BOD is the abbreviation for biological oxygen demand: the amount of dissolved oxygen required for microbial oxidation of biodegradable matter in water, usually measured over five days at 20 °C (BOD5). Food processors monitor effluent BOD to size wastewater treatment plants and meet discharge consents, since high BOD signals organic pollution that depletes oxygen in receiving waters. Reducing BOD at source by recovering product from waste streams saves treatment costs, and regulators set BOD limits in discharge permits that factories must meet through screening, biological treatment, and routine monitoring. It remains the standard yardstick of organic pollution strength in water management.