Hydrogen Sulfide Odor & Corrosion Control using PRI-SC®

A southeast municipal wastewater treatment facility needed a more cost-effective and efficient method to address hydrogen sulfide odor and corrosion control issues in their collection system. US Peroxide's PRI-SC® technology was brought in as a viable solution. PRI-SC® is a proprietary technology developed by US Peroxide and has proven to be very cost effective in large force main and gravity collection systems.

The PRI-SC® technology integrates the use of iron salts and hydrogen peroxide in a unique fashion. This technology enhances the traditional use of iron salts for odor and corrosion control. It provides treatment to non-detectable levels of dissolved sulfide at a lower cost than either iron salts or oxidizers alone. In a PRI-SC® treatment system, an iron salt is applied at a pump station(s) near the beginning of the collection system. The iron reacts with dissolved sulfide to form ferrous sulfide (FeS), an insoluble precipitate. Then, using the PRI-SC® process, hydrogen peroxide is applied to the flow at point(s) downstream. Hydrogen peroxide oxidizes FeS and regenerates the iron that is added upstream. This municipality has been utilizing PRI-SC® successfully to control hydrogen sulfide.

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• PRI-SC® Technology
• Iron Salts for Odor Control
• Hydrogen Peroxide for Oxidation
• PRI-TECH™ (Peroxide Regenerated Iron-Technology™)

Collections System Installation using PRI-SC®

This is a sample 7,800 gallon ferrous chloride (FeCl2) storage and dosing system installation within the collection system of a large Southeast municipality. The FeCl2 is used in conjunction with hydrogen peroxide as part of US Peroxide's proprietary PRI-SC® process.

PRI-SC® is a combination treatment that integrates iron salts with hydrogen peroxide (H2O2) in a synergistic fashion. At the most basic level, PRI-SC® treatment may be viewed as an oxidant (hydrogen peroxide) regenerating the spent iron salt (FeS) in-situ, yielding fresh ferric (Fe3+) iron and colloidal sulfur. The combined treatment provides cost benefits superior to either chemical alone, while allowing greater flexibility as to the placement of storage and dosing facilities. Other benefits are accrued to the reaction, including: reduced solids (FeS) loadings, accelerated reaction rates and enhanced flocculation (in clarifiers). The process has particular benefit when employed for gravity interceptors, force main discharges and headworks treatment.

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• PRI-SC® Technology
• Iron Salts for Odor Control
• Hydrogen Peroxide for Oxidation
• PRI-TECH™ (Peroxide Regenerated Iron-Technology™)

Vapor Fogging Technology for Vapor Hydrogen Sulfide and Mercaptan Control

A Southwest wastewater treatment facility was experiencing vapor hydrogen sulfide and mercaptan odors in the headspace of one of their pump stations. US Peroxide provided a proprietary vapor fogging technology (VFT) which involves fogging a dilute mixture of hydrogen peroxide (H2O2) and sodium hydroxide (NaOH) into the enclosed vapor space to oxidize H2S and mercaptan related odors. The process consists of two chemical storage/feed modules, a solution make-up tank, and a fogging apparatus. The underlying principle is absorption of gaseous H2S into an alkaline water solution, with concurrent oxidation of the absorbed H2S. The principles of operation are the same as those used in packed (and mist) tower odor scrubbers.

The fogging systems are designed to deliver the appropriate amount of each chemical into the headspace to treat the vapor H2S and mercaptan loading on a continuous basis. US Peroxide provides a full-service project delivery scope for all the VFT and H2O2 equipment components, program management, application services, equipment maintenance and operations support. Other vapor fogging technology applications include treatment plant headworks, pump station wet wells, gravity sewers, and biosolids storage tanks.

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• Vapor Fogging Technology
• Hydrogen Peroxide for Sulfide Control
• Sodium Hydroxide for Sulfide Control
• Mercaptan Control

Reduced Sulfide Loading and Odor Control Improvements

A Midwest wastewater treatment plant was interested in improving their wastewater treatment process, which included improving influent wastewater quality, reducing sulfide loading and providing odor control, improve dissolved oxygen levels entering the wastewater treatment plant, reduce aeration energy, eliminate filamentous thiothrix and eliminate the need to feed bleach.

As part of the full-service product offering, along with 50% hydrogen peroxide, US Peroxide provided a state-of-the-art 3,000 gallon chemical storage and feed system designed to meet the automation requirements of the municipality, technical applications assistance, and ongoing maintenance.

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• Hydrogen Peroxide for Sulfide Control
• US Peroxide Full Service Programs
• Total Chemical Management

Improve Safety & Operational Reliability, DHS Compliance

A steel mill was having problems with their existing H2O2 installations due to age and poor materials of construction, which led to significant routine downtime for repair.

US Peroxide was asked to supply two turn-key equipment systems, thereby improving safety and operational reliability. Replacing one of the sites also eliminated Department of Homeland Security reporting requirements for non-fixed peroxide storage containers.

US Peroxide supplied 35% hydrogen peroxide, one 1,100 gal turn-key storage and dosing system (pictured above), one 6,500 gal turn-key storage and dosing system, remote tank monitoring & product inventory management services, equipment system installation, start-up and ongoing maintenance as well as applications support and safety training. The systems have been operating smoothly and without incident since installation.

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• Applications Development
• Equipment Systems & Engineering

Fenton's Reagent Application

This specialty chemical manufacturer was experiencing discharge violations (phenols, bio-toxicity) resulting from ineffective treatment with their existing processes and needed to pre-treat a wastewater stream to reduce phenols by 90% prior to mixing with higher flow waste streams.

US Peroxide was tasked to design and provide a Fenton's treatment program whereby the iron catalyst is added to the wastewater stream in-line (static mixer), with the hydrogen peroxide injected (with mixing) into the first cell of a baffled reaction vessel. The baffled reaction vessel helps eliminate short-circuiting and provides sufficient reaction time. The hydrogen peroxide and iron catalyst dosing modules are interlocked with the wastewater pumps to ensure chemical feed stops with an interruption in wastewater flow.

US Peroxide personnel worked with a major environmental consulting firm and the manufacturer on lab scale “treatability” tests as well as design of the full-scale process. US Peroxide also conducted a successful 6-month full-scale demonstration of the technology resulting in optimization of chemical dose requirements.

US Peroxide supplies the iron catalyst, hydrogen peroxide, and turnkey storage and dosing systems for both chemicals. Supply scope includes ongoing equipment maintenance, remote tank monitoring/inventory management, and applications services. The Fenton's process is now a permanent part of the overall facility wastewater treatment process and has consistently achieved >90% removal of phenols from this stream as well as eliminated bio-toxicity violations and public relations issues.

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• Fenton's Reagent

Sodium Hypochlorite and Tote Hydrogen Peroxide Replacement

A steel mill was having issues with their sodium hypochlorite and tote hydrogen peroxide system. US Peroxide was brought in to design a bulk full-service, turnkey system to support the contact loop biodispersant and oil removal applications (filter backwash and cleaning application).

US Peroxide designed and provides 50% hydrogen peroxide (H2O2), a 3,000 gal H2O2 storage and dosing equipment system, remote tank monitoring & product inventory management, equipment start-up & maintenance, on-site applications support and product safety training.

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• Applications Development
• Equipment Systems & Engineering

Eliminate Visual NOx Emissions during Plant Start-ups

Two nitrate products producers were looking for a solution to their visual NOx emission plumes during frequent plant start-ups that would satisfy both public and regulatory expectations.

US Peroxide was brought in to design a proprietary technology solution which introduces dilute H2O2 into the NOx absorber during start-ups to reduce emissions of NOx compounds such as NO and NO2. Removals of >90% are achieved, with the NOx being converted to high quality HNO3 product. The process is offered under license designed to minimize risk and disruption to operations. The license includes chemical storage and feed equipment, piping and instrumentation, process safety controls, installation and maintenance, training and documentation as well as H2O2 supply service.

US Peroxide performed a thorough Process Hazards Analysis on the process, which has resulted in several interlocks and controls being incorporated into the basic design. The process is currently used safely in over 30 start-ups per year at two HNO3 manufacturing units. All piping, components, and controls needed to operate the process safely are included with the license and are installed by experienced H2O2 specialists. The H2O2 storage and feed systems are of modular design and are code-compliant, with years of safe operating history.

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• Applications Develoment
• Equipment Systems & Engineering

A power plant on the West Coast was experiencing problems with their large, open-circuit cooling tower system.  Excessive bacterial growth in the tower was leading to solids accumulation within the tower's fill and an increasing frequency of TSS excursions in their blow down discharges to the local municipal treatment facility.

Prior attempts at cleaning the cooling tower system with a variety of biocides, both oxidizing and non-oxidizing, proved ineffective.  They needed an immediate solution to clean the tower that was fast, cost effective, and did not require removal and manual cleaning of the tower's fill material. 

Read more: Cooling Tower Cleaning

Supplemental Dissolved Oxygen, Rapid Response, Drum Conversion

A Gulf Coast Refinery was using hydrogen peroxide (H2O2) in 55-gallon drums at their WWTU Bio Unit to supply supplemental dissolved oxygen (D.O.) to maintain target D.O. levels in the aeration basins during high COD loading periods. The drums were stored on wood pallets, which violated industry safety standards and also required handling (changing out the drums), which increased the risk of spills and exposure to operators. Furthermore, during a turnaround of an upstream unit, higher COD loading depleted the dissolved oxygen level in the WWTU Aeration Basins, resulting in ineffective treatment.

The refinery approached US Peroxide (USP) to engineer a bulk H2O2 chemical dosing system sized to meet the plant's D.O. demand. USP responded to the refinery's immediate need by quickly mobilizing a four-person Project Team that included a local account manager and experts in the areas of technical applications, equipment system design and equipment installation/maintenance.

The team installed a USP Rapid Response System consisting of a 5,000-gallon temporary storage trailer and a modular dosing control system. Upon the addition of Refinery Grade 27% H2O2, a class 1 oxidizer, to influent of the WWTU Bioreactor System, the D.O. target was maintained during the high COD loading period.

Once the temporary system was commissioned, the USP Project Team turned their attention to providing a permanent full service chemical storage and dosing system including a 5,000-gallon double-wall HDPE tank, dual pump dosing module, chemical, field service and monitoring system.

USP worked with the plant's engineers to determine the optimum dose point as well as the proper location for the chemical storage tank. The changeover occurred following the plant turnaround and was completed by the USP Field Services Team without incident and without disruption to the treatment program.

Download Gulf Coast Refinery Case Study

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• Supplemental Dissolved Oxygen
• Rapid Response Program
• Refinery & Petrochemical Applications

A refinery in the Northeast was looking at options to dispose 16,000 bbls of a high strength, high pH caustic wastewater that had been stored in one of their tanks for a while.  The wastewater had very high phenol levels (14,000 mg/L), which did not allow for processing through their activated sludge system due to biological toxicity issues. 

Offsite hazardous waste treatment options were available but would have run over a million dollars.  A less expensive, on-site temporary (and non-capital) treatment approach that would eliminate the phenols and allow for processing through their activated sludge system was evaluated and implemented at this facility.

Earlier in the year, the refinery had a major activated sludge system upset caused by high COD loading that killed the nitrifying bacteria and lowered the dissolved oxygen levels, which made it difficult to recover and achieve required ammonia removal.  US Peroxide successfully solved this problem through the use of hydrogen peroxide for sulfide oxidation and supplemental DO helping the activated sludge system recover and creating an environment that allowed the nitrifying bacteria to reestablish.  Having successfully solved this problem, US Peroxide was asked to look at the high strength, high pH caustic water in order to determine if it could be treated on-site and processed through their activated sludge system in a safe and economic manner. 

Turn-Key Advanced Oxidation for High Strength Caustic Wastewater Case History.pdf

Hydrogen Peroxide Turn-key Program helps Refinery through Aeration Basin Maintenance Outage

US Peroxide's 27% Hydrogen Peroxide Treatment Program offered the refinery several benefits:

• US Peroxide's turnkey supply scope provided a safe and cost effective solution for supply of supplemental dissolved oxygen to this large refinery during the maintenance outage.
• The biological treatment system's performance during the outage  convinced the refinery to maintain the hydrogen peroxide storage and dosing system on site to provide supplemental dissolved oxygen (DO) on as "as needed" basis during periods of high BOD/COD loading, upstream process upsets, and filamentous bulking episodes.

In the summer of 2010, a large refinery complex in the Northeast was a facing a 2-3 month maintenance outage on one of two aeration basins in their activated sludge wastewater treatment system.   During the outage, all of the refinery wastewater would need to be routed through the one remaining aeration basin.  Since the refinery periodically had difficulty maintaining dissolved oxygen (DO) levels with both aeration basins in service, they needed a temporary (and non-capital) means to provide the biological treatment system with supplemental DO during the maintenance outage.

Hydrogen peroxide has been used as a source of supplemental dissolved oxygen (DO) in activated sludge treatment systems for decades. In the aeration basin mixed liquor, H₂O₂ converts to DO according to the following reaction:

 2  H₂O₂   →  O2  + 2 H₂O

This decomposition to DO occurs very rapidly due to the catalytic effect of enzymes (i.e. catalase) present in all activated sludge mixed liquors, and thus provides an immediate source of DO to the biomass.  Since hydrogen peroxide is a liquid, and infinitely soluble in water, the amount of DO provided is not limited by mass transfer of oxygen from the gas phase to the liquid as is the case with mechanical aeration.  More information on this application is provided at this link: Supplemental Dissolved Oxygen

 Read more about this case study:  Turnkey Refinery Aeration Basin Maintenance.pdf

Re-Refinery Used Oil - Sour Water Treated with Hydrogen Peroxide

In North America, approximately 1 billion gallons of used oil are collected annually from generators such as quick lubes, truck fleets, and manufacturers.  Several companies have begun the process of re-refining this hydrocarbon-rich waste product.  Re-refining allows the lubricating oil to be repeatedly re-used as a higher value product.

Re-refining involves operations which will separate and remove contaminants in the used oil so that this oil becomes suitable for reuse. The re-refining process is much like that of a traditional refinery with similar waste treatment requirements.  Such was the case for a major used oil re-refinery facility in the mid-west.  They had a "sour water" treatment system that was not performing as designed, resulting in operational problems and safety concerns.  Sour water is hydrogen sulfide rich wastewater water that is generated from a variety of sources including hydrotreaters, reformers and hydrocrackers.

The re-refinery's sour water scrubber was experiencing extreme pH swings and generating precipitate.  The scrubber was being fed with sodium hydroxide (NaOH), aka, caustic and hydrogen peroxide (H₂O₂) to remove the hydrogen sulfide (H₂S).  The hydrogen peroxide was being supplied from totes, causing safety issues with their handling within the refinery.  Working with the re-refinery operations group, US Peroxide's engineering and applications team performed a thorough review of the scrubber system. 

US Peroxide identified the sources of the operational problems then designed a turnkey hydrogen peroxide treatment program.  Using the re-refinery's existing equipment the new treatment program would effectively treat the hydrogen sulfide, reduce the wide pH swings, eliminate the generation of precipitate, and eliminate the safety risks connected to the handling of the many totes of peroxide by the operations group.  

Hydrogen peroxide has been shown to be a convenient, cost effective and environmentally friendly part of hydrogen sulfide gas scrubbing technologies.  Scrubbing of hydrogen sulfide using sodium hydroxide and hydrogen peroxide is a well-established technology.

A typical scrubbing solution consists of dilute sodium hydroxide to which enough hydrogen peroxide is added to react with the hydrogen sulfide according to the equation:

4H₂O₂ + H₂S → H₂SO₄ + 4H₂O

The above reaction predominates at pH > 9.2, and yields soluble sulfate as the reaction product. The stoichiometry calls for 4.25 lbs H₂O₂ per lb S 2^- and it is not unusual for reaction efficiencies to approach 100%, provided that the H₂O₂ is added in a controlled fashion and the reaction medium is thoroughly mixed.

Enough sodium hydroxide must be present to neutralize the sulfuric acid formed according to the equation:

2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O

This indicates that for each weight part of hydrogen sulfide, approximately 2½ weight parts of sodium hydroxide are needed.

Following implementation of the US Peroxide treatment solution the previous operational problems were eliminated and the safety of the sour water scrubber system was increased.  The re-refinery facility has continued to rely on the new program to continue to meet their sour water treatment needs.

US Peroxide provides a full scope of supply (chemicals, equipment and services) to support emergency and ongoing applications for hydrogen peroxide and a range of water and wastewater treatment chemicals.

Total Chemical Management for Remediation

A remediation company was contracted to perform a cleanup of an abandoned gas station in south central Pennsylvania. The consulting engineer and the remediation contractor selected a treatment program utilizing In-Situ Chemical Oxidation (ISCO) as the preferred treatment technology. Due to the magnitude of the contamination and the widespread nature of the groundwater contamination, significant quantities of chemical (hydrochloric acid, ferrous sulfate, hydrogen peroxide, and sodium persulfate) and equipment were required to execute the site remediation.

The scope and structure of the project required that a high volume of multiple chemicals be mobilized quickly which created a significant operational and cost challenge for the contractor. US Peroxide developed a Total Chemical Management Program to efficiently, and cost-effectively, execute the project.

Read More About

• In-situ Soil and Groundwater Remediation
• Total Chemical Management Services

Total Chemical Management, Specialized Equipment Design

US Peroxide was contracted to provide total chemical management including chemicals, logistics, modular equipment mixing and storage systems as well as chemical management oversight for the in-situ remediation of soil and groundwater at an abandoned manufactured gas plant located in New York.

Due to significant dry chemical requirements, this project included the need to design a novel way to quickly dissolve 2000 lb supersacks of granular sodium persulfate. The resulting system pictured uses an eductor to create a vortex in water to safely mix each supersack in less than 15 minutes.

US Peroxide can supply a wide range of chemicals such as hydrogen peroxide, ferrous sulfate, sodium persulfate, sodium percarbonate, acids and others commonly used for ISCO or other remediation technologies. These chemicals are available in wet (drum, tote, bulk) or dry (bags or super sacks where applicable) form.

USP works with remediation companies to develop a cost effective, logistically optimized, and reliable chemical management program based on project specific chemicals, quantities, usage rates and other project constraints.

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• In-situ Soil and Groundwater Remediation
• Total Chemical Management Services
• Equipment Systems & Engineering

Rapid Response for Environmental Treatment Challenges

US Peroxide is uniquely positioned to rapidly respond to your environmental treatment challenges. USP combines experienced applications and equipment field support with a large inventory of storage systems and pumping modules to respond quickly to time sensitive water and wastewater treatment situations.

US Peroxide's Rapid Response Program consists of timely and effective treatment options for customers. USP maintains equipment inventory and has access to many chemical terminals throughout North America that allows for quick response. USP can respond to customer needs with a combination of technical and applications support, safety and project reviews, equipment supply, installation and service as well as multiple chemical programs. These program elements have proven to be of great value to customers.

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• Rapid Response Program

Total Chemical Management, Specialized Equipment Design

US Peroxide was contracted to provide total chemical management including chemicals, logistics, field services, equipment mixing and storage systems as well as chemical management oversight for the remediation of pesticides and petroleum products at a site located in California.

Due to significant dry chemical requirements as well as a large square footage application treatment area, this project included the need to design a novel way to spread supersack quantities of chemical in a controlled manner. The resulting system pictured uses a device at the end of the spreader to accomplish this task. Equipment requirements included three 3-ton capacity dry material spreaders, all terrain tractors and a 3-ton all-terrain forklift system to distribute dry chemicals.

US Peroxide can supply a wide range of chemicals such as hydrogen peroxide, ferrous sulfate, sodium persulfate, sodium percarbonate, acids and others commonly used for ISCO or other remediation technologies. These chemicals are available in wet (drum, tote, bulk) or dry (bags or super sacks where applicable) form. USP works with remediation companies to develop a cost effective, logistically optimized, and reliable chemical management program based on project specific chemicals, quantities, usage rates and other project constraints.

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• In-situ Soil and Groundwater Remediation
• Total Chemical Management Services
• Equipment Systems & Engineering