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SA Tenders and Contracts

Display Tender AC044680 
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Stage 2 - Strathalbyn Waste Water Storage and Treatment Process Expansion
Issued By Alexandrina Council
Request for Tender
Tender State
Closed
Tender Code
AC044680
Contract Number
5.21.021
Category
Building and Facility Construction and Maintenance Services

Enquiries

Description

Alexandrina Council of 11 Cadell St, Goolwa, SA, 5214 (the Council) invites tenders from Tenderers for the provision of Stage 2: WWTP and Irrigation Pump Station Package (the Services). The Council will enter into a Contract for Services with the successful Tenderer.

The township of Strathalbyn is serviced by a Community Wastewater Management System (CWMS), which involves wastewater collection, treatment and reuse/disposal. The scheme is primarily a Septic Tank Effluent Disposal Scheme (STEDS), meaning most connections have a septic tank for primary treatment. The township also has a number of full sewer connections. The CWMS is owned and operated by Alexandrina Council (Council).

Effluent generated within the township gravitates through a network of gravity drains into pump stations within the township, and is pumped through a network of rising mains to a sequence batch reactor (SBR) wastewater treatment plant (WWTP) near the intersection of Michelmore Road and Greenway Road. The SBR plant currently operates at 500 – 700 kL/day, and has a capacity of 1,500 kL/day. Based on field observations and a water balance assessment, the existing 120 ML polyethylene-lined storage lagoon at the plant has been found to have inadequate capacity to balance the scheme’s annual water storage variation.

This project involves the construction of a new 110 ML storage lagoon at the plant to provide additional balancing storage. In addition to the new lagoon, the project involves a range of other upgrades to address some deficiencies with the existing plant and improve operation.

The Works for the project have been split into two separate contracts:

  • Stage 1: Lagoon Civil Works Package (Currently under Construction)

  • Stage 2: WWTP and Irrigation Pump Station Package.

  • The Scope of Works for Stage 2 WWTP and Irrigation Pump Station shall include the following:

  1. Preliminaries

  2. Location of existing services.

  3. Modifications to 110 ML storage lagoon batters to accommodate new pump station.

  4. Construction of new irrigation pump station upon the batter of the 110 ML storage lagoon.

  5. Construction of 100 kL chlorine contact tank between the SBR plant decant line and the outlet drains to the storage lagoons.

  6. Modifications to the transfer mains from the balance tank

  7. Modifications to the WWTP’s gaseous chlorination dosing system.

  8. Construction of a platform and a wastewater screen on the inlet to the WWTP’s balance tank, including installation of a wash pump.

  9. Realignment of various pipework in the WWTP.

  10. Construction of an offtake line to the existing chlorine dosing water storage tank, containing a filter, actuated isolation valve and a pressure sustaining valve.

  11. Installation of actuated gate valve on the existing rising main to the Ness irrigation site.

  12. Construction of an inlet manifold on the existing low level outlet pipes from the existing 120 ML, including a new floating suction inlet.

  13. Decommissioning of the existing irrigation pump station and modifications to internal pipework at the invert of the pit to connect in to the new irrigation pump station inlet pipework.

  14. Location of existing conduit housing chlorination pipes between chlorination shed and existing irrigation pumping station. Removal of existing pipes and installation of a drawrope to allow for future communication cables.

  15. Installation of hydrostatic level sensors on existing 120 ML lagoon and new 110 ML lagoon (refer to drawings for detail).

  16. Removal and relocation of actuated valves in concrete chambers on the 110 ML storage lagoon to the new pump station.

  17. Construct outlet section of lagoon circulation pressure main into the existing 120 ML lagoon (to connect to stub from Stage 1 works).

  18. Supply and install of 150mm thick compacted quarry rubble over the WWTP area to be confirmed with the Superintendent.

  19. Testing and commissioning.

ONSITE COMPULSORY SITE MEETING

11:00AM TUESDAY 29 JANUARY 2019