06-14-21- Presentation - Sewage Odor & Corrosion Control Programf
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ATTACHMENT B
Minutes 6-14-21
Need for Odor & Corrosion Control
• As sewage ages in the collection system, Hydrogen Sulfide (H2S) is produced
• H2S has a rotten egg odor and can be detected as a noxious odor at very low
levels
• H2S also reacts with moisture in the sewer lines to create Sulfuric Acid which
eats away concrete and metal
• Most odor complaints are associated with the WWTF and the Lift Stations
and gravity sewer lines that receive sewage from a Lift Station
• Significant damage has occurred at the headworks of the WWTF and several
Lift Stations, manholes & sewer lines
ATTACHMENT B
Minutes 6-14-21
Need for Odor & Corrosion Control
• Primary culprits are the Selva Marina Lift Station and the Buccaneer
Master Pump Station
• Both stations receive sewage from a large area that has been in the
collection system for a long time
• PU primary weapon to combat H2S is Hydrogen Peroxide (H2O2)
• H2O2 is injected at the Selva Marina Lift Station and downstream of the
Buccaneer Master Pump Station near the WWTF
• H202 reacts instantly to oxidize H2S to Sulfate which has no odor
Selva Marina
Forcemain System
ATTACHMENT B
Minutes 6-14-21
• Most of the sewage generated east of ABCC and
Sherry Drive flows to the Selva Marina LS and/or
to the 11th St LS
• Most odor complaints have been on Selva
Marina Drive between ABCC and Seminole Rd
and at the 11th St LS
• Currently, H202 is injected at this LS
• The injection point may be moved to the 11th St
LS as the collection system is improved
WAST EVVAT E R
TREATMENT
FACILITY
ATTACHMENT B
Buccaneer Master Pump=2'
Station Forcemain System
• Most odor complaints have been from the
WWTF where the forcemain discharges in to the
headworks
• Sewage collected in the Buccaneer Service
District (north of Dutton Island Road) mostly
flows to the Buccaneer Master PS
• H202 is injected in to the Buccaneer forcemain
near the WWTF for maximum effectiveness
ATTACHMENT B
Minutes 6-14-21
Selva Marina LS Odor Control System
ATTACHMENT B
Minutes 6-14-21
Selva Marina H2O2 Injection Program
• H2O2 injection initiated in June 2020
• There were numerous odor complaints prior to startup dating back many years
• After startup there have been Zero odor complaints
• H2S reduced from 66 ppm to 1.5 ppm, 98% reduction
• Using ^'460 gallons of H2O2 /month at a cost of $1,900/month
• Monthly cost for equipment rental = $825
• Total MRC = $2,750
• Total Annual Cost = $33,000
ATTACHMENT B
Minutes 6-14-21
Buccaneer H202 Injection Program
• H2O2 injection in to the Buccaneer FM initiated in December 2020
• No odor complaints received after startup
• H2S levels have been reduced to level where corrosion at the headworks should
not be a continuing concern
• H2S reduced from 72 ppm to 4.8 ppm, 93% reduction
• Using ^'1,065 gallons of H2O2 /month at a cost of $4,460/month
• Monthly cost for equipment rental = $825
• Total MRC = $5,300
• Total Annual Cost = $63,400
ATTACHMENT B
Minutes 6-14-21
Looking Forward...
• Continue to adjust & optimize H2O2 dosage to reduce costs
• Optimize H2O2 injection points to maximize benefits
• Current total cost = $96,300/yr
• FY 21/21 project cost w/ inflation =^'$125,000/yr
• Based on initial estimates, reduced maintenance costs should be
somewhat equivalent to annual odor/corrosion control costs
• With an older inefficient collection system and a WWTF in the heart of
the City, we recommend that this program be continued