Our presentation will outline the key challenges and solutions in implementing the stormwater upgrade including:
Despite the good intent of the RMA framework, the structure of planning services required to gain CSCs has put limitations onto WBOPDC’s ability to manage their stormwater system efficiently and within the existing planning heart - the District Plan.
This paper will discuss the pro and cons as well as financial implications for WBOPDC.
This paper details both the historical and current development pressures that are placed on the northern Waihi Beach catchments. It also identifies some of the management methods that have been adopted to control development in areas prone to natural hazards.
Four extensive living roofs in Auckland have been monitored over periods of 8 months to over 2 yrs for stormwater quantity and quality compared to conventional roofs at the same locations. Up to 56% cumulative retention was measured from living roofs with 50- 150 mm depth substrates designed to maximize water storage. Runoff rarely occurred from storms with less than 40 mm of precipitation. Peak flow was 62-90% less than the corresponding conventional roof per storm event.
This paper discusses the suite of challenges that an investigation of this nature presents with limited time windows for CCTV inspection and the countdown on for the completion of the Tahuna upgrade project; and reflects on the successes of a structured investigative approach.
This presentation outlines how real time RDII calculation works through example in several recent flow gauging studies undertaken within New Zealand. It discusses the issues that were confronted during the trial such as subtraction catchments and timing between catchments. It also highlights the advantages to the real time approach for operational staff, and planning engineers, and consultants all working on the same catchment.
Biological treatment technology is commonly used to treat dairy factory processing wastewater in New Zealand at sites where irrigation is inappropriate. When advanced treatment was assessed as appropriate for the Stirling factory site, Membrane Biorector (MBR) technology was proposed – the first MBR plant treating dairy factory wastewater in New Zealand.
DHI were engaged by Barrhill Chertsey Irrigation Limited (BCI) to build a real-time flow forecasting and optimisation system for the Rangitata Diversion Race (RDR). The inclusion of the BCI irrigation scheme into the RDR diversion race and associated, complex, water swapping required that a “smart” real-time forecasting and optimization system be designed, developed and implemented.
The paper covers wastewater treatment and disposal, engineering design, installation and plant performance.
To achieve smart and efficient outcomes in the management of urban three waters (water supply, wastewater and stormwater) resources and infrastructure services Hamilton City, Waipa and Waikato District Councils and other Waikato regional ‘Future Proof’ partners along with consultants MWH have worked together to develop a Waikato Sub Regional Three Waters Strategy.
This paper will present the case of providing phosphorus removal, which is cheaper in capital, less complex to operate and easier to control compared to nitrogen removal involving anoxic reactors. The paper will examine the issue from a receiving environment perspective. Are we over doing it?
Wallace Corporation Ltd, utilise a common biological effluent treatment plant to treat high strength wastewater from an industrial complex consisting a meat processing plant, tannery and meat rendering plant. The combined wastewaters entering the treatment plant contain high levels of nitrogen and substantial nitrogen removal is required to ensure compliance with the sites discharge limits.
This paper reports on the development, commissioning and operational phases of the project. Although designed to operate independently and abstract water to pre-determined levels, many factors could require operator intervention. The paper reviews the actions that were taken, issues that occurred in practice and how these were addressed. It also summarises the overall performance of the scheme during the Rugby World Cup 2011 and the level of protection provided.
New Zealand Defence Force (NZDF) operates a Fire Training Unit at the Sea Safety Training Squadron at the Devonport Naval Base, Ngataringa Bay, Devonport. The school utilises a fire simulation building in which trainees are required to enter and extinguish fires. To establish the fires, diesel is used as a fire propellant to ignite piles of wood and simulate a smoky fire in an enclosed structure.
Fermentations of complex waste streams are sensitive to multiple environmental conditions, with pH being one key parameter. A laboratory-scale study was performed to describe the impact of pH on acidogenic fermentation of municipal wastewater treatment biosolids produced from a New Zealand nutrient removal plant. Duplicate batch fermentations were conducted, at two pH levels- pH 6 and 8. The effects of pH on hydrolysis and volatile fatty acid formation and purity were examined across a 15 day time series. It was expected that the pH 8 reactors would show a greater level of hydrolysis, but results indicated that volatile suspended solids destruction was greater at lower pH. Further, acidogenic formation of VFA was greater at low pH, also not an expected result. At pH6, methanogenic fermentation was suspected (but not confirmed) to impact on VFA productivity after 9 days fermentation, a phenomenon not observed at pH8.
Trihalomethanes (THM) are a bi product of the water treatment process and are formed when chlorine is used as the disinfectant. They are produced whenever chlorine reacts with natural organic matter in the water. If the levels are not controlled then they may become a hazard to health. The level of THM in NZ supplies is restricted by the DWNZ regulations. The maximum allowable value is relatively high (0.2mg/l chloroform compared to 0.1mg/l Total THM in the EU and 0.08mg/l Total THM in the US). In step with international trends this MAV is likely to be reduced in the future and will present an increased challenge to water suppliers and distributors.
The paper presents real-world modelling to enhance planning and environmental aspects, of a sewer-system backbone for a “wet” area [1500 mm/year rainfall located at the base of steep sided valleys] by predicting the stochastic nature of outflows and overflows.
In this paper, the process fundamentals are examined to provide guidance on the BNR treatment processes for high strength nitrogenous effluents. A description of the process constraints and the methods used to manage efficient nitrogen removal is discussed.
Pump stations constructed in fibreglass have been successfully used for handling municipal and industrial wastewater for ten years in New Zealand. This paper reviews these experiences, and the engineering details that have contributed to this success.
Sludge management costs have increased considerably as a result of upgrades to the liquid stream in both water and wastewater treatment plants. These have also been impacted by increases in haulage and landfill acceptance costs. This paper discusses some of the issues involved with developing a coherent, cost effective and sustainable sludge management strategy.
This paper describes the development of a water balance model which determines storage requirements for the buffer ponds. To provide confidence in the selected storage values, the model has been run using 22 years of data.
This paper investigates how fourteen years of data from seven different flow monitoring programmes was analysed to determine three key Inflow and Infiltration parameters for each wastewater catchment. These parameters were then used to rank and prioritise a city-wide rehabilitation programme to reduce Inflow and Infiltration. This has reshaped Council’s wastewater renewals works programme.
This paper will outline the various different gauge types that can be utilized to capture flow data within wastewater systems along with the various different monitoring technologies and their relative strengths and weaknesses. It is well known that budgetary considerations are a significant driver for the amount of flow monitoring undertaken.
Water utilities own and operate a number of potable water reservoirs throughout their water supply network. The behaviour of water in reservoirs can impact on water quality. It is interesting to understand the movement of water within water tanks in order to ensure that potable water is not held up in “dead zones” as increased residence time results in residual chlorine decay that augments the risk of recontamination in the network.