Preventing HABs with Innovative Aeration Technology

When monitoring and managing the health of a lake or pond, dissolved oxygen is one of the most important indicators of water quality. Dissolved oxygen refers to the level of free, non-compound oxygen present in water. It is an important parameter in assessing water quality because of its influence on the organisms living within a body of water; the vast majority of aquatic life needs sufficient amounts of oxygen dissolved in water in order to survive.

Pollutants, the decomposition of invasive aquatic weed growth, and algae blooms significantly reduce dissolved oxygen. The purpose of aeration in lake management is to increase the concentrations of dissolved oxygen in the water. Aeration systems achieve these water quality improvements by helping prevent stagnation of water, increasing circulation, disrupting thermal stratification which provides “through-column” mixing, and minimizes the occurrence of harmful algal blooms (HABs).

Princeton Hydro has been working with the Lake Hopatcong Commission and Lake Hopatcong Foundation to implement several projects aimed at reducing the impacts of HABs in Lake Hopatcong, including the installation of three innovative aeration systems in different areas of the lake. Funding for these projects have come from a NJ Department of Environmental Protection Water Quality Restoration HAB grant awarded to the Commission in 2020, with additional funding and support coming from the Foundation, Morris and Sussex Counties, and four municipalities that surround Lake Hopatcong.

Air Curtain Aeration System

Our team completed the installation of an air curtain system at Shore Hills Country Club in Roxbury Township in early November 2020. The system produces a wall of bubbles that provide the kinetic energy to push and deflect away floating cyanobacteria and other toxins trying to enter the waterway. Installed near the shoreline, the air curtain increases the movement of the water, making it more difficult for floating debris, pollutants, and HABs to accumulate near the shore and in nearby shallow water areas.


Nanobubble Aeration System
Image by: Moleaer Inc.

Image by: Moleaer, Inc.

Nanobubbles are extremely small gas bubbles that have several unique physical properties that make them very different from normal bubbles. Nanobubble aerators directly saturate the water with significantly more oxygen than traditional water aeration systems. These systems produce ultra-fine bubbles that are nearly invisible to the human eye. Unlike “traditional” aeration systems that push air bubbles to the surface in order to circulate the water and increase the dissolved oxygen levels, nanobubbles are so small that they remain within the water column for an extended period of time, directly oxygenating the water. Our team is scheduled to complete a nanobubble system install for Lake Hopatcong in the Spring of 2021.


Nanobubble Aeration System with Ozone

At Lake Hopatcong’s Lake Forest Yacht Club in Jefferson Township, our team installed a Nanobubble System with Ozone, which was completed in November 2020. This system generates ultrafine microbubbles (nanobubbles) containing ozone, which is used to disinfect water supplies and works to break down organic material in the water. These nanobubbles harness the unique biocidal power of ozone and place it into a safe delivery mechanism that is highly effective but also ensures human and environmental safety. The resulting ozone nanobubbles eliminate a wide range of polluting chemicals as well as herbicides, pesticides, and microbial toxins, which are all known causes of HABs.

The nanobubble technology is a relatively new strategy for preventing cyanobacteria blooms. Evaluation of the air curtain and both nanobubble systems in controlling and minimizing HABs in Lake Hopatcong will begin in Spring 2021. Our team will closely monitor the effectiveness throughout the 2021 season and provide detailed reports of our findings. Stay tuned for more info!

Increasing the dissolved oxygen levels in a pond or lake provides many benefits including improved water quality, healthier fish and plants, more efficient filtration, and reduced nuisance algae growth. Princeton Hydro has installed numerous aerations systems in waterbodies throughout the northeast. Contact us to determine if aeration is the right solution for your pond or lake: PHydro/LakeManagement.

Deadline Approaching for Municipal Compliance on NJ Stormwater Rule

March 2, 2021 is the deadline for New Jersey’s municipalities to comply with the new stormwater management ordinances laid out in the New Jersey Stormwater Management Rule (N.J.A.C. 7:8).

The New Jersey Department of Environmental Protection (NJDEP) revised the rule last year to now require construction projects to include green infrastructure in order to meet the three performance criteria that NJDEP sets forth for stormwater management. The new rule gives local governments an opening to revise their existing stormwater management ordinances to better manage flooding and improve compromised water quality.

The rule defines green infrastructure as, “a stormwater management measure that manages stormwater close to its source by: treating stormwater runoff through infiltration into subsoil; treating stormwater runoff through filtration by vegetation or soil; or storing stormwater runoff for reuse.”

The pre-existing rule required that major developments incorporate nonstructural stormwater management BMPs/strategies to the “maximum extent practicable” to meet their criteria. The amended rule not only gives specific suggestions for the kind of BMPs it’s looking for by adding a definition of green infrastructure, but it also makes those BMPs/strategies a requirement for compliance with the rule’s minimum standards. Also included in the rule are tables outlining the application of each type of stormwater BMP.

Another update to the rule is that motor vehicle surfaces are now incorporated into the definition of major development. The amended rule requires these motor vehicle surfaces to have 80% total suspended solids (TSS) removal in order to maintain water quality. These surfaces include standard pavement drive/parking areas and gravel and dirt drive/parking areas, according to the rule. However, the rule does not require water quality control for runoff from other impervious surfaces that are not traveled by automobiles, such as rooftops and sidewalks, or other paved walkway areas.

New Jersey municipalities need to comply with the new standards and the ordinances must be in effect by March 2nd, 2021. To make this transition a bit smoother, NJDEP released a revised Model Ordinance in Appendix D of the NJ Stormwater BMP Manual to act as a sample for municipalities to follow when adopting these new regulations.

The Watershed Institute also drafted its own Model Ordinance to help municipalities go beyond the updated rule and strengthen protections to benefit the environment. The Model Ordinance builds on the state’s baseline requirements with the following enhancements:

  • Reduced threshold definition for major development
  • Requirement for major developments to treat runoff from all impervious surfaces for water quality
  • Requirement for stormwater management for minor development over 250-square-feet
  • Stormwater management for redevelopment
  • The use of Low Impact Development techniques
  • Maintenance reporting requirements

At the end of last year, The Watershed Institute held a webinar about the state’s new Green Infrastructure rule. The webinar, attended by 240 people, included three presentations that provided a detailed look at the NJDEP’s rule updates and the steps needed for local governments to comply.

The presentations, given by the following green infrastructure experts, are available to view in full:

You can view the full webinar by clicking here.

 

At Princeton Hydro, we recognize the benefit of green infrastructure and we’ve been incorporating it into our engineering designs since before the term was regularly used in the stormwater lexicon. We’ve been following the rule amendments very closely, and, last year, we developed the following blog to help folks garner a deeper understanding of green infrastructure, interpret the rule updates, and break down the complexities of the stormwater guidelines:

Understanding The Updated NJ Stormwater Rule

If you have further questions regarding green infrastructure or stormwater utilities, we encourage you to contact us.