PROJ00001

• Contract/PO #: C153168
• Contractor Name: Delta, City of
• Contract Type: Loan
• Water District: 40
• County: Delta
• Bill Number: SB 77-35
• Loan Projects - Doc Type: Feasibility Study

I

I

I

A pressure set-rate-indicator on the effluent manifold modu-
lates the rate of flow controllers on the influent line ahead
of each filter unit to maintain a pre-set effluent pressure.
A pressure reducing valve is also installed in the effluent line
to guard against water hammer which might occur from a sudden
full opening of the rate of flow controllers. All filter operating
valves and effluent rate controllers are operated by air switches
mounted on the master control panel.

I

I

I

The record of treated water filtered (in thousands of gallons)
each month by the City of Delta since start-up in May of 1968
through 1974 is shown in Table 111-2. This information is also
shown graphically in Figure 111-6 which shows the seasonal variation
from year to year. The maximum quantity of water processed in
any year was 866,715,000 gallons filtered in 1971. The maximum
quantity of water processed in any month was 107,270,000 gallons
filtered in July of 1970. This is an average rate of 3.46 million
gallons per day.

I

I

I

Daily records of filter plant effluent for each year since
start-up in 1968 through 1974 are shown graphically in Figures
111-7 through 111-13. These records show the seasonal fluctuations
in production as well as fluctuations from day to day within
each month. The data for these graphs were taken from records
maintained at the filter plant. The majority of peaks in the
graph followed directly by a low are a result of recording effluent
over a period greater than 24 hours in the first instance and
for less than a full day in the second instance. Major depressions
lasting for several days may be indicative of one or more of
the following:

I

I

I

1.

lack of adequate supply

2.

climatic conditions influencing water use

I

3.

water restrictions influencing use

4. plant shutdown with water bypassing the treatment plant

I

5.

recording chart not working

I

I

I

I

III - 12

I