What
does the future hold for wastewater treatment? This is the question I always
ask myself when I think about the technology
that is out there. When I was given the opportunity to observe
other plant’s technology, I jumped at the chance. I was the lucky person
to participate in the operator exchange
program between Massachusetts Water Pollution Control Authority (MWPCA[1])
and Connecticut Water Pollution Abatement Association (CWPAA[2]),
my home state’s wastewater organization. As this event only presents itself
once every year, I was not about to turn down this opportunity. I wanted to see
for myself what other technologies existed that we did not have yet and what
the future holds in our field of environmental protection.
Mike Foisy
of the MWPCA, contacted me and was asked what I wanted to see? I replied,
something new, innovating, and something I had not seen before! After a brief
discussion, Mike said he would do some
research and come up with an intriguing itinerary and that he did! On the first
day of the exchange Mike and I visited three very interesting plant’s located
on the Massachusetts coast, Wareham, Scituat, and Cohasset.
When we arrived in
Wareham, we
were greeted by Dave
Simmons, the Chief Plant Operator.
Dave first started us off by giving Mike and I the basic facts about his plant. The Wareham plant is an
extended aeration plant with a daily average flow of 1.6 million gallons per
day (mgd), with wet weather exceeding 2 mgd. Any flow over 1.6 mgd, is diverted
into equalization tank’s to be added at low flow times. The plant consists of a
headwork’s building, from there the influent goes directly into the extended
aeration tank where floating mechanical mixer’s are located. Here poly-alum
chloride is added for phosphorus removal. The mixed liquor then flows from the
aeration tank to the secondary settling tank. The secondary effluent flow moves
to the denitrification filters. At the denitrification filter’s, methanol is
added and the flow continues into sand filters that are similar to a rapid sand
filter for water treatment. From there, the flow goes through an ultra violet
(UV) light disinfection, and finally to the ocean!
After Wareham, Mike and I
proceeded north on Route 3 to Scituat to meet with the Chief Plant Operator,
Robert Roland. When Mike and I made
our way into the plant, we were greeted by Rob.
Rob first started off with the
licensing requirements of wastewater operators in the state of Massachusetts.
In Massachusetts, an
operator who successfully passes an exam obtains a “diploma” stating that then
can treat wastewater. However, every two
years an operator is required to get a certain amount of continuing education
credits (CEU’S), to maintain their licenses. This was quite interesting,
because the State of Connecticut
is considering this idea, but has yet to implement this requirement.
Rob went on to some facts about his conventional
activated sludge plant. The plant’s flow is 1.6 mgd with wet weather of 3.0
mgd. The plant contains an aerobic digester where sludge is also thickened.
During our plant tour, Rob pointed out
his nitrogen removal process area, denitrification filters with methanol
addition, a Trojan horizontal mount
U.V. system and a contact
chamber.
I asked Rob about the contact chamber and why it was covered.
He said the cover is due to duck’s swimming in the chamber, and using it as a
toilet and fouling up their fecal coliform test. That was the first time I had
seen this approach to keeping the ducks away. Now it was time to say good bye, Mike and I were now on our way up to Cohasset to see
a membrane flirtation plant, this would be the highlight of the day!
As we approached
the center of Cohasset, we stumbled across the entrance to the plant. If you do
not know what to look for, you will miss the driveway to the plant, I know, we
missed it twice. We stopped at the Cohasset Fire Station for directions, the
fireman pointed across the street and there it was, well hidden in this
community. As we pulled into the driveway, we ran into the Chief Plant
Operator, Richard
Nye who works for Veolia Water’s
North America Division[3] . Richard took us into his office and proceeded to
provide us some facts about this “unique” plant.
The Cohasset plant is a micro filtration plant
that uses membrane bioreactor (MBR) technology. The Cohasset plant uses Zenon
technology or what is commonly called ZEEWEED. MBR technology is used mostly in
small package plants to reduce the overall foot print of a plant when space is
an issue, as is the case in Cohasset. The plant’s flow of 400,000 gallons per
day (GPD) is about the maximum capacity for the MBR system because wet weather
flows are too much for the plant to handle on some occasion, but Richard and his staff are always prepared.
When Richard gave us the tour, I was very surprised at how
little space he had for a foot print to fit his plant. The plant itself consists of two small buildings and a holding
tank. The main building contains the actual treatment plant, while the smaller
building contains the blowers for the process. Richard
then showed us his UV system and his plant’s effluent. The effluent is the
cleanest I have ever seen. It was as clean as drinking water. I was very
impressed with this and his plant.
On Tuesday, Mike,
myself and two of his fellow coworkers were off to Deer Island Treatment Plant[4],
the second biggest plant in the United States
based on flow, located in north Boston, in the
town of Winthrop.
As we approached the entrance to the plant, iconic egg shaped digesters were
visible, but I could not see or smell the treatment plant tanks. I was
wondering where everything was. I though to myself did the cover it up and put
it under ground? My questions would soon be answered.
Round Building;
South System Pump Station to Nut
Island
Covered, Stacked
Primary Clarifiers directly behind Pump Station
Covered, Pure
Oxygen Aeration Tanks, Yellow Aerator Drives
Final Clarifiers
at the back of the photo
Upon our arrival, Charles Tyler,
or Charlie, greeted us at the security
gate. Once we parked, Charlie led us
to the administration building for an overview of Deer Island.
During the briefing, I received a copy of their Daily monthly report, which was
literally a small book. Deer
Island maintains a staff
of twenty people just to complete the report every month. This provides you an
idea of the size and complexity of this plant. My questions were about to be
answered of how, where and why Deer
Island is the way it is.
3,500 Horsepower
Motors for the North Main Pump Station, Total
of Ten Pumps
Charlie proceeded
to tell us about the stacked clarifiers, primary and secondary, the pure oxygen
aeration basins, the egg shaped digesters, the water turbine on the plant
effluent channel, and the diffuser field sitting on the ocean floor, nine miles
off the coast of Deer Island. I could go on
and on about Deer
Island but in brief, it
is like any other activated sludge treatment plant, just bigger in size from
equipment, to staff, to tank size. Deer
Island is the ultimate
place to visit and to see things on a much grander scale. The treatment plant
makes you feel like a Barbie doll in a human sized house
.
Egg Digester with
Sludge and Gas Holding Tank in the Background
90 Feet in
Diameter, 128 Foot Water level
12 Digesters @
3,000,000 Gallons each
Exchange Operator
Kevin Shlatz and Charlie Tyler at The Effluent Diffuser Memorial, 55 Total Diffusers, 53 Diffusers are active,
Located nine miles offshore.
My last plant of
my two-day tour was Upper Blackstone Water Pollution Abatement District (UBWPAD
6), located in Millbury Massachusetts.
This is where my host, Mike
Foisy works. The Upper Blackstone
treatment plant is a regional facility that handles surrounding towns and
cities. Blackstone is going through a $200 million
dollar upgrade. I was able to observe the largest secondary clarifiers in Massachusetts in
operation and one under construction. The Upper Blackstone is well on its way
to meeting the future needs of its customers.
Upper Blackstone
Treatment Plant, Primary Clarifiers and Aeration Tanks
156 ‘ Diameter
Final Clarifier, Largest in Massachusetts
After spending two
days touring different treatment plants of various sizes I learned many
different things and came away with many grand ideas. In our ever- changing
world we need to adapt to survive. One day we will have to re-use everything we
have on this planet including the wastewater we treat. It can be done and is
being done on smaller scale projects in different parts of the world and in our
own country. Also with only so much land to go around, we can build bigger treatment
plants in smaller foot prints than we have in the past. Sooner or later cost
will not be an issue and people will realize how vital wastewater treatment is,
and how the re-use of the secondary effluent will be vital to our growing
planet.
I would like to
thank Mike Foisy form Upper Black Stone treatment
plant for being an awesome guide through my three-day visit. I would also like
to thank my plant hosts and the towns they work in for hosting my visit. I
would like to thank my supervisor, Mike Emound,
and my Department head, Ed
Soper, for supporting my
participation in this program that afforded me this eye opening experience.
Everyone should be given the opportunity to participate in this worthwhile
program.