The
Essex Junction Facility uses an Activated Sludge process
to clean the tri-town area's waste water.How Does Waste Water Treatment Work? |
The
Essex Junction Facility uses an Activated Sludge process
to clean the tri-town area's waste water.
Water
from homes and local small businesses comes to the plant on
Cascade Street.
This
combined wastewater flows into the HEADWORKS where screens
remove solids.
Next the aerated GRIT CHAMBER agitates
the flow and causes the large particles such as sand, grit, or
glass shards to drop out where they can later be collected.
The
wastewater passes into the two FLOW EQUALIZATION CHAMBERS
where it is mixed with other process waste streams. These
chambers add dissolved oxygen to the wastewater and keep the flow
heading into the plant at a constant rate.
In
the next step the wastewater is sent on to the two PRIMARY
CLARIFIERS, each 58 feet in diameter and 16 feet deep. Here
the flow slows and no further air is added. This allows gravity
to work at settling out the finer solids.
The AERATION
CHAMBERS are the first step in secondary treatment. These two
85 foot long chambers are 18 feet deep. On the bottom of the
chambers air is forced through pipes covered with ceramic
diffusers. The water is filled with millions of fine bubbles.
Microscopic organisms (bugs) utilize the oxygen to breathe while
they consume organic material in the waste water.
From
the chambers the wastewater passes into the SECONDARY
CLARIFIERS. The flow is slowed significantly here. Sludge is
separated from the liquid in these two 65 food diameter chambers.
Some sludge is wasted to the digester, while the rest is returned
to the aeration chambers.
The wastewater leaves the secondary clarifiers
looking much clearer.
In
the last building it is passed through a traveling bridge sand
filter. This step helps to remove finer particles and other
suspended solids from the wastewater. The water is then
chlorinated to remove bacteria.
The
flow moves into the CHLORINE CONTACT CHAMBERSwhere it will
remain for at least 15 minutes. These long narrow chambers give
the chlorine time to react with the water. In the last stages the
water is dechlorinated with sodium bisulfite.
The
final effluent is now ready to be recycled into the Winooski
River.
These
two sludge digesters utilize heat to decompose and stabilize
Biosolids. Dangerous bacteria are killed in the process and
methane gas is produced. The methane gas is used to fuel the
digester process heater. Any extra methane gas produced is flared
off. Plans are in place to recycle all the methane produced at
the plant to turn a generator and reduce electricity costs.
Odor is a problem for many wastewater treatment facilities. The main odor is from Hydrogen Sulfide. This is a colorless gas that has a rotten-egg smell. It can also be highly corrosive in a moist environment. (WEF Industrial Wastewater, May/June 1999). Our Wastewater Treatment Facility has taken steps to try to eliminate this problem. To prevent an odor problem in our sewer lines and at our pump stations a nitrate salt solution is added. A bacteria supplement is used separately and in conjunction with the nitrate salt, to inhibit sulfur reducing bacterial action. Flow equalization also helps to control odors at the plant itself.
Home Links Operators Facility History Internship
Opportunities Kids Only
Phosphorus Control Slide Show Nitrogen Control Slide
Show
Any
comments or suggestions concerning
the WWTF or the web page are greatly appreciated.
Feel free to contact us at:
ejctwwtf@sover.net
or phone James Jutras,
Chief Operator
at 802-878-6943
FAX 802-878-6948
2 Lincoln Street
Essex Jct, VT 05452-3685