Water authorities require robust methods to enable them to evaluate and prioritise capital expenditure - both for new water sources and for demand management initiatives.
The paper will consider a range of typical trenchless installation methods from small bore HDD to large bore Maxi Rigs and similarly for small and large bore pipeline rehabilitation in a variety of different situations and locations. It will then look at the risks to the Client, in terms of cost, time, exposure and customer perception, by not completing adequate investigation. The paper will also discuss potential mitigation and management options for these risks.
Smarter Management, Integrated catchment management plan, catchment management plan, stormwater discharge consents, resource management, assessment of environmental effects, monitoring, network discharge consents, structure planning
Globally waste stabilisation ponds (WSP) offer a sustainable and economical method of treatment for wastewater. The pathogen removal mechanisms occurring within ponds are largely unknown and only a few studies have been conducted on virus removal. While it is clear that sunlight (UV) and temperature play a major role in removal of pathogens in WSP’s there are other mechanisms present in these complex systems that also play their part in removal of pathogens such as viruses.
Integrated fixed-film activated sludge (IFAS) processes are a combination of biofilm reactors and activated sludge processes, achieved by introducing and retaining biofilm carrier media in activated sludge processes. We tested a full-scale IFAS process equipped with AnoxKaldnes media and coarsebubble aeration. This process operated independently in parallel with an existing full-scale activated sludge process. Both processes achieved the same percent removal of COD and ammonia, despite the double hydraulic load and double oxygen demand on the IFAS process.
With the world-wide drive in developed countries to further improve treated wastewater quality, removal of the nutrients nitrogen and phosphorus has moved to the forefront. However, many treatment facilities do not have enough carbon (BOD) in the influent wastewater to achieve those goals. Much research and pilot testing has been performed to identify supplemental carbon sources to increase the degradable carbon to achieve nutrient removal goals. Many cities still have industrial pretreatment programs in place to charge industries for discharging excess BOD. Many treatment facilities searching for alternative carbon sources are located in these cities that still have pretreatment surcharge systems in place. To reduce these charges, many industries have implemented their own pretreatment facilities, which was the original purpose of implementing pretreatment surcharges. However, the carbon removed from the industrial wastewater by these pretreatment systems could often be an asset to the treatment works.
In Dunedin, on 9 December 1867 the private Water Works Company commissioned the Ross Creek Reservoir. This was New Zealand’s inaugural major urban water supply, fuelling the rapid expansion of the City during the Otago gold rush and today is New Zealand’s oldest surviving large dam.
The supply of water to Wellington city is extremely vulnerable in a major earthquake. The bulk supply lines from the Hutt Valley cross the Wellington fault in five places and restoration of a limited bulk supply to Wellington city following a major rupture of this fault is estimated to take up to 55 days. Functional restoration of the local water network will take up to 30 days longer for the furthest points of the network as there will be limited water available to re-pressurise, test for and repair leaks.
This study reviews the approach to safety in design within the New Zealand health and safety framework and compares it to that adopted in the UK, USA and Australia. Health and safety statistics from the construction and water industries in New Zealand indicate that there is a need for a holistic review of our health and safety system, and with overseas evidence suggesting an intrinsic link between project design and the number of health and safety incidents that occur, it is recommended that safety in design be a key strategic initiative moving forward.
This paper also reviews the Australian Water Associations’ Biosolids Management Position Paper, developed in collaboration with the ANZBP, and will explore the activities of the ANZBP to encourage regulatory change in Australia and New Zealand.
The paper explores the collaborative dialogue used to prepare and implement the CWMS, as an alternative to reliance upon statutory processes of the Resource Management Act 1991, and asks whether the approach aligns with recommendations in the second report of the Land and Water Forum (the ‘Forum’). Finally it considers the extent to which the CWMS is influencing water plans and policies.
The small population combined with strong Maori cultural influence is evident in the way the whole community thinks about water. Drawing on the author’s observations over the past decade this paper presents some alternative views on equitable allocation of costs and explores some of the risks and challenges faced by one of New Zealand’s smallest local authorities providing water services to one of the most socio-economically deprived populations in the Country.
Here we present an overview of the innovative testing and process demonstration methodology and the systems that CPG have developed in the last decade to determine the biogas production potential and biogas process stability for a wide range of solid and liquid industrial waste materials.
In March 2011 the Dunedin City Council (DCC) delivered a bespoke Quality Management System (QMS) to its Water & Waste Business Unit (WWSBU) staff. This paper focuses on the rationale behind the decision to implement the system, the challenges, benefits and lessons learnt during the development process.
Sewage sludge production is rising around the world. This is due to population growth, stricter legislation, and new investment in wastewater infrastructure. Whilst, typically considered a nuisance, sludge has numerous benefits which can be exploited, such as the reuse of nutrients or extraction of energy. Previously in Europe, reluctance for land recycling of sludge coupled with cheap energy led to the development of sludge treatment strategies which were heavily reliant on energy intensive processing.
This paper presents a number of case studies where membranes have been used for potable supply. One case study is for the Australian Defense Force on a remote training camp. The second case study is for an Australian mining company to cater for growth. The last case study was a UF plant to replace an existing clarifier and filter system
Aeration of the activated sludge process in a typical suspended growth wastewater treatment facility can consume anywhere from 40 to 70 percent of the power consumed by the total plant. Because such a large fraction of the overall plant power is consumed by the aeration blowers, it is important to select the blower system on best value. So how does one identify best value? With a minimum of 16 different blower manufacturers, how does one sift through the sixteen different sets of manufacturers’ information to provide a comprehensive and defensible result?
This paper discusses the benefits of building redundancy and diversity into a process in the context of achieving the requirements of the current Drinking Water Standards of New Zealand, including a discussion of how the risks may vary depending on the size and type of population supplied. The design of a medium sized water treatment process which compares conventional three stage treatment and membrane treatment is presented in this paper as a case study.
New Zealand drinking water tends to lack alkalinity. Bad sludge settleability is a common problem in New Zealand waste water treatment plants. Both have one in common: dependency on cations.