Choose Your Site

MWH, now part of Stantec, is comprised of global offices in 35 countries and operating on six continents. Choose a regional site highlighting local services, experience and experts.

MWH, now part of Stantec – English

We are a global, full-service consulting, engineering and construction company. Choose a site below that highlights special service offerings or markets in which we serve.


Home > Services > Construction & Construction Management > Products & Spares > Compact Plant

Compact Plant

<< Back to Construction

Compact-Plant-1 Compact-Plant-2 Compact-Plant-4 Compact-Plant-3Key Features:

  • Concrete or steel walls
  • Reduced land area
  • Practically odourless
  • Handles shock and peak loads
  • 250 – 10,000 population

General Description:
Sewage treatment in the ‘compact plant’ is achieved by means of extended aeration. No primary sedimentation tank is required and the aeration circuit provides an extremely economical plant for the full treatment of sewage. The biological sludge formed during the process of purification is oxidised to such an extent that the small quantity produced can be easily processed without nuisance or odour. Indeed a particular feature of the compact plant is the absence of smell and fly nuisance.

The aeration zone is arranged as an annular circuit, surrounding the central final settlement tank. This arrangement considerably reduces the space required for a plant, and can also reduce construction costs as the settlement tank wall also acts as the inner wall of the aeration zone.

Oxidation within the system is carried out either by means of an aeration rotor, or fine bubble diffusers. These satisfy several functions. Firstly they provide the necessary oxygen for the activated sludge. Secondly, they maintain a flow velocity in the compact plant preventing settlement. Thirdly, they break up larger solid particles and finally they ensure complete mixing of the liquors.

Methods of construction are simple and may be either reinforced concrete tanks or steel wall tanks. The latter usually shows considerable cost advantages. Tanks are frequently situated above ground so that site excavation costs are also minimal.

The system has proved acceptable for the treatment of domestic and industrial wastes.