Nitrogen Reduction
(Unless otherwise noted, all links are in Portable Document Format (PDF) and are less than 2 MB in size.)
History:
The 2008 Legislature appropriated $1.0 million for Phase 1 of an
anticipated 3-5 year project to develop passive nitrogen
reduction for onsite sewage treatment and disposal systems
(OSTDS). The 2010 Legislature appropriated $2.0 million
for Phase 2 of the study. The original 2008 legislative
direction identified three areas of concern: (1)
Quantification of life-cycle costs and cost-effectiveness of
passive nitrogen reduction treatment technologies in comparison
to more active technologies and to convention treatment systems;
(2) Characterization of nitrogen removal from effluent in the
soil underneath the drainfield and in shallow groundwater;
and (3) Development of simple models to describe the fate and
transport of nitrogen from onsite sewage treatment and disposal
systems. The study contract was awarded on January 2009 to
a Project Team led by Hazen and Sawyer, P.C., and was based upon
an anticipated budget of $5 million over a 3-5 year project
timeframe.
Current Status:
As of December 2011, the contractor, in coordination with DOH and the Department's Research Review and Advisory
Committee (RRAC) per 381.0065(4)(o) F.S., has successfully completed portions of each major task. These tasks
include prioritization of treatment technologies, construction of a test facility, completion of several sample
events of passive systems at the test facility and at field sites, and field sampling of the soil and groundwater
under OSTDS at residential homes throughout Florida and at the test facility. Work remaining for the 2011-2012
fiscal year includes: field sampling of passive systems and of the soil and groundwater under OSTDS at residential
homes throughout Florida and at the test facility; and continuing development of a nitrogen fate and transport model.
Further testing is required to confirm the results to date with field data and to provide data for development of
the engineering specifications for full system designs. The tasks associated with the final phase include completion
of monitoring and other field activities, performing additional testing as deemed appropriate by the Legislature, and
for final reporting with recommendations on onsite sewage nitrogen reduction strategies for Florida's future.
A
status report was submitted to the legislature and the governor on May 16, 2012. Additional funding has been
requested for fiscal year 2013-2014.
Specific progress by task is as follows:
| Task A |
The technology evaluation (Task A) included a total of 7 sample events at he passive nitrogen test facility, measuring
14 different analytes at 23 sampling points in 11 systems, as well as a final report on the pilot passive nitrogen removal
study at the Gulf Coast Research and Education Center (GCREC).
Current Status as of November 2011: All sample events at the test facility have been completed. Test
results are encouraging after 12 months of testing, showing a reduction in total nitrogen of over 95%, with a final effluent
concentration of 2.6 mg/L for several of the systems. |
| Task B |
For field testing of technologies (Task B), the quality assurance project plan has been finalized. Approximately four onsite
systems, utilizing various nitrogen removal technologies, will be installed at home locations throughout the State of Florida.
It is anticipated that four field system performance monitoring events will be conducted on these systems with the current
funding level, measuring 16 different analytes at 2-8 different sampling points. A life cycle cost assessment template will
also be completed.
Current Status as of November 2011: Eleven homeowners residing at locations across Florida have agreed to
participate in the study to date for Task B, and a final determination of which sites to use will be finalized in the near future.
Home sites have been identified in Wakulla County, the Wekiva area, and several other areas throughout the State. At least one
of the home sites will have a gravity-fed system installed. Construction has been completed for one system and sampling has begun.
|
| Task C |
To evaluate nitrogen reduction provided by soils and shallow groundwater (Task C), it is anticipated that a soil and
groundwater test facility will be constructed to show how groundwater fate and transport of nitrogen occurs in multiple
soil treatment unit regimes. Three sampling events will be completed with the current funding level, sampling six different
locations at each site, and measuring multiple parameters in the effluent, soil, and groundwater. The existing OSTDS mound
system at the University of Floridas Gulf Coast Research & Education Center (GCREC) in Wimauma, Florida will be instrumented
to study how nitrogen behaves in the soil and groundwater. Four sampling events that examine multiple parameters, will be
completed at the existing OSTDS mound system at GCREC with the current funding level. At least one soil and groundwater
monitoring event will occur at up to two home sites to evaluate nitrogen movement in the soil and groundwater in the field,
measuring multiple parameters in the effluent, soil, and groundwater.
Current Status as of November 2011: Testing of media components has been completed per 381.0065(4)(m) F.S.,
one tracer test has been completed, and construction of the soil and groundwater test facility has begun. Instrumentation
of the existing OSTDS mound system at GCREC has been completed and 3 sample events have been conducted. Six homeowners have
agreed to participate in the study to date for Task C and a final determination of which sites to use will be finalized in
the near future. Two home sites have been selected and instrumented and one sample event has occurred at each site. At one
site, the groundwater flow direction could not be delineated, and no additional sampling events will occur.
|
| Task D |
To address nitrogen fate and transport modeling for Task D, a final quality assurance project plan has been completed,
and the first steps will include the development of a soil model to show how nitrogen is affected by treatment in
Florida-specific soils.
Current Status as of November 2011: Work has focused primarily on soil modeling under the current budget.
Development of a soil model is underway and will be utilized to generate a simple tool for prediction of nitrogen removal
in the unsaturated zone of Florida soils.
|
Deliverables:
The resulting contract, March 2010
amendment, October 2010
amendment,
January 2012 amendment,
January 2012 renewal, and January 2012
amendment to the renewal split
the study into five main tasks:
-
Task A: Technology Evaluation for Field Testing: Review, Prioritization, and Development
-
Task B: Field Testing of Technologies and Cost Documentation
-
Task C: Evaluation of Nitrogen Reduction Provided by Soils and
Shallow Groundwater
-
Task D: Nitrogen Fate and Transport Modeling
-
Task E: Project Management, Coordination, and Meetings
Progress Reports to Legislature:
Please
contact the Onsite Sewage Program office with any questions or comments.
*Note: Most materials are in the Portable Document Format (PDF). You may need to download the free
Adobe Acrobat Reader to view the files.
This page was last updated May 16, 2012.
