Running head: UNIT 4 ASSESSMENT 1
Unit 4 Assessment
Institutional Affiliation
Student’s Name
Instructor
Course
Date
UNIT 4 ASSESSMENT 2
Unit 4 Assessment
1. Maximizing volatile organic digestion
There are various formulas which may be used in calculating the number of days required
for the sludge to remain in the anaerobic digester. For instance, we have the use of hydrogen
peroxide which is used as a supplement for the concentration of DO. Chemical Oxygen Demand
(COD) and Biochemical Oxygen Demand (BOD) concentration is then lowered and at the same
time, hydrogen peroxide replaces oxygen.
2H2 0202+ 2H2O
As this happens, there is derivation from the stoichiometric formula for all processes
which took place during anaerobic. The equation for this process is:
C5 H7 O2+ 5O2 4CO2+ H2 O+ NH2 HCO3. If at all there is sufficient supply of oxygen, then the
second reaction would definitely occur. The formula for this is:
NH4+ 2O2 NO3+ 2H+H2 O
The two reactions lead to the conservation of oxygen and reduce nitrogen ions in the bio
solids. The two reactions help in creating a water influent which has a sludge balanced in
nutrients. The sludge can be used as a conditioner, therefore increasing the organic content of
the soils. Digester liquor can as well be used as fertilizer, instead of using chemical fertilizers
which are very expensive. In general, manufactured fertilizer has more content of carbon as
compared to anaerobic digestive fertilizer.
2. Necessary Chemistry in proper digestion of waste in anaerobic digestion
In aerobic digestion, there is much time provided for aerating primary and secondary
sludge. On the other hand, in anaerobic digestion, there is extension of respiration period. In
this case, materials which were initially stored in the cell are oxidized, and this is achieved by
UNIT 4 ASSESSMENT 3
reducing the amount of biodegradable organic matter. The organic compounds are then
oxidized. The matter is oxidized to carbon (IV) oxide, water and ammonia. As the process
continues, ammonia is converted to nitrates.
As the process terminates, inorganic compounds with reliable amounts of evaporative
matter is formed. The advantage of this process (aerobic) is that it leads to the production of
products which are biologically stable. There are various factors which affect aerobic respiration
and they include: temperature of the sludge, the loading rate of the sludge, the characteristics of
the solids and the age of the matter as well as the oxidation rate of the sludge. The colloidal
organic solids which were initially available in the final product are converted into water,
nitrates, nitrogen ions and nitrites. For this digestion process to be complete, it is necessary for
the process to make use of biological oxidation basins.
3. Cyclic Activated-Sludge System
This is a common process in the treatment of sewage waters. The process is relatively
cheaper and also has fewer footprints as compared to other methods. The efficiency of
purification in cyclic activation sludge system is also high. Influent conditions are not necessary
in the process of sedimentation and withdrawal. Less human workforce is also required, and the
process can be used in areas where people settle.
Microorganisms play an important role in the process of wastewater treatment. They
make use of nutrients products, which are used to enhance the survival of the microorganisms.
Carbon sources are important in enhancing the synthesis of the cells of the microorganisms. At
the same time, the dismissal of nutrients together with carbon is done by the prokaryotes.
The benefit of using activated sludge process is that it reduces the amount of nutrients
after the discharge which usually enters the waterways. This is very important since excessive
UNIT 4 ASSESSMENT 4
discharge of the nutrients to the environment may lead to eutrophication which in turn causes
much growth of weeds, algae among many other unwanted plants. This later ion results into an
anoxic environment.
4. Essential design considerations for engineered biological unit
There are specific designs which are necessary in making engineered biological unit.
The first one is a unit which allows free flow of fluids. This basically involves the pumping
mechanisms incorporated in the system, and the positioning of the subsequent processes.
This allows the waters to move continuously as expected. Another important design
specification is on the location of the influent tanks and the effluent tank. It is necessary for
the two to be separated. This reduces the chances of having clean waters being contaminated
by the influent.
Another important consideration is the chemicals used in the process of
detoxifications. There are various chemicals which are not favorable for the survival of the
microorganisms, which play a significant role in utilizing waste products such as the
nutrients. In other words, chemical specification is very important when designing a
biological engineered unit, to ensure that all processes are not interrupted in any way.
The last consideration is the capacity of the pipes or tanks being used in various
processes. This helps in ensuring that there adequate amount of wastewater are used for
specific processes, in order to facilitate better outcomes. This also ensures that the amount of
microorganisms matches the volume of the fluid.
