First NPDES permitted Phosphorus Reduction Program in California Looks Promising

Short term trend in response to Phoslock Application

Aquatechnex biologists performed the first NPDES permitted Phoslock application in California the last week in April.  This lake system has historically had significant problems with cyanobacteria blooms.  This has had a dramatic impact on the use of this recreational facility.  Managing phosphorus pollution is one of the key methods of restoring lake systems impacted by cyanobacteria or blue green algae blooms.  A year of study led up to this application.  Phosphorus levels in the lake, the inlets and the sediments were sampled and evaluated.  A prescription based on removing free reactive phosphorus from the lake water column and capping the lake sediments was developed.  The Regional Water Quality Control Board was very interested in this process and developed an NPDES General Permit for the application of Phoslock to waters of the State.  With the permit in hand, Aquatechnex biologists mobilized the material and application equipment to the lake and performed this treatment the week of April 29th.  As this was the first such application in California, the permit requested that we document the results of this effort for both water quality parameters and for biota.  While this work is ongoing, the first phosphorus sampling is available.  As noted in this chart the Free Reactive Phosphorus has been reduced from levels that could drive cyanobacteria blooms to a near no detect level.  Total phosphorus is also trending down nicely.  This study will continue and we will post ongoing results here as well as present them in the appropriate venues.

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