c) A chemical addition system should be provided for
addition of acid, caustic, and defoaming agent. These three
chemicals should be separately pumped at an adjustable rate to
determined manually. Prior to discharging the wastewater to a
secondary treatment plant, the operator should determine the pH
of the effluent and make adjustments as necessary. Automatic pH
adjustment with manual override can also be used. Provide a
separate containment for each of the three chemicals used for
the pretreatment. The containment basin should be designed to
keep chemicals from mixing and to control chemicals in the event
of spillage. A drain should not be provided. The containment
should be designed to hold 125 percent of the amount of chemical
drum storage intended for the area. Provide local exhaust in
the chemical containment area. The exhaust system should
manually operate from the local area.
d) When the pH is adjusted, the wastewater is ready
for discharge. If monitoring is required by local authorities,
it should be done at this time. A daily log of sampling data
and chemical additions should be maintained by the user.
Discharge to the sewer system should be controllable and
verifiable because the rate should be used for billing purposes.
The preferred system is dual sump pumps designed to evacuate the
tank in 8 to 10 hours.
e) Local municipal treatment plants will periodically
The reporting period may be short at first but then lengthened
as confidence in the pretreatment process is gained. A sampling
should best be done by a contract laboratory since its purpose
is to determine permit compliance and its final frequency should
not justify funding "in-house" capability. An automatic sample
taking machine should be provided at fire training sites to
facilitate the sample taking process. The controls for sump and
recirculation pumps should include level controls, lead-log
capability, alarm conditions for high-high and pump failure.
Alarm conditions should be sent to the central annunciator panel
in the utility building and to the 24-hour duty desk.
f) The inlet to the discharge and recirculation pumps
should be provided with readily cleanable strainer to catch
leaves and frogs, etc., which have been a problem in the past.