Incinerators with up-to-date gas cleaning systems do not have a significant impact in terms of discharging ultrafine particles into the environment, a planning hearing into Indaver’s proposed €160 million incinerator for Cork Harbour was told yesterday.
According to environmental consultants Dixon Brosnan for Indaver, a 2001 Swedish study of the emission of nanoparticles from modern municipal waste incinerators, including a detailed investigation of particle numbers and particle size distribution, found they had minimal impact.
The Swedish study found that flue gas treatment systems in all the waste incinerators that it studied were highly efficient in removing nanoparticles while the concentration of particles from most plans was of the same order as the ambient air, noted Dixon Brosnan.
In their paper, which was read into the record by Fiona Patterson of Arup Engineering, Dixon Brosnan looked at the possible impact of the proposed 240,000 tonnes municipal and hazardous waste incinerator at Ringaskiddy on Cork Harbour.
The National Parks and Wildlife Service has granted Special Protection Area status to Cork Harbour for a number of species of birds but, according to Dixon Brosnan, the impact of engineered nanoparticles on these birds’ prey is considered “extremely remote for the foreseeable future”.
Dixon Brosnan said that is due to the fact there will no aqueous or water based discharges from the incineration process into the sea. It says the only aqueous discharges during construction or operation will be surface water and the engineered nanoparticles will not be able to enter the surface water.
“There is no direct pathway to water. It is indirect and the particle concentrations in air associated with the waste to energy plant (the incinerator) are effectively insignificant when compared with the background,” said Dixon Brosnan.
“Particles in air may over time deposit on water but in this case the water body in Cork Harbour has a daily tidal flux of some 57 cubic metres per day, providing many orders of magnitude dilution of any particles depositing on water,” they added.
No fly zone
Earlier, Ms Patterson played down concerns expressed by the Department of Defence that if planning permission was given for the incinerator at Ringaskiddy, the Air Corps would have to operate a 1,000 foot (305 metres) no fly zone because of the chimney stack on the incinerator.
Last month, Comdt David Browne of the Air Corps told the oral hearing at the Carrigaline Court Hotel that the "proximity of the stack of the waste-to-energy facility to the approach paths of Haulbowline Naval Base and Spike Island is a matter of concern".
“This is due to the fact that the stack will be emitting significant amounts of exhaust gases and is seen as a potential hazard as it may render approaches by the Air Corps helicopters into Haulbowline and Spike Island as unsafe,” he said.
Comdt Browne said given that the incinerator site is located to the south and west of Haulbowline and Spike Island and the prevailing winds, the Air Corps may be forced to operate a local no fly zone around the site and a possible ban on operations to the Naval Base during south westerly conditions.
Responding for Indaver, Ms Patterson pointed out that there are already a number of existing industrial facilities in the Lower Cork Harbour such as stacks at GlaxoSmithKline and Hovione which emit exhaust fumes as well as other tall structures such as De Puy's wind turbines and ESB pylons.
She said that that the Irish Aviation Authority has recommended that aircraft including helicopters avoid all such tall structures by 150 metres while the Department of Defence recommended a 305 metres buffer or clearance over the incinerator stack.
According to Ms Patterson, a study carried out by Dr Edward Porter of environmental consultants, AWN Consulting, found the exhaust plume from the Indaver stack will comply with the recommended levels for turbulence, temperature and oxygen content within 100 metres of the stack top.
This would ensure that the Indaver stack falls within the 150 metre radius which is required in order to comply with the physical structure exclusion zone recommended by the Irish Aviation Authority, rendering the 305 metres avoidance zone unnecessary, she said.
“Even applying a worst case scenario of an avoidance zone of 305 metres around the Indaver stack ( as argued for by the Department of Defence), it is considered that the proposed development will not add materially to those existing constraints for aircraft,” said Ms Patterson.
