Development of biosorbents for treatment of industrial effluents and urban runoffs

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Remote connection: https://oulu.zoom.us/j/62279022669?pwd=ZFZRTmJ1dTlaVEFmRVlidGhDdW02UT09

Topic of the dissertation

Development of biosorbents for treatment of industrial effluents and urban runoffs

Doctoral candidate

Master of Science (Tech) Harshita Gogoi

Faculty and unit

University of Oulu Graduate School, Faculty of Technology, Chemical Process Engineering

Subject of study

Process and Environmental Engineering

Opponent

Associate Professor Eveliina Hanne Repo, LUT University

Custos

Docent Tiina Leiviskä, University of Oulu

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Exploration of alternative and sustainable materials for wastewater treatment

Industrial and urban activities generate large volume of effluent waters containing harmful pollutants. The presence of contaminants such as metals, metalloids and sulphates in water bodies can have critical impacts on human beings as well as aquatic ecosystem. This dissertation focused on the development of bio-based products for treatment of industrial wastewaters and urban runoffs in an effective and sustainable manner.

Although there are numerous conventional effluent treatment methods in practice, they often present certain drawbacks. With increasing importance of circular economy, it is important that alternative water treatment methods are adapted. Bio-based materials that are sustainable, low-cost and abundantly available, can be modified into high efficiency products for treating polluted waters. However, there is limited information available in literature on how such bio-based products would behave when applied for treating actual effluents. The main significance of this dissertation is the development of modified bio-based sorbents for industrial effluents and urban runoff treatment that are not only efficient but also have the potential to be adopted as sustainable alternatives to conventional treatments methods.

Three chemically modified biosorbents were produced from two Finnish raw materials, sawdust and peat. Biosorbents that were subjected to acid-based modification were applied for metal and metalloid removal from metallurgical wastewater and mine drainage. Additionally, a novel biosorbent was developed using peat, that was highly effective in sulphate removal from acid mine drainage. The sorption efficiency of the produced biosorbents was evaluated using different experimental conditions and set-ups.

Chemical modification performed on raw biomass significantly enhanced the sorptive efficiency of the developed biosorbents. Characterization studies revealed the extent of modification and confirmed the successful addition of reactive functional groups onto the surface of biosorbents. The modified bio-products presented high removal performance towards their target pollutants from real effluents under optimal operation conditions. The acid-modified biosorbents showed high affinity towards removing specific metal and metalloid pollutants. It was revealed that characteristics of the effluents being treated also played an important on the sorptive performance of the biosorbents. The novel biosorbent that was developed for sulphate removal presented exceptionally impressive performance under low pH conditions along with a rapid uptake mechanism and was recyclable, thus making it ideal for treatment of acid mine drainage.

It can be concluded that the overall performance of the biosorbents developed in this study indicated their potential to be adapted for treating a wide range of industrial effluents as well as urban runoffs.
Last updated: 19.11.2020