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Harlequin CAP9 Sewage Treatment Plant - up to 9 Person


Sale price £2,340.00 Regular price £2,400.00

The Harlequin CAP9 is a compact sewage treatment plant designed specifically for domestic installations for up to 6 inhabitants (4 bedrooms). It is a Continuous Aeration Plant which operates using a unique bio-media system and delivers a pollutant removal level of 96.2% whilst also combating common problems associated with small packaged domestic plants.


Bio Media System - Similar to the MBBR system, there is no fixed media eliminating blockages that are commonly found in smaller treatment plants.

Durable & Stable Product - Made from tough durable polyethylene, it is easy to transport and has a wide base for stability.

Saves Money - With an easy installation due to the systems compact size and light weight, it also promotes low maintenance reducing costs.

Easy Maintenance - At full occupancy the system only need to be emptied every 12 months, with maintenance of the compressor easily carried out located in the neck of the tank.

Compact System - A perfect compact solution for homes of up to 6 inhabitants (4 bedrooms).

Low Noise - With a near silent air compressor housed beneath the flat lid, the operation of the system is virtually silent.

How it Works:

Chamber 1 | Primary Settlement:
Raw sewage flowing to the CAP unit is received in the primary settlement zone. Here, gross solids (primary sludge) settle to the bottom of the tank, where they remain until the tank is desludged. The settled sewage displaced from the primary zone then flows into the submerged filter zone, passing under a scum baffle.

Chamber 2 | Reactor Vessel
Flow circulation in the submerged filter zone is generated by the hydraulic effect of the outlet air diffuser. This causes settled sewage entering the filter zone at high level to be drawn down through the media, aerating the sewage in the process. The flow circulation ensures that the influent sewage receives several passes through the filter bed at low flow.
In the filter zone, as the sewage passes over the filter media it is purified by micro-organisms growing on the surface of the media. Growth of these micro-organisms results in an excess which is shed as solid particles known as humus solids. Humus solids settling at the bottom of the filter zones are recirculated with the flow of incoming sewage and are deposited on the top of the primary settlement zone.

Chamber 3 | Final Settlement
Sewage displaced from the submerged filter zone flows via a DIP pipe into the final settlement zone. Liquid displaced from the humus zone has now been fully treated and is known as final effluent. It is suitable for discharge to a watercourse or soakaway as defined in the consent to discharge issued by the Environment Agency.
Humus solids from the final settlement tank are recirculated to the primary tank via the recirculation pipework. This helps reduce the sludge build up in the humus tank and prevents stagnation during very low inflow.

Standard Features:

Moulded from durable medium density polyethylene material
110mm inlet and outlet connections
Integrated lifting eyes for ease of handling and installation
Fully secured 450mm pedestrian duty, flush fitting manhole cover complies with statutory regulations
Above ground air blower housing delivers more reliable and efficient operation, and allows easy access for maintenance
Easy access to the bubble diffuser within the tank
Similar to an MBBR system there is no fixed media eliminating blockages
Virtually silent operation
Compact size and light weight reduces installation costs
Mechanically reliable with no moving parts or electrics within the tank
Certified to EN12566-3


Diameter (mm):   1840
Height (mm):   2180
Cover:   450mm diameter, pedestrian duty
Inlet depth (mm):   550


FREE delivery of this product is available to UK Mainland and Northern Ireland locations at no additional cost. However due to the size of the product they are delivered direct from the manufacturer on a high sided articulated vehicle to the kerbside or a pre-arranged delivery point. In all instances the product offloading is the responsibility of the customer.