The major use of water was in bottle washing and rinsing. This area accounted for better than 50 percent of the plant’s water consumption. It was also the main flow into the anaerobic waste treatment plant. A water reclamation system was installed, fully in accordance with compliance guidelines. Water usage was reduced by 75 percent. More important, the washing and rinsing operations were measurably improved in terms of bottle cleanliness. Microbial data confirmed that all agreed-to parameters had been achieved with a wide margin of safety.
The water reclamation system cut the flow of wastewater to the plant’s anaerobic wastewater treatment plant in half, but the BOD loading per day continued as before. Other measures were identified to reduce BOD loading via sugar treatment changes, but these were largely unnecessary. The anaerobic wastewater treatment plant operated much better with the more concentrated and consistent wastewater.
Label removal and caustic reclamation systems were identified that would accomplish two tasks.
With high recirculation flows, rapid straining out of labels before they could be “pulped” in the caustic bath improved machine performance and gave a cleaner caustic solution.
Caustic reclamation extended caustic life 300 percent (minimum), saving considerable money, as well as improving machine performance. An automated neutralization system was installed to protect the wastewater treatment plant.
The surface water supply was confirmed to be at risk to waterborne organisms, and a total plant barrier concept was introduced. All incoming water would be treated specifically to guard against pathogens of concern. Whether water was to be used for gardening, cooling, general purposes or even fire control stand-by, the barrier would be in effect at the plant inlet. For production purposes, the water would still be treated and subject to a multiple-barrier system.
These case studies show that the key to an effective audit is to approach it with an ulterior motive in mind. Using normal approaches to restrict or reduce water usage often means giving away a margin of safety – something that today’s food industry is determined not to do.
An audit should start with a specific objective and that objective should address a specific opportunity. It should be done by experienced personnel, and should always include an experienced plant engineer, operator or scientist.
Harry DeLonge is a consultant for US Filter’s Food & Beverage Market Team. He can be reached at DelongeH@usfilter.com.