The following specification particularly describes the invention and the manner in which
it is to be performed.
STATEMENT OF INVENTION
The present invention discloses the inhibition of microbial growth which is basically seen in the
form of films on the inner surface of pipes and fittings such as valves, joints, taps etc. in drinking
water distribution system. The main work is the synthesis of solutions named asChlor-Z-l and
ChIoro-Z-2 solution.. Chlor-Z-1 solution is used for inhibition ofbiofilm growth on the surface of
the pipes and fittings by flushing through the drinking water distribution system whereas Chloro-
Z-2 solution is used to inhibit growth of biofilm hi stored water tanks.
First of all a test section (a pipe fitting) is weighed and then it is washed with 5% glucose solution
(in water). After that it is fitted to the experimental set-up. Under the normal conditions, E. coli
bacteria are found to be grown on the test surface with the glucose solution as the nutrient. After
the significant growth of E.coli bacteria, the test section in the experimental set-up is weighed and
then (lushed with Chlor-Z-1 solution. It is observed that biofilm growth on the surface of the test
section is affected day by day which is further ensured by the decrease in weight of the test section
each day. The whole experimental procedure is repeated for two more times for confirmation of
the observations. Similar observations are obtained in three sets of experiments.
The microbial growth in water tank is observed by storing water in an open tank for about 10 days
under normal conditions with the addition of 10% glucose solution as the nutrient. Then the count
of microbial growth is observed. After 10 days of water storage, Chlor-Z -2 solution is added in
the water tank. Then water is checked for microbial growth each day for about three more days.
Considerable reduction in microbial growth within the tank is observed day by day implying the
effectiveness of Chloro-Z solution to be very good.
Chlor-Z-1 SOLUTION
From a number of combinations the optimal solution is basically 3% Chloramine and 2% Zinc
Meta Phosphate by weight in water i.e. 3 grams of Chloramine and 2 grams of Zinc Meta
Phosphate are dissolved in 1000 ml of water.

Chlor-Z-2 SOLUTION
From a number of combinations the optimal solution is basically 8%Chloramine and 5% of Zinc
Meta Phosphate by weight in water i.e. 8 grams of Chloramine and 5 grams of Zinc Meta
Phosphate are taken in 1000 ml of water.
BACKGROUND OF THE INVENTION
Waterborne diseases are estimated to cause millions of deaths each year. These deaths are
attributable to inadequate public sanitation systems. The main cause of these water borne diseases
is the growth of micro-organisms in the water distribution system. These harmful microorganisms
basically grow in the form of a biofilm. A biofilm is developed by any group of microorganisms
where cells stick to each other on a surface. These adherent cells are frequently embedded within
the self-produced matrix of extracellular polymeric substance (EPS). Biofilm (EPS) which is also
referred to as slime, is a polymeric conglomeration generally composed of extra cellular DNA,
proteins and polysaccharides. Biofilms may form on living or non-living surfaces and can be
prevalent in natural, industrial and hospital settings. They not only affect human lives but also
become the cause for corrosion. Their growth on the surfaces can lead to corrosion in low pressure
water boilers thereby reducing heat exchanger efficiency and reducing cooling tower efficiency.
In order to inhibit the growth of biofilm in the drinking water distribution system the Chlor-Z-1
and Chlor-Z-2 solutions are synthesized. An experimental setup is designed and made ready for
experimentation. The experiments are carried but to observe the effects of Chlor-Z solutions on
the growth of microorganisms (E. Coli) on the selected pipe fitting in the experimental setup as
well in the water tank.
OBJECTIVE OF THE INVENTION
The broad objective of this project is to synthesize a solution which inhibits the biofilm (E-
Coli) growth on the surface of pipes and fittings in the drinking water distribution system.
As it is required to observe the biofilm growth and its inhibition for certain period of time an
experimental set up is required to be developed. Thus the specific objectives are found out as

(i) To get observation on biofilm growth by designing an experimental set up
demonstrating the drinking water distribution system which allows E-Coli to
grow on the inner surface of pipes and fittings.
(ii) To use the synthesized solution (Chlor-Z solution) by flushing with water to
observe the inhibition (disinfection) results on growth of E. Coli.
SUMMARY OF INVENTION
First of all an experimental set up is designed for the water distribution system. A 20 liters plastic
tank is taken as reservoir. Stainless Steel (SS) pipe of] inch diameter is. used for the piping as well
as for test section. The test section is weighed and fitted in the pipe line with round Stainless Steel
joints. A pressure gauge is fitted in the pipe line to measure pressure of the water flowing through
the pipe. A centrifugal pump (with 1 kW rating) is used to pump the fluid. After fitting all the parts
the experimental set up is installed in the laboratory. The reservoir is filled with water. The test
section (a piece of pipe) in the pipe line is washed with 10 % glucose solution. Water is pumped
and allowed to flow through the pipe line at 1.5 to 2 kg/cm2 pressure. E. Coli are observed to grow
first on the inner surface of the test section at faster rate as 10% glucose solution acts as the nutrient
to these microbes. E. Coli are then found to grow slowly in the entire pipe line. The same condition
is allowed to prevail for 3 days indicating that the pipe line is exposed to the E. Coli solution. A
significant film of E. Coli is noticed to develop on the inner surface of the pipe roughly on fourth
day. The test section is then removed, weighed and reinstalled. The Chlor-Z-1 solution is then
allowed to pass through the test section of pipe. Chlor-Z-1 solutions prepared at different
combinations i.e. 1, 2 & 3% of Chloramines with land 2% of Zinc Metal Phosphates (fig.-l &
fig.-2) are used to check the best inhibition. After the inhibition (disinfection), the test section is
removed and weighed. The difference in weights is observed. From both the figures, it is observed
that Chlor-Z-1 solution with 3% Chloramine and 2% Zinc Metal Phosphate gives the best
inhibition for which this combination is selected for further experimentation. The same procedure
is repeated each day for 7days with the selected combination of Chlor-Z-1 solution which is
recycled to the experimental set-up at 1.5 kg/cm2. The observed reduction in weight of test section
with the biofilm is plotted against number of days, line whole process is again repeated thrice.
Three experimental observations are shown in Fig. 3-5. Same trend is observed in all three cases.

Same procedure is repeated to check the inhibition of microbial growth in the tank by using Chlor-
Z-2 solution with different compositions of Chloramine and Zinc Meta Phosphate. The best
composition is selected for the maximum microbial inhibition of tank water system. Chloramines
in 3, 5, 8 and 10% are combined with 2, 3, 5 and 7% of Zinc Meta phosphates respectively for
analysing the inhibition Best inhibition result is obtained with 8 %Chloramine and 5 % Zinc Meta
Phosphate solution Thus 8 % Chloramine ami 5 % Zinc Meta Phosphate is considered as Chlor-
Z -2 solution



Discussion
Higher compositions are not considered as there is no significant change in inhibition on microbial
(biofilm) growth rather cost of the process is found to increase for both material and pumping of
sohitioa Again it may not be possible to carry out flushing operation properly with higher
concentrations of Chlor-Z-1 solutioa
RESULT
From the above investigations it is observed that the inhibition (disinfection) effect with the use of
Chlor-Z-1 Solution (3% Chloramine and 2% Zinc Meta Phosphate) is better. On comparison with
other disinfection methods applied within the distribution system itself use of Chlor-Z-1 solution
is also found to be most effective in inhibiting the biofilm growth on the piping surface.

RESULT
From the above experiments it is observed that the inhibition (disinfection) effect with the use of
the 8% Chloramine and 5% Zinc Meta Phosphate is excellent in comparison with other
compositions in the Tank system for water distribution system. That is why Chlor-Z-2 solution has
been used for further investigations. On comparing with other disinfection methods applied within
the distribution system itself, the Chlor-Z-2 solution is also found to be most effective in inhibiting
the biofilm growth in water tank system for water distribution.
CLAIMS
1. We Claim the inhibition of biofilm growth by Chlor-Z solution.
2. We Claim 3% chloramine and 2% Zinc Meta Phosphate as Chlor-Z-1 solution to be an
excellent biofilm inhibitor in piping system which is flushed with water at 1.5 kg/cm2
pressure.
3. We claim 8% chloramine and 5% Zinc Meta Phosphate as Chlor-Z-2 solution to be good
microbial inhibitor in tank system.
4. We claim chlor-Z-1 and Chlor-Z-2 solution as Chlor-Z solution in different compositions
for inhibition of microbial growth in drinking water distribution system.
EXAMPLES
1. The reduction in microbial growth at the end of the experiment 1 was found to be about
6%.
2. The reduction in microbial growth at the end of the experiment 2 was found to be about
2%.
3. The reduction in microbial growth at the end of the experiment 1 was found to be about
11 %.
4. The reduction in microbial growth at the end of the experiment 1 was found to be about
7%.
5. The reduction in microbial growth at the-end of the experiment 1 was found to be about
1.5%.

6. The reduction in microbial growth at the end of the experiment 1 was found to be about
2%.