Grantee Research Project Results
2021 Progress Report: Environment and Community-Friendly Wastewater Treatment
EPA Grant Number: SV839486Title: Environment and Community-Friendly Wastewater Treatment
Investigators: Richardson, Ruth E. , Conboy, Lindsey , Milstein, Badyn , Chung, Yuxhin , Gangadhar, Ananya , Grasso, Dominic , Liu, Emily , Tentori, Egidio , Wood, Emily , Cullings, Ian , Matai, Kanha , Chen, Katrina , Frederick, Kyra , Blahut, Nina , Heryapriadi, Rafael , Fang, Shania , Starnes, Valentine , Ruan, Erica , LaGorga, Lydia , Aden, Mohamed , Ishfaq, Ahad , Chan, Winnie , Jackson, Jennifer , LaGorga, Lydia , Chen, Zachary , Bard, Francesca , Smith, Cara , Kaminsky, Isa , Aishe, Jahin
Current Investigators: Richardson, Ruth E.
Institution: Cornell University
EPA Project Officer: Page, Angela
Phase: II
Project Period: April 1, 2019 through March 31, 2021 (Extended to March 31, 2023)
Project Period Covered by this Report: April 1, 2021 through March 31,2022
Project Amount: $75,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2019) Recipients Lists
Research Category: P3 Challenge Area - Safe and Sustainable Water Resources , P3 Awards
Objective:
Untreated wastewater is a human health risk that contributes to water-borne diseases such as typhoid fever, cholera, and dysentery. Wastewater also contains excess amounts of nitrogen and phosphorus, which leads to eutrophication and anoxic conditions in bodies of water. The United Nations World Water Assessment Programme (2017) estimates that over 80% of the world’s wastewater is released into the environment without treatment, putting both ecosystems and human health at risk.
Conventional wastewater treatment methods used in the United States are not suitable for many small rural communities as they are expensive, energy intensive, and use mechanical parts that require a reliable source of electricity. The objective of this research is to develop a small-scale, decentralized wastewater treatment system that will be affordable and accessible to rural communities. This research focuses on Upflow Anaerobic Sludge Blanket (UASB) technology, which can remove organic matter from wastewater and be designed to operate without electricity. UASB reactors have the additional benefit of incorporating waste-to-energy technology by producing methane gas which can be harvested and burned as stovetop cooking fuel. Before release to the environment, the UASB effluent would be polished using an additional process, e.g. activated sludge tank, membrane biofilm reactor, trickling filter, constructed wetland, or lagoon for additional removal of nutrients and pathogens.
Phase I of research focused on developing a complete design for a gravity-powered UASB reactor, including a gas capture system and influent dosing system. Phase II research focuses on four main goals (with Completion status in bold in parentheses):
- Improving the influent dosing system and floatables removal (completed)
- Characterizing startup and performance of gravity-powered UASB reactors (first reactor done; second reactor startup is future work in final year of project)
- Determining appropriate options for effluent post treatment and biogas utilization (ongoing/current work with polishing via membrane bioreactors)
- Iterating designs and installing and testing a distributed UASB reactor in Honduras or Puerto Rico (current/future work)
Progress Summary:
In June 2021, we finally reinstalled the UASB post-Covid19 in a new location and resumed operation after pumping stored UASB granules into the reactor and starting the flow back up and feeding the tipping bucket (which dumps/pulses a four liter dose into the UASB. We improved the methods for measuring biogas production rates of the UASB and the methane content (fraction methane versus fraction carbon dioxide) of the biogas produced. Our team designed a simple tubing-based membrane bioreactor for delivery of oxygen at levels that support a diversity of functional groups of microbes – e.g. for the nitrogen cycle encouraging simultaneous methane oxidation from dissolved methane in the UASB effluent and partial nitritation/anammox to remove fixed N (organic N and ammonia and any nitrite or nitrate to N2 gas). Additionally, we started up UASB-polishing reactors (as a polishing treatment of UASB effluent that removes dissolved methane and fixed nitrogen (ammonia, organic N, nitrate) without stripping via bubbles of air/oxygen. Students have developed methods and acceptable standard curves for common water contaminants (COD, ammonia, GC based O2 and methane levels) and has established a wet test meter for monitoring of biogas production (Liters/day, e.g.). The biogas collection is in bags (Tedlar bags when doing biogas methane levels; otherwise tire innertubes (~70 Liters)) that would then be taken outside when full and flared.
Future Activities:
Comparing dosing schemes (pulse flow with the tipping bucket versus continuous flow) vis-à-vis performance (gas production, COD/BOD removal, phosphorus, nitrogen compound biogeochemistry, fecal indicators, pharmaceutical chemical conversions). We will distribute the UASB granules between the first and second reactor and compare them side by side but with one receiving the tipping bucket dosing (“pulse-flow”)and the other as continuous trickle of wastewater. We will increase flow rate starting with the current 10 hour retention time and decreasing to the “breaking point” on the low-end of retention time.
Field testing of the UASB reactor will be explored with Puerto Rican communities (Dr. Richardson will be taking sabbatical in Puerto Rincon Spring 2023 to advance AguaClara technologies pilot testing in communities in need across Puerto Rico, a US territory that lags behind in access to safe sanitation and water access. Hosting students in P.R. in January between semesters is planned. Though implementation may be delayed until after the end of this grant, we will make inroads for finding communities in Puerto Rico – which, though part of the US, lags behind the US states in water security.
Future work in UASB effluent polishing is starting to be upscaled from a 1 L benchtop tubing-based membrane bioreactor to a 20 L pilot test at the Ithaca WWTP. This would be the first full test of the two reactors in series (UASB feeding into the Membrane reactors) in treating real wastewater. The scale up of the reactor is a major future focus for the UASB team. Scale up challenges are in delivery of effective deliveries of oxygen to attain hypoxic conditions that will remove dissolved methane and nitrogen from the UASB effluent. We will work with the Ithaca WWTP lab to perform quality controls/quality assurance of data values. The manual for the UASB will be finalized and shared and the membrane reactor (parts, construction, and operation) added to the manual.
To date, the UASB research team successfully designed, fabricated, and installed a UASB reactor at the Ithaca Area Wastewater Treatment Facility (IAWWTF) for testing and bench scale simple membrane reactors for further treatment of UASB effluent. Significant design work was conducted to create an effective gas capture and metering system, a method to remove fats, oils, and grease that may accumulate on the water surface, and an intermittent influent feed system that minimizes preferential flow through the reactor.
Through the first months of monitoring the performance of the UASB reactor since restarting, we showed that the simple, pulse based deliver system was able, with a 10 hour retention time to remove ~50-60 % of the COD, and the polishing membrane reactor removed an additional 40% (including >99% of the dissolved methane) and 50%of the ammonia. The UASB reactor is stably producing 30-50 L per day of biogas.The team is eager to learn if this bed expansion causes enough mixing to prevent water from preferentially flowing through the same section of the granule bed. Ensuring a uniform flow of wastewater through the sludge granules is important, because it would increase the contact area of the wastewater with organic-consuming microorganisms, therefore increasing the efficiency of the reactor. This improvement would allow UASB reactors to treat higher flow rates of wastewater and would make UASB reactors more viable and accessible to small, rural communities.
Journal Articles:
No journal articles submitted with this report: View all 14 publications for this projectSupplemental Keywords:
wastewater treatment, Upflow Anaerobic Sludge Blanket (UASB) Reactor, Anaerobic Digestion, Scalable, Biogas, membrane bioreactorRelevant Websites:
AguaClara Cornell Webpage Exit , AguaClara UASB Github Repository Exit
Progress and Final Reports:
Original AbstractP3 Phase I:
Climate & Community Friendly Wastewater Treatment | 2018 Progress Report | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
- Final Report
- 2020 Progress Report
- 2019 Progress Report
- Original Abstract
- P3 Phase I | 2018 Progress Report | Final Report