Saving water saves money 20th April 2009
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A FOCUS on more efficient use of resources, including water, can not only make a difference to the environment but also to a company's bottom line.
AstraZeneca's "Nova" manufacturing facility in Sydney's North Ryde produces a range of pharmaceutical products.
Since 2004, the company's water saving program has halved the site's water consumption. An estimated 180 megalitres has been saved.Engineering manager support services at AstraZeneca, Mike Crompton, says the program focuses on reducing water demand and substituting recycled water where possible.
"The program has been undertaken in partnership with Sydney Water's Every Drop Counts (EDC) Business Program and involved investigating where water was being wasted, introducing water efficient equipment, and including water saving considerations into all new projects," Crompton explained.
"The three main areas of water consumption identified were the reverse osmosis/continuous de-ionisation (RO/CDI) water purification plants, process water, and cooling towers.
"Instead of being discharged to drain, wastewater from the RO/CDI plants is fed into the recycled water system and utilised for the cooling towers.
"In addition, two process water reclaim systems have been installed. The first was established in 2006 at a cost of some $42,000. Average harvesting performance since commissioning is 65.6 kilolitres per day.
"Based on current (net) water prices, this represents cost avoidance of $57,000 per annum, and the estimated payback period was just over six months.
"The second water reclaim project, which came on stream in 2008 at a cost of around $92,000, has returned an average harvesting performance of 183.2 kilolitres per day since commissioning.
"At current water prices, this represents cost avoidance of $160,000 per annum, and the estimated payback period is just under seven months."
This year the company plans to investigate the development of a stormwater collection system at the site to further reduce the consumption of mains water.
Stormwater harvesting
Lafarge Plasterboard, in Sydney's Matraville, has installed an innovative stormwater recovery system designed to minimise the use of town water in the production of plasterboard.
Company engineer, Derek Maynes, says that solid rainfall in the month of February meant that the company was able to continuously use stormwater for nine days in the plasterboard process.
"In excess of 1 million litres of town water was saved in the month of February alone, which meant a cost saving of $1669," Maynes told Manufacturers' Monthly.
"The aim of the project is to reclaim a percentage of the stormwater from the Matraville site and introduce it into the process water system.
"Stormwater is harvested primarily from the roof of the plasterboard dryer facility and the gypsum stockpile storage area, and the main elements of the system include a stormwater silt arrestor pit, stockpile spray tank and spray tank transfer pump, stormwater storage tanks, and stormwater feed tank and pump.
"This is a sophisticated fully automated system that is controlled via SCADA Graphics. The system depicts tank and bar level indicators as well as enabling the stormwater feed set-point to be adjusted.
"SCADA also allows the system to be enabled or disabled as well as depicting water flow totalising and batch, and a dynamic graphical representation of the entire stormwater recovery system can be provided.
"In addition, historical trending of stormwater recovery tank levels and flows can be viewed.
"Stormwater from the dryer roof and gypsum stockpile storage area is diverted to the stormwater silt arrestor pit, which has a holding capacity of 400,000L.
"Once the capacity is reached, the rest of the stormwater is diverted to the public stormwater system via an overflow weir ahead of the stormwater silt arrestor pit.
"If the stormwater storage tanks are not full, a pump will transfer stormwater from the silt arrestor pit to the spray tank, which once full, will overflow into the stormwater storage tanks.
"When the stormwater storage system is depleted, and the stormwater feed system is still enabled, the stormwater feed tank will be replenished with town water at a minimum level to ensure the stormwater feed pump does not run dry," Maynes said.
