3 Rivers Proud News - Winter 2021

Arletta Scott Williams



Diving into Plant Construction

Despite pandemic challenges, ALCOSAN employees continue to work 365/24/7 treating the region's wastewater. Oftentimes jobs like these are done behind the scenes with little fanfare. But we want to continue to pull the curtain back a bit and explain how some of the water treatment work gets done.

In this issue, we will share an update on the construction activities to increase the capacity of our wastewater treatment plant, how we continue to fund meaningful source control projects in partner communities, and not forgetting to fulfill our mission that includes caring for our community. While our focus is realizing the goals of the Clean Water Plan, I’m proud to say that we also are rallying around our community in impressive ways.

The ALCOSAN family always has had a big heart, and this past pandemic-filled year was no exception. With a commitment to safety, many of our employees found ways to reach out, dig deep and be charitable to our neighbors during such a difficult year. You’ll see some of the outreach in the story below.

In addition to following the dirty water trail, take a look at some of our plant expansion construction photos. These show that we are diving right in to adjust our footprint and ready ourselves for the future.

Arletta signature

Arletta Scott Williams
Executive Director

ALCOSAN Plant Expansion Aerial View of Plant before Construction



One of the more challenging and exciting pieces of ALCOSAN’s Clean Water Plan is the expansion of our wastewater treatment plant. Sitting on 59 acres that is bordered by the railroad on one side and the Ohio River on the other, ALCOSAN doesn’t have a lot of space to grow. But thanks to the ALCOSAN staff, we have a creative path forward.

Below are some highlights of ongoing construction at the ALCOSAN wastewater treatment plant. Check out the photos showing the first visible signs of change.

  • New flow meters were installed recently in the main pump station to help monitor the amount of wastewater entering the plant.
  • The north-end plant expansion has begun with the demolition of our sodium hypochlorite building, making room for a new final disinfection tank to be built starting mid-2021.
  • Construction of a new chemical building which will house the sodium hypochlorite and sodium bisulfite feed and storage systems. This will be built next to the new final disinfection tank.
  • Work on a new river wall is slated to begin in early 2021. The wall will be secured with king piles that provide a bulk of the wall’s structure. These piles will be anchored by tiebacks that will be drilled and cemented into the rock bed for stabilization. The wall surface will be made of approximately 1,000 feet of steel sheeting, viewable from the river, and back-filled from the plant-side.
  • Once the new river wall is constructed, aggregate stones, large rocks and boulders will be placed in a staggered fashion along the river bank below the wall to provide a foraging, security and resting habitat for macroinvertebrates and fish.
  • We also are looking forward to the addition of two new final clarifiers at the north end in 2024.
ALCOSAN Construction Demo Moorings and Diver entering river

The removal of mooring cells at the north end of ALCOSAN's wastewater treatment plant supports the Authority's Clean Water Plan expansion. Divers and other experts cut metal sheet piles away, preparing for the new river wall construction.
Sodium Hypochlorite Building razed

ALCOSAN razed the sodium hypochlorite building at the plant's north end, which had been used to disinfect flows for more than 20 years. Construction of a new final disinfection tank begins mid-2021.

Stay tuned for more updates! For the latest information and to learn more, visit our Clean Water Plan page.

Newsletter-Article-GROW Awards


ALCOSAN’s successful Green Revitalization of Our Waterways (GROW) program recently awarded $15.1 million in grant offers to 23 municipalities and municipal authorities for meaningful source control projects. These 27 projects, ranging from sewer separation to green stormwater infrastructure, are projected to remove 48 million gallons of overflow volume per year.

Three projects – Pittsburgh’s Wightman Park green stormwater infrastructure and two sewer separation projects in the Borough of Crafton – took advantage of the new funding cap with a combined award of $7,712,559 for the three. For a complete list of the awardees, please visit our GROW Program page.

Earlier in 2020, ALCOSAN released Controlling the Source, a scientific-based, area-specific evaluation of all types of source control that provides municipalities information on where projects can be completed that both are cost-effective and provide the most overflow reduction. Eight concepts identified in Controlling the Source were awarded funding in this round (Avalon, Bellevue, Brentwood, Carnegie, Crafton, Wightman Park, Rankin and Wilkinsburg).

Created by ALCOSAN in 2016, the GROW program’s first four grant cycles offered grants worth $28 million for 101 projects, leveraging another $25 million in municipal, authority and third-party funding. In all, those projects are expected to reduce the volume of overflows into the region’s waterways by nearly 140 million gallons.

Any municipality or municipal sewer authority within the ALCOSAN service area is eligible for GROW grants. The sixth phase will begin later this year, and ALCOSAN already is scheduling informational meetings to assist municipalities in the application process.

ALCOSAN Treatment Plant



As we rejoin the wastewater treatment journey from your place to ours, recall that trash and large solids were removed from the dirty water and prepared for landfill disposal. The remaining sludge, made of smaller particles, grease and scum, also were skimmed away for proper disposal.


Wastewater from municipal sewer systems flow to ALCOSAN for treatment, passing through this main pump station at a rate of 180,000 gallons per minute.

Although somewhat cleaner, there still is a lot of work to be done to finish the dirty water treatment journey. It’s now time for the secondary treatment, which some here call dessert time for naturally occurring bugs.


Once ALCOSAN removes trash and large solids from received wastewater, the secondary side of treatment begins by bringing biology into play.

Our expert inhouse operators determine precisely how to treat up to 250 million of gallons of dirty water each day. ALCOSAN’s eight aeration basins are filled with secondary wastewater that is mixed with diffused, compressed air. This is done to help maintain a healthy colony of microorganisms during this activated sludge process.


Wastewater is brought into contact with naturally occurring microorganisms that break down matter into harmless by-products. This is a close-up of a rotifer, one type of these helpful bugs.

The water flows through the tanks for four hours, with the air bubbles causing the bugs to roll and mix within the activated sludge. The microorganisms gobble up nutrients and break down remaining organic matter into harmless by-products.

Final clarifiers are an important part of wastewater treatment. Here, remaining activated sludge is settled out for proper disposal.

The secondary treatment process continues by moving the water through secondary clarifiers. Here, the microorganisms return to the aeration tank for some more munching, or they are pumped to the dewatering facility for disposal. This clarification process is distributed over 16 units and takes two and one-half hours to complete.


Treated wastewater spends about a half-hour being disinfected in chlorine contact tanks.

We now are more than half-way to our discharge destination. Next, the wastewater makes three passes through two disinfection chlorine contact tanks. Any remaining bacteria are eliminated with a potent disinfection solution of sodium hypochlorite, which is 10-to-15% chlorine bleach. Depending upon the flow rate, this important step can take up to 30 minutes to complete.

The dechlorinating process is monitored closely and is aided by bubble diffusers that help to neutralize remaining chlorine before the treated water is discharged to the river.

The last stage requires rigorous monitoring. Sodium bisulfite, used to dechlorinate the water to eliminate the formation of harmful biproducts, is added using coarse bubble diffusers.

The reclaimed water travels slowly through the tank channels. Some say that this phase reminds them of a lazy-river amusement park ride. Even the local ducks are known to stop in for a relaxing float now and again.

Since that first drop of dirty water entered the main pump station, the water has been traveling this journey between nine to 12 hours. The treatment process is complete and we’re ready for the big push. The force of gravity rushes the fully treated wastewater downward and out into the Ohio River at a rate of approximately 140,000 gallons per minute.

The treated water is discharged from the outfall to the Ohio River at a rate of approximately 140,000 gallons per minute, and the treated water is cleaner than what’s in the river.

It’s here that you can really see that we take our environmental stewardship responsibility seriously. Every day, we treat wastewater and return it to the Ohio River cleaner than the water in the river.

Although we were able to treat and reclaim 99% of the water, the remaining solids need to be handled appropriately. In an average year that adds up to a whole lot of tons of waste. The next chapter in our clean water journey will touch on how we efficiently draw energy from that waste.




ALCOSAN helps formal and informal education partners to network and share best practices through its Science and Environmental Education Advisory Collaborative (S.E.E.A.C.) quarterly workshop series.

S.E.E.A.C. offers teachers unique opportunities to gain information about real-work environmental and engineering applications related to water. These Scholastic Outreach workshops also offer teachers the chance to earn ACT 48 continuing education hours at no cost.

To meet with the safety demands of the times, ALCOSAN shifted to a virtual format for its teacher workshop. Their first session in the 2020-2021 series focused on adapting and applying hands-on student activities that could fit into virtual, in-person and hybrid classroom settings.

ALCOSAN Virtual Educational Programs

Teachers become the students during ALCOSAN’s virtual workshops like this one with the Science and Environmental Education Advisory Collaborative.

Educator participants were introduced to three activities: creating towers, solving mysteries and coding robots to work from a distance. While working through the activities, the educators discussed and discovered some of the best teaching formats for student learning within a variety of environments. Engagement was at a high level as teachers shared their own enthusiasm for sharpening virtual learning skills that play a critical role not only in our everyday lives, but especially during the COVID-19 pandemic.

The second workshop, Virtual Engineering, engaged teachers in hands-on challenges using the engineering design process. Service providers and teachers from nine districts and service areas joined in the learning.

Participants explored hovercraft, found simple machines in the objects around them, discovered how the natural world inspires innovation, and took on a fun challenge to build a better hoop glider.

Prototypes of hoop gliders were tested and redesigned by using basic problem-solving skills. There also was considerable enthusiasm when the educators moved to online CAD software to complete the assignment of designing a touch-free key to support COVID-19 safety practices.

The learning never stops! Share this with a teacher you know. Future workshops include a focus on technology and much more. Visit the ALCOSAN Scholastic Outreach and Educational Professional Development program.




The job we do at ALCOSAN is non-negotiable and essential to protecting public health; it’s a job that we do all day, every day, without exception. Even in the midst of a pandemic. While we take this responsibility seriously, our employees know how fortunate we are to continue working, and that we need to help those less fortunate.

During 2020, the COVID-19 virus put so many things on hold, but the ALCOSAN team enhanced its commitment to charitable outreach. The year started with our annual United Way campaign and Jeans Days for Tickets for Kids. Then our employees really stepped up to the plate, raising nearly $22,500 for the Pittsburgh Food Bank in our annual Purple Shirt Celebration.

Yearly, the Authority holds a Turkey Bowl fundraiser for the KDKA Turkey Fund to help make sure families have enough to eat. Usually the event includes a pot-luck lunch and a cornhole tournament. Of course, the pandemic nixed the normal activities, so our employees put their heads together and created a successful, socially distanced putt-putt fundraiser tournament. Proving extremely popular, the event raised $3,775, which was matched by PNC Bank for a total of $7,750.

Overall, the Authority’s employees donated approximately $46,500 in 2020, helping to ease the burden of the pandemic for those in need.

Clean Water Assitance Fund - www.dollarenergy.com

Did you know that ALCOSAN has a Clean Water Assistance Fund? This program for low-income homeowners who are served by ALCOSAN can help with your sewage bill. See if you qualify by visiting www.dollarenergy.org or by calling Dollar Energy Fund at 1-888-282-6816.