CIVE 5094: Water and Wastewater Treatment - Domestic Waste Report

This report provides a comprehensive overview of water and wastewater treatment, with a specific focus on the treatment of domestic wastewater. The report begins with an introduction highlighting the importance of water treatment in eliminating waterborne diseases and the selection of treatment methods based on water source characteristics. It presents calculations for the percentage of pollutant removal for BOD, total nitrogen, and soluble phosphorus. The core of the report delves into the treatment of domestic wastewater, detailing the sources, contaminants, and the three major treatment stages: primary, secondary, and tertiary. Each stage is described with its processes and objectives, from screening and sedimentation in the primary stage to biological treatment and disinfection in the secondary and tertiary stages, respectively. The report concludes by emphasizing the varying quality of water sources and the significance of treating wastewater to ensure safe and clean water for various uses and environmental protection.

WATER AND WASTE WATER TREATMENT
By Name
Course
Instructor
Institution
Location
Date
1

Summary
Water treatment has been identified as one of the effective ways of eliminating water borne
disease. This is because it makes water free from the germs. The method of treatment will vary
depending on the available resources. The selected method may be accompanied with the
calculation of the required standards parameters. In this particular paper calculation of reduction
of pollutant percentage has been done before the recommendation is given in regard to the
domestic waste water treatment.
2

Contents
Summary.....................................................................................................................................................2
Introduction.................................................................................................................................................3
Results and Discussions...............................................................................................................................3
Calculation of the Percentage of pollutant removal............................................................................3
Treatment of domestic waste water.......................................................................................................4
Conclusion...................................................................................................................................................7
REFERENCES................................................................................................................................................8
Introduction
It is important to note that the selection of the methods of water treatment may be guided by the
original source of water to be treated. Water sources with large amount of the suspended
3

particles need to be filtered and taken to through the sedimentation processes. In the presented
case study, the focus was laid on the characteristics of water source as defined by the period.
Other treatment mechanisms are employed for general removal of solid suspensions as well as
the impurities that occurs naturally. The above mentioned processes involve a series of principles
as elaborated below (Hülsen et al. 2016).
Other than disinfection, high quality ground waters require little or no chemical or physical
treatment. Dissolved air floatation is an alternate technique to sedimentation. In this technique of
sedimentation, water under great air saturation at higher pressure is taken to flocked water,
whereby tiny bubbles of air attach to the flocks to make them float on water surface. Compared
to sedimentation, air floatation is rather a faster method with typical loadings of 5-12 m/h. this
method is commonly preferred for treating low-turbidity, colored as well as waters full of algae.
Results and Discussions
Calculation of the Percentage of pollutant removal
Original values= 550 mg L-1 BOD, , 60 mg L-1 total nitrogen (comprising Total Kjeldahl
Nitrogen (TKN), nitrate and nitrite, and ammonia) and 15 mg L-1 soluble phosphorus (SP).
Required levels
< 30 mg L-1 BOD, < 15 mg L-1 for total nitrogen, < 2.5 mg L-1 for SP.
For BOD;
(30 mg-550 mg)/ 550 mg*100%=94.54%
For total nitrogen;
4

(15 mg L-1-60 mg L-1)/ 60 mg L-1*100=75%
Treatment of domestic waste water
Water that comes as a result of different activities performed by human beings like garbage
disposals, laundry, toilets, bath, dish washing among others is referred to as the domestic
wastewater. Domestic wastewater though contains contaminants to the lowest levels is still in
position to impact negatively on the lives of individuals. For this reason, a proper installation and
maintenance of systems of sewage treatment within the residents basically for treatment as well
as disposal of domestic wastewater is necessary to lower the level of impact caused on
individuals.
In the current state, domestic wastewater treatment stands a great chance to ensure a proper
treatment of most if not all the sewage, to make it safe, clean and suitable to the extent that it
cannot affect the environment. Sewage systems within homesteads are installed in a way to
ensure that all wastes are treated before disposal. The most common household wastewater
contaminants are excess nutrients like nitrate, bacteria causing diseases, harmful chemicals and
infectious viruses.
5

Figure 1: Sample uses of recycled domestic waste water (Plouviez et al.2019)
The two major fluxes that domestic wastes comprised of are grey water generated by kitchen
sinks, showers, laundry washing, washing basins, baths among others and the black water
generated by urinals and toilets. There are 3 major treatment stages involved in treating
household, these include:
Primary Stage
This is the initial stage in wastewater treatment capable of removing up to around 60% of solid
suspensions.
Screening is done in the process to get rid of the larger particles like stones, sticks and others
which when left may block inlets to the tank.
It consists of the grid chamber to lower the speed at which wastewater flows into the tank
facilitating natural falling of grit to bottom surface of the tank where it can be easily taken away.
6

The sedimentation tank or the settling also referred to as the primary clarifier if for eliminating
both light and heavy density contaminants.
After partial treatment of wastewater in primary tank, the water is channeled into another system
for secondary treatment.
Secondary Stage
At this stage, wastewater from primary treatment system receives biological (both aerobic and
anaerobic) treatment to remove organic matter to around 90%.
This stage involves the process of activated sludge that implements use of dissolved oxygen to
facilitate rapid growth of biological floc for substantial removal of organic matter.
A continual re-circulation process is maintained within the aeration tank for activated sludge
comprised of bacteria to boost the rate at which organic matter decompose.
The finely divided and dissolved solid suspensions serves as a residing place for the bacteria and
these cannot be gotten rid of just with primary sedimentation (Zhang et al.2018).
The water under treatment is directed to settling tanks to resettle the sludge, this makes it to
around 95% pure.
Tertiary Stage
In case secondary treatment effluent is not trusted, and advanced level of treatment is
improvised.
This stage offers an ultimate treatment to maximize the quality of effluent to match the required
standards.
7

At this stage, the wastewater is still composed of fine particles and some suspensions which are
completely removed (Brienza et al.2019).
Water that leaves this stage is regarded to be free from chemicals and other harmful substances
and can therefore be reused, recycled or discharged to the surrounding.
Tertiary stage also referred to as disinfection stage employs use of UV as a disinfectant as it does
not have any impact on the quality of water.
Conclusion
Sources of surface water, that is, the ones over the earth surface consisting of wide varying water
quality, from those of high quality with little contaminants (may include treated or untreated
wastewater)to rivers in the lower lands comprising of large amounts of contaminants from varied
sources. Waters that are regarded to be of high quality are the deep ground waters that naturally
occur within the subsoil. Though ground waters are of high quality, some are prone to local
contamination especially ones in highly permeable stratum and the ones at shallow levels more
so by volatile substances of chlorinated hydrocarbons like trichloroethylene. Springs are of high
quality and comprises of a source of water whereby the underground water encounters
impermeable rock stratum and squirts the surface.
REFERENCES
Brienza, M., Nir, S., Plantard, G., Goetz, V. and Chiron, S., 2019. Combining micelle-clay
sorption to solar photo-Fenton processes for domestic wastewater treatment. Environmental
Science and Pollution Research, 26(19), pp.18971-18978.
8

Hülsen, T., Barry, E.M., Lu, Y., Puyol, D., Keller, J. and Batstone, D.J., 2016. Domestic
wastewater treatment with purple phototrophic bacteria using a novel continuous photo
anaerobic membrane bioreactor. Water research, 100, pp.486-495.
Plouviez, M., Chambonnière, P., Shilton, A., Packer, M.A. and Guieysse, B., 2019. Nitrous
oxide (N2O) emissions during real domestic wastewater treatment in an outdoor pilot-scale high
rate algae pond. Algal Research, 44, p.101670.
Zhang, L., De Vrieze, J., Hendrickx, T.L., Wei, W., Temmink, H., Rijnaarts, H. and Zeeman, G.,
2018. Anaerobic treatment of raw domestic wastewater in a UASB-digester at 10 C and
microbial community dynamics. Chemical Engineering Journal, 334, pp.2088-2097.
9