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 a. Two pier sewer systems accepted in San Diego had blockage problems.
One pier main was unable to carry the sewage flow from an AS and a submarine
at the same time. An investigation found five 5-gallon cans of extraneous
debris left in the main by the contractor. A pier recently accepted from a
contractor was given a salt water flow test. The salt water backed up in a
manhole on the system and overflowed into the street. It was found that the
contractor failed to remove a blank that was put on the main to the lift
station incident to an air test required in the contract specifications.
b. A salt water test was made on a pressure manifold section of a pier
sewer accepted from a contractor. It was found that the salt water
pressurized all outlets on the pier connected to the manifold. Standard
Operating Procedures (SOP) were established to assure that sewage spills
will not occur on this pier when disconnecting sewage hoses from the pier
risers.
B.12 Several test sequences were conducted to evaluate hose cleaning
techniques.
a. AS-12: contaminated hose, salt water flush, 2 l/2-inch main at 90
psi 23 November 76.
Time of Flush
Total Coliform Count
Test
#1
5 min.
150,000/100
ml
Test
#2
10 min., same hose
6,000/100
ml
Test
#3
15 min., same hose
50,000/100
ml
20 min., same hose
Test
#4
30,000/100
ml
Salt water background
300/100
ml
Test
#5
b. AS-12 : contaminated hose, salt water flush, 2 l/2-inch main at 90
psi 17 November 76:
Time of Flush
Total Coliform Count
Test
#1
5 min.
12,000/100
ml
Test
#2
10 min.
1,000/100
ml
300/100
ml
Test
#3
15 min.
80/100
ml
20 min.
Test
#4
0/100
ml
25 min.
Test
#5
30 min.
>300/100
ml
Test
#6
Salt water background
300/100
ml
Test
#7
c. A series of tests were made on hoses contaminated by submarines;
the hoses serving black water and/or gray water tanks are so indicated.
Test #1: Flush with potable water l-inch source 80 psi, hose #1, black
water.
B-2
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