A tanker carrying 800 kg of BOD waste accidently overturns and spills into a pond with a volume of 100,000,000 L. Assume the pond is completely mixed and has an initial DO of 6.4 mg/L and a temperature of 20°C. If the kd of the waste is 0.3/d and the kr of the pond is 0.2/d, what would the minimum DO of the pond drop to as the waste is degraded? Hint: you will have to use the equilibrium solubility equation for gases to determine the DOsat.