by Nicole Capozziello
Published December 16, 2019
It’s a sunny spring day and a group of environmental engineering students are 19 miles south of UB’s North Campus, just inland from Woodlawn Beach State Park.
“There’s nothing like being out in the field. I love getting to talk to people about this project,” says Abdulrahman Hassaballah, a PhD student in environmental engineering, looking down a six-meter length of piping. He takes a sample from one of the pipes, and then does tests on it a few feet away.
It’s here – at the Southtowns Advanced Wastewater Treatment Facility – that this team of researchers, comprised of undergraduate and graduate students, led by Ning Dai and Lauren Sassoubre, assistant professors in the Department of Civil, Structural and Environmental Engineering, spearheaded a pilot program to explore a novel method of wastewater treatment. The two-year project was a collaboration between UB, the Erie County Division of Sewerage Management, and PeroxyChem, a Tonawanda-based chemical company, and was supported by the New York State Pollution Prevention Institute.
“When Ning approached us about a potential collaboration, I was thrilled,” says Joe Fiegl, Deputy Commissioner of the Erie County Department of Environment and Planning. The department operates seven sewer districts throughout the county, managing all the assets, including sewers, manholes, pumping stations, and treatment plants, within each district. The Southtowns plant, built following the Clean Water Act of 1972, has been operating since 1980 and serves a population of over 90,000 in the suburbs south of Buffalo.
“The county is always interested in exploring better solutions for sustaining water quality, protecting public health, and delivering the services that we provide,” says Fiegl. “And by working with UB, we can draw on expert resources in our own backyard.”
Dai has been making connections in the local environmental community since coming to Buffalo in 2014. On campus, she advises student clubs, and off campus, she facilitates student tours of local plants, and takes part in professional organizations. It was through one of these organizations, the Western Chapter of the New York Water Environment Association (NYWEA), a non-profit educational group that focuses on protecting and enhancing our water resources, that Dai met Fiegl.
“Joe is very forward-thinking – he’s a visionary,” says Dai of Fiegl, who asks questions like, how do we optimize the treatment plants to balance the environment, costs and people? How do we upgrade and maintain our facilities in a way that also improves environmental protection? And how can this all be achieved in the long-term?
“The fact is, we as a society – entities from little kids up through large corporations – produce a lot of pollution. And if this pollution is discharged into our environment untreated, we have major problems. What we do at our treatment plants is we take that pollution and eliminate it.
We produce clean effluent that’s protective of water quality and protective of public health,” says Fiegl. “But for us to be able to do that takes a lot of energy and money.”
Erie County has long disinfected the wastewater received at the Southtowns Facility using sodium hypochlorite, or chlorine, which is the most common method of wastewater disinfection in the United States. Effluent from the facility is treated using a specific dose of chlorine for the required contact time, before being discharged into Lake Erie through an outfall pipe. While chlorine removes pathogenic organisms, like enterococci and fecal coliform, it also produces byproducts that, if in too high of concentration, can be toxic to aquatic life.
In 2012, the Southtowns Facility received a new State Pollutant Discharge Elimination System (SPDES) permit that included new, lower regulations for the total residual chlorine allowable in wastewater effluent. This meant that Erie County, like many others across the country, would need to find a way to lower the chlorine levels in its wastewater. Simply using less chlorine was not a possibility – the bacteria levels would remain too high. This left three options: continue using chlorine and add sodium bisulfate, a dechlorination compound, at the end of the process, disinfect the water using UV radiation, or disinfect the water using peracetic acid (PAA), an emerging method in wastewater recycling. Working with PeroxyChem and Erie County, the UB team conducted a crucial test of PAA’s effectiveness here in Buffalo.
“The fact is, we as a society – entities from little kids up through large corporations – produce a lot of pollution.”
-Joe Fiegl , Deputy Commissioner of the Erie County Department of Environment and Planning
“Whenever we need to make major upgrades, we go through our full range of options,” says Fiegl. The department’s first step was to hire engineering consultants to provide a preliminary exploration of the three options, including the capital costs, such as the needed equipment and construction, and the ongoing and operational costs of each.
For UV radiation, there are costs associated with the new equipment, ongoing electrical costs, as well as the replacement of the UV bulbs. For chlorine and PAA, the major expense is the initial investment of and then the ongoing cost of the chemicals, another reason why finding the appropriate dosage is so important. When weighing options, Fiegl commented that looking solely at capital costs and ignoring ongoing operation and maintenance may adversely impact ratepayers.
“We don’t want to implement a short-term fix,” says Fiegl. “When analyzing and assessing the various options, it’s important that we look at the life cycle costs – the capital costs, plus the ongoing and operational costs over a 20-year period.”
In addition, Fiegl and his department consider potential short- and long-term costs to public health and the environment, such as each option’s carbon footprint. Referred to as “triple bottom line,” finances are evaluated along with the social and ecological impacts as part of a holistic analysis.
For sodium hypochlorite and PAA, this includes the electricity it takes to produce each of these chemicals, as well as the fuel costs of the tankers that truck them in.
When Erie County initially looked at the various options, the results of the consultants’ bench study on PAA were ultimately inconclusive, though it pointed to PAA being the most expensive of the three options. Enter UB researchers, who in partnership with PeroxyChem, began a pilot program, a larger scale test that would be more representative of what could be installed. “We set out to determine what dosage of peracetic acid would provide us with the needed kill on the bacteria,” say Sassoubre and Dai, who launched the program in 2016. They assembled a team of environmental engineering students: Christine Hart, Benson Chen, Jeremy Nyitrai, William Goodridge and Abdulrahman Hassaballah. The students worked closely with maintenance, laboratory and field operations staff at the Southtowns facility. (Editor’s note: Lauren Sassoubre has since left UB.)
“All of our partners and collaborators are amazing people,” says Hassaballah, who had previously done laboratory-scale testing on wastewater treatment.
“The success of this project would not have been possible without such a committed and wellrounded team.”
-Abdulrahman Hassaballah, Environmental engineering PhD student
“The success of this project would not have been possible without such a committed and well-rounded team.” This collaborative pilot scale study and its results serve as vital components of Hassaballah’s dissertation, which explores alternative disinfectants for wastewater treatment.
The team conducted the pilot study over a four-week period from May 14 to June 8, 2018 at the Southtowns facility. The pilot reactor was provided by PeroxyChem, with the main part comprised of PVC pipes that were 27.7 meters, or about 91 feet, in total length. The pipes were arranged in four six-meter sections connected by three 180-degree turns, also known as a “serpentine” pipe arrangement. Wastewater flowed at a flow rate of 20 gallons a minute through the reactor. The PAA solution was continuously pumped through a peristatic pump and mixed into the wastewater stream via an inline static mixer. The piping approximated a plug flow reactor and had six sampling taps along its length, each corresponding to a different contact time. The study also included the installation of a low-pressure UV lamp at the end of the pilot reactor on day 18.
Ultimately, the team found that PAA disinfection is able to meet the disinfection requirements. In the next phase, the consulting team will rerun the economic logistics associated with the life cycle costs of PAA and see how it compares to the other options. If deemed the most all-around effective, the benefits are numerous and wide-reaching; the adoption of PAA would not only provide safe, cost-effective wastewater treatment, but would also be a boon for local company PeroxyChem and establish Erie County as being at the cutting edge of PAA technology.
The potential benefits of using PAA in wastewater treatment may go beyond disinfection. Current treatment facilities are designed to remove bacteria but as more and more pharmaceutical compounds enter our environment, many are evaluating the oxidation properties of PAA as well, which removes other contaminants from the water. While pharmaceutical compounds are not regulated yet, some preliminary research has shown promise for PAA in removing some of these compounds.
“It was a pleasure working with UB. From students to professors, everyone was accommodating, professional and worked well with our staff,” says Fiegl. “As soon as the project was done, I said to Dr. Ning, ‘what’s next?’”