|
WaterTECH Wastewater |
Sandfilter SystemHow the Watertech ISC 1200 system worksAll wastewater from the house enters a very large primary tank. This primary tank performs as an anaerobic digester i.e. it utilises bacteria - as found in the human stomach, which perform in the absence of oxygen to break down waste to form simpler molecules. A healthy primary tank will develop a floating 'scum' layer above a relatively clear liquid with a sedimentary 'sludge' layer. (This layer will require extraction and removal at approximately eight year intervals).
Pump ChamberDigested liquid from the Primary tank trickles through a 'Biotube Filter', a special polymer plastic tubing arrangement that promotes the growth of attached 'bioslime' and filter fine particles - to a pumpout chamber. This pump chamber contains a timer and float controlled pump directing effluent towards the Sand Filter and a high level alarm float. Control PanelThis electrically designed device controls the pumps that manage the movement of liquid within the Watertech Treatment System and signal the occurrence of abnormal liquid levels overriding the timed operation to pump to the sand filter. Effluent is directed across the Sand Filter at timed intervals, for short periods of time. (Typically 30 sec pumping every 30 minutes unless overridden by high levels)
The Crux of the Sand Filter SystemCoarse river sand is layered with aggregate over a polymer plastic lined excavation. Effluent is distributed over these layers through a network of distribution pipes.
The wastewater is pumped through the distribution pipework and percolates ever so slowly through the sand. The sand filter operated aerobically (presence of oxygen) with an aerobic biomass developed within the first 300mm of river sand digesting effluent waste and remaining sand providing physical filtration of solids.
Drained and digested liquid is collected from the base of the Sand Filter within a pumpout chamber located adjacent to the primary tank manhole and typically appearing at ground level as a 375mm round lid. Pipework and integrity of the riversand/aggregate filter is protected from ground level landscaping by a layer of geofabric and approximately 100mm of sandy topsoil.
Tank lids and capped pipes should be left exposed or accessible to enable access for service or maintenance. Ground contouring should ensure run off water does not pass onto or over the sandfilter or tank. It is vital that the Sand Filter be able to 'breathe' and the distribution pipework protected from root intrusion. Large plants should not be grown above the sand filter.
Domestic Strength Sewage - BOD (Biochemical Oxygen Demand) in Primary Sewerage is 250 to 300 mg/L. This must be reduced to under 20 mg/L after the wastewater is treated. With Sand Filters the BOD is almost always below 5 mg/L TSS (Total Dissolved Solids) 200 to 300 mg/L. After treatment this parameter is reduced to under 30 mg/L. With Sand Filtration it is almost always below 5 mg/L.The Aerobic Sand Filter is recognised by the Queensland Government (Department of Natural Resources and Mines) as the best performing treatment system. This means that the downstream irrigation system will have a longer life with a sand filter.
We can engineer a treatment process that will bring secondary treated waste-water back to "class A" recycled water that can be used for toilet flushing, car washing or external washing around the house and commercial applications.
|
