Discussion
339
to 20 mg/1 BOD and 30 suspended solids standard or thereabouts. The river has an average flow of 6
M^s, including an average effluent flow of M s. In storm time the quality deteriorates and the
DO is reduced to zero. The use of river purification lakes is proposed to settle suspended solids,
reduce the BOD and oxidise some soluble BOD. It would be about 500 acres in extent and retain the
average flow of the river for 4 to 5 days; storm flow would be settled for about 10 — 12 hours. Does
the author consider this approach is likely to be the most effective and economical for protecting the
river downstream of the lake from the effects of storm, assuming always that all continuously
discharged effluents are purified to 20:30 standards or better?
339
to 20 mg/1 BOD and 30 suspended solids standard or thereabouts. The river has an average flow of 6
M^s, including an average effluent flow of M s. In storm time the quality deteriorates and the
DO is reduced to zero. The use of river purification lakes is proposed to settle suspended solids,
reduce the BOD and oxidise some soluble BOD. It would be about 500 acres in extent and retain the
average flow of the river for 4 to 5 days; storm flow would be settled for about 10 — 12 hours. Does
the author consider this approach is likely to be the most effective and economical for protecting the
river downstream of the lake from the effects of storm, assuming always that all continuously
discharged effluents are purified to 20:30 standards or better?