peroxide to eliminate any harmful organic matter. After irradiation, the
water now meets the WHO standards for drinking and can be added to the existing clean water
supplies such as dams and reservoirs.
Advantages of bioremediation of waste water
This process has several advantages as compared to other methods. It is a natural process since it
only involves the use of microorganisms such as bacteria, fungi and algae. It is also cheap as
compared to other techniques of waste water treatment. In this process, the wastes or toxins from
the water are completely removed (Khan, Mondal, & Sabir, 2012, p. 1048). This is in contrast to
other techniques where the contaminants are just merely separated. It is also a cost effective
method. This is because the anaerobic degradation of the sludge produces methane. The methane
is in return used as fuel to run the waste water treatment plant. The method needs less manual
supervision. This is because once the microorganisms are introduced, the process can go on
smoothly.
Disadvantages of bioremediation of waste water to drinking water.
Despite the many advantages, this process has some shortcomings. It is a very slow process.
Since this process has several phases, it takes time to completion. It lasts for several days or even
months before it is completed (Lee, 2013, p. 94). In this process, it also impossible to remove
heavy metals. This is due to the fact that it involves the use of microorganisms which only breaks
down organic matter but not non-organic matter such as copper and Sulphur. If the metals are not

conspicuous enough to be seen physically, then that means they will get into the body of human
beings which will lead to different types of cancers (Miranda et al., 2017, p. 2). The biggest
disadvantage with this technique is the fact that little knowledge on microbial ecology,
physiology as well as the genetic expression and site expression which makes it difficult to
design the process. A concrete scientific base is therefore needed to be used in rational designing
of the process and success.
Future scope of bioremediation of waste water treatment.
Bioremediation of waste water treatment is an important technique that reduce water pollution
and bolsters natural biodegradation. However, there are gaps especially in the elimination of
non-organic compounds (Rahman & T Ellis, 2012, p.3). Therefore, there should be further
research towards the same .Further knowledge is also needed on the genetics of the
microorganisms since this will improve the ability of breaking down the contaminants of water.
It is also important for scientists to identify the right microorganisms to be used during
bioremediation as this will make the whole process cheap and provide opportunities for
improvement (Shandilya & Pattarkine, 2016, p. 1). Since each microorganism has different
requirements for growth, it is necessary for scientists to isolate and grow them in laboratory
under suitable conditions to be used later in bioremediation. There is no need to use genetically
modified microorganisms.

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