Cleaning Toxic Wastewater With Used Toilet Paper
Medical waste in wastewater is becoming a significant problem in the water purification process. The Water Authority ‘Vallei en Veluwe’ in the Dutch city of Ede, developed a unique way to purify this toxic water using ‘used’ toilet paper.
Image: Sarah Hall-Kirchner
Medical waste is proving to be an increasing problem during the purification process of wastewater. It can harm animal- and plant-life when medical drug residues find their way into surface water. Water Authority ‘Vallei en Veluwe’ came up with a solution to use the carbonic elements of used toilet paper to isolate the toxic parts of medical waste.
Carbon is well-known for its absorbing capabilities. It can absorb many types of components, among them medical waste.
How does it work?
The process of extracting the carbon from toilet paper goes as follows: dried up paper is pressed into cellulose rich cubes and placed in a so-called pyrolysis oven. While adding oxygen to the heating process, the particles smolder – just like when you light up a barbeque. During the process, steam comes in contact with the cubes, essentially turning them into active carbon. The particles can then be used to treat medical waste in wastewater.
The acids that are released during the smolder process, can be used to recover phosphor and better remove nitrates. In addition to that, the derived bio-oil can be sold as fuel.
Not all toxic waste can be removed with active carbon. Different types of waste require other types of chemical processes . Some can be removed with ozone, others with membranes.
Water Authority ‘Vallei en Veluwe’ are currently building a test facility in Ede. The plant will purify one third of the city’s wastewater, getting rid of 80% of medical waste that generally contain parts of oxazepam and benzotriazool. Ultimately the organization wants to reach a 90% or higher purification rate.
The test plant costs € 1.2 million, € 700,000 of that is part of the EU Interreg-grant. The goal is to commercialize the project, eventually resulting in reduced water taxes for Dutch households.
If the project is successful, the authorities also want to use roadside clippings and slush from the paper manufacturing industry to purify the water.