Nelson Regional Sewerage Business Unit news

Regional Pipeline Upgrade - Progress Report 8 August 2011

Thu, 11 Aug 2011 10:38:14 +1200

Currently, March Construction, pipeline subcontractor to Downers Ltd, have installed approximately 650m of both the 800mm dia and 250mm dia HDPE pipelines. They have started at the Bells Island end and are working towards Saxton Island and will then move towards Monaco. March are presently working in the inter-tidal area north west of Saxton Island and excavating the trench during periods of low tide.

March Construction have been liaising with the Iwi monitors directly with respect to the day to day programme of works and keep them informed as to when excavations of the foreshore area are to be carried out, and this has been working well.

Progress to date has been slower than expected. The trenching is taking longer as fine silt and sediments often flow back into the excavation before the pipe can be installed. This means the trench needs to be re-excavated several times to ensure the pipe invert is at the correct depth and at an appropriate grade. The weather has also impacted on progress with wind in particular causing issues. March Construction has advised wind speeds for the period 1st May to 11th July to be demonstrably higher than normal. In addition, the February earthquake in Christchurch meant delays in getting staff and equipment on site initially.

Installation of the bedding material has also proved challenging for the contractor as more material than initially thought is needed to compensate for the extra excavation that is required. The bedding material is an important component of the pipeline as it provides protection for the pipe from larger stones being placed against it as well as supporting the pipe when the backfill is placed. March Construction intends to start transporting bedding material across to Saxton Island via a barge being loaded at Monaco boat ramp this week. This bedding is for the section of trench currently being excavated and additional stockpiles will be made on Saxton Island for that section of pipeline.

Quality is also a focus for both ourselves and the contractor. There are two main areas that have been the subject of several discussions. The welding of the HDPE pipes. It is important this welding is done correctly to ensure integrity of the pipeline. We are confident the procedures in place, record keeping and checking being done mean the welding is of a high standard. Also concentrated on is the depth and gradient of the pipe, with a particular focus on ensuring the pipe gradient is appropriate, that is with no unintended high or low spots. March are using GPS technology on their excavators to confirm the depth and alignment is as per design, divers to check trench condition before laying the pipe and an independent survey firm to confirm the as built location.

In the coming weeks, March will be installing pipes up to and along Saxton Island. This will present its own challenges as all access for personal, plant and materials, is via boat or barge. On the positive side, this section of trench is less prone to impact from both tidal currents and wave action.

Project is on programme for completion by December at a revised cost of just under $13mil.

The regional pump stations at Beach Road and Saxton Road are being upgraded as part of the Regional Pipeline Upgrade project. The work is progressing well and both pump station are expected to be operational in October 2011.

Regional Pipeline Upgrade

Fri, 04 Mar 2011 12:44:45 +1300

The Nelson Regional Sewerage Business Unit begins work next week on the installation of a new waste water pipeline across the Waimea Estuary from Monaco to Bells Island.

Chairperson Donna Hiser says that it will be a great relief to soon have the new pipeline in place as it is known that joints in the current pipeline are at high risk of failure.

“It has not been possible to investigate and replace those joints as any disturbance of the area around an unstable joint could have resulted in untreated sewage being released into the estuary.

“The new pipeline will be installed at sufficient distance from the old pipe that we can be sure that the unstable joints should not be disturbed.

“As well as being of historical and environmental importance, the Waimea Estuary has substantial significance for local iwi as a food source, so that protecting it from potential contamination is a very high priority.” The pipeline upgrade will also include the installation of new pumps at Beach Road and Saxton Road pump stations, the Songer Street pump station will be replaced by an improved facility, and the Airport pump station will have its control mechanisms upgraded.

At the same time as the new waste water pipe is put in place, the Nelson City Council will take the opportunity to install a smaller pipeline in the same trench and this will carry treated waste water back from Bells Island to the City so that it can be reused for irrigation.

“Re-using treated waste water makes great economic and environmental sense for the region long term”, says Donna. “We are delighted that Nelson City Council is undertaking this initiative. The Business Unit already has several other re-use initiatives such as using treated waste water for pasture irrigation on Bells Island and, of course, the long term use of treated solids as fertiliser on the Rabbit Island forest. While many regions are sending treated solids to landfill, often with increasing landfill charges, the Nelson Tasman region is both saving money and protecting the environment with these initiatives.”

Tenders let for pipeline upgrade

Fri, 10 Dec 2010 10:42:23 +1300

A tender to the value of $8,746,500 was let to Downer EDI Works Ltd for the construction of the works associated with the construction of the Regional Pipeline Upgrade contract.

The contract for the supply of the generators for the four pump stations (Beach Road, Saxton Road, Songer Street and Airport) was let to Powergen Group Ltd.

The supply of pumps for the upgrade works at the Beach and Saxton Road pump stations was let to Mono Pumps (NZ) Ltd and the pumps for the Songer Street pump station was let to Grundfos.

The physical works on the project is expected to start in February and finish in October 2011.

Annual Report 2009-10 now available

Fri, 19 Nov 2010 12:14:09 +1300

The NRSBU Annual Report for 2009-10 is now available. NRSBU is pleased to highlight significant achievements in the 2009/10 financial year, including the construction of the new inlet works, primary clarifier, partial completion of the dewatering facility and the improvements to the hydraulics between the primary clarifier and the ponds that will allow better distribution of loads between the facultative ponds; the Regional Pipeline Upgrade project's approval by Nelson City and Tasman District Councils; and the NRSBU website.

Resource consent granted for regional pipeline project

Fri, 19 Nov 2010 12:05:18 +1300

Resource consent has been issued for the Nelson Regional Sewerage Business Unit (NRSBU) to construct a duplicate wastewater pipeline across the Waimea Inlet between the Monaco Peninsula and Bells Island.

Tenders closed in October and it is expected that work will start in February 2011 with a project completion date in October 2011

The duplicate pipeline will safeguard against the potential failure of the existing estuary pipeline. The existing pipeline is in a poor state of repair and has been assessed as being at a high risk of failure. The environmental implications of such a failure and the resultant uncontrolled discharge of untreated sewage to the Waimea Inlet are considered to be unacceptable and there is an immediate need to address this existing situation.

The proposed duplicate pipeline will follow the route of the existing pipeline from the Monaco Peninsula via Saxton Island to the Bells Island wastewater treatment plant. It will carry the entire Richmond and Nelson South catchment flow across the estuary to the treatment plant, providing a critical link in the regional sewerage network.

Download this and other resource consents issued to NRSBU.

Rising main design underway

Mon, 26 Apr 2010 08:30:00 +1200

The ~$20m project to create a new regional sewage pipeline from Monaco to Bells Island is underway, with the project currently in the resource consent process. Consent approval is expected around July 2010.

In order not to delay the completion of the project it was resolved to continue with the detailed design while the resource consent process is running. The full project, including auxiliary works to the Beach Road, Saxton Road and Airport pump stations as well as the construction of a new pump station at Songer Street, is programmed for completion in May 2011.

Diagram of the rising main

Downloads

You can download the full resource consent for the duplicate pipeline, but please note the large files sizes that are due to scanning original documents. The document can be downloaded in full, including the application, appendices, and annexes, or it can be downloaded in four smaller documents.

Full resource consent

Download the full resource consent including application, appendices and annexes (36MB PDF)

In parts

Download the resource consent application (442KB PDF)

Download appendices A, B, C and D (16MB PDF)

Download appendices E, F, G, H and I as well as annexes A, B and C (20MB PDF)

Business Plan 2010/11 under review

Fri, 12 Mar 2010 08:30:00 +1300

Each year NRSBU prepares a business plan for the consideration of its owners. The 2010/11 business plan has been forwarded to the Joint Shareholders Committee of NCC and TDC. The Committee will consider the plan and forward it to the individual Councils for consideration and approval in April/May 2010.

Treatment plant upgrade on schedule

Thu, 11 Mar 2010 09:35:47 +1300

The Bells Island Wastewater Treatment Plant is currently being upgraded with an estimated $9m effort to construct a new primary clarifier, inlet chamber and screen and dewatering facility.

With reinforced concrete work associated with the 33m diameter primary clarifier now complete the focus has shifted to the assembly and installation of the mechanical components such as the scraper and pumps required to separate waste components and transport the different components to other parts of the Waste Treatment Plant for further treatment of effluent and solids.

The upgrade is on target and is expected to be fully integrated into the treatment plant by June 2010.