Grantee Research Project Results
2020 Progress Report: Environment and Community-Friendly Wastewater Treatment
EPA Grant Number: SV839486Title: Environment and Community-Friendly Wastewater Treatment
Investigators: Weber-Shirk, Dr. Monroe
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, 2020 through March 31,2021
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:
-
Improving the influent dosing system and floatables removal
-
Characterizing startup and performance of gravity-powered UASB reactors
-
Determining appropriate options for effluent post treatment and biogas utilization
-
Iterating designs and installing and testing a distributed UASB reactor in Honduras
Progress Summary:
Just prior to this project period, in March 2020, access to the IAWWTF was restricted to city employees, preventing team members from accessing the UASB reactor. At this time, the team was also informed that construction at the wastewater plant would block access to the influent wastewater connection-point needed to supply the UASB reactor with wastewater.
The UASB reactors were disassembled and are temporarily being stored at the IAWWTF. Additionally, the sludge granules were stored by IAWWTF personnel with intermitent feeding with wastewater to maintain their viability.
Because of our team having to pause completely in running the pilot test, we had a near-complete cessation of activities from April 2020 to March 2021. Some supplies were ordered and used during our team to validate chemical analysis that will be done by our team on the UASBs once we are able to re-access the WWTF and install the reactors. These included methods for measuring biogas production rates of the UASB and the methane content (fraction methane versus fraction carbon dioxide) of the biogas produced.
To date, the UASB research team successfully designed, fabricated, and installed a UASB reactor at the Ithaca Area Wastewater Treatment Facility (IAWWTF) for testing. Significant design work was conducted to create an effective gas capture 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, the team learned that warm temperatures may be a critical component to shortening the startup phase of reactor operation. The team also observed that the intermittent influent feed system causes the height of the sludge bed to expand approximately 5 cm when water is pulsed into the reactor. 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.
Future Activities:
When access to the Ithaca Area Wastewater Treatment Facility (IAWWTF) resumes post-Covid and construction shutdowns, the pulsed-flow UASB reactor will be reinstalled at the plant and the sludge granules will be allowed to reacclimate and grow. Meanwhile, the second UASB reactor (fabricated with a continuous-flow influent system) can be installed at the IAWWTF to directly compare the performance of each influent system. The reactor effluent will be regularly tested for chemical oxygen demand (COD), nutrients (especially ammonia and phosphorus), and fecal coliforms. The effluent quality of the pulsed-flow UASB reactor and continuous-flow UASB reactor will be compared to IAWWTF performance to determine the efficacy of gravity powered wastewater technology against conventional designs. UASB start-up performance, effluent quality tests results, and biogas production rates will be used to inform appropriate options for effluent post treatment and biogas utilization.
Additional literature review and design iterations may be needed to understand how site-specific characteristics in rural Honduran villages will affect the efficiency of AguaClara’s UASB reactors. For example, the small size of the villages which will be employing AguaClara reactors introduces a highly variable organic loading rate which may disrupt the reaction kinetics of a UASB reactor. Field testing of the UASB reactor will be conducted in Honduras in partnership with Agua Para el Pueblo (APP), a non-governmental organization working on water and Sanitation, and AguaClara Reach, a not-for-profit working towards globalization of AguaClara Cornell technologies. However, this will only be possible with a no cost extension on the grant, given the 12+ month pause in the work during the Covid 19 shutdown. Because it is not possible to fake wastewater (synthetic wastewater made with, e.g. dog food and milk powder) we are forced to wait until we again can access the WW treatment facility to restart the reactors.
References:
WWAP (United Nations World Water Assessment Programme). 2017. The United Nations World Water Development Report 2017: Wastewater, The Untapped Resource. Paris, UNESCO.
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, BiogasRelevant 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
- 2021 Progress Report
- 2019 Progress Report
- Original Abstract
- P3 Phase I | 2018 Progress Report | Final Report