The food and beverage industries have come to place a high value on the conservation of fresh water. This is no accident; it is a response to the dual forces of rising costs for wastewater discharge and more onerous environmental regulations.
Consider the sector at large. Water is more than a utility here; it is integral to the operation. It is required for the product, for boiler feed and cooling, and for the sanitation and clean-in-place work on equipment. But that kind of activity produces effluent. What a processor puts out is a variable cocktail of organics, nutrients, dissolved salts, suspended solids, and chemical contaminants, not to mention FOG (fats, oils, and grease) and other waste, all dictated by the day’s production and cleaning.
Before any of it can be reused or released, the treatment plant must see it through screening, equalization, and both biological and tertiary stages. Some would say just let the municipal plant take every gallon, but there is merit to dealing with process water on-site. It is good for sustainability and curbs freshwater use. In an area where water is costly or in short supply, having a year-round source of recycled water makes sense for a processing or distribution facility. The EPA has been clear in its framework for reuse, and those in the business know that proper water management is as much about being a good operator as it is about compliance.
Food Industry Facility Applications
Design must be subordinated to food safety. There is no ambiguity in federal law regarding sanitary standards for potable water or anything touching food production and packaging. A reclaimed system must be well documented and fit within the HACCP plan.
That said, most facilities are practical and will relegate their reclaimed water to non-food uses. Provided the permit allows it, discharging a fine effluent is one thing, but you have to be realistic about what the water can do. It may be fit for irrigation or to top off groundwater, but it is not a substitute for what goes into a cooling tower or for sanitizing. Set your wastewater treatment goals accordingly.
The Treatment Process
This starts with screens and filters to get rid of the gross solids. At DeJong, we have found that DAF and screening effectively reduce TSS, BOD, and FOG; for suspended solids, dissolved air flotation is the preferred method.
Then comes secondary treatment to keep the organic load and the associated BOD expense in check via biological means. For heavier wastewater, an anaerobic digester to produce methane or an aerobic system might be called for. If the goal is to strip salts and contaminants from reclaimed water, nothing does it better than reverse osmosis, provided the membranes have been pretreated to avoid fouling.
The Bottom Line for Food Plants
There is a case to be made for seeing the treatment system as an investment. The high-volume user will see operating expenses drop when they are no longer paying for fresh water or surcharges on heavy discharge. It is a cost-effective way for the food processor to put some savings in hand. Then there is the matter of keeping local authorities and their rules at arm’s length; an operator with a dependable system need not worry over fines.
The DeJong Way
We are not in the habit of offering an off-the-shelf solution for a reclamation project. Each plant has its own rhythm, and we build around that, whether it is the wastewater discharge or the treatment that follows, always within the letter of the law. Our process expertise is put to work in the design, so there is no risk to the product or the people, and the plant can have full faith in the system.
If an expansion or new line is on the table down the road, our counsel is to include water reclamation in the equation from the outset. That is the only way to be sure the system can stand up to the job and the water footprint.