Lake Seminole Bypass Canal Alum Stormwater Treatment System
CLIENT: Pinellas County, Florida
CONTACT: Kelli Levy, M.S., CPM - Project Manager (727-464-4425)
PROJECT DATES: 2004-2009
PROJECT DIRECTOR: Dr. Harvey H. Harper, P.E.
PROJECT ENGINEER: H. Wayne Harper, P.E.
FIELD OPERATIONS SUPERVISOR: Chip Harper
LABORATORY SUPERVISOR: Vanessa Permaul
PROJECT BUDGET AND SCHEDULE
CONSTRUCTION COST: $1,879,872
CONSTRUCTION COMPLETION DATE: September 2009
ENGINEERING FEES: $495,000
During June 2004 Environmental Research & Design, Inc. (ERD) was selected by Pinellas County to perform a feasibility study and engineering design for an off-line alum stormwater treatment system to treat water transfers from the Bypass Canal to Lake Seminole. The treated inflow will improve flushing in Lake Seminole and provide a supply of clean water to the lake. Water is removed from the Bypass Canal at a constant rate of 10 cfs, treated with alum, and released into Lake Seminole. The floc is collected in a 600 ft long trough with an automatic floc removal system which discharges accumulated floc into the sanitary sewer on a daily basis.
The Phase I - Preliminary Design work efforts included:
- Evaluation of the historic and current project site conditions
- Hydrologic characterization and modeling of the contributing drainage basin areas
- Collection of canal water samples for laboratory evaluations
- Estimation of annual mass pollutant load reductions achieved in the treatment system
- Evaluation of the feasibility of using alum to maximize removal of total nitrogen, total phosphorus and total suspended solids while minimizing cost
The collected canal samples were evaluated in a series of laboratory jar tests to determine the optimum alum treatment dose and evaluate settling characteristics. The laboratory testing indicated that the alum treatment would significantly reduce effluent concentrations of nitrogen, phosphorus, and TSS. Floc collection is provided in an off-line linear trough.
Capital and O&M costs were calculated for the treatment system along with mass load reductions for total nitrogen, total phosphorus, and total suspended solids.
During the Final Design Phase, ERD prepared construction drawings, contract documents, technical specifications, and opinions of cost for the chemical treatment system. ERD was also responsible for obtaining permits from FDEP for construction of the project. ERD prepared and submitted 100% construction documents, including construction drawings, contract documents, technical specifications, and an opinion of cost. ERD also performed system operation and training and provided oversight for post treatment water quality monitoring.
RELEVANT WORK PRODUCTS
- Collection of canal surface water and laboratory testing to evaluate optimum chemical dose and floc generation
- Preparation of opinions of cost, annual O&M requirements, annual O&M cost, and 20-year present worth
- Estimated annual mass loading reductions for total phosphorus, total nitrogen and total suspended solids for the proposed alum treatment system
- Preparation of construction drawings, technical specifications, contract documents, and opinions of cost at the 60%, 90% and 100% completion milestones
- Preparation of the FDEP ERP Permit Application
- Construction administration, O&M and training
- Post-construction performance monitoring assistance