This paper provides a brief synopsis of the new Auckland Council ‘Guidance Document 04’, the update to Technical Publication 124 ‘Low Impact Design Manual for the Auckland Region’. The paper specifically highlights and discusses the new elements captured within the document.
This paper presents the pragmatic approach that Dunedin City Council Water and Waste Services is taking in response to outputs from a comprehensive 3 waters modelling project and the subsequent development (in parallel) of ten integrated catchment management plans (ICMPs) for stormwater management.
The paper compares and contrasts different approaches and how they can be integrated as part of the Catchment Management Planning process.
This paper presents the expected different pollutant removal pathways induced by a FVI as well as the monitoring methodology used to assess the overall efficiency of a retention pond with a FVI compared to an unvegetated one. Sampling and analysis methodologies to quantify the magnitude of each pollutant removal pathway are explained and a preliminary analysis of plant roots from a well established FVI is presented.
This paper will describe a methodology adapted from international literature to provide a quantified cost benefit approach to flood protection investment decisions. It will describe the scenario, the approach adopted and the sources of flood damage cost information used. It will further describe the limitations of available information and the work needed to provide more robustness in this area.
To control a city’s urban expansion and minimise the city’s environmental effects it is becoming more critical to look within existing urban boundaries for development opportunities.
This paper presents results from pilot studies undertaken on highly variable, turbid river water in New Zealand, with naturally occurring high organic matter levels. The LP MF system continuously provided excellent filtrate water quality, while handling turbidity spikes of up to 450 NTU without the need to shut down. The MF system reliably removed the targeted contaminants of concern, as well as demonstrating low rates of fouling over months of continuous operation.
In July 2007 Matamata Piako District Council (MPDC) received an E grading from the MoH for their 5ML/d Matamata WTP. This paper details the unique path that MPDC followed using a combination of innovative process design and in-house knowledge to turn an E grade plant into an A grade plant at the lowest possible cost to their rate-payers.
Groundwaters in the Waikato region are often naturally contaminated with iron and manganese at levels of up to 20.0 mg/L and 0.9 mg/L respectively. When present with elevated levels of silica and/or organic matter, these waters upon oxidation can form highly stable and difficult to filter brownish colloidal suspensions.
The objective of this paper is to raise awareness of the potential for biological processes as sustainable methods for water treatment and to highlight their advantages, disadvantages, and issues. This will be done by giving examples of existing full-scale biological treatment systems and showcasing the results of recent research in biological processes for water treatment.
Rodney District is on the fringe of metropolitan Auckland, and has one of the highest growth rates in the country. The Infrastructure Directorate spends 72% of the Council’s operating budget and delivers a $100m capital works programme.
The Botanical Wastewater Treatment System for on-site domestic wastewater management was patented in NZ in 1997. Its concept is well proven by experience in Germany with over 300 wastewater wetland systems installed from 1988 until introduced to NZ.
The Patea Wastewater Treatment Plant (WWTP) discharges treated wastewater into the tidal reaches of the river. Before the upgrade in 2008 the WWTP consisted of a single oxidation pond, with a highly variable effluent quality due to short circuiting, particularly for pathogen indicators.
Two major regions of Australasia with similar population sizes are concurrently making changes to their water and wastewater industries, with the overall goal of achieving efficient and effective delivery of services to customers. Both industries are in public ownership therefore the changes are driven through public policy as opposed to pure market driven incentives.
Over the last decade in Australia, prolonged drought and increasing demand have prompted the consideration and implementation of a range of centralised and decentralised technologies and methodologies for the development of alternative water resources and demand reduction. The concept of “Fit for Purpose” water is becoming more prevalent as water users seek to apply alternative water supplies for the most appropriate use.
As municipal wastewater discharges to land become increasingly common, so does the pressure to utilise hill country. This country is often at risk of some degree of erosion. Land based wastewater treatment systems have tended to focus on the hydraulic properties but in hill country slope, geology and erosion must also be considered.
The extreme drought that Greater Melbourne is experiencing is quite unprecedented in its duration and severity. For the past 10 years, stream flows to the reservoirs have been below average. The water storage level in August 2007, according to Melbourne Water, was 35%. This is the lowest level recorded in the past 10 years.
The aim of this study was to investigate the possible inter-relationships amongst viruses, bacteria and algae, and the environmental factors that affect these relationships. Flow cytometry was used a rapid and effective method to assess the potential relationships between these micro-organisms and their effect on nutrient cycling in Lake Okaro.
This paper reviews the project completed in July 2009 and looks at the installation process, selection of materials and impacts of the construction on the surrounding environs.
This paper is the follow-up/validation of the concept paper presented in the 2009 Water NZ conference on the digester upgrade and indicative costs (Thiele, 2009). We present the results from the digester operation with primary sludge before and after the mixing system upgrade.
The city of Palmerston North, New Zealand, has two aerated lagoons as its secondary treatment facility. Interest about treatment efficiency led to an investigation into the hydraulics in the second lagoon to determine if further optimisation was viable. A tracer study using rhodamine WT was undertaken to ascertain the stimulus response output. Samples were also taken at 24 points within the lagoon to determine the tracer concentration profile throughout the lagoon.
This paper will highlight several limitations present with computing inflow data from pump status and wetwell records and will provide practical solutions to overcome them. These limitations can have a significant influence on the ease and accuracy of subsequent modeling and the use of the data for other purposes.
This paper describes the methods employed to estimate in-pipe, near and far field dynamics of suspended waste water material in the marine environment. The methods employed use a combination of existing and new “kiwi made” techniques which combine to provide a state-of-the-art assessment for the outfall, including multi-year simulations to quantify ENSO influences.
This paper examines the issues involved in achieving a robust calibration of the hydraulic models to be used for master planning. Despite a comprehensive field test plan being executed prior to calibration of three zone models, significant anomalies were identified, that required further investigation to meet the model calibration criteria set by Metrowater.