Investigating the Impact of Domestic Wastewater on Soil Around Plants

This report investigates the impact of treated domestic wastewater from treatment plants on the physical, chemical, and microbial properties of the surrounding soil. It reviews existing literature to determine whether treated wastewater can be safely used for irrigation purposes. The literature review covers various studies analyzing the effects of treated wastewater on soil fertility, salinity, nutrient levels, and overall soil quality. Some studies suggest that treated wastewater can improve soil properties and crop yield by increasing water holding capacity and mineral concentration, while others caution against potential adverse effects like increased salt concentration and heavy metal accumulation. The report concludes that the impact of treated wastewater on soil properties depends on factors such as the treatment process, soil type, and duration of exposure. Desklib offers a wealth of similar resources for students seeking to expand their understanding of environmental engineering and related topics.

Effect of Domestic Water on Soil Properties aroundTreatment Plant
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Table of Contents
Research Question......................................................................................................................3
Literature Review.......................................................................................................................3
Evaluation of research................................................................................................................7
References..................................................................................................................................8
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Research Question
There have been several researches which support the claim that the domestic wastewater
retrieved from the treatment plants can be used for the purpose of agriculture. The researchers
have indicated that treatment of wastewater decreases its toxicity and the water is safe enough
to be used for the purpose of agriculture (Sklarz et al., 2013). The research question, on
which the entire research is based, will detect the impact of the treated domestic water on the
quality of the soil and its physical, microbial and chemical properties. The research question
can be summarized as-
“What is the impact of domestic wastewater from treatment plants on the physical,
chemical and microbial properties of the soil around treatment plants?”
It will also investigate that “Can this water be used for the irrigation purposes?”
Literature Review
This research aims at finding out the effect of domestic wastewater from treatment plants on
soil properties. We will try to evaluate effect on physical, chemical and microbial properties
of the soil around treatment plants, with the help of secondary as well as primary research
techniques. This literature review will help in undertaking secondary analysis by looking
upon results of different researches done by various researchers on the same topic.
Used water collected from apartments and houses is called domestic waste water, also
referred to as sanitary sewage. This waste water is the residual water flushed out after
performing domestic cleaning, cooking, bathing, and other household chores. Waste water is
composed of 99.90% water and 0.10% solids and minerals. This 0.10% part other than water
is the major cause of concern. It consists of grease, oils, and fats that come from body lotions
and cooking oils; nutrients like nitrogen and phosphorus, Biochemical Oxygen Demand
(BOD), and other solids. The process of waste water treatment in the treatment plants
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partially removes the solids present in the waste water and partially decomposes complex
solids into minerals or less complex organic solids (EPA, 2009).
Waste water is treated chemically, physically, as well as biologically in the treatment plant.
Physical processes involve removal of solid impurities through filtration, sedimentation,
aeration, screening, etc. Chemical processes involve treatments such as ozonation,
chlorination, coagulation, etc. Biological processes involve aerobic treatments like trickling
filtration and activated sludge treatment as well as anaerobic treatments such as lagoons and
septic tanks. The residual water after passing through the septic tank moves to the drain field
and get into the soil. As this whole process of waste water treatment take place in
underground area, the properties of the surrounding soil get affected. It affects fertility and
salinity of the soil (Wtreat, 2018).
As per the study conducted byAl-Othman, 2009 indicates that there is no major effect of
treated domestic waste water on the properties of soil. No significant effect on the micro-
organism counts, physico-chemical properties and soil texture was seen,up to 15 months after
the irrigation with TDW. It was analysed that due to the sandy nature of the soil, it’s water-
holding and cation-exchange capacity becomes less and hence, there is no significant effect
observed. The research focused upon the significance of reusing the treated waste water for
the purpose of irrigation. It causes minimum level of environmental hazards and also helps in
maximizing the efficient usage of water from the available resources of water (Al-Othman,
2009).
Darvishi, et al., 2010 is in agreement with the findings of the above research. There is no
significant harm found on the microbial, chemical, and physical properties of the soil due to
dumping of treated waste water from domestic setup. It was being shown in the results that
domestic waste water could be filtered by the soil and the levels of COD and BOD in the
waste water was also reduced by the soil. Usage of treated waste water for irrigation helps in
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increasing the nutritive elements of the soil and proves as a great nutrient source for the
plants. This study might provide applicable advice to agricultural researchers and farmers in
context of proper use and management of water (Darvishi et al., 2010)
Another study conducted by Day, et al.(2012) shows the similar conclusion as above. The
research took place in Arizona, in order to analyze the effects of effluents disposed off from
the treated domestic waste water, on the soil. The research involves comparison of the effects
of the treated waste water with effluents with the supplemented well water upon irrigation, on
the soil. It was found that the soil irrigated with effluent containing waste water had lower
rates of water infiltration and higher concentration of nitrogen, phosphorus, and salt. The soil
also had a higher rupture modulus. There was no adverse effect recorded on the quality of the
soil irrigated by the treated waste water with effluents. Also, there was no decrease in the
yield of the crop (Day et al., 2012).
In agreement with the above studies, Ladwani, et al. (2012) stated that the volume of
domestic waste water is increasing due to increase in population. The reuse of treated waste
water for irrigation purpose and crop yield can be proved as significant source of water and
waste management. Depleting resources of fresh water results into high usage of domestic
waste water from the treatment plants for agricultural and relative purposes. In this study,
crops were fertilized by both treated domestic waste water and ground water. Same dose of
fertilizers were applied on the crops for the treatment. Physiochemical properties, crop yield,
and nutrient status of the soil treated with domestic waste water were improved as compared
to the soil treated with groundwater. Overall, the fertility of the soil was also improved
(Ladwani et al., 2012).
According to Alghobar, et al.(2014), the use of treated domestic waste water for irrigation
positively affects the soil property and crop yield. It increases the water holding capacity and
mineral concentration of the soil. It improves the fertility status and overall chemical
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properties of the soil. The research was conducted by using ground water and treated waste
water for irrigating the soil. Treated waste water reduces the pH level of the soil and also
contains essential plant growth elements as compared to the ground water. There was a
significant increase in the nutrients like N, P, K, Ca, Na, and SO4while the level of same
nutrients level were found low in the soil treated with ground water(Alghobar et al., 2014).
The results of the research conducted by Agrawal, et al.(2014), are in alignment with the
results of the above studies. The research was conducted to investigate the effect of treated
domestic waste water on the soil fertility and other properties. It was found that the overall
physio-chemical and microbial properties of the soil irrigated with TDW get improved as
compared to the soil irrigated with ground water. The fertility of the treated soil was found
increased along with the increased yield of the crop on the treatment with domestic waste
water. Total organic carbon content and nutrients contents like N, P, K, has been increased by
application of the domestic waste water (Agrawal et al., 2014).
Hasan, et al.(2014)is in disagreement with the results of the above studies and states that
treated domestic waste water adversely affects the physical and chemical properties of the
soil on its application. The quality of the plants produces was found worst after application of
100% TDW for irrigation. It was found that when treated waste water from domestic
households was mixed with potable water and then applied on the soil, it showed better
results on the quality and growth of the plants. Aggregate stability of the soil was reduced
and salt concentration was increased highly with the application of only the TDW (Hasan et
al., 2014).
Singh, et al.(2012) is in agreement with the Hasan, et al., 2014. The study showed that treated
domestic waste water or sewage water constains high amount of heavy metals, nutrients and
organic matter. If these heavy metals are reduced by physical treatments such as filteration
and screening, the TDW can be very much beneficial for the overall crop yield and in
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increasing the soil fertility. But on the other hand, if the soil is put to the application of TDW
for longer period of time with high concentration of heavy metals, this can lead to
phytotoxicity of the crops (Singh et al., 2012).
After conducting the secondary research with the help of this literature review, it can be
concluded that treated domestic waste water is benficial to be used in irrigation of soil. If put
to correct use with right amount of treatment both physical and chemical, it can increase the
overall fertility, stability, and nutriens level of the soil. Crop yield and plant growth is also
seen as one of the major advantages of the TDW. If used without much treatment and for
long term, it can cause ill effects like high concentration of Fe and other heavy metals
resulting into poor plant quality. Type of soil and region also governs the effects of the TDW
on properties of soil.
Evaluation of research
The literature treview claims that the treatment of the wastewater removes the potentially
toxic solids from the soil and degrades the complex organic compoiunds into lesss organic
ones. Thus, the harmful impact of these compounds on the soil are reduvced to minimum and
the water does not degrade the properties of the soil (EPA, 2009). This evidence is high;ly
important for our research because it confirms that the water obtained after domestic
wastewater treatment is free from the toxic substances and hence, does not impaact the
qualuity of soil negatively. Similarly, Sklarz and his colleagues in 2013 confirmed the fact
that the domestic wastewater obtainbed from treatment plants is less toxic and can be used for
for the irrigations purposes (Sklarz et al., 2013). It proves that this water does not impact the
soil qulaity in a worse manner. Darvishi in 2010 also claimed that the treated domestic
wastewater improves the quality of the soil and increases the amount of nutritive elements in
the soil which, in turn, can serve as the source of nutrition for plants (Al-Othman, 2009).
References
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Agrawal, V., Bhagat, R. & Thikare, a.N., 2014. Impact of Domestic Sewage for Irrigation on
Properties of Soil. International Journal of Research Studies in Science, Engineering and
Technology, 1(5), pp.60-64.
Alghobar, M.A., Ramachandra1, L. & Suresha, a.S., 2014. Effect of sewage water irrigation
on soil properties and evaluation of the accumulation of elements in Grass crop. American
Journal of Environmental Protection, 3(4), pp.283-91.
Al-Othman, A.A., 2009. Effect of treated domestic wastewater on physical and chemical
characteristics of soils. Journal of Applied Sciences, 9(5), pp.901-08.
Al-Othman, A.A., 2009. Effect of Treated Domestic Wastewater on Physical and Chemical
Characteristics of Soils. Journal of Applied Sciences, 9(1), pp.901-08.
Darvishi, H.H., Manshouri, M. & Farahan, a.H.A., 2010. The effect of irrigation by domestic
waste water on soil properties. Journal of Soil Science and Environmental Management, 1(2),
pp.030-33.
Day, A.D., Stroehlein, J.L. & Tucker, a.T.C., 2012. Effects of Treatment Plant Effluent on
Soil Properties. Journal (Water Pollution Control Federation), 44(3), pp.372-75.
EPA, 2009. How Waste Water Treatment Works - The Basics. Washington DC: Office of
Water.
Hasan, H., Battikhi, A. & Qrunfleh, M., 2014. Impacts of Treated Wastewater Reuse on
Some Soil Properties and Production of Gladiolus communis. Journal of Horticulture, 1(3),
pp.1-9.
Ladwani, K.D., Ladwani, K.D., Manik, V.S. & Ramteke, a.D.S., 2012. Impact of Domestic
Wastewater Irrigation on Soil Properties and Crop Yield. International Journal of Scientific
and Research Publications, 2(10).
Singh, P.K., Deshbhratar, P.B. & Ramteke, a.D.S., 2012. Effects of sewage wastewater
irrigation on soil properties, crop yield and environment. Agricultural Water Management,
103, pp.100–04.
Sklarz, M.Y., Zhou, M., Chavez, D.L.F. & Soares, M.I.M., 2013. Effect of Treated Domestic
Wastewater on Soil Physicochemical and Microbiological Properties. Journal of
Environmental Quality, 42(4), pp.1226-35.
Wtreat, 2018. Wastewater Treatment Methods and Disposal. [Online] Available at:
http://web.deu.edu.tr/atiksu/ana52/wtreat.html [Accessed 13 September 2018].
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