Upadhyaya, Giridhar, Upadhyaya

Upadhyaya, Giridhar

Giridhar Upadhyaya has more than 26 years of experience in biotechnology, environmental engineering, and environmental chemistry. His work experience ranges from proof-of-concept evaluation, pilot- and demonstration-scale testing, and process optimization and full-scale design criteria development. He is Carollos Southern California R&D lead and has led multiple research studies and projects on aerobic and anaerobic biological surface and groundwater treatment. His has worked on multiple contaminants removal from drinking water sources, including nitrate, perchlorate, arsenic, selenium, hexavalent chromium, uranium, PCE, TCE, and DCE. He is currently managing and leading two WRF projects related to PFAS and DPR.

Titles from this speaker

Description: Benefits and Challenges of Blending Advanced Treated Water With Source Water...

Benefits and Challenges of Blending Advanced Treated Water With Source Water Upstream of a Surface Water Treatment Plant for DPR

Abstract

Water scarcity, climate change, and ever-increasing population are encouraging utilities to expand their water supply portfolio by leveraging all potential water supply sources. Recycled water is increasingly being considered as an important water source that can be treated through Advanced Water Treatment Processes (AWTPs) for supplementing potable water supply. AWTPs have been demonstrated to effectively remove chemicals and pathogens from recycled water, protecting public health. Previous larger scale potable reuse projects typically focused on advanced treatment followed by groundwater replenishment (i.e., indirect potable reuse [IPR]). Direct potable reuse (DPR) provides economic advantages over IPR due to limited additional infrastructure requirements (e.g., injection and extraction wells) other than conveyance of DPR source or advanced treated water (ATW). Blending ATW may help utilities during high demand periods (i.e., summer). Figure 1 presents the general scheme of supplementing drinking water sources with ATW. When blending ATW with the raw water source at a surface water treatment plant (SWTP), the differences in water quality may introduce operational challenges and considerations for achieving treatment goals. It is critical to understand whether the blending compromises pathogen removal at the SWTP or provides additional partial pathogen log reduction value (LRV) credit. The Water Research Foundation (WRF) Project 5049: Public Health Benefits and Challenges for Blending of Advanced Treated Water Upstream of a Surface Water Treatment Plant in DPR intends to determine the effects of ATW blending on SWTP operational efficiency and efficacy and develop operational strategies and approaches for establishing LRV credits under DPR regulatory frameworks for SWTP unit processes. Bench-scale testing was conducted with raw water and ATW collected from the SWTP and Advanced Water Purification Facility (AWPF) of five participating utilities with conventional or direct filtration SWTP. The bench-scale jar testing included various blends of raw water and ATW (i.e., 0% to 50% ATW) to assess the impact to zeta potential and coagulation, filterability, and assessing the effects of pre-ozonation. Table 1 summarizes the bench-scale testing results. In general, blending ATW up to 50 percent did not appear to challenge coagulation and flocculation. A 6-week pilot testing was conducted at Plant B to further characterize the effects of blending ATW with raw water. The pilot-scale system included ozonation, coagulation/flocculation, and filtration in series (Figure 2), simulating a direct filtration facility. Tests were conducted with 0% (i.e., raw water), 10%, and 50% ATW blends. Table 2 presents water quality characteristics for the raw water and ATW used during the pilot testing. The test results confirmed that pre-ozonation (0.3 to 0.7 mg/L O3) of the filter influent effectively generates micro-flocs and helps maintain turbidity less than 0.1 NTU in the filter effluent. Additionally, turbidity removal, headloss across the filter, and filter runtime were not affected by blending ATW with the raw water. The results confirmed that blending ATW does not appreciably affect treatment performance at a SWTP in this specific case. Additional pilot testing will be conducted at Plants A and C from Dec 2021 through Feb 2022 with pilot-scale systems representing conventional filtration to further explore treatment- and site-specific effects of blending ATW and approaches for minimizing the effects, if any. This presentation will discuss the results from the bench-scale and pilot-scale testing. Utilities considering ATW blending for source water augmentation are anticipated to benefit from the discussion.

For direct potable reuse, blending advanced treated water (ATW) with raw water sources upstream of a surface water treatment plant (SWTP) is an option, which requires critical assessment to understand the effects of the blending on plant operation and performance. Extensive bench- and pilot-scale tests were conducted with various ATW blends. Blending ATW did not affect TOC removal, while it improved filter hydraulics and pathogen removal, indicating that utilities may benefit from ATW blending.

SpeakerUpadhyaya, Giridhar

Presentation time

13:30:00

13:55:00

Session time

13:30:00

15:00:00

TopicAdvanced Level, Potable Reuse, Research and Innovation, Water Reuse and Reclamation

Author(s)

Upadhyaya, Giridhar

Author(s)Giridhar Upadhyaya1; Kimberly Shust2; Risa Guysi3; Jason Assouline4; Andrew Salveson5; Gil Crozes2

Author affiliation(s)Carollo Engineers, Costa Mesa, CA1; Carollo Engineers, Los Angeles, CA2;Carollo Engineers, San Diego, CA 3; Carollo Engineers, Denver, CO4; Carollo Engineers, Walnut Creek, CA5

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2022

DOI10.2175/193864718825158593

Volume / Issue

Content sourceWEFTEC

Word count21

Description: Holistic Biofiltration Optimization Can Lower Overall Treatment Costs Without...

Holistic Biofiltration Optimization Can Lower Overall Treatment Costs Without Compromising Treatment Goals

Abstract

Historically, biofiltration optimization has focused on characterizing and optimizing biofilter performance, considering biofilter as an isolated unit process. In contrast, holistic biofiltration optimization and integration advocates for biofiltration optimization in tandem with upstream unit processes. Through holistic optimization approach, utilities may realize significant cost savings through reduction in chemical and power use, and minimization of sludge production and management. In collaboration with the City of Columbus, the Water Research Foundation (WRF) tailored collaboration (TC) project 4731 intended to combine much of the knowledge gathered from previous biofiltration studies and demonstrate holistic biofiltration optimization and integration at full-scale facilities. Bench- and full-scale tests were conducted at the City of Columbus' Dublin Road Water Plant (DRWP) and Hap Cremean Water Plant (HCWP). Biofiltration optimization tests included phosphorus supplementation, pre-chlorination, and biofilter maintenance strategies during a filter shutdown. Upstream process optimization included coagulant dose and O3:TOC ratio optimization.
Phosphorus (50 to 450 Âµg/L) was fed to With-P filter influent. Tests were conducted at filter loading rates of 1.3 and 2.5 gpm/ft2. The effects of phosphorus supplementation were evaluated by comparing hydraulic, water quality, and microbial parameters in No-P and With-P filters. Both No-P and With-P filters performed similarly (Figure 1), suggesting that the phosphorus supplementation did not improve system performance. The impact of pre-chlorination was evaluated targeting approximately 0.25 mg/L free Cl2 in filter influent of the Test filter (i.e., With-Cl2 filter). Pre-chlorination significantly lowered headloss in Test filter compared to the Control filter (i.e., No-Cl2 filter) (Figure 2). TOC removal was not significantly different in the Test and Control filters and the biofilters removed a majority of DBPs formed during pre-chlorination.
Maintenance strategies for filter shutdown focused on assessing the importance of backwashing a filter before shutting down, comparing the effects of chlorinated versus non-chlorinated backwash before filter shutdown or immediately before resuming filter operation, and dry versus wet storage during filter shutdown. Filters stored wet were assessed for the effects of weekly water replenishment, daily 10-min aeration without water replacement, or daily low-rate backwashing. Furthermore, the shutdown testing also included evaluating the effects of short-term (i.e., 72-hour shutdown) and long-term shutdown (i.e., two-week shutdown). While the shutdown did not affect hydraulic performance in the filters, TOC removal was lower after resuming filter operation compared to before shutdown, which was likely due to lower temperature. Turbidity remained similar in all filters before and after shutdown. The results also indicated that it may not be necessary to backwash a filter before shutting down. Two coagulation approaches were evaluated at the bench-scale: (1) normal approach (i.e., using 85 mg/L alum) practiced at DRWP and (2) alternate approach (i.e., using 50 mg/L alum with 5 mg/L cationic polymer). The test results indicated that 0.3 mg/L TOC could be transferred to biofilters without affecting the filtered water TOC concentration. At the full-scale, alum dose was sequentially lowered from 90 mg/L to 55 mg/L without affecting filter effluent TOC (Figure 3) or turbidity (Figure 4).
Ozone dose was sequentially lowered at the full-scale system from 3 mg/L to 2 mg/L, which resulted in O3:TOC ratio ranging from 0.82 to 1.2 in the biofilter influent. Lowering the O3:TOC ratio did not significantly affect TOC removal across the biofilters. With the holistic optimization approach, it was determined that DRWP would save more than $600,000 per year (Table 1).
This presentation will discuss results of biofilter performance strategy testing and holistic biofiltration optimization and associated potential benefits. Utilities that are operating or considering biofilters for drinking water treatment are anticipated to benefit from the discussion.

Holistic biofiltration optimization was performed at the City of Columbus' two conventional surface water plants. Through extensive bench- and full-scale testing, the study demonstrated that holistic optimization may result in economic benefits to a utility without affecting the overall plant performance due to reduced chemical use, sludge production, and number of sludge transportation trips.

SpeakerUpadhyaya, Giridhar

Presentation time

09:00:00

09:15:00

Session time

08:30:00

10:00:00

TopicIntermediate Level, Microconstituents and Contaminants of Emerging Concern (Non-PFAS), Potable Reuse, Research and Innovation, Water Reuse and Reclamation

Author(s)

Upadhyaya, Giridhar

Author(s)Giridhar Upadhyaya1Jennifer Nyfennegger2; Greg Pope3; Rod Dunn4; Matt Steele4; Jess Brown1

Author affiliation(s)Carollo Engineers, Costa Mesa, CA1; Carollo Engineers, Sarasota, FL2; Carollo Engineers, Austin, TX3; City of Columbus, Columbus, OH4

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2022

DOI10.2175/193864718825158526

Volume / Issue

Content sourceWEFTEC

Word count13