Research on the topic coagulation process " Water Treatment Plant " .. Among the topics of Sanitary Engineering

1. Enhancement of coagulation
process by Chlorination
BAGHDAD UNIVERSITY
SANITARY ENGINEERING DEPARTMENT
M.SC. STUDENT : MARWA MOHAMMED

2. Coagulation and disinfection
Coagulation and disinfection are the main units in the drinking
water treatment technology in both developing and in
dustrialised countries.
enhanced coagulation
is broadly defined as the addition of an excess coagulant dosage
for improved removal of such contaminants as normal organic
matters (NOMS), color , arsenic, and other heavy metals from the
water

3. Perchlorinating Process
 Prechlorination is a process that involves adding chlorine to
the collection system of industrial plants and other industrial
settings, mainly for corrosion and odor control. At times, it is
also applied for the purpose of disinfection and for the
removal of oil particles.
 It is also used in water treatment to control aquatic growth
as well as taste, and as an aid in settling and coagulation

4.  In prechlorination, chlorine is added to the raw water prior to flash
mixing and post screening. The excess chlorine is beneficial in the
various stages of treatment by:
 Aiding coagulation
 Controlling of algae problems
 Reducing odor and mud ball formation
 Moreover, chlorine can produce prolonged contact time once added
during the start of the water treatment process. Thus, prechlorination
can increase safety when controlling corrosion and disinfecting
extremely contaminated water. This process can be very useful in the
sense that it aids the elimination of microorganisms like protozoa,
bacteria and viruses that can cause damage to structures and illness to
humans. With this process, the safety and integrity of water meant for
consumption and industrial uses can be maintained.

5. What Is Enhanced Coagulation
Enhanced coagulation is defined as meeting
the TOC removal level shown in Table below by
coagulation, usually by lower coagulation
pH ranges and higher coagulant doses.
And that done by the Per chlorinating Process

7. Coagulation is expected to eliminate particles and colloids via a
coagulant, like alum or ferric chloride,
while Disinfection is applied to inactivate pathogens by
disinfectants like aqueous chlorine hypochlorous acid (HOCl),
and/or hypochlorite ion (OCl-).

8. Improves the efficiency of performance by reducing
the value of Ph and coagulation increases its efficiency
by the lack of Ph ratio so that increases the process of
ATTACHMENT and the greater the ATTACHMENT as
the particles produce more flog . As the flog is formed,
the process of sedimentation increases and that is why
the Enhancement is achieved
How does that
happen ?

9. STUDY CASE : Effect of pH
 During the experiments, big flocks were observed, especially for
condition at pH 3. Smaller and fewer flocks were seen for pH 5 to 9.
As can be seen in Figure 2 the percentage of turbidity removal for
pH 1 to 3 is about 99%. On the other hand, at pH 11, the percentage
of turbidity removal rose again to 97%. It seemed that the
coagulation is good at acidic pH less than 6 and also at pH greater
than 11.

11. For aluminum sulfate coagulation, the optimum pH for TOC removal
typically occurs in the range between pH 5 to pH 6. For ferric sulfate
coagulation, the optimum pH for TOC removal typically occurs in
the range between pH 4 to 5. So if your facility is operating at a
higher coagulation pH for turbidity removal and is required to
achieve higher levels of TOC removal, lower coagulation pH ranges
may have to be considered. These coagulation pH values are
targeted because organics adsorb more readily to the metal
hydroxide floc at the lower pH ranges.

13. Thank you