Nguyen, Lam

Mr. Nguyen has more than 20 years experience working in the industry specifically focused on the Municipal water and wastewater treatment market. He...

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About Nguyen, Lam

Mr. Nguyen has more than 20 years experience working in the industry specifically focused on the Municipal water and wastewater treatment market. He has been with USP Technologies since April 2002 and is part of the Technical Committee. Mr. Nguyen is a key member of the Commercial and Technical Team that oversees the Program Management team, application of technology and overall program compliance. He received a Bachelor of Science in Chemical Engineering from the University of California Riverside and a Master of Business Administration from Keller School of Management in California.

Nguyen, Lam

Titles from this speaker

Description: Addressing Biosolids Hydrogen Sulfide Odor Complaints While Meeting Effluent Metals...

Addressing Biosolids Hydrogen Sulfide Odor Complaints While Meeting Effluent Metals Limits--A Win-Win for a Brewery

Abstract

ABSTRACT A brewery wastewater treatment plant (WWTP) experienced high hydrogen sulfide (H2S) concentrations in and around the biosolids handling building which led to concerns around worker safety, overloading of the existing odor scrubber, and odor complaints from the surrounding neighborhoods. The Brewery WWTP dewaters a total of 250,000 300,000 gallons per day of mixed primary and waste activated sludge (biosolids). Of the total flow to the dewatering presses, 80% is from the brewery and the remaining 20% from a nearby municipal wastewater treatment plant. Historically, the brewery fed sodium permanganate ahead of the belt filter press in an effort to reduce H2S odors in and around the biosolids dewatering area. A second permanganate dosing point of was added in 2021 to address the continued odor complaints. Later in 2021, both permanganate injection points were decommissioned due to operational concerns. Permanganate was also suspected of contributing to elevated manganese levels at the effluent due to release of manganese in the filtrate. In early 2022, the brewery WWTP embarked on a 90-day field trial of Peroxide Regenerated Iron Technology (PRI-TECH ®) to address H2S odors generated in the biosolids dewatering facility and also eliminate a source of manganese in the final effluent. For H2S control, PRI-TECH ® functions in two ways: 1) Direct oxidation of H2S by hydrogen peroxide (H2O2) and 2) regeneration of bound iron (e.g, FeS) in-situ, yielding either free ferrous (Fe2+) or ferric (Fe3+) iron and colloidal sulfur. This regenerated iron is now available to bind additional H2S in the biosolids handling process, functioning the same as if fresh iron salts were being added. Pre-trial laboratory testing showed that there were already significant levels of total available iron present in the brewery biosolids (15 25 mg/L total Fe). This equates to 35 40 lbs. per day of iron that was available for regeneration. In this case, the iron needed for PRI-TECH ® was already present in the biosolids and could be used for the benefit of H2S control in the belt filter press area. For the PRI-TECH ® trial, hydrogen peroxide was fed into the combined biosolids line upstream of the belt filter presses to oxidize H2S and regenerate free iron (Fe+2, Fe+3). Baseline (untreated) H2S levels at the belt press ranged from 5 90 ppm with an average above 10 ppm. The brewery safety committee set the H2S compliance target below an average of 10 ppm during dewatering operations to ensure worker safety and to reduce complaints from surrounding neighborhoods. Trial results showed that PRI-TECH ® reduced the sulfide levels by >95% with operational vapor level averages <1ppm inside the belt filter press room. Operations noticed a substantial reduction in local and personal H2S alarms (alarm at 10 ppm) in and around the dewatering building, local odor complaints also decreased, and there were no effluent manganese violations since beginning the PRI-TECH ® program, supporting compliance with metal discharge limits. Based on the successful trial results, the brewery WWTP will continue utilizing PRI-TECH ® to maintain effective H2S control in the dewatering facility to ensure worker safety and maintain effective H2S odor. Future work is planned to further optimize PRI-TECH ® program, with additional investigation into the improvement in critical metals reduction.

This paper was presented at the WEF/IWA Residuals and Biosolids Conference, May 16-19, 2023.

SpeakerNguyen, Lam

Presentation time

16:15:00

16:45:00

Session time

13:30:00

16:45:00

SessionSession 08: Dewatering and Polymer Optimization

Session number08

Session locationCharlotte Convention Center, Charlotte, North Carolina, USA

TopicThickening & Dewatering

Author(s)

L. Nguyen

Author(s)L. Nguyen1, B. Blake2, M. Fagan3, 4,

Author affiliation(s)USP Technologies LLC1

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2023

DOI10.2175/193864718825158866

Volume / Issue

Content sourceResiduals and Biosolids

Word count16

Description: Full Scale Trial of a Low-Hazard Buffered Iron Product (SulFeLox®) to Control...

Full Scale Trial of a Low-Hazard Buffered Iron Product (SulFeLox®) to Control Hydrogen Sulfide Odors at The City of Portland, OR

Abstract

BACKGROUND The City of Portland serves over 600,000 customers and about 100 sewage pumping stations and more than 2,500 miles of sewer pipes conveying to the Columbia Boulevard Wastewater Treatment Plant. Focusing on one of the major stations; 86AV and Fanno Basin (FABA) pumping station consists of two pump sets designed to operate at all times. 86AV the 'LEAD' pumping facility for base flows up to 15 MGD (23 cfs) and FABA will operate during 'wet' season to increase flow to 30 MGD (46.5 cfs). Historically 86AV and FABA is equipped with a chemical feed system injecting calcium nitrate into the wetwell. 86AV and FABA discharge to two 30-inch force mains, referred to as Line A and Line B, each approximately 16,000 feet in length with a retention time of 4 â€“ 8 hours. The Burlingame Trunk Sewer (BTS) conveys the flows from the 86AV and FABA FM discharge structure to the Southwest Parallel Interceptor (SWPI) along Taylors Ferry Rd and SW Virginia Ave. The Taylors Ferry Ventilation odor control facility (ARQ452) extracts foul air from the sewer system at SW Virginia Avenue at Taylors Ferry Road via a 24-inch odorous air duct. The City of Portland receive numerous odor complaints along the BTS and SWPI, particularly along SW Custer St and SW Virginia Avenue. These complaints have correlated to the force main discharge odor migration from 86AV and FABA FM discharge. The City attempt to control these odors with calcium nitrate, which is injected at 86AV PS wetwell. Odor from the 86AV and FABA FM discharge continues to cause odor complaints at the FM discharge and downstream gravity segments with addition of calcium nitrate. The City of Portland and Carollo Engineering requested evaluation of an alternative low hazard chemical dose approach to effectively address odor release at the 86AV and FABA force main discharge and reduce vapor and liquid H2S migration downstream along the gravity segments. USP Technologies along with the City of Portland and Carollo Engineers conducted a 6-week field demonstration comparing cost and performance efficiency of a low hazard buffered -Fe product (SulFeLoxÂ®) feeding at 86AV and FABA PS in the fall of 2020 to compare to the current calcium nitrate program. Extensive sampling and monitoring took place during the 6-week field demonstration looking at performance, usage rate, and cost comparing SulFeLoxÂ® to calcium nitrate at the force main discharge structure and downstream gravity interceptor. OBJECTIVES Compare performance efficiency of low hazard buffered iron (SulFeLoxÂ®) to historical calcium nitrate for hydrogen sulfide odor control along the 86AV and FABA Pumping Station FM discharge and impact downstream of the gravity interceptor segments. The trial focused on the following: - Reduce hydrogen sulfide odor generation at the 86AV and FABA Pumping Station force main discharge and downstream along the gravity segments of the interceptor - Document and log odor complaints during the duration of the trial and compare to historical odor complaints logged - Determine treatment cost and chemical usage at equal and improved performance to calcium nitrate at the 86AV and FABA Pumping Station discharge and downstream gravity segments of the interceptor METHODOLOGY Both vapor and liquid H2S were collected throughout the trial period. Data loggers (OdalogTM) were used and deployed at two main control points 1) 86AV and FABA Pumping Station FM discharge and 2) gravity segment at 1.5 miles downstream from the FM discharge point. Liquid samples were also grabbed at the two locations listed above. Liquid grabs were taken every day once during the AM and PM periods. Each liquid sample were analyzed on the spot for the following: - Total and dissolved sulfide - Liquid and ambient temperature - pH - Total and soluble iron The City of Portland and Carollo Engineers provided historical vapor and liquid data based on calcium nitrate feed in 2020 and the data collection provided would yield valid comparison between the two technologies. FINDINGS The calcium nitrate treatment level of 72 gpd was followed by a SulFeLoxÂ® rate of 98 gpd for six days which translated to three days of treatment on each force main due to the operations practice of alternating between the FM each day. A 55% reduction in H2S vapor levels were observed at the force main discharge, and a 95% reduction in H2S vapor levels at the downstream interceptor monitoring point during the conditioning phase when compared to calcium nitrate. Following the conditioning-period, SulFeLoxÂ® dose was reduced to 72 gpd to match the calcium nitrate dose. At the same dosage of 72 gpd, SulFeLoxÂ® showed a 63% and 96% vapor reduction when compared to calcium nitrate at the FM discharge and downstream gravity segment respectively. (Table 1, Figures 2 & 3) The City of Portland requested to use 144 gpd of calcium nitrate as the optimized feed rate for upcoming rate comparisons. Three different SulFeLoxÂ® rates were tested during the trial: 72 gpd, 48 gpd, and 37.5 gpd. Below are vapor percent reduction when compared to 144 gpd of calcium nitrate (Table 2, Figures 4, and 5): - 77 GPD SulFeLoxÂ® â€“ 42% and > 99% respectively at the FM discharge and downstream gravity interceptor. - 48 GPD SulFeLoxÂ® â€“ 27% and > 99% respectively at the FM discharge and downstream gravity interceptor. - 38 GPD SulFeLoxÂ® â€“ 4% and 84% respectively at the FM discharge and downstream gravity interceptor. RELAVANCE Iron salts are an inexpensive solution, their hazardous nature constrains use outside the treatment plant, particularly for smaller pump stations in commercial districts and residential communities. Chemicals with lower hazard levels, such as calcium nitrate, are thus the odor control technology of choice for many such applications (Jiang, 2009). SulFeLoxÂ® is a low-acidity form of iron salt, having a pH of approximately 4.0-4.5 which contributes to its low skin irritation potential and carrying an NFPA placard of 1-0-0. Having a low hazard iron product option, as an alternative to e.g., calcium nitrate and magnesium hydroxide, allows agencies to access the inherent benefits of iron for controlling sulfide levels in sewer lines that pass through residential neighborhoods and commercial districts. Based on the trial at the City of Portland, the SulFeLoxÂ® technology provided equal to better performance when compared to calcium nitrate at the 86AV and Fanno Basin (FABA) pumping station FM discharge and downstream gravity interceptor segments. Results clearly validated that a reduction in chemical feed by 74% (37.5 gpd SulFeLoxÂ® vs 144 gpd calcium nitrate) and 60% (29 gpd SulFeLoxÂ® vs 72 gpd calcium nitrate) during the fall and winter seasons respectively. This would result in reduce chemical delivers and overall annual chemical expenditure of 25% for the City of Portland.

This paper was presented at the WEF Collection Systems Conference in Detroit, Michigan, April 19-22.

SpeakerNguyen, Lam

Presentation time

10:15:00

10:45:00

Session time

8:30:00

11:15:00

Session number14

Session locationHuntington Place, Detroit, Michigan

TopicInnovative Technology, Low-hazard chemicals, Odor and Corrosion Control

Author(s)

B. Sherwood

Author(s)B. Sherwood1; K. Kairouz2; L. Nguyen3; J. Zucek4; M. Fagan5

Author affiliation(s)WEF Member Account1; Carollo Engineers2; WEF Member Account3; WEF Member Account4; USP Technologies5

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Apr, 2022

DOI10.2175/193864718825158341

Volume / Issue

Content sourceCollection Systems

Word count22

Base text size -

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