Food Processing Wastewater Treatment

food processing, dissolved air flotation

Water is a precious and essential resource in the food processing industry. Food production processes use and generate massive amounts of wastewater. The characteristics of the effluent varies depending on the production process, however, Enviro Concept provides a range of treatment solutions required to achieve discharge limits. One of those treatment process is the Dissolved Air Flotation (DAF) and it is a preferred treatment option for wastewater from food processes.

Why Are Grease Arrestors Not Adequate?

Several food-related or food manufacturing businesses use grease arrestors which may not be sufficient for treating their wastewater for discharge. Grease arrestors are the simplest devices for removal of oil and grease and suspended solids.  However, the effectiveness of the device can drop greatly due to a number of reasons:

  • Sustained periods of high inflow rate could reduce the retention time and the arrestors ability to separate contaminants
  • Poor aeration of wastewater could promote anaerobic decay of the contaminants and lead to foul odours and acidic discharge to sewer
  • Arrestors cannot retain significant amounts of suspended solids, oil and grease and some of it carries over to the sewer.

There are several trade activities where grease arrestors prove to be inadequate pre-treatment.

  • Industrial activities such as food manufacturing
  • Processes that generate discharges with high oil & grease and suspended solids concentration
  • Food courts and large food service based businesses

In such cases, a Dissolved Air Flotation (DAF) is recommended as an effective source of pre-treatment.

What’s in Food Processing Wastewater?

The wastewater from food processing contains suspended solids, BOD, COD, fats, oil-grease (FOG) and many other nutrients like Nitrogen, Phosphorous and Potassium. To separate large solids, a simple process of screening can be used. However, for plants that produce high amounts of FOG, a Dissolved Air Floatation unit is an effective way to remove FOG and suspended solids. Depending on the application, and especially for BOD removal, a biological treatment may be added to the DAF, and in our case, we would provide the DAF fitted with a Bioreactor.

The DAF and Bioreactor

Food processing wastewater may have higher loads, flows and higher temperature that may result in poor separation of contaminants from the wastewater. Enviro Concepts Dissolved Air Flotation (DAF) is highly efficient in treating this type of wastewater. At the heart of the DAF is a mixing tank that performs air dissolution process. Micro bubbles of air are introduced into the water. The bubbles combine with insoluble contaminants and lift them to the surface where they are removed by a scraper. For the full DAF process read our articles on the DAF Advantage and the DAF system.

Some food processes like dairy and cheese contain high BOD and therefore require either or both aerobic and anaerobic treatment. Enviro Concepts Bioreactors encompass a variety of mechanisms and processes using dissolved oxygen to promote growth of biological floc that substantially (above 85% BOD reduction) remove the organic pollutants. Our Bioreactors use proven and reliable suspended growth activated sludge process (i.e. CAS, SBR, MBR, etc) or attached growth biofilm reactors (e.g. trickling biofilter).
Download our DAF specification sheet for technical details. If you have questions on your food processing wastewater, DAF or Bioreactor, contact us.

washbay, wastewater, oil water separator