Section 6: Council Activities

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Wastewater

Responsibility

Brent Manning (Manager Water and Wastes)

Description of service

Collection, treatment and disposal of domestic, commercial and industrial wastewater from the urban areas of New Plymouth, Bell Block, Waitara and Inglewood. The service areas are to be extended with commissioning of the Oakura sewerage scheme (2009) and ultimately transfer of Waitara sewage (2015 to 2017) to the New Plymouth Wastewater Treatment Plant. On commissioning (anticipated September 2009), household connections will be available in Oakura. As well as reticulated domestic wastewater services, the Council undertakes to identify and monitor trade waste flows into the sewerage systems; and to provide disposal facilities for liquid effluent from industrial and domestic septic tanks. Part of the treatment of all waste from the New Plymouth Wastewater Treatment Plant involves the production and sale of Taranaki Bio-Boost 6-3-0® fertiliser, a thermally dried, pathogen-free product derived from dewatered sewage sludge.

Scale of service

This describes the size and scope of the activity.

24 million litres (average) of wastewater treated daily, with potential to increase to 30 million litres by 2019, as new urban areas are connected to the system.
Total discharge consent at New Plymouth Wastewater Treatment Plant for 86 million litres per day.
Treatment plants at New Plymouth and Waitara and disposal of treated effluent through separate outfalls at Waiwhakaiho and Waitara. The existing Waitara outfall consent is being renewed; it is the Council’s intention to pump Waitara sewage to New Plymouth for treatment from 2017. The Waitara outfall will be retained for emergency overflows thereafter.
Inglewood urban area is connected to the Bell Block sewer network and treated at New Plymouth Wastewater Treatment Plant.
28 pump stations, increasing to 32 when Oakura is connected to the New Plymouth system.
413km of sewage mains, increasing to 470km to connect the Oakura and Waitara urban areas.
24,500 properties and 82 per cent of the district population connected, with the potential to rise to 25,000 connections and 85 per cent or more by 2019.
$240 million network replacement value.

Rationale for activity

Collection, treatment and disposal of waste is essential to minimise the impact of large concentrated populations and their industrial processes on the environment. This ensures that human and industrial waste does not threaten the sustainability of our current environment, development and business practices. This contributes greatly to the community well-beings, in particular the environmental well-being.

The protection of river and ocean environments is also of high importance to the entire community and particularly tangata whenua, who have rights to these resources under the Treaty of Waitangi. In order to protect these rights and environments, wastewater is treated to such a degree that its impact on the environment is negligible. This also ensures that traditional fisheries and recreational waters are protected from pollution.

An assessment of water and sanitary services (including sewage disposal and solid waste) has been published as required under the Local Government Act 2002.Return to top

Contribution to Community Outcomes

The primary contribution of this activity is to the Secure and Healthy Community Outcome through the collection, treatment and disposal of waste to protect public health, and to minimise any adverse effects on the environment.

Secure and Healthy

A district that provides a safe, healthy and friendly place to live, work or visit.

S&H2 The environmental, physical and mental health of the people of New Plymouth District is maintained, enhanced, promoted and protected.

This activity also makes a significant contribution to the Connected, Prosperous and Sustainable Community Outcomes, by ensuring that low impact wastewater disposal is available at low cost to enable economic growth for people and business.

An unpolluted marine environment is also of increasing value to the New Plymouth District’s citizens and their quality of life, as it is increasingly used for recreational purposes. Preservation of the ocean and river environments is especially valued by tangata whenua. The health of all residents and visitors using the natural environment is protected from organic and inorganic pollutants through the provision of this service. This addresses the Sustainable Community Outcome.

Negative impacts on community well-being

The broadening of the district’s sewage collection systems to Oakura and the eventual transfer of Waitara’s sewage to New Plymouth will mitigate the negative impacts of sewage on these local environments.

Some residents may consider that the potential for subdivision, arising from smaller allowable lot sizes as properties move from septic tanks to a reticulated system, has a negative effect on local character and places pressure on local services and facilities. Such concerns need to be carefully and sensitively weighed against the rights of willing property owners and buyers. Existing district planning and application in accordance with the Coastal Strategy will manage these concerns.

Facing the challenges – assumptions and risks

Assumptions

Demand for wastewater will increase in line with any increases in population, growth in tourism and the expansion of the urban area through subdivision.
Urban customers will continue to expect more reliable wastewater services. In rural areas customers may aspire to have the same service as urban customers. There is a need for greater information on on-site system management as the council has no plan to provide a reticulated sewerage network service to rural properties.
New Plymouth Wastewater Treatment Plant is required to expand in order to accommodate future growth and the inclusion of Oakura and Waitara sewage. A new clarifier was completed and commissioned in 2008 at the New Plymouth plant to accommodate the additional flows from Oakura and Waitara. An upgrade to the plant treatment process is required in order to ensure the plant can treat the additional sewage load (measured in Biochemical Oxygen Demand or BOD). Preliminary assessment of the options for the plant’s expansion have commenced and the cost of expansion included in the long-term budget forecasts.
Preliminary plans for a future sewerage scheme for Urenui and Onaero Beach villages has been completed in 2006 to 2009. However no funding is available to continue this work within the 10 years covered by this plan.

Risks

Network failure through deferred maintenance or reduced maintenance expenditure.
Changes to design and environmental standards, or significant change to the current service, which may result in failure to achieve compliance or involve a significant cost to implement.
Contamination of raw waters, which causes a significant public health risk. Return to top

Managing risks

Risks associated with water and wastewater plant and equipment can be reduced by regular inspection, up-to-date management and maintenance plans and the recruitment and retention of skilled staff.
Changes to standards can be managed by ensuring that the Council’s procedures and codes of practice are continually revised and ensuring the council has input into the development of national standards.
Most system overflows to raw waters occur at pumping stations, which are continuously monitored and alarmed. In the case of alarm a pump or maintenance crew responds to either prevent or contain the overflow. In the event of an overflow occurring incident management protocols are in place with the Taranaki Regional Council.

Levels of service and performance measures

The following levels of service and performance measures outline the objectives we will set and how we will measure our progress.

Asset information

Assets required

The diagram represents those infrastructural assets both currently employed and planned to be incorporated in service delivery for the wastewater activity area.

Managing improved and/or expanded services

Expanding reticulated areas for treatment and disposal to include Oakura (2009 to 2010).
Improve quality of treatment and disposal by decommissioning the Waitara Treatment Plant and pumping Waitara sewage to New Plymout.h for treatment and disposal (2015 to 2017).
Upgrading the New Plymouth Wastewater Treatment Plant to cope with the increased wastewater flows, while still complying with effluent discharge quality standards (2012 to 2015).
Producing biosolids to meet new national standards. Return to top

Funding

Only people using the system pay for it. Direct operating expenses such as maintenance, energy, depreciation, debt servicing and staff costs are paid from the current operating revenue collected from uniform annual charges and trade waste charges.

Uniform annual charges (UACs) are calculated on average cost, so that users who have similar consumption characteristics are charged the same. That is, the costs of providing reticulation to similar users does not vary greatly, so having all similar users paying the same fee is fair and administratively efficient.

Treatment costs, however, can vary considerably where extraordinary discharges have to be dealt with. These extraordinary discharges add significant extra cost to the treatment process and usually come from commercial and industrial properties. Where they occur, trade waste charges are calculated according to the particular discharge characteristics of the business. The charges are derived annually according to the formula specified in the trade waste bylaw.

Large capital expenditures for quality or capacity improvements are generally funded by loans so that their costs can then be spread over time. In this way current and future users of the system pay for their use of the system. The loans are serviced and repaid from UAC and trade waste charges revenue.

Funds for the renewal and replacement of assets come from the activity’s operating revenue and are accumulated to pay for these expenses as needed to maintain the asset’s ability to continue providing the agreed level of service.

Managing change

Current demand growth in existing (New Plymouth, Waitara and Inglewood) and proposed service areas (Oakura) is two per cent per annum. Ongoing review and upgrading of the Wastewater Treatment Plant in New Plymouth will accommodate anticipated growth.

The 2006-2016 Community Plan included funding for a sewer scheme to be constructed for Urenui and Onaero. Recent estimates show the cost of this scheme to be in excess of $13m and beyond the funding provisions included in 2006 to 2009. The Council has decided after public consultation conducted within this plan to study possible alternatives to the proposed scheme but that study will not be funded until 2012/13. Capital funding required for the scheme implementation is therefore not included in this plan, however monies have been allowed in 2012 to 2015 for the study of alternatives, further design, consenting and associated land access costs.

Maintenance, renewal and replacement of assets

Existing wastewater assets are maintained, renewed and replaced by the Council and external contractors according to the specific service lives of the component parts of the system and as described in the Water and Wastewater Asset Management Plan (WWAMP). The Council’s asset management plans can be viewed at the Civic Centre, Liardet Street, New Plymouth at any of the libraries and service centres at Bell Block, Inglewood or Waitara or district libraries.

Maintenance expenses are funded from the targeted rates (UACs) and trade waste charges used to fund all wastewater operating costs.

Asset renewal and replacement expenses are funded from depreciation reserves. Depreciation reserves are calculated annually as a percentage of the total asset value, and are funded from operating revenue (UACs and trade waste charges).

This means that only those using the services pay for their upkeep.