Answer Happy

(b) A river has the following characteristics: Width = 24 m Average depth = 1.6 m Flow rate = 22 m/s Bed slope = 0.0035 0) What range of size of turbulent eddies would you expect to find in the river? [1 mark] (6) Using the bed shear velocity, determine estimates of the lateral turbulent diffusion coefficient and longitudinal dispersion coefficient for use in a model of the river. [2 marks] () Using the Peclet number, determine which type of distributed-parameter model is most appropriate to model a 10 km long stretch of the river. [1.5 marks] (iv) A wastewater treatment plant discharges effluent into the river from the riverside. Under steady-state conditions, what mass loading can be input to the system if a concentration of 20 mg litre cannot be exceeded at the outfall. Assume the concentration of effluent in the river upstream of the plant is 0.5 mg litrert and the plant discharge rate is 0.5 m s. [2.5 marks] (V) Two water intake pipes are located 1 km and 10 km downstream of the wastewater treatment plant outfall on the opposite side of the river. Calculate the steady-state concentrations of effluent in the river at both intake pipes and ascertain whether the plume will have fully mixed across the river by the time it reaches the first intake pipe [3 marks)