FIT TO DRINK

摘要

Faced with new drinking-water standards that rated Dunedin's water as Ee, the lowest of the low, Dunedin City Council decided it had to replace one of its two main water treatment plants. FIONA CLARKSON reports on the new plant, which incorporates New Zealand's first submerged-membrabe water treatment process. DUNEDIN CITY COUNCIL and project managers and civil works designers MWH New Zealand Ltd are justifiably proud of the Southern Water Treatment Plant. The use of a submerged membrane barrier against Cryptosporidium and giardia spores was a first for New Zealand. And, after a lengthy lead-up, the project was completed on time, at 15 per cent below budget, and was virtually problem-free from the first day of operation. Eleven years ago, Dunedin conducted a major strategic review of its water treatment processes, after a change in drinking-water standards meant the city's water went from an A to Ee rating overnight (that's E for treatment and e for reticulation). The review concluded that a 12-year plan of capital works upgrades was needed to achieve an Ac grading, and the city's two main treatment plants, Mt Grand and Southern, would be the focus.