Adding Redundancy To Lake Aeration

Connecticut Water Company (CWC) has multiple GZA designed and installed aeration systems in Shenipsit Lake.  Historically, these systems have maintained aerobic conditions within Shenipsit Lake at the managed depth, which in turn reduces internal loading of nutrients and reduces the potential for cyanobacteria blooms. An air line leak caused one of the systems to be shut down for a long period of time, leading to a problematic cyanobacteria bloom and associated treatment problems in the water treatment plant.

Challenge

CWC sought to improve the redundancy of there existing system by installing additional aeration capacity in the reservoir to prevent a repeat of the cyanobacteria blooms during the previous shutdown. 

 

Solution

The GZA team designed and installed a new layer aerator. Additionally, CWC installed a new compressor to manage the additional compressed air output needs. The results showed increased aerobic conditions at the target depth, resulting in a lower chance of internal loading of nutrients and potential cyanobacteria blooms. The increased capacity will be able to deal with potential system down time for maintenance or repairs without disruption operational capacity of the system.

 

Benefit

The benefits of a robust aeration system include:

• Keep greater portions of the water column aerobic
• Decrease of internal loading from lake sediments
• Reduces cyanobacteria density and bloom formation by nutrient reduction and water circulation (disrupts buoyancy regulation of bacterial).