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.

ends

© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Revenue Renewal: Tax Modernisation Programme Launched

Revenue Minister Todd McClay today released the first two in a series of public consultations designed to modernise and simplify the tax system. More>>

ALSO:

Scoop Business:
NZ Puts Seven New Oil And Gas Areas Put Up For Tender

A total of seven new areas will be opened up to oil and gas exploration under its block offer tendering system, as the New Zealand government seeks to concentrate activity in a few strategically chosen areas. More>>

ALSO:

Half Full: Dairy Payouts Steady, Cash Will Be Tight

Industry body DairyNZ is advising farmers to focus on strong cashflow management as they look ahead to the 2015-16 season following Fonterra's half-year results announcement today. More>>

ALSO:

First Union: Cotton On Plans To Use “Tea Break” Law

“The Prime Minister reassured New Zealanders that ‘post the passing of this law, will you all of a sudden find thousands of workers who are denied having a tea break? The answer is absolutely not’... Cotton On is proposing to remove tea and meal breaks for workers in its safety sensitive distribution centre. How long before other major chains try and follow suit?” More>>

ALSO:

Get More From Scoop

 
 
 
 
 
 
 
 
 
Business
Search Scoop  
 
 
Powered by Vodafone
NZ independent news