Q / 2: A city discharges 115000 m³/d of wastewater into a stream whose minimum rate of flow is 8.5 m/s. The velocity of the stream is about 3.2Km/hr, the temperature of the wastewater is 20 °C and that of the stream is 15 °C. The BOD5 at 20 °C of the wastewater is 200mg/l and that of the stream is 1mg/l. The wastewater contains no dissolved oxygen but the stream is 90% saturated upstream of the discharge. At 20 °C kj is estimated to be 0.3 day", and ký is 0.7 day". Determine the critical oxygen deficit and its location, also estimate BOD5 at 20 °C of the sample taken at the critical point. Use temperature coefficient of 1.135 for ki and 1.025 for k2, also plot the dissolved oxygen sag curve.