Cedar Creek Water Pollution Control Plant: Digester Tank Cleaning/Repair

Wantagh, NY

Nassau County DPW

Contract Value:
$15.3 Million

Project Dates:
2014 to 2019


Digester Tank Cleaning/Repair


The project consists of the cleaning and repair of nine digester tanks. Once a digester tank is drained and contents are removed, the tank is disinfected and inspected. Upon inspection, concrete repairs are made to the tank walls and footing. Steel within the floating cover is also inspected and then stripped of the existing paint, and localized repairs are performed and repainted accordingly. All piping and valves for each tank are to be replaced before the tank is put back into service. Once one tank is complete, Posillico is given another tank to repeat this process. In addition to the tanks, there are five heat exchangers that need to be cleaned and repaired. One of the heat exchangers will be removed and replaced with a new unit. There are also four methane gas compressors to be replaced with new units.


What makes this job complex is that 90% of the job is a permit required confined space. Any worker entering the tank or attic space must be confined space trained and certified. Another aspect of this project that increased the complexity was the discovery of lead paint on all of the digester covers. As a result of the potential hazards, air/gas monitoring must be done continuously as work is being performed to ensure safety of the workers. Further complications within these confined spaces are other potential hazards such as falls, low visibility, poor air quality, entrapment, and engulfment. The combination of all these potential hazards requires a very strict health and safety plan that must be continuously followed by all.


Posillico always tackles complex aspects of a project before they become problems. Whether this is done through our on-site training unit, our OSHA training program, an Activity Hazard Analysis or our daily tool box talks, Posillico will keep its workers aware and safe. We also ensure that the brightest minds are on site to plan exactly how each piece of the project can best be accomplished.