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ABSTRACT
This paper describes the evolving odor control program of the City of Wichita, Kansas from 2008 to 2015. In 2010, the City reduced odor control technology expenditure due to a reduction of revenues. The odors increased resulting in an upswing in citizen complaints as well as more corrosion in existing plant and lift station equipment. In 2013, the City re-evaluated their existing technology approaches to odor control and implemented optimized chemical dosing strategies to maximize cost-effectiveness and provide wide-ranging benefits. USP Technologies (USP) partnered with the City to implement state of the art chemical dosing controls to efficiently target sulfides with their hydrogen peroxide (H2O2) and peroxide regenerated iron sulfide control (PRI-SC®) treatment programs. Implementing the proper treatment technology and chemical dosing controls resulted in dramatically reduced sulfide levels in both the liquid and gaseous phases while providing more cost-effective treatment.
KEYWORDS
Odor control, cost-conscious approach, Wichita, hydrogen sulfide, PRI-SC®, peroxide regenerated iron – sulfide control, hydrogen peroxide, ferrous chloride, RFQ process, odor complaints, corrosion control
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Download Wichita – OAP 2016 (pdf)
Download Wichita Odor Control PPT – OAP 2016 (pdf)[/vc_column_text][/vc_column][/vc_row]
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ABSTRACT
In 2015, a maintenance turnaround of the wastewater aeration tank was undertaken at United Refining Company in Warren, PA. During the planned 70 day turnaround, the refinery needed a temporary chemical oxidation program to maintain compliance with permitted effluent phenol levels. This paper will present data and key learnings from all phases of this successful project, including laboratory treatability testing, process design, full scale implementation and successful completion.
KEYWORDS: Phenol, Aeration Basin, Oxidation, Permanganate, Dissolved Air Flotation (DAF), Total Suspended Solids (TSS)
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Download United Refining Company – IWC 2016 (pdf)[/vc_column_text][/vc_column][/vc_row]
ABSTRACT
This paper presents a systematic, step-by-step approach to assist utilities in developing an effective, priority-driven, sulfide and corrosion management plan for their collection systems. Along with aging infrastructure, utilities are faced with problems with high hydrogen sulfide and corrosion in their collection systems. One of the main challenges in addressing these concerns is developing a method to prioritize critical areas of concern for rehabilitation/replacement and/or corrosion treatment. The systematic approach presented herein provides a comprehensive means which includes six key steps as listed below:
- Identification of potential Critical Areas of Concern (CAC) for corrosion
- Review of current schedule for Capital Improvements Projects (CIPs)
- Risk assessment of interceptor condition and risk rating of CAC
- Evaluation of odor control and corrosion treatment methods
- Rating of interceptor repair and replacement techniques
- Development of corrosion management program (CMP)
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Download TRA Black and Veatch – WEF Odor Conference 2012 (pdf)[/vc_column_text][/vc_column][/vc_row]
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ABSTRACT
The City of Tolleson, Arizona operates a 44.7 cubic meter per hour (m3/hr) [17 million gallon per day (mgd)] capacity, wastewater treatment plant (WWTP). Several residential and commercial developments have been built within ó kilometer of the Plant and odor complaints have increased. The Plant-wide odor control study was initiated in 2006 to determine the best long-term odor control approach. The initial results of the odor study, plus the urgency of the situation with adjacent neighborhoods, required immediate odor mitigation efforts – specifically by implementing an aggressive chemical addition program utilizing ferric chloride plus hydrogen peroxide. This chemical combination had been tried elsewhere, and had shown considerable success in reducing odors at trickling filters preceded by primary clarifiers. The test work demonstrated that the majority of sulfide reduction and odor control is accomplished with just ferric chloride. The addition of hydrogen peroxide produced approximately 30 percent reduction in sulfide and hydrogen sulfide emissions from the trickling filters.
KEYWORDS: Sulfide, ferric chloride, hydrogen peroxide, trickling filters, odor control
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Download Tolleson – WEFTEC 2009 (pdf)[/vc_column_text][/vc_column][/vc_row]
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ABSTRACT
Shell Puget Sound Refinery (PSR) is a fully-integrated production facility that first went on stream in September 1958, initially processing up to 45,000 barrels of crude oil per day. Currently, the plant processes up to145,000 barrels (6.1 million gallons) of crude oil per day producing many useful products — including several grades of gasoline, fuel oil, diesel fuel, propane, butane, petroleum coke.
The Effluent Plant’s Bioreactor at Shell PSR is a three channel oxidation “ditch” style biotreater (a.k.a. Racetrack) built in the early 1990’s. The Bioreactor is a concrete basin with three 14’ deep channels. While the Bioreactor has gone through several upgrades over the years, including the addition of boat-type aerators and the recent addition of steel brush-type aerators, it was limited in aeration capacity to treat peak load, non-routine wastewater while maintaining target dissolved oxygen. Bioreactor aeration capacity required processing peak load wastewater at reduced rates and led to storage issues. The lack of dissolved oxygen in the first stage of the Bioreactor led to odors and subsequent complaints from neighboring communities. In an effort to process wastewater without odors, Shell would store (divert) the peak load material and process it back to the Bioreactor slowly.
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Download Shell PSR Paper – WEFTEC 2013 (pdf)[/vc_column_text][/vc_column][/vc_row]
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ABSTRACT
The paper will present results of a trial initiated in February 2004 by the San Antonio Water System (SAWS) to quantify the impacts of hydrogen peroxide injection prior to dissolved air flotation thickening of wastewater sludges. Since February 2000, the San Antonio Water System has successfully used iron salts (FeSO4) for odor and corrosion control in the Dos Rios Water Recycling Center (WRC) collection system. In May of 2003, the Dos Rios WRC began receiving about 300,000 gallons per day of a mixture of primary and waste activated sludges from SAWS’ Leon Creek WRC. When the Dos Rios WRC facility started receiving sludge from Leon Creek, several negative impacts were observed. Operators immediately noticed a significant increase in sulfide odors from the DAF units treating the Leon Creek sludge. In addition, a 2-3% decrease in percent solids of combined Leon Creek/Dos Rios belt filter press dewatered sludge was observed. In addition, volatile solids reduction through the anaerobic digestion process decreased dramatically. Finally, an expected increase in methane production due to increased sludge volume was not realized.
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Download SAWS – WEFTEC 2006 (pdf)[/vc_column_text][/vc_column][/vc_row]
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ABSTRACT
San Diego’s Point Loma WWTP is a 160 MGD (240 MGD permitted), 100% advanced primary treatment plant that has historically used iron salts for collection system sulfide control and chemically enhanced primary treatment. Beginning in 2006, a PRI-SC® (Peroxide Regenerated Iron – Sulfide Control) program was implemented by adding H2O2 at the intermediate pump station PS2 (in place of the FeCl3), and again to the plant influent (ahead of FeCl3 addition for CEPT). The application of PRI-SC® in the Point Loma system was designed to provide at least $685/day in cost savings, to be achieved through reduced ferric chloride use at PS2 and Point Loma, while improving sulfide control and CEPT performance. Since integrating the PRI-SC® program full-time in 2008, SDMWD is realizing savings of approximately $4,700 per day (~$1.72 million/yr) compared to the 2007 baseline iron salts program. At the same time, both sulfide control and CEPT performance has improved. The cost savings were helped by the hedging aspect of the PRI-SC® program – iron salt price volatility in 2008 and 2009 was upwards of 45%. The PRI program has reduced the total iron salt use from the 2007 baseline rate of 32.5 dry tons per day to approximately 19.3 dry tons per day in 2009, with the core savings coming from an overall reduction in ferric chloride use at PS2 and the treatment plant (Table 1). Significantly, ferric chloride use at PS2 was eliminated and, for CEPT, it was reduced from 24 mg/L to 10 mg/L (16.6 to 6.8 dry tons per day) with no loss in performance. In addition, total sulfide removal has improved over baseline levels, and average CEPT performance exceeds the permit levels at 89% for TSS and 65% for BOD, and effluent water quality has improved (with 60% less spent iron (as FeS) present in the ocean discharge). For the most part, digester biogas H2S levels were maintained below the permit requirement of < 40 ppm, but required approximately twice the baseline FeCl2 feed rate. Even so, the overall program has maintained the stated savings benefit.
KEYWORDS: Sulfide control, iron salts, Chemically Enhanced Primary Treatment (CEPT), hydrogen peroxide, PRI-SC, Peroxide Regenerated Iron.
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Download San Diego PRI-TECH – WEFTEC 2010 (pdf)[/vc_column_text][/vc_column][/vc_row]
Abstract
Corrosion of collection system piping and components has become a big problem for many municipalities trying to handle growth while obtaining the maximum service life for existing collection system infrastructure. The goal of this paper is to present the results of a trial initiated in August 2005 by The Regional Municipality of York (York Region) to quantify the impacts of Peroxide Regenerated Iron-Sulfide Control (PRI-SC) for control of hydrogen sulfide (H2S) in a long retention time section of the collection system. Results showed that PRI-SC technology was able to provide significant reductions of H2S over a 12 hour retention time section of the collection system. In most sections that were monitored, the reduction of H2S was over 90% in both the gas and liquid phase. The Aurora forcemain discharges displayed a unique dose response during the trial due to gas pocketing and high turbulence at the discharge structures. Further monitoring at manholes immediately downstream from the Aurora forcemain discharges confirmed the hypothesis of gas pocketing at the discharge structures. Sections further downstream of the areas of interest in the Southeast Collector also showed some reductions in H2S levels. As expected, the levels of reduction were less than in the upstream sections due to additional H2S loaded wastewater mixing with the treated wastewater.
Keywords The Regional Municipality of York, Hydrogen Sulfide, PRI-SC, Hydrogen Peroxide, Iron Salts, Odor Control, Corrosion Control, Collection System, Wastewater
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Download Region of York PRI-SC – WEAO 2006 (pdf)
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ABSTRACT
The City of Raleigh has been using ferrous sulfate (FeSO4) for years in their collection system for hydrogen sulfide and plant phosphorus control. Several years ago the Neuse River wastewater treatment plant upgraded their ultraviolet disinfection (UV) system to a higher intensity lamp technology. Although the UV system was equipped with mechanical wipers, manual cleaning by plant personnel was required due to the elevated iron levels carrying over to the disinfection stage coupled with the lamp sleeve’s higher temperature. In 2008, the City of Raleigh implemented Peroxide Regenerated Iron Sulfide Control (PRI-SC®) as a means to improve collection system sulfide control and maintain plant phosphorus removal while reducing the amount of iron salts in the collection system. PRI-SC® chemical savings were found to be $80,300 per year. Manual UV sleeve cleaning frequency was reduced from 2 weeks to 2 months, saving 32 man hours per cleaning or $25,600 per year.
KEYWORDS: Hydrogen Sulfide, PRI-SC®, Hydrogen Peroxide, Iron Salts, Alum, Odor Control, Phosphorus, Ultraviolet Disinfection
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Download Raleigh PRI-SC – WEFTEC 2010 (pdf)
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ABSTRACT
Iron salts are used by municipalities worldwide to control hydrogen sulfide within collection systems and to enhance primary clarification at treatment plants. However, the two uses are not synergistic: the product of the sulfide reaction is predominantly ferrous sulfide (e.g., FeS), a tightly-bound black precipitate that does not enhance flocculation. Further, dissolved sulfide present in the plant influent can scavenge free iron added to enhance clarification. Adding supplemental iron salt for both purposes would increase costs and potentially cause problems associated with e.g., higher volume solids production, reduced alkalinity, elevated salinity levels, and depleted dissolved oxygen. This paper presents the results of a field trial conducted at the Orange County Sanitation Districts using a novel technology to moderate these shortcomings – Peroxide Regenerated Iron – Sulfide Control (PRI-SCTM, patent pending). The combination treatment involves adding an iron salt at the upper reaches of the collection system and hydrogen peroxide at points downstream. The process may be viewed as an oxidant (H2O2) regenerating the spent iron salt (FeS) in-situ – yielding ferrous / ferric iron and colloidal sulfur. The study involved three major interceptors and the results show the PRI-SC technology met the control objectives at a significantly lower cost than other commonly used chemical technologies. Further, much of the ferrous salt added in the collection for sulfide control was shown to converted to hydrous ferric oxide at the treatment plant for enhanced clarification purposes. OCSD has since extended the field test into a full year evaluation.
KEYWORDS Hydrogen sulfide, odors and corrosion, iron salts, hydrogen peroxide, enhanced clarification
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Download OCSD PRI-SC – WEFTEC 2003 (pdf)