Efficient waste water treatment processes can help reduce the pharmaceutical load released into the environment

Finnish Environment Institute SYKE, LUT University and University of Helsinki

The load of active pharmaceutical ingredients released into the environment can be reduced by treating waste water at primary sources, such as hospitals, healthcare institutes, households and pharmaceutical industry, and by boosting waste water treatment at municipal waste water treatment plants. When choosing a treatment method, particular attention should be paid to the presence of the most harmful pharmaceutical agents.

A large research project produced new information about reducing pharmaceutical emissions at primary source and municipal waste water treatment plants and studied suitable methods for reducing these emissions. It also identified pharmaceutical residues that are most harmful to the environment, and the most efficient technological solutions for their treatment.

Amount of pharmaceutical residues in waste water on the rise

Population growth and ageing increase the use of pharmaceuticals, which in turn increases the amount of their residues in waste water. Urbanisation means that pharmaceutical emissions are more localized. Pharmaceutical residues can be found in treated waste water and sewage sludge, from where they enter into the environment. These residues are also a challenge for the safe recycling of the nutrients found in urine and sewage sludge.

Pharmaceuticals are intended to be effective at low concentrations. Even though their environmental concentrations are generally low, they have been found to have the potential to impact, for example, the sexual development (hormone residues) and behaviour (residues of mood-altering medication) of organisms. In addition, there is not enough information on the mixture effects of these residues in the environment, or their cumulative interactions with other contaminants present in waste water.

“The environmental drug load can be reduced by introducing effective treatment techniques at the primary emission source or at municipal waste water treatment plants. In addition to technological solutions, environmental load should be reduced by various policy instruments, such as legislation, recommendations, guidelines and communication, to improve appropriate waste management and to reduce unnecessary medication. Studies that focus on information of pharmaceutical emissions, their environmental risks and ways to reduce them promote the implementation of the EU Strategic Approach to Pharmaceuticals in the Environment at the national level”, says Leading Expert Taina Nystén from SYKE.

Aeration tank at a waste water treatment plant in Hyvinkää. © Vanessa Riki.

With the support of Business Finland and several organisations, Finnish Environment Institute SYKE, LUT University, University of Helsinki and their partners implemented the EPIC project “Efficient Treatment of Pharmaceutical Residue at Source”. The project ran for nearly four years. The project looked at pharmaceutical residues from various emission sources, such as hospitals, healthcare facilities, the pharmaceutical industry and households, that enter municipal waste water, assessed the environmental risks of pharmaceuticals, mapped effective technical solutions and instruments to reduce the most harmful emissions and issued recommendations for reducing the pharmaceutical load into the environment.

The most harmful pharmaceutical agents

The content of hospital waste water explains the majority of certain compounds that enter the treatment plant. For example, hospital waste water has a higher antibiotic load per person than regular domestic waste water.

“In treated waste water, harmful concentrations of the antibiotic trimethoprim and non-steroidal anti-inflammatory drug diclofenac were detected. Hospital waste water had higher concentration of trimethoprim than domestic waste water, when it was the other way around for diclofenac. A risk review also identified substances that have not been measured in the environment in Finland but whose environmental concentrations are estimated to exceed the no-effect-concentration. These substances include, for example, clotrimazole for treatment of fungal infections and perphenazine that is an antipsychotic”, says researcher Lauri Äystö from SYKE.

Environmental analytic information is poorly available for several pharmaceuticals. “When assessing the environmental load, more emphasis should be given to metabolites, which can be toxic in themselves or return to their active form in the environment. In addition to chemical properties, the route of administration has a particular effect on the form in which a pharmaceutical agent is excreted”, says Tiina Sikanen, docent of the University of Helsinki and Academy Research Fellow.

Removal of the most harmful pharmaceutical agents

The project tested various removal techniques and their combinations, suitable for the removal of pharmaceutical residuals. “Oxidation, membrane filtration and adsorption methods are suitable for the removal of pharmaceutical agents. Oxidation by pulsed corona discharge removed the majority of the pharmaceutical agents. Membrane filtration is basically the only option for more extensive purification of waste water. In addition to pharmaceutical agents, membrane filtration with nanofilter or reverse osmosis system removes bacteria, viruses and nutrients”, says Professor Mika Mänttäri from the LUT University.

Costs and benefits of the treatment methods

In terms of technology, it is more efficient to remove pharmaceutical residues at the primary source where the concentrations are higher than in the municipal plant’s waste water, sludge or drinking water. If pharmaceutical residues are removed at source, it would also reduce the emissions entering into the environment in connection with sewage leakages, pumping station overflows or waste water bypasses.

Load assessment for different types of emission sources, such as healthcare facilities and households, help companies and decision makers to focus treatment methods directly on the source. In buildings under construction, such as hospitals, space could be reserved for pre-treatment of waste water.

“We also assessed the costs of the treatment methods. The most effective method is reverse osmosis but it is also the most expensive in terms of investment and operating costs. The most cost-effective solution is to combine different methods, which gives a good treatment result at reasonable cost. We were able to successfully assess the efficiency and costs of the tested treatment methods but more information is needed particularly on the difference of treatment conducted at source and a WWTP and the efficiency of removal of the most harmful substances”, says Head of Unit Jyrki Laitinen from SYKE.

The project’s extensive collaboration network promotes utilization of results

In addition to research organisations and the subcontractor Law and Water Ltd, project participants included operators in health care, waste water treatment plants, waste water treatment technology as well as in the field of water and environment. A total of 13 organizations took part: South Karelia Social and Health Care District (Eksote), The Hospital District of Helsinki and Uusimaa (HUS), Hospital District of Southwest Finland, Rinnekoti Foundation, Lappeenrannan Lämpövoima Oy, Helsinki Region Environmental Services Authority HSY, Kymen Vesi Oy, Turun Seudun puhdistamo Oy, Water Protection Association of the River Vantaa and Helsinki Region (VHVSY), WatMan Engineering Ltd Oy, Watrec Oy, Wapulec Oy and Water Utilities Development Fund.

The project results and active interaction have promoted the understanding of consumers and health care professionals of the environmental risks caused by pharmaceutical agents and the need to reduce their emissions. This increased awareness has in turn boosted the development of water treatment technologies and policy instruments.

Further information

• The final report (in English) and project publications on the EPIC project website
• Consortium head of the EPIC project, Leading Expert Taina Nystén, Finnish Environment Institute SYKE, tel. +358 (0)295 251 470, firstname.lastname@ymparisto.fi
• Emissions, risk identification and policy instruments for sustainable management of pharmaceutical agents, Researcher Lauri Äystö, SYKE, tel. +358 (0)295 251 843, firstname.lastname@ymparisto.fi
• Testing of treatment technology of waste water containing pharmaceuticals, Professor Mika Mänttäri, responsible researcher at LUT University, tel. +358 (0)40 734 2192, firstname.lastname@lut.fi
• Cost-efficiency of treatment methods, Head of Unit Jyrki Laitinen, SYKE, tel. +358 (0)29 525 1346, firstname.lastname@ymparisto.fi
• Tiina Sikanen, University of Helsinki, responsible researcher at Faculty of Pharmacy, Title of docent, Academy Research Fellow, firstname.lastname@helsinki.fi

Examples of pharmaceutical agents that were found to cause a potential environmental risk in the water body receiving treated waste water, and possible treatment methods investigated in the EPIC project.

^a) Äystö et al. 2019, Predicted no effect concentration
^b) Predicted concentration in waste water because there is no chemical measurement data available in this study or in Finland. For this reason, the removal efficiency of these substances from waste water has not been determined. Based on the molar mass of clotrimazole and perphenazine, their expected removal efficiency in nanofiltration exceeds 95%.
^c) NF (nanofiltration), RO (reverse osmosis) and PCD (pulsed corona discharge). Adsorption can also be used to remove pharmaceuticals from biologically treated municipal waste water. Degradation of compounds can be boosted by increasing the energy used for oxidation and, in case of metoprolol, complete removal within the measurement accuracy can be reached.