CHEMICAL DOSING
An OR-TEC Blend emulsion polymer feed system automatically makes
up and delivers the polymer and water solution to the injection site.
As an alternate, a solution of suitable polymer is made up in a stainless
steel chemical mixing / storage tank. The tank is usually designed with
a capacity for one day’s operation of the system.
FLOCCULATION
Sludge is pumped to a stainless steel flocculation tank by a variable
capacity pump. Prepared polymer is simultaneously injected to the
inlet of the flocculation tank by a variable speed chemical dosing pump.
Here a thorough mixing occurs that is aided by a variable speed
flocculator fitted in the tank. Speed adjustments are manual.
GRAVITY DRAINAGE AREA
Flocculated sludge flows from the flocculator down a sludge feed chute.
This chute provides a gentle and even distribution of sludge over the
gravity drainage section and a uniform thickness on the dewatering belt.
The drainage area allows for the separation of the free water contained
within the sludge and its consequent discharge into the drainage tray.
Capillary action takes place as the dewatering belt moves across tracking
and pressure rollers. The drainage area is sealed by polypropylene
skirting that is bolted to the top trays and rests on the filter cloth.
ROLLER PRESSURE DEWATERING ZONE
Further liquid removal is achieved as the belt and sludge are pressed
between a series of rubber covered rollers. Gradually the sludge is
squeezed by adjustable rollers that have been preset during commissioning.
SLUDGE DISCHARGE
Dewatered sludge is continuously removed by a fixed scraper blade acting
against the final roller and allowed to fall into a horizontal stainless
steel conveyor. The conveyor can transport the sludge cake to the
outside of the building. Sludge cake can also be elevated with a
stainless steel inclined screw auger for discharge to a waste hauling
vehicle for off site removal. A dry cake pump can be used as an
alternative to the conveyor or auger.
FILTER BELT WASHING
The filter belt is continually washed by pump generated high pressure
water sprayed through fine nozzles. Belt wash water and filtrate are
collected in a stainless steel drainage tray. This runoff is funneled
to the customer’s drainage system via the supplied 4” diameter
flanged outlet in the tray. In most cases, the filtrate is acceptable
as reuse for wash water, as is the final effluent of the W.W.T.P.
CONTROLS
The system can be automatically controlled. Start-up is simple and
requires a minimum of time. The unit’s design, incorporating variations
in both speed of the main elements and in roller pressure, offer a high
degree of flexibility to the&nbdp;user.
