Anaerobic Wastewater Treatment, Summer 2013

Walker Grimshaw, Fanny Okaikue, Sushil Shanbhag

Abstract:

The summer 2013 wastewater treatment team was the first group in AguaClara to explore wastewater treatment for developing countries. The long term goal of the wastewater treatment research is to apply the governing concepts of AguaClara: Drinking Water to the sustainable treatment of wastewater. This involves small-scale treatment strategies that utilize minimal energy and treat water of greatly varying flow. The technology must be transparent and easily operable by an individual with minimal training. The research in the summer of 2013 attempted to initially design and construct multiple upflow anaerobic sludge blanket (UASB) reactors to better understand the operation of such an anaerobic technology. Additionally, anaerobic granules were studied for their makeup and metabolic processes. Throughout the summer, two reactors were constructed, one of which was modified for use with a support media, in this case sand. During operation, COD removal and gas production were monitored, both of which initially reached a high level before declining greatly until the reactors were abandoned. Each reactor was operational for approximately one month. Future research will work to improve treatment efficiencies and maintain a constant effluent quality through use of support media and further investigation of the metabolism of anaerobic bacteria involved in wastewater treatment.

Anaerobic Wastwater Treatment, Fall 2013

Ge Gao, Maithili Gokarn, Walker Grimshaw, Caitlin Rose McKinley, Liankun Zhu

Abstract:

Wastewater treatment is an important issue worldwide. Over one billion people across the world have connections to disposal methods for wastewater that remains untreated and instead is directly deposited into the environment, posing great human and environmental health risks. This research represents a union of the AguaClara program at Cornell and the Richardson Lab, with the long term goal of developing a gravity driven system for wastewater treatment and to characterize the general mechanism for anaerobic waste treatment. This team has and will operate under the principles of reducing human impact on the environment by effectively treating domestic wastewater before reintroduction to natural bodies of water and treating waste as a source of energy rather than a sink. Anaerobic treatment methods have been identified as the most appropriate for use in the global south due to their small footprint, low energy requirements, and slow rate of biomass growth. This semester six lab-scale reactors were constructed and operation begun to determine methods for controlling waste treatment efficiency and methane capture. Full scale reactors will use the methane produced within as an energy source to make the waste treatment an energy neutral or energy positive process. Of the six reactors, three were Anaerobic Fluidized Bed Reactors (AFBR) and three were Upflow Anaerobic Sludge Blanket (UASB) reactors. Though the reactors were only operated for a short period of time, they will continue to be operated in the future while data is collected for Chemical Oxygen Demand (COD) removal in addition to biogas production and specifically the methane levels within this biogas. One mathematical model was developed this semester to understand the fluidization characteristics of bio-granules as they develop on support media in the AFBR reactors. This model influenced the decision to use 0.1 mm quartz powder as a support media, and tests will be performed in the future to ensure this model corresponds with the fluid dynamics within the reactors. Microscopic techniques were investigated to determine their efficacy for elucidating the orientation and activity of microbial populations within the anaerobic granules. It is likely these techniques will be used in the future along with quantitative PCR techniques to understand the granules better. Other short term objectives for the study of wastewater treatment in the global south are to reach steady state operation of the reactors in terms of methane production and COD removal and exploration of new influent geometries to best fluidize the sand bed with such small support media.

Granular Sequencing Batch Reactor (GSBR) - Fall 2015

Amiel Middlemann, Nisarg Gohil, and Andrea Whalen

Abstract:

The AguaClara Wastewater team returned in Fall 2015 with two teams investigating both anaerobic and aerobic wastewater treatment reactors. The GSBR (Granular Sequencing Batch Reactor) team worked to expand knowledge about this potentially innovative and sustainable wastewater treatment technology. The goal of the Fall 2015 semester was to investigate potential improvements to reactor operation that would improve nitrogen removal. Furthermore, the team was interested in the stability of granular sludge under lower aeration requirements. One continuously operating reactor was inherited by the GSBR team at the start of the semester, which had been inoculated during the summer 2015 by visiting student researchers from Brazil. Lastly, the team considered the feasibility of this technology in implementation.

Results from monitoring ammonium and nitrate concentrations through several cycles of operation indicated that improvements to nitrogen removal did not result from operational changes that were installed. Conclusions from the semester included a decreased nitrification efficiency under lower aeration supply. However, granule stability and chemical oxygen demand (COD) removal remained under lower airflow conditions.

Upflow Anaerobic Sludge Blanket (UASB) - Fall 2019

Francesca Bard, Katrina Chen, Shania Fang, Kyra Frederick, Dominic Grasso, Ahad Ishfaq, Lydia LaGorga, Emily Liu, Cara Smith, Valentine Starnes, Emily Wood

Abstract:

Since spring 2017, the AguaClara Upflow Anaerobic Sludge Blanket (UASB) team has been working on designing and fabricating a gravity-powered wastewater treatment system for communities looking for an alternative to releasing waste directly into streams and rivers. During fall 2019, the team installed a Pulsated Flow Reactor (PFR) at the Ithaca Area Wastewater Treatment Facility (IAWWTF), fabricated a Continuous Flow Reactor, and began construction on a third reactor. Different design parameters in the reactors will help determine which features optimize reactor efficiency. Finally, the team conducted a set of laboratory tests in order to better characterize the influent quality, effluent quality, and site characteristics which may impact reactor efficiency.

Expanded Granular Sludge Bed (EGSB) - Spring 2016

Qiu Shen, Stephen Galdi, Zoe Maisel

Abstract:

The Expanded Granular Sludge Bed (EGSB) team was created to work within the wastewater subteam to design and run new, bench-scale, high rate anaerobic reactors. New reactors were designed to create a system with increased upflow velocity of influent, a fluidized bed, and decreased hydraulic retention time without decreased granular retention. Reactors were designed with simple operation in mind, with narrow modules in series rather than a single large reactor with recycle. The reactors were inoculated following abiotic testing of pumping rates, connection seals, and methane sensors. Immediately after inoculation, the granules began to form blockages and back up the reactor. Various forms of agitation seem to alleviate the problem, and automated solutions to the blockage problems has been proposed. In addition to blockages, the first module of the reactor was acidifying due to the low hydraulic residence time and relatively high specific organic loading rate. However, the following three modules were observed producing significant amounts of methane via the sensors, and at the end of an uninterrupted week of operation a COD test indicated about 40 percent total COD removal. With improved methane sensor calibration and a blockage prevention system, the bench-scale setup for high rate anaerobic treatment could potentially become a very versatile tool for testing the limits of anaerobic wastewater treatment and methane bioenergy reclamation.

UASB - Summer 2017

Zac Chen

Abstract:

No abstract included in report.

Conclusion:

The granule settling experiment from Spring 2017 has reached a conclusive result. Due to the high capture velocity relative to the upflow velocity, a full system of plate settlers will not be required of a full scale UASB reactor. There is no substantial impact from drastically decreasing capture velocity. Rather, a smaller settling apparatus such as a sloped exit weir can achieve the similar solid retention rates. More specifically, it was established that a 0.023 mm/s capture velocity can be utilized to increase effluent turbidity. It is with these conclusions, that the Summer 2017 UASB team recommend that future UASB teams move forward with the fabrication of the full-scale design.

UASB - Spring 2017

Zac Chen, Subhani Katugampala, Serena Takada, Linping Xu

Abstract:

Upflow Anaerobic Sludge Blanket (UASB) Reactors are a conventional primary wastewater treatment technology. Improvements to UASB reactors are required for the development of affordable small-scale wastewater treatment systems. This semester, the feasibility of two design modifications to conventional UASB reactors were explored: (1) a submerged gas capture lid (SGCL) to increase gas capture capacity, and (2) plate settlers to improve solids (granules) retention. The results of the SGCL prototype testing showed that the SGCL was gas-tight, which is not achieved in traditional UASB reactors. Additionally, granule settling tests demonstrated that plate settles do not improve settling capacity for small-scale UASB reactors. In the immediate future, AguaClara should fabricate a full-scale UASB reactor that incorporates the SGCL design and other design modifications detailed in the January 2017 EPA P3 Proposal. Eventually, AguaClara should explore post-treatment options to couple with the UASB reactor to develop a complete small-scale wastewater treatment system.

Fluoride - Fall 2017

August Longo, Victoria Zhang, Michelle Cheng

Abstract:

The Fluoride subteam seeksto dvelop a sustainavble, inexpensive fluoride removal system for implementation in upcoming AguaClara plants located in India. After earning an EPA Phase II grant for the Spring 2016 fluoride remocal reactor, the subteam continued to improve fluoride purification by testing lab-scale systems consisting of either a single reactor or two reactors in series. During the experimentation process, clay was incorporated into the influent stream to abate PACl buildup at the bottom of the reactors. As the subteam seeks to transplant their system to India, it is currently working to optimize fluoride removal by minimizing use of resources. Thus, the team is currently trying to eliminate the use of clay and lower PACl dosages by increasing upflow velocity and further redesigning its reactor. Initial tests suggested insufficient fluoride removal for potable effluent, but the team is looking to repeat its previous experiments using the summer 2017 High Rate Sedimentation subteam’s reactor design

Fluoride Auto - Fall 2018

Fluoride Automated System

Tigran Mehrabyan, Janak Shah, Samba Sowe

Abstract:

The Fluoride Auto subteam seeks to develop a sustainable, inexpensive fluoride removal system for implementation in upcoming AguaClara plants in India. Using the apparatus developed in previous semesters, the team continued running experiments testing how various concentrations of PACl affect fluoride removal. The team then analyzed the variability of the Langmuir isotherm generated by the summer 2018 Fluoride team. This analysis factored into the overarching goal of developing a model to predict an optimal coagulant dosage given both influent and target effluent fluoride concentrations.

UASB - Spring 2019

Cara Smith, Rafael Heryapriadi, and Jahin Aishee

Abstract:

For the past two years, the AguaClara Upflow Anaerobic Sludge Blanket Team, also known has UASB, has been in the works of designing and fabricating a pilot-scale Upflow Anaerboic Sludge Blanket reactor, a system which treats wastewater via anaerobic digestion, producing biogas in the process. UASB's design is completely gravity-powered and is a low cost solution to treating wastewater in rural communities that cannot afford typical wastewater treatment plants.

This semester, the UASB Team divided into the two sister teams of UASB Research (UASB-R) and UASB Design (UASB-D). UASB-R is focused on benchtop testing of a model UASB, researching ways to increase the reactor's efficiency, and test out designs in lab before being implemented by UASB Design.