Plumbing industry gets smart about water use
Following a prolonged drought and pressure from a growing population demanding potable water, State Governments around Australia have sought industry and community input to reduce potable water consumption.
The Government of Victoria, in conjunction with Melbourne’s water companies, established and jointly operate the Smart Water Fund.
The aim of the fund is to encourage and support innovative development of water, biosolids recycling and water-saving projects.
Cleaning the carrots
As is the case on the fringe of most cities, market gardens supply many of the fresh vegetable needs of residents.
Due to their city proximity, many market gardens access the mains water supply. In Melbourne, a capital city with a population of 3.5 million, residents have been on water restrictions for three years, and farmers must also help to ease the water crisis.
Rick Butler is a fourth-generation farmer and was advised by provider South East Water that his farm was one of the top 1000 users of potable water.
“We were using a lot of water to wash our vegetables in preparation for supermarket sale,” Butler says.
“Our daily use was about 80,000L (21,000 gallons). The water came straight from the mains and, once used, went into a holding dam. Although we were able to make secondary use of the water for crop watering, the run-off was lost.”
The farm’s vegetable washing machine, installed in 1991, was ready to be supplemented and eventually replaced by a more efficient model. The Smart Water fund allowed Butler to design a water-saving solution.
He feels particularly proud of the new soft-vegetable washing machine installed with the help of the Smart Water Fund grant, because he designed it himself.
“The idea for the machine had always been in my head. But the Smart Water grant allowed me to pursue and develop a machine for commercial use that would treat and recycle water as it washed the vegetables.”
The concept for the new equipment was developed in consultation with a local company, Tripax Engineering, which then built and installed the final product.
The new machine saves about 90% of the water the farm used to consume for processing, bringing the daily use down to about 5,000L (1,300 gallons).
The machine’s ability to wash soft vegetables which are hard to handle – for example, lettuces and Asian greens – made it unique and secured the grant.
Presentation of the produce is very important to Butler and his major customers, which demand ISO accreditation to ensure quality for supermarket shelves.
So how does it work? The machine has three tanks, containing water of varying degrees of freshness.
One tank is filled with fresh water for a fine spray – from above and below – over vegetables traveling along a conveyor belt.
“Some vegetables are difficult to wash,” Rick says. “The spray aims at the vegetables with precision, so there is minimum wastage.”
Excess water is caught in a tray and channeled to another holding tank via a series of increasingly fine filters that sift out soil and sand, which collects at the bottom of specially designed V-shaped tanks. Recycled water is then treated with an electronically controlled dose of biocide to remove bacteria.
“We were using chlorine for sterilization purposes, but chlorine is in the past,” Butler says.
“We wanted to move to a safer, biologically based product, not only to improve the quality of the vegetables but also for the health and safety of our staff. We now use a biocide that is integrated into the recycling process and automated by the machine. There are several on the market to chose from.”
The automatic system ensures that precise doses of biocide are released into the recycled water. At specific levels, the biocide effectively kills bacteria. The system also monitors biocide levels in the water in parts per million.
“The product is completely biodegradable and turns into a vinegar-like substance that goes safely into the holding dam,” Rick says.
The message is that plumbing engineers and contractors can take this water-saving idea to farmers in their own cities rather than wait for them to ask for assistance, as they probably don’t realize the savings that can be made.
We have included a copy of the equipment plan which can be easily replicated locally.
Butler and Tripax Engineering are keen to see others pick up on their design ideas and save water in market garden processing sheds the world over.
Money laundering
The rapidly growing City of Ballarat, 110km north-west of Melbourne, has a population of 90,000.
Due to the drought, Ballarat has had to take even more stringent water-saving measures than Melbourne, as its water storages are at the critically low level of 10% at the time of writing.
Again, the community and industry have been asked to look for innovative ways of reducing consumption.
A well-established business, Eureka Linen, supplies clean linen to hospitals, aged-care facilities and the accommodation industry in the region and also in Melbourne.
This business was advised by its water supplier, Central Highlands Water, that its annual consumption of 60ML (15.9 million gallons) of the city’s potable water supply placed it in the top 10 users in the region.
Eureka’s business – and its water use – was growing rapidly, so it was clear that the company had to assess its situation and investigate water recycling.
“Eureka Linen provides about 55 tonnes of rental linen a week to health-care and hospitality facilities,” manager Paul Robinson says.
“We service the Royal Women’s Hospital in Melbourne and several health-care facilities around Victoria, as well as regional hotels and motels.”
The company also provides specialized services for medical theatres, including green theatre drapes, so it was essential for any cleaning process using recycled water to be of a clinical standard.
“We also wanted to ensure there would be a reasonable return on any investment we made,” Robinson says.
“Some of our chemical suppliers were able to offer solutions, but we didn’t want to install water-saving equipment that contracted us to a single chemical supplier.
“We hired a consultant engineer to look at ways of improving water efficiency and shared the cost of the consultant with Central Highlands Water.”
The consultant audited Eureka Linen’s water use practices and suggested a range of alternatives, from harvesting roof water to recycling rinse-cycle water plumbed from individual machines.
The solutions suggested in the final report included small-scale, short-term ways of saving water as well as more ambitious schemes.
“We chose to invest in a large-scale project in which all the wastewater in our pit would be recycled – wash and rinse-cycle water,” Robinson says.
“This was the most water-efficient, long-term solution.
“We checked out what market solutions there might be and eventually decided to work with Econova, a local system supplier that is earning a lot of respect.”
The project developed into a joint initiative between the Victorian Government, Ballarat Health Services and Central Highlands Water.
“We approached the Government for funding and received some from the Department of Sustainability. To be eligible for the funding the project had to be a new initiative in Australia.
“We argued our case successfully on the basis that most of the components of the proposed system were Australian made. The project is the first of its kind in Victoria.”
Econova general manager Christian Uhrig says the NovaUltra system is a containerized ultra-filtration unit that is shipped with a ready-made platform and tank.
“Once on site, water is plumbed through from the washing machines to the plant and back into the machines,” Uhrig says.
Water is recycled through a membrane with 0.01 micron apertures (a micron is one-millionth of a metre), leaving any particles behind.
“That’s like trying to put a Boeing 747 through your front door,” Uhrig says.
“The quality of water that has been subjected to ultra-filtration is 10 times that of the water coming out of a potable reservoir.
“With desalination or reverse osmosis – typically used for meeting drinking water regulations – only 50-60% of the water can be reused, because a large quantity is discharged as waste.
“Ultra-filtration takes out only the contaminants and very little is lost – 98% of the water can be reused. In addition, less energy is required to put water through the process.
“Determining the level of filtration depends on the purpose for which the water is used.
“Water used by Eureka Linen does not need higher levels of filtration because it is not intended as drinking water. There is a very low risk of contamination from laundry water, which tends to contain a high level of cleaning chemicals with only a small loading of solids, bacteria and pathogens.”
On-site water recycling of the sort being pioneered by Eureka Linen is highly regarded as a sustainable work practice. As well as saving many thousands of liters of water a day, the system is energy efficient.
“Local authorities here use up to 50% of their total energy output to pump wastewater to treatment plants, and to provide water to residents and businesses in the first place,” Uhrig says.
“On-site recycling by individual businesses saves an enormous amount of energy.”
Robinson says gaining funds from the Government was very involved and took a lot of work, but the result was well worth it.
These two projects demonstrate the benefit of government and industry working together to achieve a win-win situation.
Are there opportunities for you in your local area to take such an initiative?