TM 5-814-9
concentration (pH), total dissolved solids
in accordance with the instructions in
(TDS), and suspended solids (SS) levels.
Standard Methods for the Examination
of Water and Wastewater.
(a)
A recycle system should be monitored
6-27. Lagoon system
at least weekly for the first year of
operation. This time span will give the
Using lagoons as a secondary treatment system for wastewaters
installation a good profile of the
from a CVWF is not the recommended standard. The use of
treatment system's operation. After the
lagoons instead of intermittent sand filters requires Office of the
first year, the system may need to be
Chief of Engineers (OCE) approval prior to programming and
monitored once per month or every
design. Lagoons can be used for secondary treatment only if
other month. These data should be
ponds exist in the vicinity of the CVWF and they are
compared with the initial profile data
environmentally, hydraulically and structurally acceptable; and
to confirm that the system is working
if they are more cost effective than sand filters; and long term
properly.
settling test confirm the ability of lagoons to produce acceptable
water quality. However, past designs have used the lagoon
(b)
If primary treated and equalized water
treatment system for secondary treatment at CVWFs as
is discharged to a sewage treatment
described below.
plant, the system should be monitored
weekly for the first 3 to 4 months to
a.
Description. A lagoon system, like an intermittent
assure the plant operator that the
sand filter system, includes a sediment basin for
biological, solids, oils, or hydraulic
sediment and free oil removal (fig 6-18). If the
load being discharged from the wash
wastewater is to be recycled, an equalization basin
facility are in compliance.
and wash water supply basin are also required. The
polishing lagoon is sized to give a minimum of 14
(c)
A system that discharges to the
days detention time for the wastewaters after pre-
environment will require permitting in
treatment. This minimum detention time is calcu-
accordance with the state regulatory
lated at peak hydraulic flow conditions into the
agency. The agency must be consulted
lagoon. Sediment storage within the lagoon must be
to determine the monitoring frequency
provided for the design life of the lagoon. This
required.
Measurements
and
storage volume is calculated by multiplying the
laboratory tests should he performed
6-22
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