Innovations in Environmental Engineering: Reusing Coal Mining Byproduct to Treat Hospital Wastewater

The contaminants in hospital wastewater pose significant public health and environmental risks if released into a municipal water system. Environmental engineers at Penn State have discovered that filters using manganese oxide are highly effective at removing hazardous substances from hospital wastewater.

From harmful bacteria to pharmaceutical residues and radioactive particles, the biohazards contained in untreated hospital wastewater form a toxic soup dangerous to people and wildlife. Image Credit: United States Department of Agriculture via Wikimedia Commons.

According to statistics cited in a recent Civil and Structural Engineering article, hospital wastewater accounts for as much as 50 percent of the contaminants present in water entering municipal wastewater treatment facilities. The nature of the pollutants in the wastewater from hospitals, which includes pharmaceutical residues, bacteria and other pathogens, radiological particles, as well as toxic chemicals pose significant hazards to public health and environmental safety. Even though the concentration of these contaminants becomes diluted in municipal sewer systems, they continue to pose health and environmental hazards due to their bioreactivity.

Examples of some of the contaminants found in hospital wastewater and the hazards they pose include the following:

• Flushed pharmaceuticals like endocrine disruptors cause diseases and genetic deformities in fish and other aquatic life. (EPA)
• Bacteria, viruses, and other pathogens that tend to thrive in water often lead to outbreaks of intestinal diseases. ( Water Online)
• Silver and other toxic metals, as well as radioactive particles, from mammograms, x-rays, and other imaging technology are also found in hospital wastewater. (EPA).

While there are no specific Federal laws regulating hospital wastewater treatment in the United States prior to discharge into municipal sewer and wastewater systems, the WHO recommends the following:

• Prior to discharge into municipal wastewater systems, at least 95 percent of the bacteria load should be eradicated.
• Hospital wastewater management officials need to ensure the water discharged from their medical facilities into to the municipal sewer systems contain little to no toxic chemicals, drug residues, radioactive particles, cytotoxins, nor antibiotics.

What are the latest options for hospital wastewater managers to achieve these guidelines?

The Efficacy of Membrane Bioreactors to Sanitize Hospital Wastewater

Bioreactive membranes remove many pharmaceuticals but do not eliminate the contrast media used in MRIs and other imaging techniques. Image Credit: Sustainable Science Alliance via Flick

In 2012, a group of Swiss environmental scientists published the results of their pilot study in the journal Environmental Science and Technology.  Their research testing the efficacy of a bioreactive membrane engineered to remove pharmaceutical particles and metabolites from hospital wastewater reduces the load of these micropollutants by 22 percent. According to the authors, the reason the efficacy appears limited is due to the iodized contrast media present in the effluent. What are other options for hospital wastewater treatment?     

The Use of Ceramic Membranes to Treat Hospital Wastewater

The contaminants present in hospital wastewater are often found in freshwater samples if they are not removed onsite at the facility prior to entering the local wastewater treatment system. Image Credit: Department of Agronomy, Iowa State University via Wikimedia Commons.

In October 2014, a group of Danish environmental engineers and scientists announced their successful use of ceramic membranes in the removal of bacteria and other micropollutants from hospital wastewater. The onsite process they employed is as follows:

• Untreated hospital wastewater flows through ceramic membranes to remove bacteria and other particles.
• The next step involves treating the water with ozone and activated carbon, which removes pharmaceutical particulate matter.
• The final step involves exposing the water to ultraviolet light to remove the ozone and any remaining pathogenic materials.

According to the research group, testing indicates that this process removes 90 percent of the pharmaceutical residence and the pathogen load in the treated water was well below detectable limits.

The Promise Offered By Manganese Oxide Filters

Recently released research findings suggest that filtering hospital wastewater through manganese oxide filters may be the most effective means of treating hospital wastewater. Image Credit: United States Environmental Protection Agency via Flickr

Recently released research findings by environmental engineers working at Penn State University indicate that using manganese oxide filters sourced from coal mine drainage systems effective removes 94 percent of 21 micropollutants from hospital wastewater samples. The filters effectively oxidize pharmaceuticals and other particulate matter. In addition, the bioanalytical assays of the treated hospital affluent found that biologically active pathogens were below detectable levels. The team reports future research will focus on reducing the 24 hour treatment time required for their process.  

What would you suggest as a hospital wastewater solution?