Membrane plants have been commonplace throughout the world and in New Zealand for many years and large metropolitan city councils have been implementing them with confidence. However, the majority of smaller rural councils continue to utilize traditional coagulation, filtration and sedimentation process streams for drinking water.
Grampians Wimmera Mallee Water Corporation own and operate 26 Water Reclamation Plants (WRPs) in the state of Victoria, Australia. St Arnaud and Warracknabeal WRPs are two such sites which were identified as having business cases for renewal in 2009. The triggers for renewal were the age of the WRPs, ongoing maintenance issues, and growing uncertainty about reuse scheme availability. In 2010 AWT Water developed a preliminary and then detailed design to upgrade the two sites with a common sequencing batch reactor (SBR) design.
This paper discusses the development and implementation of a stormwater strategy for Ashburton. The aim of the strategy was to understand issues with flooding, improve the resilience of the system, protect the receiving environments, accommodate future growth, support development, and is also expected to meet increased community expectations, a more stringent regulatory environment and climate change. This integrated approach to stormwater management is an example of how far stormwater management has evolved, and will optimise capital expenditure and provide better overall solutions for the Ashburton Community.
This paper discusses the contributing factors which led to the development of hydraulic models for small rural communities and the benefits that council believes these models will bring.
The Rocklands Rural Water Supply (RRWS) scheme is the largest of Dunedin’s water schemes by geographic area, covering almost 21,000 hectares, but servicing the smallest number of consumers of any Dunedin water scheme.
Against a background of a changing regulatory environment and the need to address increasing demand on limited resources, the stockwater races and the water that supports the races of the Ashburton District are currently being examined. These 100 plus year old races have been identified as a key opportunity in the ability to deliver water efficiency improvements in mid Canterbury and to increase flows in the Ashburton River.
This paper presents the drivers for upgrading the scheme, the challenges such an upgrade faces, the proposed design concept and how the works have been procured to date.
This paper describes the methodology and reasons for selecting the HRAS process, the innovations and other unique features required for the conversion of the PSTs to this process, and how the process has performed.
This paper will present information and data showing the affects of inadequate DO controls and subsequently will present the improvements that have been implemented to achieve improved control and delivery. This project has allowed us to gain valuable insight into a common problem with a number of plants around the country.
The Christchurch Water Supply Rezoning project involves changing zone boundaries and pressures for many of the large water supply zones of the Christchurch water supply. The Christchurch earthquakes highlighted the vulnerability of large water supply zones. Changes to the water supply zones offer an opportunity to improve resilience of the system, as well as extend asset life through pressure management and reduce operating expenses.
The design of pressure sewer systems in New Zealand has typically been carried out using static models; yet pump systems on the market today are ‘smart systems’, so why not design smarter? Dynamic modelling can optimise the design of pressure sewer systems, allowing the smart functions of the pump systems to be incorporated into the design. This is a relatively new concept in New Zealand, generally being perceived as costly and unnecessary. However, in using the right approach and understanding the hydraulic software, dynamic modelling can provide a robust, optimised design that reduces capital costs and better informs the client about how their asset will perform.
With the La Nina weather cycles increasing rainfall along most of eastern Australia and New Zealand in the past 3 years, the reduction of rainfall dependent inflow and infiltration (I/I) as a means of reducing wastewater overflows is now firmly back on the agenda of wastewater system managers on both sides of the Tasman. The Water Services Association of Australia (WSAA) is an industry membership organisation that represents the 25 largest water companies/authorities in Australia and New Zealand. To respond to the evolving market need of its member organisations, WSAA recently engaged GHD, in association with local consulting partner Urban Water Solutions (UWS) to develop a Best Practice Guideline Document on I/I Management.
Currently, wastewater from Ashhurst is treated at the Ashhurst wastewater treatment plant and then discharged into the Manawatu River. With the discharge consent of this plant expiring shortly, Palmerston North City Council identified efficiencies in diverting the Ashhurst wastewater system to the Palmerston North wastewater treatment plant. An additional advantage to this connection is that it will pass through and could provide service to the Whakarongo residential growth area, located 8 km from Ashhurst.
A recent survey identified the disposal of excess water and reduction of the loading to failing septic tank systems as the key drivers for greywater reuse in New Zealand. As a result, unregulated greywater disposal practices are more common than previously believed, particularly in rural areas of high environmental value. There are increasing demands for greywater systems as the general public becomes more water conscious; particularly as water metering is introduced throughout New Zealand. Some councils, such as Kapiti Coast District Council and Gisborne District Council, have developed specific guidelines for greywater use in their regions.
In August 2012 loss of chlorination of the Darfield backup water supply coincided with failure of the borehole pump for the primary secure groundwater source. At around the same time as this incident, there were 138 suspected cases of campylobacter in the Central Canterbury town. This paper discusses learning from an event that no water supplier would want to happen.
This paper highlights how the value and innovation framework has developed, how a culture of innovation has been enhanced and gives examples of types of innovation that have come from both the designers and delivery teams (contractors). It highlights key learnings around the innovation process and how we all can continue to share best practice to drive our industry forward
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This paper will also outline the twisted path of the design process, with assessments of costs, risks and differing hydraulic performance implications given to options (and sub options)
The Independent Water Schemes Association (IWSA) project involved the review of 5 previous upgrades and designs for 14 member villages across both islands. Many existing gravity schemes were inadequate, in poor condition with poor source quality.