How many backlogs are allowed in engineering

EU pilot plant fishes drugs from hospital wastewater

Water: Drug residues in drinking water and wastewater worry consumers and researchers alike. So far there is no clear indication of how dangerous these residues actually are for humans. It is estimated that there are more than 100,000 chemical substances in circulation in Europe, around 3,000 of which are medicines.

The Federal Environment Agency (UBA) puts the amount of residues in German waters at several 100 t / year. "Better monitoring should help to identify the main stress points and ecological effects of drugs and to make medical care more environmentally friendly," says UBA President Jochen Flasbarth.

This problem is also being dealt with by the Wumenk Congress for Technologies in Medicine and Energy Efficiency in Clinics, which will take place from June 11th to 13th, 2012 in Würzburg. Under the program item “Hygiene and Technology”, the Emschergenossenschaft reports on its experiences in the treatment of wastewater from hospitals and care facilities.

Marienhospital sewage treatment plant is a PILLS showcase project

The Essen Water Management Association can draw on practical experience. In 2007, the Emschergenossenschaft took over the lead management of the cooperation project PILLS (Pharmaceutical Input and Elimination from Local Sources), in which six European partner institutions from Germany, France, Great Britain, Luxembourg, the Netherlands and Switzerland are involved. It is scheduled to be completed next September, and its total budget is around € 8 million.

The showcase project is a sewage treatment plant that was built on the grounds of the Marienhospital in Gelsenkirchen and put into operation in July 2011. “We deliberately chose the location because it is here that trace substances are concentrated in the wastewater,” says project manager Issa Nafo from the strategic river basin management department at the Emschergenossenschaft.

The Marienhospital produces around 200 m³ of wastewater every day, which until recently was discharged untreated into the Emscher system. "Especially in hospitals where the concentration of drug residues or X-ray contrast media is particularly high, treating the wastewater is extremely effective," explains Frank Netz, technical director of the clinic. The effects on human health have hardly been researched, but it is important to keep the pollution of the wastewater as low as possible, according to Netz.

Sewage treatment plant tests various processes

The sewage treatment plant has both a mechanical and a biological and chemical-physical clarification. The various stages include membrane filtration, ozonation, activated carbon adsorption followed by sand filtration. The various procedures are being combined in the ongoing test phase in order to find the best solution in the end. “There are a total of ten different combinations,” explains Carsten Bräuer, who is responsible for on-site plant operation at the Emschergenossenschaft.

The final investigations should be completed by July. “Which operating method will ultimately prevail depends on the overall package,” says Nafo. In addition to the purity of the water, material and energy costs, time and personnel costs play an important role. “Ozonation, for example, is particularly energy-intensive,” says the project manager. Against the background of increasing environmental pollution and rising energy prices, this is a factor that should not be underestimated and that is included in the assessment.

The wastewater is first freed from organic substances. "Even after this stage, the treated wastewater is comparable to the quality of bathing water thanks to the membrane filtration," explains Nafo. It is then treated with ozone. A so-called activated carbon filtration can optionally take place in a third phase. A sand filter is used to hold back the powdered carbon particles and thus also the trace substances in the PILLS sewage treatment plant, while the now clean water can first flow into the Schwarzbach and then later into the Emscher.

In times of rising costs, however, thought must also be given about how to deal with the high-quality treated wastewater, such as recycling this water. “There are enough areas of application in hospitals if this were permissible,” says Nafo. For this, however, the economic viability would have to be checked.

Only a small proportion of drugs end up in the wastewater from clinics

Anyone who thinks that hospitals are responsible for the majority of drug residues is wrong. "Only a small proportion is at the expense of the clinics, the rest is eliminated at home," says Frank Netz from Marienhospital. The burden on municipal sewage systems can therefore only be reduced in part. "However, a hospital can be a local hotspot, in which case it makes sense to reduce the inputs there before mixing it with household waste water," adds Nafo.

The findings from the Gelsenkirchen pilot plant are also to be used for other plants. Drug residues, industrial chemicals and loads of hard-to-detect poisons such as cocaine are also increasingly affecting wastewater treatment in megacities. For example, the city of New York recently invested more than $ 3 million in two projects for the treatment of drinking water and the treatment of wastewater. Here, too, the aim is to minimize drug and synthetic drug residues and to protect the human organism.

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