WPL HiPAF Bespoke Solution

Sewage and wastewater treatment for the water utility companies

The WPL HiPAF bespoke sewage and wastewater treatment plant is a below ground solution for properties of up to 5,000 plus people where mains drainage is unavailable. The bespoke design consists of a separate primary settlement, a HiPAF SAF (submerged aerated filter) for biological treatment and final settlement modules.

WPL can create a bespoke design to ensure that the plant meets each water specification. The HiPAF package offers a complete in-house design and specification service including a turnkey service of initial site survey, commissioning and project liaison if required.

Suitable for larger applications the WPL HiPAF bespoke sewage treatment system is manufactured from glass reinforced plastic (GRP) and installed below ground.

Bespoke above ground solutions are also available from WPL, units can be manufactured from GRP, steel, stainless steel or GRP with a steel or stainless steel  ‘exoskeleton’.


Features and benefits of the WPL HiPAF bespoke sewage treatment system plant:

Low maintenance

  • The HiPAF design has no internal mechanical moving parts therefore it requires minimal annual maintenance
  • Emptying of the tank is also not required during maintenance as WPL’s design can isolate and remove sections of the air distribution system

Low running costs

  • Significant reduction in power consumption can be achieved using VSD’s, timers, instrumentation and control to deliver the lowest TOTEX solution

Low installation costs and flexibility on site

  • Only a small excavation is required due to its compact design allowing flexibility of positioning on site

Bespoke configurations

  • Energy saving options and chemical dosing packages can be configured to the HiPAF design for site specific requirements

Minimal visual impact

  • The HiPAF sewage treatment plant does not impede views due to the below ground installation

Variable flows and loads

  • During low flow conditions the level in the primary tank is reduced utilising forward feed air lift pumps. This creates a buffering volume that reduces the impact during high flows

Reliable operation

  • Underpinned by the supply chain partners that WPL uses

Robust operation

  • Proven WPL SAF technology based on 25 years empirical data

Easy access

  • Large access lids therefore no requirement for confined space entry reducing health and safety risks
    Access also offers ease of maintenance and process optimisation.

Simple tankering operation

  • Humus and primary sludge’s are stored in one place for simple tankering operation


  • BS1509001 CDM regulations and BIM maturity level 1 (working towards level 2) – promoting collaborative working methods

Tank 25 years life

  • GRP is UV stabilised with an external gel coat finish which extends the asset life to 25 years
  • WPL HiPAF plants and kiosks are produced in a quality controlled environment at the WPL factory

WPL tailor our robust and reliable HiPAF bespoke wastewater treatment solutions to meet our clients’ demanding specifications and expectations

Bespoke design options can include:

    • Lid type, orientation and colour finish options are available
    • Single or three phase power supplies
    • Blower kiosk cooling fan
    • N-SAF tertiary treatment options
    • Inverts 0.5m as standard
    • Volt free telemetry contacts on control panel
    • Form  2 or form 4 control panel
    • Pumped inlet flow control
    • Duty/standby and duty standby assist blower upgrades
    • Blower and airline hose upgrades for long hours
    • Kiosk options including walk in kiosk
    • GRP or steel construction for transportable plants
    • Above ground or below ground solutions
    • Permanent or temporary solutions

 Design Parameters

HiPAF WPL bespoke design sewage and wastewater treatment parameters


The WPL HiPAF™ brand (High Performance Aerated Filter) references the unique hydrodynamic profile within the filter bed.  The benefit is a stable even biomass growth, during high or low flows meaning WPL is offering higher treatment efficiencies over other similar solutions on the market.

WPL’s robust biological treatment process guarantees to suit both BOD and ammonia removal and is underpinned by 25 years of empirical data offering treatment for carbonaceous ﴾BOD﴿ removal, nitrification and de‐nitrification ﴾Total N﴿ when strict standards are required.

WPL HiPAF Wastewater Treatment Plants

Image of WPL bespoke HiPAF solution for utilities

WPL HiPAF below ground installation, manufactured from GRP


Special project request. Above ground steel WPL HiPAF at Letwell


Walk in WPL kiosk supplied for the Letwell project

MK3 lids for the UK Water Utilities specification:

  • Anti-slip pads on the lids
  • All lids are lockable
  • Two lids per width of the tank – lids less than 25 kilo’s to lift
  • Lockable stainless steel stays
  • Grating held in position under the lid when in the down position allows ease of access to all air distribution pipework
  • Grating when in place prevents risk of fall
  • Raised air distribution pipework allows for ease of maintenance

Image of WPL MK3 lids with grating showing air distribution pipework, part of the bespoke wastewater treatment system, the WPL HiPAF  Image of WPL MK3 lids showing grates to walk on, part of the bespoke wastewater treatment system

Ease of access is also a key feature of the WPL HiPAF sewage treatment range.  The internal sections of the plant are accessible from the top by opening the large access lids, allowing for easy service, maintenance and de-sludging.

Standard Kiosk Design

Each HiPAF comes complete with a discreet, weatherproof, acoustically lined GRP kiosk, situated above ground. This houses the blower(s), a Form 2 control panel and air distribution manifold.

Included as standard is 10m of airline, to connect the blowers to the tank. Blower and airline upgrades are available if the kiosk is sited further than 10m from the plant.

The Form 2 control panel, automatically controls the operation of the plant.  Form 4 is also available.

Kiosks upgrades available on request e.g. walk in kiosk.

Standard kiosk for the UK water utilities (image below)

Image of a standard WPL kiosk for the water utilities, a component of a sewage and wastewater treatment solution

Kiosk Examples:

WPL T300 tanks with form 4 and control panel and “wardrobe” kiosk

WPL T300 tanks with form 4 and control panel with wardrobe kiosk

WPL T300 tanks with form 4 and control panel and “wardrobe” kiosk

Image of WPL walk in kiosk at the Eon site for sewage and wastewater treatment

Walk in kiosk at a power station