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ABSTRACT

The Orange County Sanitation Districts (OCSD) currently utilize PRI-SC™ technology to control hydrogen sulfide emissions within its collection system. With PRI-SC™, ferrous chloride (FeCl2) is added for sulfide control and then the combined iron is regenerated using hydrogen peroxide (H2O2). OCSD also adds ferric chloride (FeCl3) at its treatment plants to enhance solids separation (CEPT). We previously reported on the improved sulfide control efficiencies in the collection system using PRI-SC™; however, little data were available at the time on regenerating that iron a second time (at the treatment plant) to benefit CEPT. This paper discusses the economic and performance benefits of doing so using hydrogen peroxide and bleach at OCSD Plant No. 2. The study involved beaker tests, jar tests and field trials, as well as an analysis of the historical plant records.

Read More Download OCSD PRI-CEPT – WEFTEC 2005 (pdf)[/vc_column_text][/vc_column][/vc_row]

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ABSTRACT

In August of 2012, Monroe County DES initiated a demonstration of Peroxide Regenerated Iron – Sulfide Control (PRI-SC®) technology as a performance improvement over the existing hypochlorite and hydrogen peroxide odor and corrosion control program. This demonstration was designed to control hydrogen sulfide (H2S) odors and corrosion along a line from Mill Seat Landfill PS where landfill leachate is introduced into the collection system along the Churchville force Main and gravity line (hereafter referred to as the “Churchville Line”) through to the Gates-Chili-Ogden (GCO) pump station. The program was specifically designed to moderate peak sulfide levels at critical points to lessen and eliminate odor complaints as well as moderate corrosion. It was designed to dovetail with peroxide feed at the GCO pump station to reduce the H2S loading entering the GCO Lift Station and reduce peroxide usage for sulfide control further downstream to the critical odor control point at Shaft 2. Shaft 2 is located on a small green area in the middle of a densely populated residential section of Rochester and was heretofore a source of multiple odor complaints.

The demonstration of PRI-SC® technology from the Mill Seat Landfill PS through the Churchville line to the GCO Lift Station provided odor and corrosion control in an additional 22.5 kilometers (14 miles) of pipe along the Churchville force main and gravity line, from Mill Seat PS to the GCO PS, while enhancing the GCO/Shaft 2 odor and corrosion control program at comparable cost to the current peroxide and bleach program.

KEYWORDS: Monroe County DES Pure Waters, Leachate, Hydrogen Sulfide, PRI-SC®, Hydrogen Peroxide, Iron Salts, Odor Control, Corrosion Control, Collection System, Wastewater

Read More Download Monroe PRI-SC – Leachate – WEF Odor Conference 2013 (pdf)[/vc_column_text][/vc_column][/vc_row]

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ABSTRACT

The results of a full-scale trial initiated in May 2006 by the Manatee County Southwest Water Reclamation Facility are presented, and the impacts of peroxide regeneration of spent iron salts on the removal of hydrogen sulfide (H2S) from anaerobic digesters at the SWWRF are examined. Treatment with hydrogen peroxide was initiated in a thickened primary sludge line containing an average 300 Lbs/day Fe (primarily as FeS) and 80 mg/L dissolved sulfide. Prior to treatment, dissolved sulfide levels in the primary digester averaged 20 mg/L and were found to drop to < 0.1 mg/L throughout the course of the trial. The vents of the primary digesters exhausted biogas containing an average 200 ppm H2S. After treatment, biogas H2S concentration reduced to 20 ppm on average. Within two sludge ages, similar effects were noted in the secondary digester. Additional positive changes were noted in the volume and quality of biogas produced, and in finished biosolids quality.

KEYWORDS Anaerobic digestion, odor control, corrosion control, hydrogen sulfide, hydrogen peroxide, iron salts, mercaptan, peroxide regenerated iron…

Read More Download Manatee PRI-DE – WEFTEC 2007 (pdf)[/vc_column_text][/vc_column][/vc_row]

Summary

This paper will present results of an odor control field study initiated in July 2008 by Lexington-Fayette Urban County Government (LFUCG) to quantify the impacts of iron and peroxide injection in the collection system on liquid and gaseous sulfide levels as well as the secondary benefit of phosphorus removal and sodium aluminate savings at the treatment plant.

Read More Download Lexington – WEFTEC abstract 2009 (pdf)[/vc_column_text][/vc_column][/vc_row]

Read More Download Langley PAA – WEFTEC 2014 (pdf)

ABSTRACT

Historically the technology to continuously monitor “odors” or odor units in real time has not been available. Since October 2009, the Hampton Roads Sanitation District (HRSD) has been successfully demonstrating new technology that is performing real time odor monitoring of the odors from the uncovered portion of the aeration basin at HRSD’s Chesapeake-Elizabeth wastewater treatment plant in Virginia Beach, Virginia.

The odorous emissions from the aeration tanks are measured continuously by a network of three OdoWatch® electronic noses. The network measures the odors continuously at 5-second intervals (dilution to threshold or odor concentration). The real time odor monitoring allows us to know the level of odors from the aeration tanks and potential off-site impacts with and without chemical dosing, instantaneously or historically. Chemical dosing of peroxide and iron is being performed at the raw influent to provide seasonal odor control of the uncovered portion of the aeration basin. The odor monitoring system includes a weather station so as to use dispersion modeling to map the odor plumes from the aeration basin in real time.

Read More Download HRSD – WEF Odor Conference 2012 (pdf)

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ABSTRACT

Historically, ferrous chloride (FeCl2) injection has been utilized to successfully control odors and corrosion within the sanitary sewer collection system of Fargo, North Dakota. However, increased odor complaints prompted an evaluation of the odor conditions present in the sanitary sewer system. Study results indicated that the current FeCl2 dosing rate was insufficient to control odors. In response, a number of liquid phase odor control treatment alternatives were evaluated. Due to the existing FeCl2 injection program, iron regeneration and improved odor control were realized through the innovative use of hydrogen peroxide. A program was initiated to demonstrate the efficacy of the proposed treatment strategy on a full-scale level. In response to improved sulfide treatment, reduced FeCl2 injection rates, and economic benefits realized during the demonstration program, the City of Fargo elected to incorporate the technology as part of their upcoming collection system improvements.

KEYWORDS: Odor Control, Hydrogen Peroxide, Ferrous Chloride, Hydrogen Sulfide, Dissolved Sulfide.

Read More Download Fargo PRI-SC – WEFTEC 2009 (pdf)[/vc_column_text][/vc_column][/vc_row]

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Abstract

The transition from splash fill and ACB fill to cellular plastic “high efficiency” film fill in cooling towers has reduced capital and operating costs. However, the generally tight and tortuous path that provides exceptional contact between air and water in these fills also makes them highly prone to fouling. In the US Power industry, environmental regulations limiting chlorine usage, inadequate or non-existent clarification and filtration equipment, and generally lower treatment levels exacerbate the difficulty of controlling deposit formation in the fill packs. Fouled fill sacrifices the “high efficiency” performance gains and, in advanced stages, results in fill collapse into the sump and expensive fill replacement. The purpose of this paper is to outline and review successful, pro-active fill cleaning techniques that preserve thermal efficiency and avoid fill replacement. Several case histories are provided.

Keywords: Cellular plastic fill, film fill, high efficiency fill, cooling tower, cleaning

Read More Download Effectively Cleaning Cellular Plastic Cooling Tower Fill – Electric Utility Workshop 2013 (pdf)[/vc_column_text][/vc_column][/vc_row]

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ABSTRACT

In 2008, the Green Bay (Wisconsin) Metropolitan Sewerage District acquired the De Pere Wastewater Treatment Facility and interceptors from the City of De Pere. Two of those interceptors received wastewater from paper mills exhibiting high biochemical oxygen demand and high temperatures. Mill wastewater contributed 80 percent of the total interceptor flows, making conditions highly conducive to sulfide generation. Control measures were necessary to prevent unacceptable hydrogen sulfide concentrations in the interceptors. A computer model was used, along with 7 months of collected field data, to assess the effectiveness of treatment alternatives. The calibrated sulfide generation factor in the model was lower but within a magnitude of the recommended value by Pomeroy-Parkhurst. To eliminate vapor phase hydrogen sulfide issues in one of the interceptors, a force main was installed to allow wastewater to be pumped from one of the mills directly to the treatment plant. A biological slime layer that formed in the force main appeared to inhibit sulfide generation or transfer of sulfide to the wastewater. The slime layer resulted in elevated force main pressures and lower flow rates. Hydrogen peroxide addition successfully reduced the slime layer. The two mills discharging to the second interceptor employed liquid phase chemical treatment using ferrous chloride and hydrogen peroxide to mitigate sulfide generation.

KEYWORDS: odor, hydrogen sulfide, paper mill, interceptor…

Read More Download DePere – WEF Odor Conference 2012 (pdf)[/vc_column_text][/vc_column][/vc_row]

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Abstract

Free Nitrous Acid (FNA) is the active agent underlying a new biofilm removal technology (“Cloevis”) for controlling sulfide production in wastewater force mains. The technology was developed at the University of Queensland and, after initial field testing in Australia, commercial field tests in the U.S. began in late 2015. These early test sites were chosen to reflect a range of force-main situations, including: short vs long retention times; small vs large wastewater flows; and force mains heretofore treated with nitrate, iron salts, or no treatment. In all cases, the Cloevis technology was able to bring the sulfide levels under target limits, although auxiliary (complementary) treatments are needed in two scenarios: where pre-existing sulfide enters the force main segment either through the influent flow or through a manifolded (interconnecting) force main; and where the candidate force main has accumulated deposits of fats, oils, and grease that coat and protect the biofilm. This paper will describe the Cloevis technology and discuss the results from three of the early field tests in the U.S.

Keywords

Sulfide Control, Corrosion Control, Odor Control, Force Mains, Biofilm Treatment, FNA, Free Nitrous Acid, Cloevis…

Read More Download Cloevis BRS – WEF Odor Conference 2016 (pdf)[/vc_column_text][/vc_column][/vc_row]