top of page

How does the Marco WWTP compare to our neighbors?

Let’s consider three of the Collier County Wastewater Treatment Plants (WWTP): Ave Maria, Marco Island, and the City of Naples. The FDEP permits for these plants are available at The attached table summarizes the differences in the permits for these sewage treatment operations and the oxygen concentrations in these waterbodies.

The Ave Maria WWTP is called an Activated Sludge plant and does not target the removal of nutrients. Ave Maria is not even required to REPORT the concentrations of nutrients distributed in the reuse water. FDEP imposes no nutrient limits.

According to the Collier County Pollution Control Department (FY20 Collier County Surface Water Report), the Camp Keais Waterbody that contains the Ave Maria WWTP has deficient oxygen levels with Dissolved Oxygen (DO) of 0.9 mg/L. A waterbody's DO should generally be above five mg/L to be considered healthy. The Camp Keais waterbody is seriously impaired in oxygen.

Marco Island has a sewage treatment process called Modified Ludzak-Ettinger (MLE). This process removes nitrogen but does not remove phosphorus. The FDEP permit for Marco Island contains NO LIMITS to the number of nutrients in the reuse water. Marco is only required to “report” the nutrient concentrations in the reuse water.

Even if the Marco WWTP wanted to remove phosphorus, it could not do so - the equipment to do this does not exist in the Marco MLE plant. An upgrade of the Marco plant to Advanced Wastewater Treatment (AWT) would be required to remove phosphorus.

The oxygen in the Marco waterways has been declining for five years and, at 4.6 mg/L, is now routinely below the healthy level of 5 mg/L. The Marco waterways are currently regularly experiencing algal blooms, which deplete oxygen in the waterways

The City of Naples plant was upgraded to Advanced Wastewater Treatment (AWT). An AWT process removes BOTH nitrogen and phosphorus. The Everglades City WWTP was severely damaged during hurricane Irma and will be upgraded to AWT this year. The Naples Bay Dissolved Oxygen (DO) averages 6.0 mg/L, which is healthy.

The City of Naples WWTP meets the Florida Grizzle-Figg statute limits of 3 mg/L nitrogen and one mg/L phosphorus. The Grizzle-Figg statute was introduced in the 1990s as part of the restoration of Tampa Bay. This statute saved that estuary. Marco Island has been given an “agricultural” permit and is not required to comply with this statute.

Marco must upgrade the WWTP and stop dumping excess nutrients into the waterbody.


Nanette Rivera

Candidate for Marco Island City Council

67 views0 comments

Recent Posts

See All


bottom of page