COMPOSITION AND WASTE LOAD OF UNIT EFFLUENTS FROM A COMMERCIAL LEAFY GREENS CANNING OPERATION

Abstract

Analysis of data on composite waste loads from canning of collard, turnip, mustard, spinach, and kale greens revealed no significant differences among the five types of greens. For unit effluents from the dunker washers, reel washers, and blancher, significant differences were found for solids load and total acidity. The most concentrated effluent was from the tumbler fillers. It contained 16% of the composite COD load and 1.3% of the total flow. Segregation and separate treatment of this effluent was recommened. Washing and blanching operations accounted for 77% of the composite COD load and 90% of the flow. The average composite waste load for all leafy greens was 20.2 ± 5.7 lb./ton COD, 8.5 ± 2.8 lb./ton BOD, 2.8 ± 1.2 lb./ton suspended solids, and 2,666 ± 427 gal/ton waste water. These values are less than one-half of those previously reported for wastes from spinach greens. These results suggest possible improvement for in-plant control of waste from leafy greens, and may also be relevant to the setting of effluent standards for the fruit and vegetable industry.