Case Study Sam Dennigan & Co

Originating in 1976, the family-run business Sam Dennigan and Company has grown to become a thriving international company of 350 people, all motivated to provide the best possible service and highest quality products to their customers.


The Integrated Constructed Wetland (ICW) at Sam Dennigan & Company’s Palmerstown premises has been in operation since 2016.

It treats wastewater derived from the Company’s logistics and potato processing facility.

The ecologically engineered facility provides both high quality water treatment and a range of additional services including amongst others biological diversity, carbon capture and amenities for staff.

Since its commissioning in 2016 the ICW has matured with the establishment of diverse emergent vegetation. This vegetation thrives on the nutrients it receives from the inflowing water derived from the potato washings and staff toilets/canteens at the premises.

The emergent vegetation, comprising largely of sedges and rushes provide almost complete cover in each of the three main treatment wetland cells. Together the wetlands and retaining embankments provide habitats for a wide range of native species – vertebrate and invertebrate.

Waterfowl inhabiting the wetland have successfully reproduced, demonstrating the nature-value resource the ICW provides.

Integrated Constructed Wetlands

An Integrated Constructed Wetland (ICW) is a multi-disciplinary approach to the total management of contaminated waters, incorporating natural interactions of water, land and air.

An Integrated Constructed Wetland is a series of shallow cells (generally 4-7) connected by pipework and densely planted with a mix of emergent wetland vegetation.

Effluent is generally pumped from the village or facility to a tank or settlement pond where it flows by gravity to each cell before discharge to a stream or river.

ICWs are licenced under the same EPA discharge licence system as traditional wastewater treatment systems.

VESI Environmental Ltd. provide designs, construction, and management of constructed wetlands for wastewater treatment. Our focus is on delivering a wide range of ecosystem services for the benefit of both society and our natural environment.

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