AOX removal

Adsorbable organic halides (AOX) are compounds containing chlorine, bromine or iodine that need to be removed from industrial wastewater and liquids to protect the environment and human food chain, meet the acceptance criteria of wastewater treatment plants (WWTPs), and boost product quality. 

They are commonly found in cleaning, pharmaceutical, chemical and agricultural products, including dichloromethane (DCM) and certain pesticides. Some are persistent organic pollutants (POPs) which do not biodegrade, instead accumulating in the environment and entering the human food chain. When found in the environment, they are a sign of pollution. AOX can also be found as impurities in process liquids. 

Activated carbon is recognised as a Best Available Technology (BAT) for AOX removal. DESOTEC offers mobile, sustainable activated carbon filtration solutions that also remove other contaminants often found with AOX, measured together as chemical oxygen demand (COD). As well as acting as a standalone treatment, our filters can serve as a pre-treatment to protect biofilters or physicochemical technology, or to flatten peaks of concentrations and meet WWTP acceptance criteria. They can also be used downstream from complementary technology as a polishing step, reducing AOX concentrations to very low levels.  

Activated carbon is a highly effective way to treat the AOX that is often found in groundwater after spills or leaks at former or current industrial sites. Many regions and countries, including France, mandate that any AOX found in groundwater during construction work must be remediated. 

DESOTEC’s activated carbon filters treat pumped-up groundwater so that it can be discharged back to the land or sent to a WWTP. Our air filter models treat vapours from soil extraction during in-situ remediation, or emissions from thermally treated soil in ex-situ remediation.

Activated carbon filtration is a reliable technology to enable companies to comply with AOX regulations; in the EU, this is the Water Framework Directive and Urban Wastewater Treatment Directive, alongside country-specific legislation. Similar laws exist in other regions. Local environmental authorities set very low AOX limits for industrial operating licences. DESOTEC has regional know-how and technology to help your company comply with the regulatory landscape.

Activated carbon filtration is recognized as Best Available Technology (BAT) for AOX removal, and mobile filtration is often the most cost-effective and sustainable option – but it does depend on various factors.

For example:

• Where production is discontinuous, activated carbon is generally more cost-effective than alternatives.
• If space is tight, e.g. at building sites, DESOTEC filters have a smaller footprint than most alternatives.
• For short-term usage, our filters are mobile and rental – unlike more permanent installations.
• If treatment is needed immediately, our filters can be delivered fast and are plug-and-play – some alternatives have a lengthy lead-in time.
• If your needs might change in the future, our systems are modular – other technology might be less adaptable.

DESOTEC is keen to help customers find the best treatment for their needs, and our experts will tell you if they think an alternative technology might be more suitable than activated carbon. 

Activated carbon is a very versatile technology, so there are many ways to optimise set-ups – e.g. placing filters in series, using different carbon grades, or combining filters with complementary technology such as scrubbers or dust filters.

DESOTEC’s experts carry out testing, advise on set-up design, and offer ongoing support as part of our full-service solution. Our activated carbon filtration solutions have a low total cost of ownership (TCO): they have minimal capex costs, and our service includes maintenance, upgrading, and sustainable carbon waste handling. Thanks to our circular approach, waste carbon is reactivated wherever possible, cutting your costs and helping you reach your green goals.