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Contaminant Glossary

Hydroxyl has over a decade of wastewater treatment experience with a wide array of organic and many inorganic contaminants found in industrial wastewater, municipal wastewater, contaminated groundwater, and landfill leachate.

Keys to Economic Wastewater and Groundwater Treatment:

The Proper Match of Process with Contaminant

Contaminants vary greatly in their susceptibility to different processes. Hydroxyl is equipped to test and deliver systems based on a wide selection of technologies including biological treatment and advanced oxidation. Consequently, we have excellent prospects of developing the right solution for many contaminants.

A Combination of Treatment Processes

Complex wastewaters will often require more than one process for cost-effective treatment - Hydroxyl is uniquely qualified to test and deliver integrated treatment systems.

Accurate Testing with Scalable Results

The most effective wastewater or groundwater treatment approach is selected through a comprehensive testing program to ensure the full-scale implementation will match laboratory results. Hydroxyl has batch and continuous flow apparatus to test water under realistic conditions using bench simulation, computer modeling, or pilot scale testing methods.

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Bulk or Generic Organics

Bulk biodegradable organics as measured by COD, BOD, TOC are usually treated most economically through biological processes. If concentrations exceed ~30,000 mg/L, anaerobic biological treatment may be indicated depending on a number of factors. For most applications, biofilm carrier processes are ideal and provide very high volumetric efficiency for COD/BOD removal.

Hydroxyl ActiveCell™ biofilm carrier technology is more tolerant of toxic shock than conventional suspended growth processes. Hydroxyl has developed specialized processes to maximize the treatment effect of biofilm carrier processes for refractory waters which results in improved treatment economics.

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Ammonia and Nitrate

Ammonia exists in sewage and is often present in many forms of wastewater. Toxic to aquatic life at low concentrations, conversion or removal of ammonia is often required by regulations. Conversion of ammonia to the oxidized form, nitrate, is often environmentally acceptable and is best accomplished via the biological nitrification process.

If removal of the nitrogen is required (for example, receiving waters potentially suffer eutrophication from excess nutrient), biological denitrification can be used to convert the nitrate to nitrogen gas that is released to the atmosphere.

Hydroxyl ActiveCell™ biofilm carrier technology is ideal for these contaminants as the attached biofilm allows the slower growing organism to proliferate in smaller tank volumes.

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Suspended Solids

The measure of total suspended solids (TSS) is an important water quality parameter. Suspended solids influence other water quality parameters such as turbidity, color, BOD, COD, and UV transmittance for disinfection. Removal of suspended solids prior to biological treatment often reduces the total organic load, reducing the physical size of the treatment system.

Removal of suspended solids following biological treatment removes excess biology developed in the biofilm carrier process and improves water quality. Hydroxyl ActiveFloat (DAF) technology is specifically designed for removal of suspended solids following the biofilm carrier process. This process is highly compact and extremely efficient in removing suspended particles. An additional benefit of the technology is the efficient generation concentrated sludge in low volumes.

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Chlorinated Solvents

Chlorinated solvents are common groundwater contaminants, particularly at military facilities and sites where heavy machinery and aircraft have been serviced. Some of these compounds are among the most persistent and refractory contaminants. They are also prominent in the list of EPA priority pollutants.

Chloroalkanes such as DCA, TCA, methylene chloride, and carbon tetrachloride are generally poorly adsorbed onto granular activated carbon (GAC) and are not good candidates for AOT since their reaction rates are relatively slow. Others, like vinyl chloride (VC) polymerize on GAC causing premature fouling. However, airstripping usually provides a cost effective approach for chloroalkanes. Chloroalkenes such as DCE, TCE, PCE adsorb reasonably well on GAC, however these compounds can also be destroyed easily, and economically by advanced oxidation processes like the Hydroxyl Photostack™ UV advanced oxidation process. The most cost-effective treatment approach for these compounds is always case specific.

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BTEX

Benzene, toluene, ethylbenzene, and xylene, known carcinogens, are present in gasoline and often appear as target contaminants in groundwater contaminated with gasoline. A common treatment objective is 5 ppb.

Hydroxyl has several methods of treating BTEX. Prominent among these are the line of Hydroxyl PhotoStack™ UV advanced oxidation technologies as well as the ActiveCell™ process.

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Chlorinated Aromatics

Chlorinated benzenes such as chlorobenzene, 1,2,4-trichlorobenzene and o-dichlorobenzene can be treated by Hydroxyl PhotoStack™ UV advanced oxidation technologies as well as the ActiveCell™ process.

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Polynuclear Aromatic Hydrocarbons (PAHs)

Polynuclear aromatic hydrocarbons such as benzopyrene, chrysene, anthracene and pyrene are readily attacked by AOT due to the presence of ring structures and as such are excellent candidates for destruction via the Hydroxyl PhotoStack™ process. ActiveCell™ processes can also be employed for biodegradable streams.

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Energetic Compounds and Nitro-Organics

Nitro-organics such as RDX, HMX dinitrotoluene (DT), trinitrotoluene (TNT) and nitroglycerine (NG) are extensively used as explosives. They are found in process waters and wastewaters at explosives manufacturing sites and can enter surface water or groundwater as a result of spills at such sites, or via the air through the destruction of munitions. They are associated with a variety of adverse health effects including abnormal liver function. Biological treatment is typically ineffective on these compounds. Total destruct technology such as PhotoStack™ advanced oxidation processes are much preferred over traditional "transfer" technologies such as carbon adsorption or air stripping due to associated handling, storage, and disposal costs of hazardous materials.

Nitrosodimethyl amine (NDMA) is a product of degradation (oxidation) of unsymmetrical dimethylhydrazine (UDMH), a rocket propellant and is a common groundwater contaminant near certain military sites. Other propellants (and their by-products) include UDMH, monomethylhydrazine (MMH), dimethylamine (DMA), methylamine (MA), aniline, and NDMA. All can be destroyed readily using Hydroxyl PhotoStack™ advanced oxidation processes.

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Cyanides and Nitriles

Cyanide is a toxic compound, highly soluble in water, and is found either as free cyanide (i.e., amenable to oxidation) or complexed with metals such as iron, nickel, cadmium, etc.

Complexed cyanides are particularly challenging to treat with conventional technologies. Iron cyanide (ferricyanide) is notoriously difficult, however, Hydroxyl PhotoStack™ ultra-violet advanced oxidation systems are ideal for destroying the most difficult forms of cyanide. Hydroxyl has a great deal of experience in remediating water and wastewater contaminated with free and complexed cyanide and has installed full scale treatment systems in North America for the oxidation and removal of cyanides in process waters.

Nitriles, such as acrylonitrile are toxic, mutagenic, and carcinogenic and commonly found in process wastewater from the plastic industries. These compounds can be destroyed by both AOTs and by biological oxidation using ActiveCell technolgoy.

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Ketones

Ketones include ubiquitous organic solvents such as acetone as well as more specialized industrial solvents such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK). A poor carbon adsorber with limited strippability, it also is a poor candidate for advanced oxidation as the destruction rates are relatively low. As a result, ActiveCell™ biofilm carrier processes are the most economical process solution for ketones such as acetone.

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Ethers and Oxygenates

Ethers in general and 1,4-dioxane and tetrahydrofuran in particular are highly soluble in water, biorefractory, and adsorb poorly on GAC. However, they can be destroyed efficiently and economically by Hydroxyl Photostack™ advanced oxidation processes.

Oxygenates added to gasoline, principally methyl-t-butyl ether (MtBE) and co-contaminants such as t-butyl alcohol (TBA) have become a major groundwater contamination problems. Hydroxyl has pioneered the application of advanced oxidation to treat these compounds and in 1999 established the first full-scale commercial MtBE treatment system utilizing an advanced oxidation process (AOP).

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Phenols and Aldehydes

Phenols and chlorophenols react very rapidly with hydroxyl radicals, the main oxidizing reagent produced in PhotoStack™ advanced oxidation processes, and are generally refractory to biodegradation. Hence phenol, cresols, and chlorinated phenols such as pentachlorophenol (PCP) are often best treated with advanced oxidation technology. Using special procedures, Hydroxyl has been able to achieve effective biological treatment of phenols with the Hydroxyl ActiveCell™ process at concentrations in the hundreds of ppm.

Aldehydes such as formaldehyde are often found with phenols in industrial resin processes. It is also biorefractory at high concentrations but susceptible to oxidation by advanced oxidation processes. High phenol and/or formaldehyde concentrations often coexist with high background COD. In cases such as this, ActiveCell™ and PhotoStack™ hybrid or integrated systems are often considered.

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Alcohols

Alcohols such as isopropanol (IPA), ethanol, methanol and n-butyl alcohol (NBA) are biodegradable via ActiveCell™ biofilm carrier processes. In low concentration applications such as recycling of spent semi-conductor rinse water, treatment by PhotoStack™ advanced oxidation processes can also be an economic approach.

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Acetates and Formates

Compounds like n-amyl acetate, n-butyl acetate, ethyl acetate, isopropyl acetate and methyl formate are all biodegradable via ActiveCell™ biofilm carrier processes, depending on the concentrations and presence of co-contaminants.

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Glycols

Propylene glycol and ethylene glycol are common constituents in deicing fluid and other wastewaters and is readily biodegradable via ActiveCell™ biofilm carrier processes.

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Pharmaceutical Residuals

Many pharmaceutical residuals are resistant to conventional treatment. Some have been discovered in surface water bodies (USGS Survey, 2002), having arrived there from human or animal sewage or plant effluent.

Many of these compounds pass unaffected through humans or animals as well as through conventional physical and biological treatment processes. Most of these compounds, such as estrogen, can be readily treated by PhotoStack™ advanced oxidation processes.

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Pesticides and Herbicides

Compounds such as dieldrin, endrin, aldrin, atrazine, and chlordane may be effectively and efficiently treated by PhotoStack™ advanced oxidation processes.

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