ASK Piearcey

Odour Control Systems – One of UK’s Largest Sewage OCUs

A.S.K. Piearcey Ltd were engaged by their exclusive waste-water treatment partners Plasticon UK, to carry out the process design and flow balancing of  a flag ship odour control plant situated on the South Coast.

The system handles up to 250,000 m3/hr of odorous air from the main plant and there 2 further satellite systems handling approximately 3000 m3/hr each.

ASKP Ltd provided the process design based on a concept from the main process consultant. The system comprised venturi scrubbing for dryer off-gas solids removal and acid scrubbing for ammonia removal. This was followed by caustic-hypochlorite scrubbing and final carbon adsorber polishing.

Venturi Separator Sump

Venturi Separator Sump


The venturi system handled up to 19100 m3/hr of dryer off-gas but had 2 modes of operation with automatically varied flow control set point and alarm level adjustment. The venturi throat could be varied by means of an adjustable throat plunger and worked on a constant overflow of final effluent from the separator vessel (above).

Acid Scrubber

Acid Scrubber

The Acid scrubbers handle around 47,000 m3/hr of the high odour (from direct coupled extracts) and are there primarily to remove ammonia and some of the amine present.

Hypo-Caustic Scrubbers

Hypo-Caustic Scrubbers

The Hypo-Caustic Scrubbers handle the entire air flow at 250,000 m3/hr and can temporarily handle this with just 2 of the 3 duty scrubbers in operation


Carbon loading unit

Carbon loading unit

The 3 carbon units held around 125 tonnes of copper oxide impregnated carbon to fine tune the odour control performance of the system. Each had to be loaded with a specially built carbon loading system (above).

The air was conveyed from the various field extract points via a vast network of ducting.

Field Process  Odour Extract

Field Process Odour Extract

3m diameter Combined Exhaust to Stack

3m diameter Combined Exhaust to Stack


The ducting was fabricated up to 3m internal diameter to meet the agreed velocity consents.

Carbon adsorber units, also containing copper oxide impregnated carbon were used for odour control in satellite pumping stations.

The system below shows a system with duty standby extract fans and local control panel.

Odour Control Unit at Satellite Pumping Station

Odour Control Unit at Satellite Pumping Station

The Entire project value was circa £6.5 million. ASKP also assisted with HAZOP, HAZChem and commissioning. We provided Detailed Design, Operational instructions, Control Philosophy, commissioning schedule and training for the entire odour control system.

Fan Pressure Testing by ASKP Ltd

Fan Pressure Testing by ASKP Ltd











ASK Piearcey Ltd Design Odour Control Biofilters for Spain

ASK Piearcey Ltd have designed a number of odour control systems for projects in Spain. We have partnered with JSF Hidraulica (leading manufacturers of Aluminium Covers for odour control) to provide Sewage odour control systems into

the Spanish Market

Sewage odour control 3 biofilter

The above shows the smaller of 2 bio-filters constructed from lined aluminium.

Sewage odour control biofilter

The Bi0-filter uses a porous pumice stone media for the biomass support. The media is seeded with specific bacteria to promote a biomass tailored to the contaminants found in this type of application. The installation is on the back of very successful pilot trials conducted in southern Spain by JSF, with our guidance.

The project was turnkey and ASK Piearcey Ltd also provided pressure loss calculations for fan sizing.

Odour extraction ducting

The odour containment system had general and point extraction. The smaller system was rated at 3600 m3/hr whereas the larger system was rated at 13,000 m3/hr

Sewage Odour Control Pilot Trials in Spain

A.S.K. Piearcey (ASKPL) have assisted Cover manufacturing specialists JSF Hidraulica (JSF) of Madrid in developing their odour control portfolio in Spain.

After some preliminary design work by ASKPL, JSF have built and tested a pilot system (below) consisting of a bio-filter and a Carbon polisher.

JSF have tried a number of different media in the vessels to find an optimum for sewage odour control.


JSF are leaders in the aluminium structures, solid tank covers (below) and floating
tank covers market place. Odour control was a natural progression from their
various tank covering projects and they had received a number of enquiries to
provide odour abatement with their covers. They decided that a pilot trial was
an effective and economic means of developing track
record and confidence in the approach suggested by ourselves.


After extensive pilot trials involving various media they have developed a system
(with design assistance from ASKPL), which
can be used to handle the majority of the sewage odour control applications that
they come across. The bio-filter was entirely constructed from
aluminium and lined with a chemical resistant liner.


Measurements of air flow, H2S  inlet and outlet as well as temperature and irrigation were made and data-logged where practical.

The pilot trial, in Fuengirola  (south coast of Spain) was so successful that the plant manager is seeking to replace the existing scrubbers with the bio-filter approach.

JSF have since secured 2 large orders involving bio-filters and carbon adsorbers with design assistance from ASKPL.

H2S detector 1