Sustainable Designs for Water Systems
Sustainable food plant design and operation requires the thoughtful application of water supply and drainage systems. Using the proper amount of water for cleaning, along with efficient water heating systems will reduce your overall water consumption and energy usage.
The primary factor in designing for waste reduction is not only to take into consideration the efficiency with which natural resources are converted, but also the total consumption of the natural resources. For example, a low-pressure water cleaning system may be an efficient means for using water for cleaning, however total water consumption might be reduced if a high-pressure system were implemented.
Food processing facilities produce a copious amount of wastewater that must be drained and conveyed out of the facility. Our design team understands the need to remove water resulting from production, clean-up, and other facility activities.
Floor drains vary in design and purpose, so they must be chosen and placed appropriately for proper function. Food Plant Engineering’s design team knows how to space drains in your facility, what materials can hold up to foot/equipment traffic, and which drain types can endure the temperature and pressure of your cleaning methods. We can help you answer questions such as:
- Should you choose stainless steel, cast iron, or composite drain materials?
- Where is it appropriate to use an area/point drain, a trench drain, or a slot drain?
- How can you plan for the location of hub drains when you need an indirect drain for your equipment?
- Which options will best hold up to acid/corrosive waste streams or cleaning chemicals?
- What drains are the least likely to contain harborage points for listeria and other pathogens?
The materials, layout, and sizing of a facility’s sewer system must be properly evaluated for each food processing operation. The sewer pipe material should be selected to handle the sanitation chemicals, wastewater temperature, wastewater acidity, and physical cleaning methods employed (e.g., hydro-jetting and snaking). Options such as PVC, CPVC, and stainless steel should be considered depending on operational needs.
The layout of the process sewer system must specify the spacing of each drain along the floor surface for proper drainage sloping. In addition, a proper venting system must be designed to prevent air or vapor locks from occurring in the process sewer system and restricting flow. The slope should also allow for full drainage flow in the pipes. Sanitary and process sewers must be kept separate in a food processing facility with no connections inside the building.
Many piping materials are available for water and sanitation waste, and the selection depends on the specific needs of each operation. Copper is commonly used for both cold and hot water supply systems. Stainless steel is also an option for water with slightly corrosive properties.
PVC and CPVC for water supply should be used on a limited basis and only with proper supports. However, both PVC and stainless steel can be used for the supply of sanitizer and detergents when a central chemical delivery system is needed. Insulation for these systems, if required, is typically a closed cell elastomeric foam. Fiberglass may also be used on hot water and other high temperature lines. Jacketing can be PVC or stainless depending on the location of the piping and sanitation needs.
Water Heating Systems
Direct Gas Fired
Indirect Gas Fired
Direct Steam Heated
Indirect Steam Heated
Indirect steam uses both a storage tank and a shell-and-tube heat exchanger to heat water. Steam supplied from a boiler flows through a heat exchanger’s tubes, and the water is heated as steam passes through the shell on the outside of the tubes. The water is then circulated through the storage tank and held at the desired hot water supply temperature.
A variation of this system is a semi-instantaneous design: it delivers hot water by channeling the incoming cold water directly over the tubes of the heat exchanger in a controlled manner to maximize the heat transfer rate. With a semi-instant design, a large storage tank is typically not needed. However, this system requires a larger steam supply rate than its standard shell-and-tube counterpart.