Kyabram / Shepparton Water Improvement Scheme, Victoria, Australia

An AU$17 million state-of-the-art upgrade of the Shepparton wastewater treatment plant by Tenix Alliance began in November 2002. This is the latest element in a series of improvements along the Tongala-Kyabram-Shepparton corridor, which began in 1997 with the replacement of the water treatment plant and the rehabilitation of the existing wastewater treatment plant at Kyabram. The scheme forms part of a major programme to upgrade water infrastructure across the region undertaken by Goulburn Valley Water (GVW).

In addition to the work at Shepparton and Kyabram, the improvement scheme in the western zone of GVW's Central District involved a number of other projects. These included upgrades to the raw water treatment and storage facilities at Tongala, improvements to both the WTP and WWTP at Rushworth, sewerage extension projects at Stanhope and Merrigum and a general expansion of wastewater treatment capacity.

The total cost of the scheme to date is around AU$40 million and a further AU$95 million remains to be spent on the whole regional project, spread over the five-year period up to 2008.

BACKGROUND

The Australian water sector has seen many changes over recent years, with the wider adoption of corporate management principles, the introduction of competitive operating licences and customer contracts, on top of increasingly stringent environmental legislation. For GVW, in a region dominated by the processing of fruit, vegetables, beef and dairy products, this has meant improving the quality of supply water to both these industries and its urban customers at a competitive price, while meeting the area's need for environmentally sustainable wastewater management.

Australian waterways are very sensitive to pollution, making the use of advanced approaches to wastewater treatment and re-use particularly important, a factor borne in mind throughout the design of the improvement scheme. To comply with the new regulations, reclaimed water is now principally destined for irrigation rather than discharge into streams. While this circumvents one potential environmental impact, it makes effective treatment systems essential to avoid harming the local groundwater, which already has a history of damage from human intervention.

In 1994, samples were taken from 27 bores in the Tongala-Kyabram area and analysed for physical parameters, chemical constituents including heavy metals and trace elements, environmental isotopes, nutrients, microbial loadings and pesticides.

The results suggested that the quality of the shallow groundwaters in the area studied had been adversely affected, directly or indirectly, by human activity, with all but one of the samples exceeding Australian Drinking Water Health Guidelines for at least one parameter. Pesticides were detected in 22% (six) groundwater samples; Faecal Indicator Bacteria (FIB) also occurred at the same rate. Only 15% (four) of the bores supplied water that would be considered suitable for irrigation purposes, though 44% provided groundwater which met the guidelines for livestock watering.

A number of recommendations arose from this groundwater quality assessment including the preparation of vulnerability and risk maps, the identification of contaminant sources and a review of water management; two years later, the water improvement scheme was underway.

KYABRAM WATER TREATMENT AND WASTEWATER TREATMENT

There were two parts to the improvement works undertaken at Kyabram - the replacement of the water treatment plant and the upgrade of the town's wastewater treatment facility.

The AU$3.3 million contract for the design and construction of the 15,000m³/day WTP and associated 6,000m³ treated water storage was awarded to Aquaclear Technology. Their design used Dissolved Air Flotation Filtration (DAFF) and a plant layout which maximised the use of the existing infrastructure.

Construction began in April 1997 and the plant was officially opened on 20 May 1998 on time and within budget.

In the winter, reclaimed water from the Kyabram WWTP had normally been discharged to the adjacent Coram Drain, which outfalls into the Goulburn River. Upgrading the plant to avoid disposal to the waterway required increasing the winter storage capacity to 224,000m³, the refurbishment of an existing treatment lagoon, inlet improvement works, rehabilitating the pumping station and the development of a new irrigation system.

SHEPPARTON WATER TREATMENT AND WASTEWATER TREATMENT

The work at Shepparton had three main elements. Firstly, like Kyabram, the town required a replacement WTP; secondly, a modern tertiary treatment stage was constructed at Shepparton wastewater facility; finally the WWTP is also currently being upgraded with the addition of a high rate anaerobic digestion system.

The original water treatment plant had been in service for over 60 years. Its limited capacity and the difficulties involved in modifying it to meet modern Environment Protection Authority guidelines made its decommissioning and replacement inevitable.

The new 40,000m³/day plant was designed to meet projected demands through to the year 2012, with the ability to be easily expanded in the future, as required. The DAFF process was again selected, since it was judged to be the best suited to the nature of the raw water supply and able to ensure a safe and reliable supply in the event of an algal bloom. The project was completed under budget at a cost of AU$4.2 million and was officially opened by the Deputy Premier, Pat McNamara, on 11 March 1998.

The Shepparton Wastewater Management Facility is GVW's largest WWTP, the industrial effluents it receives contributing to an equivalent load of some 700,000 people. Most of the reclaimed water is used for irrigation, but the size of the plant necessitates some discharge to the Goulburn River.

OTV Kruger were awarded an AU$3.8 million contract to construct a state-of-the-art Actiflo process plant - the first of its kind in Australia - to remove phosphorous and algae from treated wastewater prior to its discharge.

Designed to remove 20t of phosphorus, 60t of nitrogen and 600t of suspended solids each year, this process significantly reduces the annual nutrient load on the receiving waters.

This project was completed in October 2002.

The final part of the work at Shepparton is still ongoing and involves the construction of a 200,000m³ High Rate Anaerobic Lagoon (HRAL), the largest project ever undertaken by GVW. This includes the construction of the new lagoon itself which, when finished, will be sealed with a 5ha polypropylene cover, gas collection and flaring equipment, lagoon aeration facilities and extensive interconnecting pipelines.

The biogas produced by the AD process will be collected and initially flared at 700°C, though plans are being considered to make use of it for power generation in the future.

The project is clearly of great benefit to Shepparton since it will allow the large effluent discharge from local industry to be processed at the plant economically and in a more environmentally sustainable manner.

The reclaimed water will be used to irrigate 230ha of pasture during the summer. During winter, when it is too wet to irrigate, the reclaimed water will continue to be discharged to the Goulburn River, having first been passed through the tertiary treatment stage implemented earlier to remove phosphorus and algae.

The work commenced in November 2002 and was scheduled for completion by December 2003, ahead of the peak fruit processing period. However, wet weather delayed the installation of the lagoon's huge cover until the end of March. Although commissioning will take several months, the plant is expected to be fully operational later in 2004.

KEY PLAYERS

Goulburn Valley Water own and operate the plants and were partly responsible for funding the improvement programme. The State of Victoria provided around 40% of the funding, with other contributions for various elements of the scheme coming from the Australian Government, the National Heritage Trust and local industry. Aquaclear was the main contractor for the Kyabram WTP with a separate contract for upgrades to the storage and inlet works being awarded to R.Collie Contracting. Aqua-Tec Fluid Systems worked on the Kyabram WWTP improvement phase. OTV Kruger were responsible for installing the Actiflo tertiary treatment plant at Shepperton WWTP. Tenix Alliance are the main design and construction contractors for the Shepperton HRAL. Other contractors involved in the regional improvement scheme include McClure Earthmoving and Contract Control.