Organic micropollutants (MPs), in particular xenobiotics and their transformation products have been detected in the aquatic environment and the main sources of these MPs are wastewater treatment plants. Therefore, an additional cleaning step is necessary. The usage of activated carbon (AC) is one approach to provide this additional cleaning.
Industrial AC derived from different carbonaceous materials is predominantly produced in low-income countries by polluting processes. In contrast, AC derived from sewage sludge by hydrothermal carbonization (HTC) is a regional and sustainable alternative, based on waste material.
Our experiments demonstrate, the HTC-AC from sewage sludge was able to remove most of the applied MPs. In fact more than 50% of Sulfamethoxazole, Diclofenac and Bezafibrate were removed out of artificial water samples. With the same approach Carbamazepine was eliminated to nearly 70% and Atrazine more than 80%.
In addition a pre-treated (phosphorous reduced) HTC-AC was able to eliminate 80% of Carbamazepine and Diclofenac. Atrazine, Sulfamethoxazole and Bezafibrate were removed to more than 90%. Experiments using real wastewater samples with high organic content (11.1 g m3) succeeded to prove the adsorption capability of phosphorous reduced HTC-AC.