AMP Summary - Wastewater

Transcription

1 AMP Summary - Wastewater Introduction Taupō District Council provides wastewater services for 12 towns and communities in the District. This wastewater asset management plan enables Council to manage and demonstrate its stewardship of wastewater assets on behalf of its communities in order to provide those services cost-effectively, both now and into the future. Strategic issues Council operates within the context of these strategic issues: Protecting public health the primary purpose of Council owned wastewater systems is to protect the health of communities. Protecting our waterways from nitrogen flows and untreated wastewater. Council is responsible for reducing its nitrogen discharge into the Lake Taupo catchment by at least 20% by 2020, as part of the Lake Taupo Protection project. Wastewater assets Council s wastewater schemes include physical assets valued at $136.5 million (August 2009). In addition, Council has 15 resource consents from Waikato Regional Council (EW) to allow it to dispose treated water and control odour. The schemes vary widely in size and age, and therefore in the technology they use. A list of the schemes is given below with a map showing their location on the following page. Figure 1 Taupo District Wastewater Schemes Scheme No. of rateable properties Resource Consent (m 3 /day) Typical discharge volume recorded (m 3 /day) Average discharge per property (m3/day) Taupō Town 10,952 15, Turangi 3,274 2, Mangakino 1,483 1, Kinloch 1, Omori/Pukawa/Kuratau 1, Acacia Bay Motuoapa Waitahanui / 5 mile Bay Whareroa Atiamuri Whakamaru Motutere motor camp Wastewater AMP Summary July of 6

2 Wastewater AMP Summary July of 6

3 In order to provide wastewater services, Council has the assets given below. Figure 2 Wastewater assets Process Asset Number Reticulation Pipes 350 km Manholes and lampholes 6712 Plant & Treatment plants 12 treatment Pumping stations 104 Levels of service Council originally owned and operated its wastewater assets as a public health service. More recently, environmental health and especially the health of lakes and waterways has been added as an objective of Council s wastewater services. Council provides a level of service that meets all of these measures: There is sufficient capacity to serve communities within current wastewater schemes Wastewater services do not cause public health problems Wastewater services are supplied continuously unless there is a system failure System failures are addressed in a timely fashion Odour control at treatment facilities requires certain upgrades in particular to Taupo, Acacia bay and Motuoapa WWTP to meet consent conditions. Users are satisfied with their sewerage disposal services Effluent discharge from treatment facilities meets WRC consent conditions Council s objectives include preventing sewer overflows from pump stations and reticulation facilities, and preventing overflows into Lake Taupo, streams and rivers. State of the assets Taupō township Council has upgraded the capacity of the Taupo township s wastewater treatment plant (WWTP), beginning with a new trickling filter, a new digester and associated works ($6 million). Any further upgrades will occur only when growth causes demand for services to exceed capacity. Turangi Council opened a substantial new wastewater treatment plant in Turangi in That system enabled Council to reduce nitrogen by 22% from the treated water. Some works are proposed for 2012/13 to improve the operating performance of the plant. Mangakino Council s treatment facilities in Mangakino were upgraded in 2008 to ensure that effluent does not overflow, and the system has sufficient capacity to meet its current and projected future needs. Council has a program to monitor some outputs to ensure the effective operation of the existing soakage trench. Acacia Bay Council has recently applied to WRC for a new 35 year consent for the plant. Because WRC believes the plant may be causing near-shore effects further work is required to finalized this consent. TDC is currently undertaking a process optimization review of the WWTP. Wastewater AMP Summary July of 6

4 Kinloch Council has recently applied to WRC for a new consent for the plant. As growth occurs increased amounts of nitrogen are discharged. TDC is currently undertaking a process optimization review of the WWTP. Irrigation of treated wastewater remains an option. Other schemes The remaining wastewater schemes are in good condition, and have sufficient capacity to meet projected growth for the next ten years. Demand forecast Council s growth model (wastewater) projects growth of an additional 1,040 residential lots and 92 HEU in commercial growth see Figure 3. Figure 3 Projected growth in rateable properties, 2012/ /22 Year 12/13 13/14 14/15 15/16 16/17 17/18 18/19 19/20 20/21 21/22 Residential Commercial HEU Cumulative Total ,132 Council s growth modelling has reduced the 2009 forecasts because lot creation has been much lower than predicted in every year since the growth model was first developed, and especially since This means Council has delayed capital spending for new works to meet the original (possibly over-optimistic) growth projections. When the Taupō wastewater upgrade project is completed, Council expects to have sufficient capacity for the foreseeable future for all its schemes. Lifecycle Management Tactics New works New works are completed to meet resource consent conditions and to provide for growth when it occurs or when public health factors mean a reticulated system is the most cost effective method for managing wastewater in a community. Renewal Council replaces assets when performance is unacceptable, based on criteria of: age, condition, service breaks and complaint volumes. Operations and maintenance The operational services team has a preventive maintenance programme to optimise the life of assets and reduce renewal costs. Council staff use CCTV for identifying network issues more actively, and for enabling repairs to be completed more efficiently. Maintenance services for all three waters are provided by contract (currently Fulton Hogan). Disposal When assets no longer provide the required level of service, they are removed and, if possible, reused in Councils other schemes. Consideration is being given to retiring of the Rakanui Road facility for disposal of treated effluent. This may allow council to make Rakanui Road available for commercial development. Wastewater AMP Summary July of 6

5 Financials The ten year financial forecast was determined by the continuation/evaluation of current maintenance and renewal strategies within each of the components, i.e. pumps, treatment unit processes, chemicals, energy cost, telemetry, compliance etc and identification of new works. The 10 year projections are summarised below: Figure 4 Proposed budget, Wastewater expenditure, 2012/ /22 New works Capital costs vary each year due to project timing for the Taupō plant and reticulation upgrade. The higher CAPEX from 2016 are for View Road expansion (2015/16), Taupo primary settling bio-filters (2016/17), storm flow diversion pump station and pipework (2017/18) and Eastern Trunk Sewer (2019/20 to 2021/22). Renewals Renewal costs vary according to the age and performance of the plant and network. Because the network is relatively young, Council does not yet need to invest as heavily in renewals as it will later in the life of the assets. At the moment, the depreciation value is $3.7 million per year but the actual average renewal expenditure is budgeted at an average of only $2.1 million per year. Operations & maintenance Operation costs are projected to average approximately $4.05 million per year for the next 10 years, which is about 20% lower than the average operations costs in ($5.08 million). Technical Notes Risk management Risk management is essential for management of Council assets so that essential wastewater services can be provided consistently. Council imposes high health and safety standards for its plant and network, especially where wastewater treatment plant or pump stations are built on low-lying land near lakeshores or riverbeds, or volcanic and/or seismically unstable areas lie just offshore. Using a likelihood and consequence matrix to assess risks, the following high risks have been identified: Wastewater AMP Summary July of 6

6 Fire damage to the reticulation network or treatment system, due to structural or electrical system damage to pump stations, treatment plants or computer systems. Earthquake - damage to the treatment system due to failures such as electrical system failure, earth slip, mechanical failure, structural failure (e.g buildings, control room, settling tanks, clarifiers, trickling filters, digester, belt press, etc.) and pipe fracture Flood making treatment plants inaccessible, and therefore, inoperable Tomos - damage to reticulation system External contractor failure, leading to failures in the reticulation system, service failures, sewer overflows, and compliance failures Public safety matters such as open manholes, leaking pipes, inadequate wastewater treatment, exposure to open manholes, inadequate training All of these risks have potentially serious consequences for the District s population, and for the District s economic wellbeing because they jeopardise the District s reputation and therefore, the visitor industry Asset Management Practices Council uses a range of decision making tools to establish its maintenance, renewal and new works expenditure, including: process, analysis and evaluation techniques for life cycle asset management; information systems to store and manipulate data; and data and information from a number of sources (technical, financial, customer service) Plan Improvement Programme Councils are required to have plan improvement programmes to improve their asset management planning. Council staff will continue to work through the various elements of the improvement plan. International Infrastructure Management The plan is an intermediate plan based on the requirements of the International Infrastructure Management (IIM) Manual. Wastewater AMP Summary July of 6