Biosolids (treated or stabilised sewage sludge) are a product of human excreta and a vehicle for numerous contaminants (heavy metals, human pathogens, pharmaceutical and personal care products). They makeup about a third of organic wastes and are generally landfilled in New Zealand. While the presence of microcontaminants including emerging contaminants presents challenges, biosolids are carbon-rich and can contain high concentrations of valuable plant nutrients which offer opportunities for reuse.
The results presented in this Paper will demonstrate how the technology and engineering processes used in the North Shore City Optimisation project provide a robust method for evaluation of options to deliver least-cost solutions; allows the cost of different level of service (LOS) and other planning objectives to be quantified; and, by definition, saves money.
This paper briefly outlines the development of the model RTC, and discusses the option assessment performed on the RTC scheme to develop a range of operational RTC scenarios and the implications of these schemes to network performance.
This paper tracks the development of the feasibility works and demonstrates how a formal optimisation framework can significantly improve the financial, hydraulic, sustainability and reliability outcomes for complex infrastructure development projects.
This paper briefly outlines the development of the Project CARE strategic wastewater model, details the methodology applied to assess network performance from historical and forecast climate change rainfall, and summarises system performance impacts and the cost implication of the forecast climate change.
This paper provides a guide to the derivation of rainfall data for use in urban storm water modelling and is aimed primarily at younger practitioners. It will also assist decision makers regarding outcomes that should be achieved by a rainfall analysis.
Many New Zealand water suppliers are facing significant financial burdens to achieve compliance with NZ Drinking Water Standards (DWS). This paper presents studies that URS New Zealand Ltd has undertaken for Central Otago District Council in Alexandra and the NZ Defence Force in Woodbourne, to seek alternatives to high cost treatment plants.
This paper presents a case study that uses an open source solution base to build a robust platform to view real time monitoring data and run hydrologic and hydraulic models within a web environment. The application allows the end-user full control of hydraulic model inputs and enables them to create, delete, edit, and run “what if” scenarios under a full parent/child implementation of scenario management.
This paper considers seven recent Auckland wastewater studies retrospectively to assess the role flow monitoring, modelling, and alternative analysis tools played respectively. Opportunities to achieve cost and programme efficiencies are considered to achieve the same or greater confidence in the outcomes. Hindsight has 20/20 vision, so hindsight is applied to the studies to assess the confidence in the outputs, and whether there was a “better” way of delivering them
Demand on water resources for irrigated agriculture on the Canterbury Plains is strong. Against a backdrop of tightening regulatory controls, demand for water has not abated, which is perhaps unsurprising given the significant economic benefits to be generated within the region from irrigated agriculture. Current demand is tangibly impacting on surface water resources in some places and there is concern about unrealised impacts from consented takes that have not yet been exercised.
This paper explores the innovative engineering designs employed to upgrade their existing equipment, and the motivations and results for choosing a low-pressure membrane solution to reduce the impact of the effluent discharge on New Zealand’s natural water resources.
The Masterton District Council is upgrading its Wastewater Treatment Plant (WWTP) at Homebush. The scheme, which has an estimated cost of $22.8 M, includes irrigation of treated wastewater from six new treatment ponds over an area of up to approximately 150 ha of land to the west of Ruamahanga River, a sensitive receiving environment.
This paper outlines the requirements, processes and outputs of the model, and presents the results of testing of the first batch of meters replaced according to the model results.
This paper discusses the challenges of gaining approval from all stakeholders for, and designing, a wastewater treatment plant with the ability to discharge directly into the local waterways. The performance of the system to date will also be presented.
Fresh water is coming under increasing pressure globally from the conflicting demands which are placed upon this limited resource. The Canterbury region is one of the driest in New Zealand, and conflicts have arisen over the use of water for irrigation, and the preservation of iconic braided rivers, aquatic habitats, recreational waterways and community water supplies.
Around the world the use of recycled water, either from stormwater or from treated wastewater, is gaining in popularity. Many water utilities are utilising recycled water for non-potable uses, such as open space irrigation and industrial use, or for augmentation of drinking water supplies though aquifer and reservoir recharge. Recycled water is also being used to enhance the environment with schemes such as reduction of salt water intrusion and boosting river flows.
The paper will by way of an example discuss an integrated planning approach, as implemented for various regional bulk water supply systems in South Africa. This approach provides an innovative adaptive management decision-support framework to ensure water security and timeous decisionmaking.
Capacity Infrastructure Services (Capacity) approached Sinclair Knight Merz (SKM) to develop a streamlined system to ‘lift the veil’ on their procurement of physical works. Capacity previously received tender evaluation reports of varying quality, with inconsistencies between tender assessment team’s evaluations. As a result the process of procuring contractors was drawn out, much to everyone’s disappointment.
Building new pipeline infrastructure in highly congested urban environments is causing some interesting challenges for engineers and construction companies, demanding innovative new pipeline solutions.
This paper will cover the differences between ‘standard’ directional drilling projects for gravity sewers and long distance directional drilling that have been encountered. It will identify specific technological aspects of long distance directional drilling, such as steering technology, which were used on the project, plus the outcomes of NZ’s longest on-grade pipe drill, and the lessons learnt.
The Parsons Brinckerhoff Brisbane office has been involved in three major horizontal directional drilling (HDD) projects for water and wastewater infrastructure in south-east Queensland for local government clients.
Three case studies illustrate the methodology developed for the geotechnical investigations and preliminary design for HDD projects, and highlight the key issues to be addressed in the preparation of AS 4300–1995 General Conditions of Contract for Design and Construct tender documents
One of the improvements identified as part of the Water Services Association of Australia asset management processes benchmarking was to undertake further analysis to support the risk-based maintenance strategy. The strategy would include analysis of pipe failures, modes and effects to confirm the economic asset life and the replacement criteria.
This paper will discuss a case study on sealing the incoming lateral connections onto the rehabilitated sewers in North Shore City.
This paper presents a comparison of floating wetland systems, including an evaluation of their suitability of wastewater treatment and effluent polishing in the New Zealand context, where natural wastewater treatment process such as oxidation ponds, is more dominant.