The improper disposal of large quantities of milk has put significant pressure on wastewater infrastructure, Irish Water has said.
This is leading to operational issues with wastewater networks and wastewater treatment plants around the country, it said.
Furthermore, Irish Water is appealing to everyone involved in the industry to be aware of the impacts disposing large quantities of milk down wastewater networks can have on the environment and wastewater infrastructure.
Large quantities of milk that go untreated can make its way into the receiving waters and can have a major impact on the local environment, Irish Water said.
Speaking about the issue, wastewater source control lead Tony Hickey said that during the spring and summer months, they have started to experience a significant strain on the wastewater infrastructure due to large volumes of milk being disposed of.
High biological oxygen demand
"We are not talking about pouring a litre or two of milk from the fridge out, this is industrial or commercial quantities of milk that needs to be disposed of appropriately," Hickey said.
Milk, he said, has an extremely high biological oxygen demand, adding that it is 10 times that of cattle slurry or 400 times the level of domestic sewage.
"The environmental impact of one litre of milk is equivalent to a full day’s wastewater from a family household.
"Disposal of milk to sewers can create a shock load on treatment plants, with consequent pollution effects," he added.
Last year at the Grenagh Wastewater Treatment Plant in Cork, the plant could not cope with the volume of milk that required treatment, resulting in operational difficulties to treat the wastewater, Hickey explained.
There was also a similar case in Rylane, Kilbrittain and Dripsey, which Hickey said has "proved both challenging and costly".
“We are asking everyone associated with the milk industry to be very conscious of the impact this can have on wastewater networks and treatment plants and would ask that they dispose of milk and other products correctly," he said.
Large quantities of milk should be disposed of either in slurry pits or to a licenced waste facility.
"We would encourage everyone involved in the industry to spread the word of the potential damage that pouring large volumes of milk down the drain can have," Hickey said.