The transport of dried sewage from the Ringsend treatment plant will not greatly increase the amount of traffic passing through the south-east of the city, Dublin Corporation has said. Residents in Sandymount telephoned the corporation seeking clarification about the amount of traffic that would pass through the area each day, following an advertisement by the corporation for distributors to collect an estimated 28,000 tonnes of dried sludge for transportation from the plant.
The advertisement's wording could have suggested that 28,000 tonnes of the sludge would be transferred from the plant every day. However, the corporation said the current contract for transferring the dried sludge, which is like ordinary fertiliser, takes place over two years, an estimated 38 tonnes a day. Two 20-tonne trucks will carry this load from the plant each day.
The primary sludge is thermally dried at the Ringsend treatment plant, and after several further processes becomes a dry granular material. "The range of treatment is of the very highest and most stringent standards," said Mr Battie White, project engineer with the Dublin Bay Project.
An environmental impact study was carried out and published before starting the new development. "There is not in any way a danger. The whole process is very effective," said Mr White. The dried sludge can be used as a fertiliser in farming or forestry, as well as in land reclamation, or for conversion to an energy source for power generation. The dried sludge contains nitrogen and phosphates, commonly used in fertiliser, Mr White said.
Liquid sludge has been dumped into the Irish Sea about 12 miles off the coast for the past 90 years, but an EU directive says this has to stop by the end of this year, he said.
As well as converting the sewage to dried sludge, the Ringsend treatment plant is planning to carry out secondary treatment of the sewage, in addition to the current primary treatment at the plant. Tenders will be invited shortly.