Solvay Chemicals technical P U B L I C A T I O N Cost-effective Wastewater Treatment with INTEROX® Hydrogen Peroxide Introduction Nearly every industry has a problem with toxic waste in one form or another. With increasingly stringent regulations and the closing of landfills and deep injection wells, INTEROX® Hydrogen Peroxide is proving itself a costeffective solution for wastewater treatment. Beginning with its use in the 1970s for controlling sulfides, INTEROX Hydrogen Peroxide now appears in catalyzed and other advanced systems that detoxify a long list of organic and inorganic pollutants. Many chemical plants, paper mills, food processing operations, pharmaceutical manufacturers and other industries use hydrogen peroxide onsite. With it, they control amines, aldehydes, hydroquinones, mercaptans, phenols, reduced sulfur compounds, chlorine, cyanides, chromium, iron, nitrous oxides and other pollutants. Hazardous waste treatment and disposal facilities use hydrogen peroxide increasingly in their systems, treating pollutant concentrations that may range from the ppb levels up to 10%. Remediation companies are increasingly using hydrogen peroxide not only to treat ponds and lagoons, but to detoxify soil and contaminated groundwater. Treatment alternatives In general, the methods used to treat industrial wastes fall into four categories, although hydrogen peroxide treatment has enough unique features to warrant a category or two of its own. Phase transfer. These methods are primarily physical: absorbing a pollutant onto activated charcoal (going from liquid to solid toxic wastes), or stripping a liquid by volatilizing the pollutant (going from liquid to gaseous waste). While phase transfer methods change the form of the pollutant, they don’t eliminate it. In fact, they may exacerbate the problem. Thermal oxidation. Incineration may be the only feasible method for low volumes of wastewater with extremely high concentrations of pollutants. But it has many drawbacks: obtaining permits for both atmospheric emissions and residual solids disposal; funding the capital expense of building a plant and getting the wastes to it; and paying the high energy costs of continuing operation. Biological oxidation. Proven over the years, biological systems have been responsible for many environmental improvements. However, as regulations expand, three limitations arise. • Some substances may be toxic to the organisms intended to degrade them. Even where organisms have been specially adapted, removal efficiencies may vary widely with fluctuations in influent concentrations. • Some wastes slip through the system unchanged they do not kill the biological organisms but they are not degraded either. These refractory compounds must be treated by other methods. • In contaminated soils, aquifers and lagoon sludges, oxygen usually cannot reach the system in high enough concentrations for aerobic biological treatment to work. Chemical oxidation. In the past, chemical oxidation has referred to specialized oxidation reactions involving elemental chlorine, hypochlorite, chlorine dioxide or permanganate. These methods have a number of drawbacks: they may be specific to only a few pollutants; they may create toxic byproducts (for example, chlorinated organics like chloroform); or they may involve chemicals that are difficult and dangerous to handle (like elemental chlorine). www.solvaychemicals.us Copyright 2005, Solvay Chemicals, Inc. All Rights Reserved. Costeffective Wastewater Treatment with INTEROX® Hydrogen Peroxide Page 1 of 6 INTEROX Hydrogen Peroxide. Technically a method of chemical oxidation, new methods of using hydrogen peroxide take it beyond simple oxidation/reduction reactions to the powerful oxidizing potential of the hydroxyl radical. By tailoring the conditions of the reaction, hydrogen peroxide can be made to detoxify one or more specific pollutants. And hydrogen peroxide can attack a wide variety of toxic substances. Combination biological/hydrogen peroxide systems. When you combine the low operational costeffectiveness of biological systems with hydrogen peroxide’s power in handling refractory or toxic wastes, plus its unique ability to provide available oxygen, you open a new realm of possibilities in wastewater management. INTEROX Hydrogen Peroxide advantages INTEROX Hydrogen Peroxide combines advantages not obtainable with any other single form of chemical control. Powerful. The oxidation potential values in Table One show how INTEROX Hydrogen Peroxide and the hydroxyl radical stack up against other wellknown oxidants. In the form of the hydroxyl radical, INTEROX Hydrogen Peroxide is second only to fluorine in oxidizing power. Hydroxyl radicals can be created in a Fenton’s system (iron catalyzed), which creates one hydroxyl radical for every H O molecule. These radicals can also be created by ultraviolet light, an advanced system with two advantages: first, each H O molecule forms two hydroxyl radicals, and second, the UV light makes the compound to be treated more reactive. 2 2 2 Versatile. INTEROX Hydrogen Peroxide can detoxify a broad range of organic and inorganic wastes, including sulfides, thiosulfates, sulfites, mercaptans, disulfides, phenols and substituted phenols, chlorine, cyanides, organic amines, aldehydes and quinones. This range continues to broaden as other treatment methods become environmentally more questionable or expensive. Selective. INTEROX Hydrogen Peroxide can be made selective by adjusting the conditions of the reaction. For example, hydrogen peroxide normally does not react with phenols by itself, but at a pH of 45 with ferrous iron catalyst, phenol destruction takes place in minutes. Toxicity reducer. Given enough hydrogen peroxide, many organic wastes can be oxidized all the way to CO . Usually that isn’t necessary. A relatively small amount of peroxide can cleave organic molecules, reducing toxicity to acceptable levels, or making the molecules more easily managed by biological treatment systems. 2 2 Table One: Comparative Oxidation Potentials Species Volts Fluorine 3.0 Hydroxyl Radical 2.8 Ozone 2.1 Hydrogen Peroxide 1.8 Potassium Permanganate 1.7 Hypochlorous Acid 1.5 Chlorine Dioxide 1.5 Chlorine 1.4 Oxygen 1.2 Safe. INTEROX Hydrogen Peroxide is easily transported to needed sites and easy to use in aqueous solutions. When stored in original containers, the rate of decomposition is less than one per year for commercial grades. When properly handled, it is a safe and effective oxidant. www.solvaychemicals.us Copyright 2005, Solvay Chemicals, Inc. All Rights Reserved. Costeffective Wastewater Treatment with INTEROX® Hydrogen Peroxide Page 2 of 6 Bioenhancer. One of the most useful attributes of INTEROX Hydrogen Peroxide is its ability to provide a ready source of dissolved oxygen, a useful feature in many ways. • Residual oxygen sweetens the wastewater stream and prevents anaerobic conditions that could lead to sulfides downstream. • Injection of INTEROX Hydrogen Peroxide and bacterial nutrients (nitrogen and phosphorus) into contaminated soils and groundwaters turns the earth itself into a biological treatment center. • Use of INTEROX Hydrogen Peroxide with biological organisms makes possible degradation of organics in situations where either method alone would be relatively ineffective. • INTEROX Hydrogen Peroxide is an excellent method for treating ponds and lagoons that have gone anaerobic. • Dosing of INTEROX Hydrogen Peroxide in the return sludge line of an activated sludge system can be used to control bulking of filamentous bacteria. Unique combination treatment. As a bioenhancer, INTEROX Hydrogen Peroxide supplies oxygen that enables biological treatment to work in unusual situations. Hydrogen peroxide can also solve two major problems that can occur with biological systems. • Pretreatment with INTEROX Hydrogen Peroxide can degrade compounds that would be toxic to biological systems (for example, chlorinated phenols). The breakdown products of these highly toxic compounds are much less toxic and easily removed by biological treatment. This often proves to be far more costeffective than developing special biological organisms for difficult toxins. • Posttreatment or “polishing” effluents from biological treatment can eliminate those refractory compounds that slip through the biological system unchanged. Because most of the detoxification is done biologically, only small amounts of hydrogen peroxide are required. Table Two: Summary of hydrogen peroxide chemistry: organic compounds Organic Pollutants pH Theoretical Mole Ratio, H O : Pollutant, 100% Basis Reaction Time Catalysts 2 2 Amines Alkaline 1:1 Minutes to Hours None Aldehydes (Formaldehyde) Alkaline 0.5:1 Minutes None BOD/COD, TOC Acid ca. 2:1 weight ratio Minutes Fe+2 Mercaptans, Disulfides Alkaline 5:1 Minutes Chelated Fe+2 or Cu+2 generally required. Phenols, Substituted Phenols, Hydroquinones Acid 94% phenol oxidized with 2.5:1 mole ratio; 99.9% with 6:1 mole ratio; total destruction to CO at 14:1 mole ratio Minutes to Hours Fe+2 required. Extent of phenol destruction depends on H O phenol ratio. Rate of oxidation depends on Fe+2 concentration. 2 2 2 Table Three: Summary of hydrogen peroxide chemistry: inorganic compounds Inorganic Pollutants pH Theoretical Weight H O : Pollutant, 100% Basis Reaction Time Catalysts 2 2 Chlorine Alkaline 0.48:1 Seconds Catalyst not required, Reaction will not work if ammonia is present. Chromium Acid 0.98:1 Minutes None Cyanides (Free and WAD cyanides) Alkaline 1.31:1 Minutes to Hours Copper catalyst required. Metal cyanides somewhat resistant. Iron cyanides cannot be treated by peroxide. Iron Neutral 0.30:1 Minutes None Nitrous Oxides Acid 0.4 1.7:1 Seconds to Minutes None Sulfides Acid Neutral Alkaline 1.00.1 1.03:1 4.25:1 Minutes Minutes Minutes Fe+2 can be used to speed reaction time. Sulfites All 0.43:1 Minutes Catalyst not required. Thiosulfates Acid Alkaline 0.15:1 (min) 1.21:1 (max) Minutes Minutes Patented Solvay Chemicals catalyst system can be used in alkaline conditions to reduce mole ratio of H O required. 2 2 www.solvaychemicals.us Copyright 2005, Solvay Chemicals, Inc. All Rights Reserved. Costeffective Wastewater Treatment with INTEROX® Hydrogen Peroxide Page 3 of 6 INTEROX Hydrogen Peroxide chemistry Oxidation by INTEROX Hydrogen Peroxide involves complex reactions influenced by a number of variables, including pH, catalysts, temperature, peroxide dosage and reaction time. These variables control the reaction rate, the consumption of hydrogen peroxide and the end products formed. Because these variables are interdependent, changing one will affect them all. Tables Two and Three summarize the salient features of hydrogen peroxide chemistry. The general approach to treating a waste stream is first to experiment with samples in the laboratory. For detailed information on particular wastes and specific guidelines for laboratory sampling, treating and testing methods, contact Solvay Chemicals. Typical applications Solvay Chemicals has designed INTEROX Hydrogen Peroxide treatment solutions for many different pollutants and pollution situations. The following examples show some of the diversity of suitable applications. Pretreatment of a thiosulfate stream prior to discharge. One West Coast refinery was unable to discharge to the municipal treatment system because of high concentrations of thiosulfate. By pretreating the stream with INTEROX Hydrogen Peroxide and a patented Solvay Chemicals catalyst system, the refinery now reduces thiosulfate from several hundred mg/L to less than 50, within the municipality's pretreatment standards. Polishing the effluent from biological treatment. A pharmaceutical manufacturer in the Northeast was unable to treat a refractory organic compound biologically. By exposing effluent from the biological system to a UVactivated hydrogen peroxide system, they reduced the contaminant from more than 10 mg/L to an undetectable level. Supplying supplemental dissolved oxygen. A mechanical pulp mill uses an effluent treatment system that operates in two stages, anaerobic and aerobic. Plagued by hydrogen sulfide where the switch between systems occurs, the mill solved the problem with a hydrogen peroxide feed system. Oxidation of hazardous sulfides. A paper company had a problem with sulfides in the sludges from the belt filter press. Since the filter rooms are enclosed, hydrogen sulfide could have posed a real hazard to workers. Injection of hydrogen peroxide into the sludge keeps the hydrogen sulfide in the air below 1 ppm. Removal of phenols and chromium from paint stripping waste. An aircraft manufacturer uses a phenolicbased paint stripper as part of its routine maintenance operation. After solids have settled out, the phenolic waste undergoes a Fenton’s hydrogen peroxide oxidation at a pH of 5. Then the pH is raised to 11 with lime, which precipitates chromium and reduces the color of the effluent. This standard system handles phenols at concentrations up to 1000 mg/L and chromium up to 100 mg/L or more. www.solvaychemicals.us Copyright 2005, Solvay Chemicals, Inc. All Rights Reserved. Costeffective Wastewater Treatment with INTEROX® Hydrogen Peroxide Page 4 of 6 Removal of cyanide from goldmining effluent. Normally this wastewater goes into a tailings pond where the ultraviolet radiation present in natural light oxidizes the cyanide. Many facilities are under pressure to discontinue this type of treatment due to the potential of migratory bird kill. If UV radiation isn’t sufficient, hydrogen peroxide is extremely effective, because the copper naturally present in the effluent catalyzes the reaction. Reduction of phenols at a wood treatment plant. Creosoting plants routinely have high concentrations of phenols in their wastewater. A Fenton’s hydrogen peroxide system easily brings phenols down to discharge criteria. Treatment of sludge during a pond closure. In one case, the sludge to be removed contained sulfides at concentrations greater than 1000 mg/L. This caused severe odor and toxicity problems in the dewatering operation and prevented the dewatered sludge from being dumped at a nearby landfill. Hydrogen peroxide not only solved toxicity and odor problems, it did not contribute to the solids level of the sludge, which was disposable. Treatment of refinery sour water for sulfides and phenols. A Gulf Coast refinery routinely injects its sour water into a deepwell. When sulfide plugs the well, alternate sour water treatment becomes mandatory. Hydrogen peroxide removes the high concentrations of hydrogen sulfide and lowers the pH, after which the addition of a small amount of iron catalyst causes the residual peroxide in the system to attack phenols. Groundwater decontamination. In the Midwest, a leak from an underground gasoline pipeline contaminated the aquifer with 30,000 gallons of gasoline. The remediation company implemented an insitu bioreclamation project, pumping hydrogen peroxide and bacterial nutrients into the ground. They estimated that hydrogen peroxide reduced cleanup time from several decades to less than three years. Soil decontamination. A remediation company on the West Coast was hired to clean up gasoline that had leaked into the soil from underground storage tanks at a gasoline service station. They excavated the soil, treated it with hydrogen peroxide, and put it back into the ground. The entire process took less than a week. Toxicity reduction of hazardous waste. A hazardous waste treatment, storage and disposal facility in the Northeast operated a number of treatment processes, but in many cases they were forced to ship wastes offsite for commercial incineration. By installing hydrogen peroxide treatment systems, they were able to treat a variety of industrial wastes and discharge to the municipal sewer without costly incineration. Quality Solvay Chemicals strives to bring you the best in peroxygen products, service and technology. Exceeding, not just meeting, your expectations is the basis for our pursuit of continual improvement. To demonstrate our commitment, Solvay Chemicals’ Quality Management System is registered to the ISO 9001:2000 International Quality Management System Standard. Our registration encompasses the production and distribution of INTEROX Hydrogen Peroxide at both of our manufacturing facilities in Deer Park, Texas and Longview, Washington, as well as administrative activities at our Houston headquarters. Delivery Solvay Chemicals ships product from two North American plant sites and a number of strategically located distribution terminals. We operate a fleet of high purity aluminum rail cars and stainless steel tank trucks dedicated to INTEROX Hydrogen Peroxide transport. We also can provide stainless steel ISO containers to deliver, store, and dose liquid hydrogen peroxide. These “isotainers” are ideal for environmental applications at remote sites, and especially suitable for seasonal or shortterm needs. In emergency situations, we can use our Quick Response program to get isotainers of INTEROX Hydrogen Peroxide to your site right away. For the information you need, call 1800SOLVAYC (18007658292). Safety When properly handled, hydrogen peroxide and peroxygen compounds are safe, easytouse chemicals. However, as with most powerful chemicals, improper application or handling could create hazardous conditions or cause injuries to personnel. We strongly recommend you contact Solvay Chemicals before experimenting with, designing, installing or modifying an application system or using this chemical. www.solvaychemicals.us Copyright 2005, Solvay Chemicals, Inc. All Rights Reserved. Costeffective Wastewater Treatment with INTEROX® Hydrogen Peroxide Page 5 of 6 Solvay Chemicals, Inc. Administration/Sales/Marketing 3333 Richmond Avenue Houston, Texas 77098 Telephone: 713/5256800 Fax: 713/5257805 Mailing Address: P.O. Box 27328 Houston, Texas 77227 Customer Service: P.O. Box 1167 Green River, Wyoming 82935 18004432785 Fax: 307/8726610 To our actual knowledge, the information contained herein is accurate as of the date of this document. However, neither Solvay Chemicals, Inc. nor any of its affiliates makes any warranty, express or implied, or accepts any liability in connection with this information or its use. This information is for use by technically skilled persons at their own discretion and risk and does not relate to the use of this product in combination with any other substance or any other process. This is not a license under any patent or other proprietary right. The user alone must finally determine suitability of any information or material for any contemplated use, the manner of use and whether any patents are infringed. This information gives typical properties only and is not to be used for specification purposes. Copyright 2005, Solvay Chemicals, Inc. All Rights Reserved.