Wastewater Treatment Preprocessing

Proper management of food processing wastes requires consideration of individual operations from harvest through waste disposal as integrated subunits of the total process. Every effort should be made to eliminate wastes and to avoid bringing wastes from the farm into the processing plant. Where possible, preprocessing should occur in the field, returning the organic materials to the land. In the processing plant, wastewater volume and strength should be reduced at each step. This principle applies to all food processing wastes, including fruit, vegetables, meat and poultry, and dairy.

Waste segregation within a plant is important in optimizing the least-cost approach to treatment. In a typical brewery (Figure 8.2.5), where 3% of the flow contains

FIG. 8.2.5 Source and relative strength of brewery wastes

59% of the BOD, it is less expensive to treat this small flow separately than to mix it with the entire plant waste flow. This is effective when a plant treats its own wastes or releases waste to a municipality with surcharges for high-strength waste.

Food processing wastes are amenable to biological treatment, and they frequently provide nutrients essential to efficient biological treatment. Although various waste treatment methods are available to the food processor (Figure 8.2.6) there is no simple guide for the most practical and economical method.

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