Official signing ceremony in Auckland included (back row, l-4) Mike Crane, Purac; Derrick Adams, Watercare Services Ltd; (front row) Kevin Beesley and Mark Ford of Watercare Services; and Malcolm Wilkinson, Managing Director of Purac Ltd.
Click here to enlarge image"The plant at Mangere has undergone recent extensive upgrades to intensify and enhance the treatment processes thereby reclaiming valuable wetland habitat and land area previously used as large oxidation ponds," said Malcolm Wilkinson, Purac's managing director. He explained that the upgrades improved final effluent discharge quality to meet new, more stringent consent levels.
Wilkinson commented: "By improving the digestion process using sonix ultrasound technology, Watercare Services will be able to realise greater quantities of biogas, making better use of the co-generation facilities on site and significantly reduce the quantity of biosolids produced. Better digestion stability will make the plant easier to operate, minimising chemical usage for activities such as sludge dewatering, lime stabilisation and foam control."
Improvements brought about by the use of the sonix technology will be available almost immediately. The anticipated payback period for the investment meets Watercare Services stringent investment criteria, making this a cost effective, environmentally attractive solution for the advanced treatment of secondary sludge problems.
Watercare Services' Chief Executive Mark Ford explained: "When it opened in April 2003, the Mangere plant was the most sophisticated wastewater treatment plant in the southern hemisphere, featuring banks of pathogen-killing ultraviolet lights. Now with sonix ultrasonic cell lysis, we have yet another layer of protection for public health, and the ecological health of the Manukau Harbour. The improved energy efficiency is consistent with the company's sustainable business development policies."
What is sonix?
The use of ultrasound to enhance anaerobic digestion has been studied at laboratory scale for decades, but Sonico, a joint venture company between global engineering consultancy W S Atkins Consultants Ltd and leading process engineering firm Purac Ltd, developed the technology to a full-scale plant capable of delivering exceptional performance in "real world" scenarios. The technology uses high-powered, concentrated ultrasound to condition wastewaters and sludges prior to further treatment.