Coalisland WwTW

Environmental Engineering


Coalisland WwTW

Project Description

The Coalisland WwTW upgrade involved the replacement of the old works with a new plant capable of treating 80 l/s to the revised standard.

Raw sewage enters the works via two inlets which are both pumped flows and formula A flow (or less) travels forward to the two duty/standby inlet bar screens. These screens remove any screening greater than 6 mm.

Grit is removed via the grit trap and grease is collected at the interstage pumping station, and then transported to the grease tank.

Flow in excess of FFT fills the interstage pumping station and then overflows to storm tanks with a capacity to hold two hours storm retention at formula A minus FFT. If the storm tank capacity is exceeded the excess discharges to the river and is monitored via a flowmeter.

After preliminary treatment the sewerage is pumped from the interstage pumping station via the ash tanks and onto the CAS tanks where flows are combined with return liquors and RAS, where secondary treatment commences.

Flow from the CAS tanks is transferred to the final settlement tanks where it is decanted before combining and entering the duty/standby tertiary filters and onto the sample and washwater sump

Ferric dosing is available on site, designed for 110% capacity.

In addition to the process described above, there is a service water booster pump set to supply on site hose reels, and a standby generator is available for power back-up.

Project Statistic:

  • Population Equivalent: 14,510
  • Treatment Flow: 6940 m3/day

Coalisland WwTW

  • Client: NI Water
  • Completion Date: January 2012
  • Total contract Value: £7.5m