Waste Water Treatment Plants in County Wicklow

There are 35 Wastewater Treatment Plants in County Wicklow that treat the sewage from urban centres with populations ranging from 30,000 to 50. The biggest plant in the county is located in Greystones which treats a population of 30,000.

There are a wide variety of treatment processes in operation in the county. In general, the treatment systems consist of:

• Preliminary Treatment
• Primary Treatment
• Secondary Treatment
• Tertiary Treatment
• Sludge Treatment

Preliminary Treatment

This includes Coarse and Fine Screening to remove rags in the sewage and Grit removal to remove silt and sand.

Primary Treatment

Suspended solids in the sewage are settled out in large tanks and removed.

Secondary Treatment

Dissolved solids in the sewage are removed in aeration tanks and settled out

Tertiary Treatment

This consists of phosphorus removal by dosing chemicals and/or sand filtration to further reduce suspended solids in the sewage.

Sludge Treatment

Water is removed from the sludge using belt presses or centrifuges. Twenty per cent of the sludge produced in the county is lime stabilised to kill harmful bacteria before being ploughed into tillage land in the county. Eighty per cent of the sludge produced in the county goes for composting before been spread on the tailing ponds at the Galmoy Mines in County Kilkenny for land remediation.

In Donard Waste Water treatment Plant the incoming sewage is screened followed by primary settlement and thereafter is pumped to a 33 acre willow plantation for treatment. Willow is an energy crop and is normally harvested every 3 years and is used to produce wood chips for use in heating systems.

How Waste Water and Sewage is Treated

Environmental Protection Agency