The Carmel Wastewater Teatment Department has begun to implement energy-efficient initiatives throughout its facilities. Some of these initiatives include:
Solar Panels (Energy Recovery)
A solar array was installed in autumn of 2020, south of the Hazel Dell lift station (Carmel’s largest lift station and immediately precedes the WWTP). The array consists of 1,098 365W panels and is capable of outputting 400.8 kW DC power. Each year, the solar array is expected to put out 557.8 MWh of energy (enough energy to supply 66.8 homes with electricity for an entire year). The energy recovered from the solar array will be used to supplement power at the Hazel Dell lift station. Although we don’t have sufficient data yet, we estimate that approximately one third of the lift station power demand will be supplemented by the solar array.
Forced Air Recovery (Energy Recovery)
In 2019, we repaired a 150-foot segment of the forced air line between our blowers and our aeration tanks. Each of our ten (we only had 10 in 2019) aeration tanks required approximately 400scfm of forced air. Despite the demand for 4000scfm, the meters on our blowers consistently totaled an output of around 5200scfm. Also, there were indications that air was escaping the line between the blower building and the aeration tanks; water would bubble out of the pavement/ground at numerous locations when it rained.
We excavated approximately 150 feet of the 20” line between the blower building and the aeration tanks and determined that the bell joints were leaking at nearly every junction. Many of the joints were rehabilitated with new gaskets, but there were eight joints that had to be cut out and replaced with 20” repair clamps.
The project took the entire month of March 2019 to complete. Since the segment was repaired, we have been consistently equating an output of approximately 4000scfm from the cumulative blower readings. The demand readings out at the aeration tanks are significantly closer to the output readings from the blower building and we are saving approximately 1000-1500scfm (the equivalent to three aeration tanks-worth of forced air demand or 30% energy savings).
Lighting Upgrades (Energy Recovery)
Approximately 75 percent of our outdoor lighting has been incorporated into a PLC to turn on at dusk and off at dawn.
Approximately 75 percent of our indoor lighting throughout the WWTP has been updated to save energy:
Maintenance Bldg.
Installed (15) new LED wallpacks
Occupancy Sensors placed on all lighting
Bio Bldg.
Replaced (2) 2x2 surface mounted area lights (not highbay) w/ LEDs
Replaced (1) wallpack by south door w/ LED
Replaced (3) outdoor wallpacks w/ LEDs
Replaced (3) highbays w/ LEDs
Replaced (5) highbays w/ LEDS
Control Bldg.
Replaced (1) surface mount fixture w/LED; add fixture mounted occupancy sensor
Installed wall switch occupancy sensor
Replaced (4) 2lamp T12 surface mount fixtures w/ LEDs
Replaced (14) surface mounted T12 fixtures w/ LEDs
Installed (8) screw in LED bulbs
Replaced (1) 2’ Vanity light w/ LED; Installed (1) wall switch occupancy sensor
Replaced (3) surface mount 2 lamp fixtures w/ LEDs
Replaced (3) wallpacks w/ LEDs
Added (2) new LED wallpacks
UV Bldg.
Replaced (4) wallpacks w/ LEDs
Centrifuge Bldg.
Replaced (1) wallpack w/ LED
Blower Bldg.
Replaced (3) wallpacks w/ LEDs
GBT Bldg.
Replaced (5) wallpacks w/ LEDs
Galleys
Replaced (3) wallpacks w/ LEDs
Site Lighting
Replaced (14) 360* area pole lights w/ LEDs