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Cycle 7 (2018 Deadline)

Advancing anaerobic digestion in the upper Litani basin for industrial wastewater treatment

PI: Mahmoud Wazne (, Lebanese American University (LAU)
U.S. Partner: Haluk Beyenal, Washington State University
Dates: January 2019 - December 2022

Project Overview

7-101 Wazne
Photo courtesy Alyce Abi Shdid  
7-101 Wazne wastewater collection
Industrial wastewater collection - photo courtesy of Dr. Wazne
The project aims at advancing the use of anaerobic digestion treatment in the upper Litani basin and improving the treatment performance for organic industrial wastewater discharge. The main project objectives are to (1) demonstrate the applicability of anaerobic digestion and test co-digestion of combined waste streams, (2) enhance the anaerobic digestion treatment performance based on a newly developed integrated bio-electrochemical reactor technology, and (3) increase public awareness about anaerobic digestion for industrial wastewater discharge and train young researchers on this sustainable treatment option.

An innovative approach in this research is the use of co-digestion (combined substrates) of the industrial wastewater discharge. Realizing that mono-digestion (single substrate) may fail or achieve low yield, co-digestion of wastewater from multiple industries can provide a balance in substrate nutrients which will result in improved treatment results. Co-digestion of combined waste streams can also provide potential collaborative treatment modalities among the industrial wastewater generators resulting in the reduction of the required capital cost. Enhancement of the anaerobic treatment performance based on a newly developed integrated bio-electrochemical reactor technology is a cross-disciplinary integrative research project which will be utilizing and build on complementary expertise of the PEER team and the U.S. partner combining keen understanding of the electron transfer processes in the electrochemically active biofilms (sludge granules) and the environmental engineering expertise to transform microscale findings into a scaled up treatment.

The project is anticipated to raise public awareness about anaerobic digestion as a sustainable treatment for organic industrial wastewater discharge through a series of workshops and a best practices document on anaerobic digestion. The project will involve undergraduate and graduate students and prepare them for careers in the fields of anaerobic digestion treatment.

Project updates

During April-June 2022 reporting period, the microbial enrichment experiments have been ongoing using two different setups: anodic and cathodic bio-electrochemical reactors (BERs). The anodic BER experiment is ongoing (entering its third phase) while a cathodic BER was fabricated by the PEER research group and has entered its second phase. During this reporting period, both reactors were being monitored through sample extraction for COD, pH, oxidation-reduction potential (ORP) and VFA measurements. In addition, several electrochemical parameters are being examined which include current production versus time, counter electrode potential measurements, and cyclic voltammetry experiments to assess the electrochemical activity of the attached biofilm on the working electrode. Both reactors are being operated in batch feeding modes with a synthetic feed being prepared for each feeding cycle to replace the present medium. Adjustments are applied to each reactor once performance issues are encountered.

Dr. Wazne's research group has been conducting weekly Zoom meetings with Dr. Haluk Beyenal and his research group for data sharing of the enrichment data and to obtain his expert opinion on ongoing work.  The control run for the 20-L UASB has ended and is ready for the second run using the enriched biofilm obtained on the electrodes of the BERs as inoculum. Collected data from that experiment includes CH4 and CO2 quantities, reactor and effluent pH, effluent COD and VFAs and several UASB biomass characterization parameters (SVI and VSS/SS). Furthermore, two new 8-L UASBs are being fabricated from plexi-glass for future runs.

UASB DNA samples from the control reactor (before enrichment) were sent for 16S rRNA high-throughput sequencing on Illumina NovaSeq 6000, Novogene and the preliminary data was analyzed. DNA and RNA extraction Kits, PCR master mixes and primers were purchased for microbial communities’ analyses (from the anode and cathode biofilms as well as UASB granules after enrichment) and for the expression of genes associated with extracellular electron transfer (EET) in the bio-electrodes, prepared and stored for further analyses. Standard curves for qPCR were performed for all primers.
The first manuscript on co-digestion was published in Scientific Reports. Work is still ongoing on the second co-digestion paper where few co-digestion experiments are being repeated and daily monitoring of the associated reactors is ongoing.

June 17-22, 2022, Dr. Wazne gave a presentation on his project  at the 17th World Conference on Anaerobic Digestion held at the University of Michigan in Ann Arbor, Michigan,  (
In the upcoming months, Dr. Wazne's team will continue the enrichment experiment and use the enriched microorganisms for the acceleration of the startup of the UASB reactor. Dr Wazne expects to complete the repeated experiments for the second co-digestion paper and to have a draft manuscript ready for submission.

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