Oxidation ditches tend to operate in an extended
aeration mode consisting of long hydraulic and
solids retention times which allow more organic
matter to break down. Treated sewage moves to the
settling tank or final clarifier, where the biosolids
and water separate. Wastewater then moves to
other treatment processes while sludge is removed.
Part of it is returned to the ditch as RAS, while the
rest is removed from the process as the waste
activated sludge (WAS). WAS is wasted either
continuously or daily and must be stabilized prior to
disposal or beneficial reuse.
APPLICABILITY
In general, package treatment plants are applicable
for areas with a limited number of people and small
wastewater flows. They are most often used in
remote locations such as trailer parks, highway rest
areas, and rural areas.
Extended aeration plants