Partial or non-barriered oxidation ditch having momentum conservation and increased oxygen transfer efficiency

摘要

An improved barrier oxidation ditch is provided which has a channel portion for unaerated induced-flow and an inclined duct for aerated induced flow, whereby energy in the dammed-up momentum is more efficiently released. This induced-flow duct is inclided at 30 to 60 to the horizontal, preferably 45, and is disposed upstream of, downstream of, or alongside of the circulator/aerator in the intake channel. The induced-flow duct is preferably rectangular in cross- section and may have its downstream wall formed by the baffle if it is downstream of the circulator/aerator. The induced-flow duct is connected at its lower end to the discharge duct to initiate a combined-flow portion thereof. This combined-flow portion has an upper side which may be a thin wall or may be a much thicker aerator bridge. A baffle may be mounted downstream of the inlet of the induced flow duct for selectively restricting the amount of unaerated induced flow. The baffle may be fixed in position, or it may be slideably or swingedly adjustable. The combined flow portion provides prolonged bubble retention time at maximum hydraulic pressure, whereby the efficiency of oxygen transfer is increased.