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Wastewater

Bioboost

The council manages the sewage network for more than 22,000 household and businesses in New Plymouth District. The waste flows through a system of underground pipes to the wastewater treatment plants in New Plymouth and Waitara.

Residents pay for sewage reticulation and treatment through a fixed charge as part of their rates. Industry trade waste customers are charged based on waste volume and strength.

Sewer connection

To get a sewer connected you need to complete a sewer connection application form. Forms are available here or from council offices.

Once approved, you will receive a letter of acceptance from the council along with a list of council approved contractors that are able to carry out sewer connections on sewer mains up to 225mm in diameter. All financial arrangements are between you and the contractor.

The sewer connection has to be inspected by the reticulation supervisor before backfilling begins. Photos showing the connection and the property will be accepted from the contractor if the supervisor is unable to inspect it. An asbuilt drawing is required by the council at the completion of the work.

• Sewer connection/disconnection form (Six pages 502KB PDF)
• Sewer/stormwater/water fees and charges (Two pages 41KB PDF)

Sewer disconnection

To get a sewer disconnected you need to complete a sewer disconnection application form. Forms are available here or from council offices. There is no fee to get a sewer disconnected.

Trade waste connections

Trade waste connections are controlled by the Trade Waste Bylaw. Application for trade waste connections should be directed to the council and will be handled on a case-by-case basis.

Wastewater Treatment Plant

The New Plymouth Wastewater Treatment Plant was built in 1984 and is located on the eastern flats of the Waiwhakaiho River.

The plant takes raw sewage and trade wastes from New Plymouth City, Bell Block and Inglewood. It uses a biological treatment process known as activated sludge aeration to produce a high quality effluent. The clean effluent is discharged to the Tasman sea via a 480m pipeline. The quality of the water leaving the plant is one of the cleanest in New Zealand and well within the New Zealand standard for safe swimming and seafood gathering.Return to top

How does the wastewater process work?

1. Pump stations at Te Henui, Glen Avon and Bell Block pump waste water to the plant.
2. The waste passes through milliscreens, which are rotating drum screens with 3mm wide openings that remove plastic and other solids from the wastewater.
3. The wastewater then passes through a grit trap basin where steady stirring causes grit to swirl to the centre and bottom of the basin. This grit is periodically removed, washed and removed for land disposal.
4. The wastewater then passes into two aeration basins where micro-organisms, collectively called “activated sludge” feed on the organic waste in the waste water. Pathogens (disease-causing organisms) and contaminants from the wastewater stick to the activated sludge ready for removal. Each basin has six large aerators which keep the basin contents mixed and provide the oxygen necessary for the activated sludge organisms to live, feed and multiply.
5. Two clarifiers separate the activated sludge from the water. The clusters of activated sludge settle to the bottom of the clarifiers and are drawn off to return to the sludge pump station. Most of the sludge is returned to the aeration basins to maintain the biological levels, while surplus is diverted to the sludge de-watering plant and undergoes three stages of thickening followed by thermal drying to turn them into a biosolids fertiliser called  Bioboost.
6. The clarified water receives a small dose of sodium hypochlorite prior to the chlorine contact tank to kill any remaining pathogens.
7. The clean water is then piped to the marine outfall located 1km north of the plant that diffuses the water with sea water as it is released into the open sea.

Did you know?

• Each person generates about 300 litres of waste water a day made up of washing, bathing and toilet discharges.
• The New Plymouth Wastewater Treatment Plant is designed to handle a population equivalent of 76,000 people with provision for further expansion when demand requires.
• Because of the efficiency of the biological process used in the treatment of waste water, less chlorine is used to disinfect the final discharge than the amount used in municipal swimming pools.
• Biosolids are high in nutrients, such as nitrogen and phosphorus, and can be used safely as a fertiliser.

Looking after your sewerage system

• Sewerage maintenance information (24 pages 827KB PDF)

Related links

• Bylaws
• Oakura sewerage project
• WaterReturn to top