Wastewater Treatment in the Chemical Industry: Biological Processes to Treat Toxic Contaminants

Wastewaters from the chemical industry often contain high concentrations of organic compounds from various substance classes, and treating them is essential. DAS technology provides company-owned, on-site pre-treatment of operational wastewaters for a cost-effective, targeted removal of harmful substances.

Wastewater Treatment in the Chemical Industry

If wastewaters containing high loads of organic compounds remain untreated and reach natural water bodies, the high oxygen consumption resulting from the organic compounds’ degradation can cause a massive disturbance in the waters’ organic balance. In the chemical and pharmaceutical industries, process wastewaters often contain substances that are harmful and must be prevented from getting into the water cycle.
Wastewater purification, however, is often a question of cost: when the

cost for disposal with the respective treatment plant rises or when production facilities are expanded, the targeted pre-treatment of operational wastewaters provides an effective way to save on wastewater costs. Due to the highly effective and efficient technology of biological processes, wastewater treatment increasingly relies on biological treatment methods that, in contrast to chemical and physical treatment methods, continually degrade harmful substances.

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DAS offers reliable solutions to meet the individual challenges of the chemical and pharmaceutical industries. The specific, custom-tailored and flexible DAS technology is well-suited to pre-treat process wastewaters before the indirect feed into the treatment plant, during the direct release into the receiving water tank of a treatment plant, and before the treatment stage that eliminates difficult-to-biodegrade compounds.

Biological Treatment of Extremely Heavily Loaded Wastewaters

The production of specialty gases and basic chemicals produces heavily loaded process wastewaters that due to their substances’ high toxicity are difficult to biodegrade. Nevertheless, DAS Environmental Expert develops individual concepts for biological treatment that perfectly adapt to the respective conditions. The mixing-and-equilibration process, for instance, mixes highly contaminated untreated wastewater with already biologically treated water in such a way that toxicity levels fall below their threshold; and limit values are determined in system-specific safety data sheets. When needed, the upstream mixing and equalization tank offsets production-related fluctuations in wastewater amounts and loads in an uncomplicated manner.

For example, employing a biological treatment method, DAS Environmental Expert assisted a Berlin power station operator in reducing disposal costs. Prior to installing the new DAS Environmental Expert wastewater treatment system, the wastewater from the plant’s flu gas desulfurization had to be eliminated in three costly steps: collection, transportation and combustion. Further information about this example is available in our section of case studies of efficient biodegradation of harmful substances in the chemical industry.

The Effective Reduction of COD Concentration

The production of elastomers typically produces wastewaters loaded with extremely difficult-to-biodegrade COD compounds that require treatment before being released into municipal wastewater plants. DAS achieves this goal by combining treatment methods from biological pre-treatment in the MBBR (Moving Bed Biofilm Reactor) and subsequent ozone treatment (AOP – Advanced Oxidation Processes/wet chemical reaction). After the biological treatment stage, the wastewater stream is ejected into an ozone reaction tank before flowing back into the MBBR. This process continuously repeats until the required reduction of pollutants has been achieved.