Pharmaceuticals are one of the main groups of organic contaminants found in wastewater. As they are repeatedly pushed into the environment and returned to the water supply, even at low concentrations, a negative impact begins to build. These impacts are felt by humans and animals, and the chemicals can be absorbed by crops, causing further problems.
The Design Problem:
Most wastewater treatment plants are designed to remove suspended solids. They are generally not able to remove pharmaceuticals. The widespread and ever-increasing use of pharmaceuticals only increases the amounts of these materials being excreted into the wastewater. Therefore, new treatment methods that can remove these materials must be developed.
Researchers at the University of Granada are now searching for a solution. While traditionally the wastewater treatment plants use an activated sludge technology, alternative new technologies are being designed using membrane bioreactors. The membrane bioreactor provides improved process control and treatment effectiveness. However, the effects of some of the more frequently detected pharmaceuticals, such as erythromycin, ibuprofen, and diclofenac, on the membrane bioreactor has not been tested. The membrane bioreactor uses a heterotrophic biomass, which may be impacted by the presence of pharmaceuticals. Therefore, the adaptive capacity of this biomass was investigated.
The team used two different concentrations of each compound to investigate the heterotrophic kinetics and organic matter removal efficiency. Over time they could then evaluate any changes to the biomass. Both the low concentration and the high concentration trials inhibited the biomass in one month or less. The system was unable to maintain its normal level of function after the introduction of pharmaceuticals.
Further work needs to be done to develop a more robust biomass. There are many other organic contaminants of concern in addition to pharmaceuticals, such as those found in personal care products and industrial runoff. As modern life creates more kinds of contamination in our waste streams, new treatments to maintain clean water must be created.
Bermudez L, Sanchez E, Diaz J, et al. Impacts of organic emerging contaminants (erythromycin, ibuprofen, and diclofenac) on the performance of a membrane bioreactor treating urban wastewater: a heterotrophic kinetic investigation. Membranes (Basel). 2023 Jul 27;13(8):697. doi: 10.3390/membranes13080697. PMID: 37623758