Video | Agriculture | Confidence | Economy | Energy | Employment | Finance | Media | Property | RBNZ | Science | SOEs | Tax | Technology | Telecoms | Tourism | Transport | Search


Top environmental award for Kawakawa Bay wastewater system

Top environmental award for Kawakawa Bay wastewater system

Watercare’s Kawakawa Bay wastewater system has received one of three Environment and Sustainability Awards for large projects presented by IPENZ, Auckland Branch at the prestigious Arthur Mead Awards Function.

Named after long-serving Auckland City Waterworks Engineer, botanist, and outdoorsman Arthur Mead, who was responsible for the initial survey and design work on the Upper Nihotupu and Huia Dams, the awards are presented annually to the projects that best address sustainability, potential adverse environmental effects, waste management and community involvement.

Watercare Acting Chief Executive Raveen Jaduram said continuing to improve the company’s wastewater treatment services in order to enhance the health of Auckland’s harbours, estuaries and waterways remained one of Watercare’s main objectives and a key focus of the company’s capital investment plans. The Kawakawa Bay project also illustrated the close working relationships Watercare maintained with iwi, residents, and community groups across Auckland.

Designed by Australasian engineering consultancy Harrison Grierson, and constructed by Fulton Hogan, who also managed the network during its first year of operation, the Kawakawa Bay system was handed over to Watercare last year. The system enabled the removal of aging septic tanks that had over time polluted groundwater and local streams, leading to the Bay being declared unsafe for swimming in 2002. Its safe-for-swimming status was restored in November 2012.

Harrison Grierson Technical Director Colin Cranfield said the use of a vacuum system, which was a first for New Zealand, allowed shallow pipelines to be constructed quickly, minimising disturbance to the residents.

“The spread out nature of the development over four kilometres of coastline, the sandy soils, and the high water table, made a vacuum system the best option for the Bay,” he said.

In a vacuum collection system, wastewater from individual properties drains to a pit and is then drawn into the vacuum pipe network through the operation of a pneumatically controlled vacuum interface valve in the pit. Once in the network, wastewater moves along the pipeline to the vacuum pump station by the differential pressure that is created by the opening and closing of the vacuum valves throughout the pipe network. Wastewater is subsequently conveyed from the collection tank at the vacuum pump station to the treatment plant via positive displacement pumps and a pressure rising main.

The Kawakawa Bay treatment plant employs an advanced, four-stage treatment process similar to that used at Watercare’s larger Mangere and Rosedale facilities. Wastewater passes through alternating oxygen-rich and oxygen-depleted environments, enabling a range of different bacteria to break down organic contaminants.

Residual organic contaminants and nitrogen are removed in a biological membrane reactor; bacteria and viruses by ultrafiltration. The treated effluent then flows to storage lagoons from where it is used to spray irrigate forest behind the treatment plant, more than two kilometres from the foreshore.


© Scoop Media

Business Headlines | Sci-Tech Headlines


Oceans: NOAA Declares Third Ever Global Coral Bleaching Event

As record ocean temperatures cause widespread coral bleaching across Hawaii, NOAA scientists confirm the same stressful conditions are expanding to the Caribbean and may last into the new year, prompting the declaration of the third global coral bleaching event ever on record. More>>

Scoop Business: A Decade Of Government Pre-Seed Investment

More publicly-funded science is being commercialised after a decade of government ‘pre-see’d investment, according to an independent review. More>>


Solid Energy: Plan To Shut Unprofitable Huntly East Mine

Solid Energy, the state-owned coal miner in voluntary administration, plans to shut down its unprofitable Huntly East mine and lay off 65 staff after deciding the site stands "no chance whatsoever" of finding a buyer. More>>


E Tū: Merger Creates NZ's Biggest Private Sector Union

E tū has been created by the merger of the Engineering, Printing and Manufacturing Union and Service and Food Workers’ Union. It represents more than 50,000 working New Zealanders in industries as diverse as aviation, construction, journalism, food manufacturing, mining and cleaning. More>>


Internet: NZ Govt Lifts Target Speeds For Rural Broadband

The government has lifted its expectations on faster broadband speeds for rural New Zealand as it targets increased spending on research and development in the country's information and communications technology sector, which it sees as a key driver for export growth. More>>


Banks: Westpac Keeps Core Government Transactions Contract

The local arm of Westpac Banking Corp has kept its contract with the New Zealand government to provide core transactions, but will have to share peripheral services with its rivals. More>>


Science Investment Plan: Universities Welcome Statement

Universities New Zealand has welcomed the National Statement of Science Investment released by the Government today... this is a critical document as it sets out the Government’s ten-year strategic direction that will guide future investment in New Zealand’s science system. More>>


Get More From Scoop

Search Scoop  
Powered by Vodafone
NZ independent news