The Intermittent Sand Filter: (or single pass sand filter) is typically used for single family homes. It is covered with topsoil and seeded with grass so it can be used as a lawn . The Ontario Building Code lists the intermittent sand filter as a tertiary treatment system and is suitable for use with conventional gravity drainfields or Shallow Buried Trench type drainfield or other types of disposal. The intermittent sand filter is hydraulically loaded at either 1.25 US Gal/sq. ft./d for a low load sand filter or 2.5 US Gal/sq. ft./d for a high load sand filter.
Intermittent Sand Filters are an ideal tertiary treatment solution where high groundwater, poor soils, or other site constraints rule out conventional septic systems. Tucked neatly underground, out of sight of the homeowner, pre-engineered kits from Orenco Systems use high quality, reliable components. No more shopping around, piecing together parts. Regulators appreciate the advanced level of wastewater treatment from our sand filters, which typically produce BOD and TSS of less than 5 mg/L. Contractors and installers appreciate the easy installation and helpful video. And homeowners appreciate the low system maintenance and low operating costs.
A 130-year-old technology, intermittent sand filters are approved in about 40 states, representing all climate zones, and in most of Canada. Modern intermittent sand filters use pumps, liquid level sensors, and programmable controls to evenly dose the sand media with septic tank effluent throughout the day. Sand Filtration Inc.'s engineers assist with media specifications, tank sizing criteria, application rates, dosing frequency, drainfield sizing, and maintenance requirements.
Treatment Train:
The single pass or Intermittent Sand Filter is controlled by a panel attached to the house. It has a filtered pump vault in the septic tank, which feeds a network of distribution laterals on top of the sand filter. The effluent from the relatively clear zone of the septic tank is pre-filtered before distribution over the sand filter. The effluent filters down through the sand filter and is collected at the bottom of the sand filter by the 200 mm slotted underdrains. From the sand filter the treated effluent is either pumped or flows by gravity for finale disposal.
