As if it wasn’t already challenging enough to supply a quality product at a reasonable cost, produce processors are now moving toward unprecedented fresh water supply problems. They are not alone; worldwide water shortages are cutting into profits for many industries, and it’s getting tougher every year. With the world’s fresh water usage doubling every 21 years, and 40 percent of the world’s population already lacking adequate fresh water supplies, water will soon become a major cost item rather than a minor nuisance. On the other side of the coin, waste water surcharges and increases in EPA regulation are also making life difficult for produce processors. Federal funds that once supported waste water treatment for cities and counties are running out.
Between incoming fresh water costs and outgoing waste water costs, many in the produce industry are exploring new alternatives to help them get ahead of the game before water becomes a critical line item on the balance sheet. This article reviews two new systems available from a Kansas-based company–American Water Purification, Inc. (AWPI.biz), one for the recycling of produce wash water and the other for the reduction of waste water treatment penalties.
Recycling wash water
After saving poultry processors millions of dollars in fresh water costs over the past 12 years, AWPI has adapted the same technology to create a wash water quality management system for the produce industry. It uses a combination of ozone and filtration to recapture wash water, disinfect it to FDA-approved standards (GRAS)1, then return it to the front end of the process free of bacteria, color, taste, and suspended solids. The water cost savings is so significant that the return on equipment investment can occur less than two years (see Fig. 1).
Regulatory cost advantages
As increased public focus is given to dangerous byproducts that result from the use of traditional sanitizing agents, new restrictions–and their associated costs–may be right around the corner. Trihalomethanes (THMs), concentrations of biochemical oxygen demand (BODs) and other chemical residues may soon encourage regulatory constraints on the use of chlorine as a sanitation agent. Ozone systems cause none of these problems.
Safety cost advantages
Ozone is 1.5 times stronger than chlorine, is more effective over a wider spectrum of microorganisms, and kills them 3,000 times faster. It can also destroy chlorine by-products, pesticides, and toxic organic compounds in process water without creating new toxic chemicals. Because ozone is produced onsite, there is no need to store dangerous chemicals. It is much safer for employees than chlorine, reducing potential safety related costs.
Improved product quality
While chlorine dramatically reduces produce shelf life, ozone actually retards softening and browning. While chlorine is considered a carcinogen, ozone is not–and it produces no harmful byproducts during the treatment process. With proper attention given to the marketing of these customer-friendly advantages, an ozone recycling system could have even greater profit advantages for some companies.
How it works
The oxygen we breathe is a molecule made up of two oxygen atoms–hence the chemical designation “O2.” The ozone molecule is very similar, but carries a third oxygen atom–hence the chemical designation “O3.” The third atom wants to break apart from the other two, and it is this instability that gives ozone the power to kill germs. Bacteria are built to absorb normal oxygen molecules, and are perfectly happy to absorb ozone instead. When they do this, the ozone does what it already wanted to do–it gives off the extra oxygen atom and produces a burst of energy at the microscopic level. As the molecule flies apart, so does the bacteria. The only byproduct from this reaction is harmless oxygen, free of toxins and carcinogens. The simple mechanics of the process make it unlikely that bacteria will mutate into resistant strains. (This is another drawback of chlorine; germs have been known to evolve into poison resistant strains, and when this happens, that particular poison stops working, and researchers have to figure out a new way to kill the resulting “super germ.”)
At the other end of the process, AWPI’s onsite waste water treatment system provides a new way to control costs (see Fig. 2). This, too, is a technology that has long proven its value in the poultry industry. “It works reliably, right now,” says AWPI CEO Dan Gates, “and that’s important in the increasingly critical water supply environment because companies need to be able to hit the ground running when they adopt new technologies.”
The system uses heat transfer from refrigeration units to raise the water temperature in natural, anaerobic digester tanks, creating an efficient environment for beneficial bacteria to do their work. “We use a dissolved air flotation–or DAF–skimming process to separate water from a dry sludge that can be safely dumped at a landfill,” says Gates. The sludge is free of BODs, reducing regulatory costs.
Time for a change
These are challenging times, economically, environmentally, and in terms of public relations. Every penny counts, and in the days to come, pennies will become dollars where water costs are concerned.
1In 1997, ozone was self-affirmed as Generally Recognized As Safe (GRAS) as a disinfectant for foods by an independent panel of experts sponsored by EPRI.
Wynn Ponder is a freelance writer who covers health, science, industrial and marketing topics.