This paper describes the investigations undertaken during these condition surveys, the challenges of planning and completing the inspections and the modern non destructive condition inspection plus assessment options which are now available.
This paper explores the methodology adopted in this project, how it differs from more routine risk based assessments and how the results were able to then be used to programme the condition assessments and subsequent renewals. It will be of interest to readers who manage network assets and wish to be able to prove they are doing so in an efficient and cost effective manner.
This paper will describe:
We explore here a number of the successes and operating challenges that have faced TDC over the past five years. An update on the nitrogen loading rate trials, that were implemented as part of the scheme to quantify the nitrate leaching rates from the proposed scheme, are also presented.
The OSET NTP (On-site Effluent Treatment National Testing Programme) is a SWANS-SIG initiative which has evaluated the performance of 21 treatment units in Trials 3 to 8 (2007 to 2013) via a nine month testing programme in each trial.
This paper discusses the regulatory compliance of greywater reuse and disposal in a New Zealand context. Comparisons with overseas regulations and compliance allow us to develop recommendations to improve compliance, resulting in a reduced risk to environmental and public health.
The paper highlights the desirability, when consenting potentially contentious projects, of combining appropriately robust technical investigations with early and meaningful communication with key stakeholders.
The application of pressure sewer technology has been increasingly used in Christchurch following the earthquakes of 2010/11. In general, these applications have been limited to residential applications, through the rebuild of damaged infrastructure in highly liquefaction prone areas or the replacement of septic tanks in small communities on Banks Peninsula.
New Zealand's central north island economy is dominated by intensive dairy farming and forestry operations. The soils are young, porous, shallow, and are lacking of soil humus. To mitigate nutrient losses, farmers are increasingly opting to replace mineral fertilisers with humus rich organic fertilisers.
This paper outlines the technical challenges, the design solutions developed and innovative construction techniques used to construct the tank. The main tank was constructed using ‘double-tee’ precast concrete sections, whilst the inlet pumping station was constructed as a caisson and sunk into the ground. The tank has an automatic cleaning system that uses a series of Steinhardt flushing gates that are released in sequence to scour the tank floor.
Contact Energy’s geothermal power station at Wairakei, located 10km north east of Taupo, has resource consent to extract up to 245,000 tonnes per day of geothermal fluid from the Wairakei geothermal fields. Disposal of this fluid after processing for power generation and heat extraction has potential to create a number of environmental effects.
This presentation will outline the concept, establish hydraulic principles, outline the development and testing undertaken to date and present worked examples of its potential application.
The Christchurch Wastewater Treatment Plant (CWTP) has traditionally used gas and diesel fuelled engines to generate heat and power from biogas produced in sludge digesters. Until 2013 three engines provided this function – two 400kW Allen dual-fuel engines and one 1,550kW Waukesha gas engine. The two 400 kW Allen engines were at the end of their economic life.
Following the Christchurch earthquake sequence of 2010 – 2011, areas of the city are now more prone to flooding due to ground settlement. The New Brighton Road and Owles Terrace catchments in eastern Christchurch now require pump stations to convey surface waters when gravity outfalls cannot operate during high tides.
Water networks are included pipes and nodes. Usually against earthquake motions, design codes emphasis on the pipeline and try to develop solutions to strengthen the pipe body or make higher resistant joints in the pipelines.
This paper will report on recent findings from MBIE funded research into the seismic response of underground utilities. This research programme builds on work done in the reconstruction following the Canterbury earthquakes with a specific goal of promoting evidence based guidance across New Zealand. The work is presently in the second year of a four year programme.
The challenge of providing reliable sewerage infrastructure in developing countries such as Kiribati is immense. Budgets come mainly from aid money, with design usually carried out by ex-pat engineers sourced worldwide. Funds are limited, and often some reduction of scope is required to fit the available funds.
The Drinking-water Standards for New Zealand 2005 (Revised 2008) define a secure groundwater source based on the absence of surface or climatic influences, the security of the bore head and an absence of E. coli from regularly collected water samples. However, in some instances, apparently “secure” bores are still at risk of E. coli contamination. This paper provides examples of two such incidences.
This paper, based around a recent QMRA of bypass flows from the Moa Point (Wellington City) Wastewater Treatment Plant (WWTP), discusses recent advances in the use of QMRA in New Zealand. In particular, a) the adoption of human Norovirus as a key risk organism b) derivation of a non-point source model for the risk of respiratory illness and c) the move from ‘Risk of Infection to ‘Risk of Illness’ assessments.
This paper presents the issues in implementing a scheme that began after the Fonterra fire of 2005 through to the challenges during design and construction. It also highlights what many Local Authorities can face in addressing the needs of smaller communities with an adequate level of service at an affordable and practical level.