Waste streams from industry and agriculture could be used for the production of coal that can 

serve as a cheap adsorbent for water purification. In her thesis at the Industrial Doctoral 

School, Mirva Niinipuu demonstrates that the capacity of carbon materials to separate organic 

water pollution was generally low, but that they have potential for improvement. She defended 

her thesis at Ume? University on Friday, May 24.

In order to conserve our water resources and prevent the spread of environmental pollution,

 we must have access to efficient water purification. Adsorption using activated carbon is a 

common water purification technique, but the high cost of conventional active carbon limits the 

use of this technology.

At the same time, a large number of waste streams are generated—for example by the food 

industry, agriculture, and industrial processes—that are currently not being used optimally. In 

addition to generating adsorbents for water purification, the production of coal from these 

residues would also help to reduce the cost of handling and disposing of waste. This would be 

both economically and environmentally advantageous.

The purpose of Mirva Niinipuu's doctoral thesis, which was carried out at the Industrial 

Doctoral School at Ume? University, was to investigate the ability of charred residues to 

separate environmentally hazardous organic and inorganic pollutants from industrial water.

The materials she studied were coal from tomato and olive press waste, rice husks, horse 

manure, municipal wastewater sludge, and biosludge and fibre sludge from the pulp and paper 

industry. She evaluated the effects of charring temperature and the type of starting material on 

the surface properties of the generated coals and their capacity to separate water pollutants, 

thereby clarifying which surface properties are important for adsorption. In addition, she 

investigated various chemical activations of carbon materials in order to improve their function 

as water purification adsorbents.