Influence of Processing Methodology on the Strength of Wastewater From Canning Dry Beans

A study was conducted to determine the effect of soaking procedures on wastewater strength during canning of dried beans. Several soaking times (3, 6, 14 hr), temperatures (15°, 25°, 35°C) and soaking solutions (EDTA, citric acid, malic acid, H 2 O, deionized H 2 O) were studied. Wastewater strength was measured as Chemical Oxveen Demand (COD). Total Susoended Solids (TSS). and Total Phosphorus (TP). Reducing soaking times and temperature and the addition of EDTA reduced wastewater strength, while the addition of citric and malic acid increased wastewater strength. Navy beans generated more COD and TP than Pinto or Red Kidney beans. The wastewater strength from soaking Navy beans increased dramatically at 25° and 35°C as compared to 15°C. Significant interactions indicated that the type of soaking solution was of greater importance on Navy and Pinto beans than on Red Kidney.