BELFAST LOUGH ON 'KNIFE EDGE' AFTER PAUSE TO WASTEWATER UPGRADE INVESTMENT PLAN

Belfast Lough is on a "knife edge" with failure to invest in wastewater infrastructure creating a "profound" risk for its ecosystem, MLAs have been warned.

The lough's shellfish industry is collapsing in "real time" as water quality levels continue to decline, a senior NI Water representative told an Assembly scrutiny committee.

The warning comes amid similar pollution concerns over Lough Neagh, which has experienced major green blue algae blooms over recent summers.

NI Water announced last week that it had been forced to stall planned upgrades to sewer and wastewater treatment plants as part of its Living With Water Plan (LWWP) for Belfast after being unable to secure the required funding from the Department for Infrastructure .

Paddy Brow , from NI Water, told the Committee for Infrastructure on Wednesday that the deferment move could have significant consequences for Belfast Lough.

He explained that the decline of the shellfish population was a serious issue, as mussels play a key role in filtering the water in the lough.

He said replicating the function the mussels perform would add a further £50 million to the cost of upgrading the Belfast wastewater treatment facility, as well as ramping up operating costs by another £1 million per year.

"For Belfast Lough, the consequences are potentially profound," he said.

"One of the things we set out and predicted was that if we don't address the investment needs of Belfast , the water quality would continue to decline and the shellfish industry would collapse, and we are seeing that.

" Successive Northern Ireland Environment Agency (NIEA) reviews of Belfast Lough have shown that water quality is declining. The shellfish industry used to produce 10,000 tonnes of mussels a year in Belfast Lough and that's fantastic. That provides something called ecosystem services. Each shellfish, each individual mussel, filters about 18 litres of water a day.

"Now we're down to 1,000 (tonnes), the beds are moving from an acceptable class to an unacceptable class. So we're watching in real time the collapse of the shellfish industry.

"And NIEA reports are telling us the water quality is declining. If we lose that ecosystem service, it costs us a lot more to invest.

"At the Belfast wastewater treatment works alone, the additional cost could be £50 million if there's no shellfish industry there. And in terms of operational costs, which is a real challenge for us and a real concern, that would mean that the operational cost of that plant alone would increase by £1 million a year.

"We would have to import methanol, which is carbon, and pay for that to achieve more stringent standards.

"So, it just underlines that we are on the knife edge with regard to Belfast Lough. We've got to maintain the shellfish industry and protect it and deferring this investment is a real challenge."

Chief executive of the NIEA David Reid, who also gave evidence to the committee, expressed concerns for the future of Belfast Lough.

"We would have concerns in relation to the water quality in Belfast Lough," he said.

"That includes concerns that are echoed in terms of all fresh water bodies across Northern Ireland at the minute of what we're seeing in terms of pollution."