|
Seymour Phosphorus
Removal – Seymour, IN
Seymour’s collection and treatment facilities
were in need of upgrade and improvement. The treatment
facilities were originally constructed in 1957 and
expanded in 1976, with further upgrades in 1991. The
treatment plant was rated at 4.3 mgd average flow and
8.2 mgd peak flow. The plant experienced flows
exceeding the peak design flow rate capacity. This
excessive flow could be attributed to the rapid growth
in the area in recent years, wet weather flows into
combined sewers, and the presence of a high groundwater
table in a portion of the collection area. With the
proposed growth expected in the next 20 years and
effluent limitations, especially for ammonia and heavy
metals, expected to become more stringent, major
improvements at the plant were needed.
The new treatment facility can remove phosphorus in two
different ways. Standard chemical addition using iron or
aluminum salts to precipitate the phosphorus in
biological treatment phase. The second option is to
operate the outer ring of the oxidation ditch as anoxic
zone, which allows for biological phosphorous removal.
Milton Biological Phosphorus
Removal – Milton, WI
The Milton wastewater
treatment facility was the first treatment plant in
Wisconsin to remove phosphorus biologically in
anticipation of new limits for phosphorus. Full-scale
testing of biological phosphorus removal was put into
operation in December 1994. Milton had its compliance
schedule for phosphorus removal delayed in some part due
to efforts of the Rock River Partnership. The Milton
full-scale pilot plant operated in a A/O process with
Return Activated Sludge (RAS) denitrification flow
scheme. For this effort, the Wisconsin Association of
Consulting Engineers awarded the project a first place
prize in their annual design competition.
Because of recent and projected growth in the City, an
upgrade was required at the Milton plant. Construction
was completed in 2003 and included removal of the
primary clarifiers, conversion of the activated sludge
process to an extend aeration process with aerobic
digestion, and increased hydraulic capacity for an
average daily design flow of 0.625 mgd. The BPR system
was converted to the UCT process with an internal
nitrate recycle. The Milton plant is subject
to an alternative effluent phosphorus limit of 1.9
mg/L. Alum addition facilities were added for
additional removal of effluent phosphorus, if
necessary.
back to top
|
