Goel, Ramesh

Dr. Soklida Hong is a process Engineer at Hazen and Sawyer. He graduated with a Ph.D from the University of Utah in 2023. Co-Speaker Dr. Ramesh Goel is a professor of environmental engineering and microbiology at the University of Utah. He researches in nutrient removal, environmental microbiology, granular sludge process and virology.

Titles from this speaker

Description: Anoxic Granular Activated Sludge Process For Simultaneous Denitrification and...

Anoxic Granular Activated Sludge Process For Simultaneous Denitrification and Perchlorate Reduction: Process Performance and Anoxic Granulation Strategy

Abstract

Introduction
Granular sludge (GS) is an emerging biological wastewater treatment technology that is gaining world-wide attention due to its high rates of removal of both nutrients and recalcitrant organic matter from wastewater [1]. Of the various types of GS, anoxic GS (AxGS) is the least studied when compared to aerobic GS (AGS) and anaerobic GS (AnGS), where thus the formation mechanisms of AxGS are even more ambiguous. Anoxic granules comprising microbial communities mediating anaerobic ammonium oxidation (anammox) represent the bulk of previous literature on AxGS. However, AxGS bioreactors exclusively operated for denitrification have received less academic inquiry. Multiple studies have reported GS formation under denitrifying conditions [2]â€“[5], however, the complete characterization of the anoxic granulation process was not reported in these studies and thus the formation mechanisms of denitrifying AxGS still remain unclear and subject to debate. Therefore, this study seeks to characterize the anoxic granulation process under denitrifying conditions with perchlorate present as a competing electron acceptor to infer possible formation mechanisms and assess the temporal variation in biomass characteristics as the loose flocs compact into dense microbial aggregates. Microbial ecology was also assessed to determine the temporal distribution in phylotypes as anoxic granulation ensued.
Objectives
The main objectives of this study include:
(1) bioprocess optimization for concurrent denitrification and perchlorate reduction;
(2) characterizing the anoxic granulation process; and
3) to study the microorganisms comprising the AxGS biomass.
Significance
Findings from this study will contribute to the advancement of AxGS process bioreactors by demonstrating at the lab-scale the application this biotechnology.
Status
An AxGS process bioreactor has been operational for over 350-d, where dense anoxic granules have been cultivated. Bioprocess optimization has been executed, resulting in the consistent removal of >99% of the influent perchlorate and nitrate, while concurrently oxidizing >90% of the influent COD.
Methodology
A Plexiglass bubble-column bioreactor (2.625' diameter, 27' height) was fabricated to cultivate anoxic granules. The reactor was seeded with a mixture of hypersaline lake sediments, river sediments, anaerobic digester sludge solids, and aerobic activated sludge solids, previously enriched for denitrifying and perchlorate reducing organisms. Enrichment of perchlorate-reducing and denitrifying organisms was performed by providing perchlorate and nitrate as electron acceptors along with acetate as the electron donor in a basal medium described by Song et al. (2019). The anoxic granulation process was characterized through a combination of sludge settling analyses, solids concentrations, extracellular polymeric substance (EPS) extraction and analyses, microscopy, and microbial methods. Complete cycle analyses were conducted so that specific rates could be expressed. Microbial ecology of the AxGS biomass was characterized by high-throughput 16S rDNA amplicon sequencing as described by Stein et al. (2021). All anions were quantified using a Compact 930 IC Flex ion chromatograph (IC; Metrohm, USA). COD was quantified according to standard methods [8] and dissolved organic carbon (DOC) was quantified using a Shimadzu, TOC-V Total Organic Carbon (TOC) Analyzer (Shimadzu, USA). Findings Reactor Performance The overall performance of the AxGS bioreactor in terms of perchlorate, nitrate, and COD removal efficiencies, as well as chloride accumulations in the effluent, is summarized in Figure 1. The AxGS biomass efficiently reduced both the influent perchlorate and nitrate, while simultaneously oxidizing the influent COD. Average perchlorate, nitrate, and COD removal efficiencies have been 97.3Â±7.2%, >99.9%, and 90.1Â±3.07%, respectively. Average chloride accumulation in the effluent has been 153Â±23.7 mg/L, which is representative of an 80.3% (mol/mol) molecular conversion of the influent perchlorate to chloride. The initial mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) concentrations in the bioreactor were 1.09 g/L and 0.93 g/L, respectively. The biomass concentrations in the reactor steadily increased until reaching an average steady-state MLSS and MLVSS concentration of 3.11Â±1.15 g/L and 2.76Â±1.01 g/L, respectively, while maintaining a solids retention time (SRT) of 20-d. The 5-min sludge volume index (SVI5) of the AxGS biomass rapidly decreased in the first 150-d of reactor operation as the loose flocs gradually transformed into dense microbial aggregates. The SVI5 stabilized at a steady-state value of 24.9Â±11.7 mL/g. Both the specific protein and carbohydrate content of the EPS comprising the AxGS biomass steadily increased as the floccular biomass transformed into compact aggregates. Additionally, the protein fraction of the EPS became >90% as the anoxic granules matured and reached steady-state. Figure 1 also displays the results of a complete cycle analysis conducted over a standard reactor operational cycle under steady-state conditions. Nitrate was reduced to below detection 6-h into the cycle, where specific reduction rates of 6.12Â±1.68 mg NO3-N/g VSSâ€¢h were recorded. DOC became limiting 6-h into the cycle, where specific oxidation rates of 8.60Â±2.66 mg DOC/g VSSâ€¢h were recorded. Perchlorate was reduced to below detection before the effluent was withdrawn from the reactor, where specific reduction rates of 8.62Â±2.36 mg ClO4-/g VSSâ€¢h were recorded. Specific chloride production rates of 2.18Â±0.60 mg Cl-/g VSSâ€¢h were also recorded. Microscopy Figure 2 displays micrographs of the AxGS biomass captured throughout reactor operation. Initially, the biomass was comprised of loose flocs consisting of a dispersed web of EPS. The loose flocs then gradually underwent compaction until irregularly-shaped, distinguishable anoxic granules were observed on reactor operational day 97, where the EPS matrix became compact and smooth. The anoxic granules then became much larger and more compact, while also taking on a more symmetrical, spherical shape starting on reactor operation day 146. The EPS matrix of the granules became slightly rougher starting on reactor operational day 146 and remained that way. Microbial Ecology Figure 3 displays the taxonomic classification at the phylum (panel 'a') and genus (panel 'b') level for the microbial community comprising the AxGS biomass throughout reactor operation. At the Phylum level, Proteobacteria (94.1-98.2%) were dominant at all sampling events. Minor phyla identified were Acidobacteriota (0.2â€“1.54%) and Bacteroidota (0.43â€“4.74%). At the genus level, Dechloromonas (49.5â€“90.6%) and Azospira (3.16-40.8%) were the clear dominant genera throughout reactor operation, both of whom have members known to be perchlorate reducing and denitrifying organisms [9]â€“[11]. Minor genera identified were Holophagaceae (0.01-1.33%), Lentimicrobium (0.25-4.16%), Dechlorosoma (0.36-9.17%), Denitratisoma (0-5.46%), and Thauera (0.35-6.44%).

A completely sealed, bubble-column, sequencing batch bioreactor was initiated in this study at the laboratory-scale for the cultivation of granular activated sludge under anoxic conditions with perchlorate and nitrate present as competing electron acceptors. A short settling time (2-min) in concert with a feast-famine feeding regime led to the rapid cultivation of anoxic granular activated sludge (AxGS). Perchlorate and nitrate removal efficiencies >99.9% on average were recorded for over 500-d

SpeakerGoel, Ramesh

Presentation time

08:30:00

08:55:00

Session time

08:30:00

09:30:00

TopicIntermediate Level, Industrial Issues and Treatment Technologies, Microconstituents and Contaminants of Emerging Concern (Non-PFAS), Research and Innovation

Author(s)

Goel, Ramesh

Author(s)Nathaniel Stein1; Aditi Podder 2; Ramesh Goel1

Author affiliation(s)Department of Civil and Environmental Engineering, University of Utah, Salt Lake City, UT1; Brown and Caldwell, Houston, TX2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2022

DOI10.2175/193864718825158487

Volume / Issue

Content sourceWEFTEC

Word count18

Description: Combination of EBPR, Endogenous Denitrification, Partial...

Combination of EBPR, Endogenous Denitrification, Partial Nitrification/Denitrification and Anammox to Achieve Cost-effective Nutrient Removal

Abstract

To address the problem of eutrophication in the marine environment caused by excessive nutrient release and meet stringent nutrient discharge limits (e.g., TIN < 3 mg/L), a costeffective BNR (biological nutrient removal) technology is needed for equipping coastal wastewater treatment plants (WWTPs) with nutrient removal capacity. This pilot work was aimed to demonstrate how a conventional “A2O + tertiary MBBR” process can be easily modified to collectively achieve EBPR, endogenous denitrification, and Partial nitrification/ denitrification and anammox (PANDA) in one combination under novel system automation control. Nutrient discharge limits (average TIN < 3 mg/L) were met. Large amount of carbon and oxygen can be saved throughout the secondary and tertiary treatment innovation. The volume of aeration tank can be reduced.

Enhanced biological phosphorus removal (EBPR), endogenous denitrification, and Partial nitrification/ denitrification and anammox (PANDA) can be incorporated in an 'A2O + tertiary MBBR' process to achieve cost-effective nutrient removal under system automation control. Nutrient discharge limits (average TIN < 3 mg/L) were met. Large amount of carbon and oxygen can be saved throughout the secondary and tertiary treatment innovation. The volume of aeration tank can be reduced.

SpeakerWANG, JIEFU

Presentation time

09:30:00

10:00:00

Session time

08:30:00

10:00:00

SessionPdNA Whole Plant Considerations

Session locationRoom S504a - Level 5

TopicIntermediate Level, Nutrients

Author(s)

Wang, Jiefu

Author(s)J. Wang 1; Y. Sun 2 ; W. Khunjar 3; Z Wang 1; M. Winkler 4; R.K. Goel 5;

Author affiliation(s)Department of Biological Systems Engineering, Virginia Tech 1; Hazen and Sawyer 2 ; Hazen and Sawyer 3; Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA, USA 1; Department of Civil and Environmental Engineering, University of Washington 4; Department of Civil and Environmental Engineering, University of Utah 5;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159157

Volume / Issue

Content sourceWEFTEC

Word count15

Description: Successful Implementation of Biofilm Anammox in IFAS A2O Process for Simultaneous N...

Successful Implementation of Biofilm Anammox in IFAS A2O Process for Simultaneous N and P Removal in Main Stream Treatment Train

Abstract

This research studied integrated fixed film activated sludge (IFAS) technology to simultaneously remove N and P in real municipal wastewater by combining anammox biofilms with flocculent activated sludge for enhanced biological P removal (EBPR). The study was conducted in a sequencing batch reactor (SBR) operated as a conventional A2O (anaerobic-anoxic-oxic) process with an 8.8 h hydraulic retention time. After achieving steady-state operation, the reactor showed robust performance, with average removal efficiencies of 91.3±4.1% for total inorganic nitrogen (TIN) and 98.4±2.4% for phosphorus (P). Denitrifying polyphosphate accumulating organisms (DPAOs) were responsible for 15.9% of P uptake during the anoxic phase, while biofilms showed anammox activity in the aerobic step. The IFAS configuration with a low solid retention time (SRT) of 5 days prevented the washout of biofilm anammox bacteria and allowed selective washout of unwanted organisms. The results demonstrated the successful coexistence of anammox bacteria with other bacteria for efficient nutrient removal in real wastewater conditions.

This paper was presented at WEFTEC 2023 in Chicago, IL.

SpeakerGoel, Ramesh

Presentation time

09:00:00

09:30:00

Session time

08:30:00

10:00:00

SessionPdNA Whole Plant Considerations

Session locationRoom S504a - Level 5

TopicIntermediate Level, Nutrients

Author(s)

Goel, Ramesh

Author(s)R. Goel 1; S. Hong 1 ; R. Goel 1;

Author affiliation(s)Department of Civil and Environmental Engineering, University of Utah 1; Department of Civil and Environmental Engineering, University of Utah 1 ;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159156

Volume / Issue

Content sourceWEFTEC

Word count21

Description: The Effect of Change in Temperature and Exposure of Sulfide and Heavy Metals in...

The Effect of Change in Temperature and Exposure of Sulfide and Heavy Metals in Anammox Process

Abstract

The effect of change in temperature, exposure of sulfide, lead, mercury, arsenite and cyanide on anammox activity was studied. Specific anammox activity (SAA) reduced from about 0.4 to 0.25 g N/g VSS d when the temperature dropped from 35 to 21°C and reduced to 0.05 g N/g VSS d at 13°C. Sulfide was also found to have a tremendous negative effect on SAA, where the anammox activity decreased with the increasing sulfide concentrations. Severe decrease in SAA for CN- concentration of 0.5 mg/L and Hg2+ concentration of 0.8 mg/L was observed. A slight decrease in SAA was seen at Pb2+ concentration of 0.8 mg/L. A multi-day inhibition test performed to study the recovery response. Partial recovery of SAA for maximum CN- concentration 0.15 mg/L and Hg2+ concentration of 5 mg/L was observed

SpeakerGoel, Ramesh

Presentation time

09:50:00

10:10:00

Session time

08:30:00

10:10:00

SessionInnovative Nitrogen Removal Approaches and Pathways

Session number511

TopicEnergy Production, Conservation, and Management, Facility Operations and Maintenance, Intelligent Water, Municipal Wastewater Treatment Design, Nutrients

Author(s)

R. GoelR. GoelB. BhattaraiB. BhattaraiS. Hong