HIPAF Sewage Treatment


High-performance sewage treatment system for sites with 25–2000 persons

HIPAF sewage treatment plant at golf club

The HiPAF® SAF (Submerged Aerated Filter) is a market-leading sewage treatment system. Its simple and innovative design combines efficient processing and reliability contained within a robust GRP construction.

Designed to order the system features:

  • Guaranteed performance
  • Techology used by all the major Water Utilities
  • Innovative and simple process
  • No moving parts
  • Minimal visual impact
  • Small installation footprint
  • Able to cope with variable flows


  • Academic
  • Camping and caravan sites
  • Construction Sites
  • Garden centres
  • Golf and leisure centres
  • Hotels
  • MOD Facilities
  • Motorway Service Stations
  • Nursing homes
  • Hospitals
  • Restaurants
  • Public houses
  • Stables/kennels
  • Large country estates
  • Villages, rural communities and housing associations
  • Zoos/theme parks/leisure attractions

Inside the HIPAF® Sewage Treatment Plant

Inside the HIPAF Sewage Treatment Plant
  1. Primary settlement tank
  2. Settled solids at bottom
  3. Unique air lift forward feed into biozone
  4. Biological treatment unit (biozone)
  5. Air diffusers at the bottom of each chamber
  6. Filter media
  7. Settled sludge air lift back to primary
  8. Final (humus) settlement tank

The HIPAF® 3-Stage Treatment Process

  • Primary - Primary settlement is in accordance with BS6297, giving the required hydraulic retention time and ensuring that 30% of the BOD will settle out in the primary tank. HiPAF plants below 500 persons will have sludge storage integral to the primary tank. The primary settlement tank is equipped with baffles to prevent floating scum entering the biological phase of the treatment process. It also incorporates a unique forward feed system which lowers the level in the tank, during periods of low flow, to provide a buffering capacity for possible surges in the
  • Biological - After primary settlement, the settled liquor flows to the biological treatment unit by displacement and via the air lift forward feed. The biozone is fully segmented internally to eliminate the risk of process short cuts. Each biozone segment is filled with high voidage plastic filter media, where both carbonaceous and nitrifying processes take place, mitigating process risks associated with variable loads. Air to oxygenate the influent and to scour excess biomass from the filter media is introduced continuously below each chamber by a series of diffusers.
  • Final - Following biological treatment the effluent flows into the final (humus) settlement tank where the excess biomass settles out. The humus tank is equipped with air lifts which are arranged to automatically transfer settled humus sludge to the primary tank for co-settlement. The treated effluent flows under gravity to the works outfall.

HIPAF® Range

HiPAF® Compact Plant (single-tank) 1-60 Persons
Compact below-ground GRP package plant containing primary settlement, biological treatment and final settlement modules

HiPAF® Midi Plant (single-tank) 60-250 Persons
Below ground GRP package plant containing primary settlement, biological treatment and final settlement modules

HiPAF® Modular Plant (multi-tank) 250-3000 Persons
Below ground GRP package plant containing individual primary settlement,  biological treatment and final settlement modules

HiPAF® Transportable and Temporary SAF Plant
Ideal for temporary use (e.g. construction sites) or where existing plant is failing. The HiPAF-2-GO incorporates primary settlement, biological treatment and final settlement all contained within an easy to transport steel container.


The right solution for you

To discuss your requirements and arrange a no-cost survey please contact Watling Hope on 01789 740757 or use our on-line enquiry form.

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