L-63N Canal Phosphorus Removal Via Maintenance Dredging
CLIENT: South Florida Water Management District (SFWMD)
CONTACT: Odi Villapando, Ph.D. (561-682-2936)
PROJECT DATES: January 2003-September 2004
PROJECT MANAGER/DIRECTOR: Dr. Harvey H. Harper, P.E.
DIRECTOR OF FIELD OPERATIONS: Chip Harper
LABORATORY DIRECTOR: Vanessa Permaul
PROJECT BUDGET AND SCHEDULE
PROJECT BUDGET: $75,000
FINAL COST: $75,000
PROPOSED SCHEDULE: 21 months
ACTUAL COMPLETION TIME: 21 months
During 2003-2004, ERD performed an evaluation for the SFWMD to quantify the existing accumulation of organic sediment material in the L-63N canal, located near the City of Okeechobee, and quantify the mass of phosphorus removed during the resulting dredging project. The specific work efforts performed by ERD were: (1) quantify the amount of phosphorus in water and sediments removed from the canal during the dredging project: (2) perform water quality monitoring prior to and during dredging operations to ensure compliance with Class III water quality standards and FDEP permit requirements; and (3) design and operate a chemical treatment system to reduce concentrations of particulate and dissolved phosphorus in the dredged water to 40 ppb or less prior to discharge back into the canal.
During the L-63N dredging project, approximately 52,000 yd³ of phosphorus-laden material was removed from the canal, returning the canal to its original design depth. The water-sediment slurry was pumped into a series of four linear containment cells located on District property. Pre-dredging sediment monitoring was conducted by ERD to define the depth of sediment accumulations and establish chemical characteristics of the existing sediments. A chemical treatment system was designed, constructed, and operated by ERD to maintain a TP limit of 40 ppb or less in final discharges from the treatment cells.
RELEVANT WORK PRODUCTS
- Evaluation of sediment accumulations of organic muck over a 1 mile segment of the L-63N canal
- Collection and analysis of sediment core samples to characterize sediment P
- Laboratory testing to evaluate the effectiveness of various chemical coagulants for reducing phosphorus concentrations in a simulated slurry solution
- Design, construction, and operation of a chemical injection system to treat the dredged slurry to meet established water quality goals
- Daily on-site field management of dredging operation and chemical treatment system
- Preparation of opinions of O&M costs for the treatment system, including present worth costs for phosphorus removal
- Preparation of Draft and Final Reports