Water and Wastewater Treatment: Drought, Flood, and Treatment Methods

This report presents a comprehensive analysis of water and wastewater treatment methods, focusing on two distinct scenarios: water sources during drought and flood seasons. The report begins by examining the characteristics of water obtained from a flooded river, including high turbidity, a...Read More

WATER AND WASTE WATER TREATMENT
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Summary
In order to save on energy used in the processes of water treatment, a lot of effort is usually put
on the analysis of the properties of water as determined by the source. In this particular paper,
there is analysis of two cases of water sources like for the case of flood seasons and drought
seasons. The recommended treatment methods have factored in the properties of water as per the
seasons.
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Contents
Summary.....................................................................................................................................................2
Introduction.................................................................................................................................................3
Water from flooded river Source.............................................................................................................3
Factors considered/Reasons................................................................................................................3
Chlorination.................................................................................................................................................4
Coagulation, sedimentation and filtration...........................................................................................4
Sedimentation and flotation................................................................................................................5
Filtration..............................................................................................................................................5
Water obtained during Drought..............................................................................................................6
Distillation............................................................................................................................................6
Applicable Treatment method for both situations..................................................................................7
Conclusion...................................................................................................................................................8
REFRENCES..................................................................................................................................................9
Introduction
Drinking water should be maintained in a good state before consumption. This is achieved either
through purification or treatment for good health of an individual. In case the water an individual
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need to use is contaminated and maybe there is lack of water bottle, there are varied techniques
of water purification currently under implementation having both advantages and disadvantages.
These purification methods involve filtering which is good for basic treatments like removal of
chlorine and sediments although reverse osmosis serves as the best. Much attention is given to
units of reverse osmosis at Schultz Soft Water following the low energy consumption and the
minimum time taken to get distilled water. In places where reverse osmosis may not apply, there
are other four techniques of purifying water to make it safe for drinking which can be used.
Source of water may determine the best method of treatment.
Water from flooded river Source
The obtained water from this particular source was characterized by the following features:
 Colour 80 HU
 Turbidity 75 NTU
 DOC of 1 12 mg L-1
 TDS dropped to < 150 mg L-1,
Factors considered/Reasons
The above characteristics of water imply that there will be need to properly remove the
suspended materials which are apparently responsible for the higher turbidity. Such high
turbidity implies a lot of organic matter and hence more pathogens. The best way to practice this
kind of removal is by the use of chlorine chemicals.
Chlorination
The basic reason for treating water is to maintain good health of the consumer by removing
impurities that may negatively impact on their lives. The intricate reason is to check on
impurities which may not directly impact on the health of individuals but result into discoloration
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and corrosion (Park, Sukias and Tanner 2019). All these are attained by setting filtration as well
as coagulation barriers to remove impurities by means of precipitation and particle capture which
are responsible for higher turbidity of turbidity 75 NTU. The last barrier created to remove
impurities is the disinfection chamber. Treatment of contaminated water is done before
disinfection in order to make it reliable and effective for the disinfection process, which involves
removal of solid suspensions which may lower the efficiency of disinfection. The processes will
be as summarized below:
Coagulation, sedimentation and filtration
Coagulation: settling as a method cannot afford to remove all impurities in natural water. This
may be as a result of the colloidal (finely divided) state or their dissolving nature in water.
Chemical coagulant is added to the contaminated water to make large particles tiny particles,
floes that easily settle. The most common coagulant preferred for settling particles are ferric salts
and aluminum. Metal hydroxide precipitate is formed on addition of the above mentioned
chemicals to remove suspensions of solids, color and algae in a number of techniques comprising
of trapping and adsorption. Hydraulic or mechanical mixing results into the agglomeration of
impurities alongside hydroxide precipitate into flocks some distant away from the diameter wall.
Polyelectrolytes are other chemicals that are used to implement or replace coagulants of iron or
aluminum to generate flocks of larger size. Filtration will then be conducted to remove the
flocks on their formation which is then closely followed by sedimentation.
Sedimentation and flotation: This is the process implied in removing volumes of flocks to limit
the bulk on filters along the downstream. The process of sedimentation occurs in horizontal
basins laid either in a circular or rectangular shapes for discrete settling of flocks, in most cases,
as designed in Europe, whereby the flow of water in ‘flock blanket’ clarifiers occurs over
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fluidized bed of flocks to leave the treated water at the top of the clarifier. The density of flocks
is believed to be slightly greater than that of water; this lowers the rate at which water is treated.
The typical loadings of the tank fall within the range of 1-5 m/h.
Filtration: The residual particles will be removed through conducting deep-bed filtration on
sand. Water to be filtered is allowed to go through a bed of sand of diameter 0.5-1.0 mm grains,
and at a depth of 1m. A number of mechanisms are involved in the filtration process that is,
interception, sedimentation, straining and electrostatic adhesion. The rate at which the process of
filtration is conducted is at 4-10 m/h. an increased resistance to flow is achieved s the bed traps
the particles calling for maintenance of large water pressure for a constant flow rate. On attaining
a limiting head loss, or at the instant at which solids gets out of the filter, a back-flush with clean
water is performed to clean the filter (Habib et al.2017).
In turbid water treatments, sedimentation process is performed first before filtration whereby
filters are of type open ‘gravity filter’. For some cases of turbidity waters comprising the colored
moorland waters, immediate filtration may be conducted rather than sedimentation. With this,
the process of filtration helps in conserving hydrostatic head.
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Figure 1: Chlorination process
Water obtained during Drought
One of the outstanding properties is that this particular water tends to be visibly clear. The
characteristics possessed including : turbidity < 5.0 NTU TDS) concentration > 1500 mg L-1,
DOC of 1 mg L-1 and colour < 10 HU will definitely call for a more complex treatment method.
The focus will be removal of concentration > 1500 mg L-1 which is very high. This can be
effectively achieved by use of distillation process.
Distillation: This is a technique of purifying water whereby heat is employed to obtain pure
water in vapor form. Scientifically the distillation proves effective considering the low boiling
point of water compared to that of contaminants and other elements that may be found in
contaminated water. Heating is done to boiling point after which water is left at that state to
vaporize. The vapor is then condensed by a condenser. On cooling, liquid water which is clean
and safe for drinking is obtained. In the distillation container remains substances of high boiling
points in the form of sediments.
This mechanism of water treatment is more applicable in doing away with salts, germs, bacterial
together with heavy metals like mercury, arsenic as well as lead. It is mostly preferred for raw or
untreated water. It is however slow process of purifying water and again source of heat is
necessary for purification to occur. Despite the cheap energy sources under implementation, this
method of water purification still remains to be costly. The method is only effective in places
where small quantities of water are involved.
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Figure 2: Distillation process in water treatment (Bozkurt et al.2016).
Applicable Treatment method for both situations
Boiling
This will basically make water just safe for use in both cases. A cheap and safe method of
purifying water is attained through boiling. Water maybe contaminated at the source or at the
distribution channels (Park et al.2017). The method involves boiling clean water and then left
for around 3 minutes on the rolling boil. It is advisable for those who reside in areas of high
altitude to boil their water for a longer duration following the lower temperatures experienced at
higher altitudes. After boiling, the water is covered till it gets cool after which it is safe for
drinking. Water from wells is safe for drinking after filtering the compounds that settle on
cooling.
Conclusion
Surface waters requires frequent treatment before drinking since they are more susceptible to
contamination compared to ground water. Prior treatment of water may be attained through
storing of water in a reservoir; this leads to sedimentation of solid suspensions and greatly
reduces the number of pathogens that may be present in the water.
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REFRENCES
Bozkurt, H., van Loosdrecht, M.C., Gernaey, K.V. and Sin, G., 2016. Optimal WWTP process
selection for treatment of domestic wastewater–A realistic full-scale retrofitting study. Chemical
Engineering Journal, 286, pp.447-458.
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Habib, R., Asif, M.B., Iftekhar, S., Khan, Z., Gurung, K., Srivastava, V. and Sillanpää, M., 2017.
Influence of relaxation modes on membrane fouling in submerged membrane bioreactor for
domestic wastewater treatment. Chemosphere, 181, pp.19-25.
Park, J.B., Sukias, J.P. and Tanner, C.C., 2019. Floating treatment wetlands supplemented with
aeration and biofilm attachment surfaces for efficient domestic wastewater treatment. Ecological
Engineering, 139, p.105582.
Park, Y., Cho, H., Yu, J., Min, B., Kim, H.S., Kim, B.G. and Lee, T., 2017. Response of
microbial community structure to pre-acclimation strategies in microbial fuel cells for domestic
wastewater treatment. Bioresource technology, 233, pp.176-183.
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