Ireland’s Largest Water Treatment Plant with Onsite Hypochlorite Generation

Siemens Water Technologies (USA) will provide two onsite hypochlorite electrolytic chlorination systems to Dublin City Council for the Ballymore Eustace Water Treatment Plant in County Kildare, Ireland. The OSEC systems from Siemens, which will replace Ballymore’s chlorine gas systems, are part of a series of enhancements that are being made to the 72-year-old plant over the next five years. Once operational in 2009, this will be the largest electrochlorination plant in the UK and Ireland.

Ballymore is Ireland’s largest WTP, serving approximately 70% of Dublin. The expansion will allow the plant to increase its capacity from 250 Ml/d to 318 Ml/d, with a planned peak capacity of 400 Ml/d.   Through the electrolysis of a brine solution, the OSEC system produces a 0.8% sodium hypochlorite solution, consuming only salt, water and electricity. This solution is stored in a day tank and injected into the distribution system by a metering pump. Fifty-seven liters of 0.8% sodium hypochlorite is equivalent to 0.45 kgs of chlorine gas or 3.79 liters of commercial sodium hypochlorite (12%).   The plant and its engineering contractor, Earth Tech of Dublin, considered onsite hypochlorite generation systems from other manufacturers, but Siemens provided one of the smallest footprints. A comparable competitive system would have required multiple units to produce 1,000 kg/d of chlorine, compared to Siemens’ OSEC systems that will each be capable of producing 1,000 kg/d of chlorine. Both units will operate in tandem producing 24 hours’ worth of chemical during the 8 hour low-tariff energy period, thus saving costs.