A blog from University of Borås

Wednesday, November 6, 2019

PhD thesis: Biogas or hydrogen from wood and plastics?

Biogas production from food wastes, sludge, or agricultural residuals is easy to produce. The bacteria eat these materials in an oxygen-free vessel and produce biogas or biomethane. But, what to do if the materials are not degradable such as wood or plastics? Our PhD student Konstantinos Chandolias worked on this topic, where the materials first gasified (burned with little oxygen) to produce syngas that is mixture of hydrogen, carbon monoxide and CO2. He gave this syngas to the bacteria to eat it happily and to produce biogas or hydrogen. He studied details of this process, using membrane bioreactors and to develop many technical factors. He nailed his PhD thesis today that is about "Enhanced Methane and Hydrogen production in Reverse Membrane, Bioreactors via Syngas Fermentation" and will defend it on 29 Nov. We wish him good luck.

His thesis had these papers:

1- Rapid bio-methanation of syngas in a reverse membrane bioreactor: Membrane encased microorganisms
2- Syngas Biomethanation in a Semi-Continuous Reverse Membrane Bioreactor (RMBR)
3- Effects of heavy metals and pH on the conversion of biomass to hydrogen via syngas fermentation
4- Protective effect of RMBR against syngas impurities
5- Floating Membrane Bioreactors with,High Gas Hold-Up for Syngas-to-Biomethane Conversion

Friday, October 25, 2019

PhD thesis: Membrane bioreactors for ethanol production

Membrane bioreactors (#MBR) are used so far mainly for wastewater treatment, where the reactors are fed with very diluted wastewater. The MBR provides high concentration of the bacteria to treat the wastewater faster in smaller vessels. However, the question is if we can use this technology to produce biofuels. This was the topic for Amir Mahboubi who developed MBRs for production of ethanol from lignocellulosic materials in his PhD thesis. He developed membrane processes that can handle high concentration of the material, high cell concentration, materials with bacterial contamination or even high inhibitors concentrations, where the process can run continuously in a stable condition. Today, Amir nailed his thesis that is about Immersed flat-sheet membrane bioreactors for lignocellulosic bioethanol production. He will defend his thesis on 18 Nov., and I wish him good luck.

The publications involved in his thesis are:

6-    Concentration-driven reverse membrane bioreactor for diffusion-based fermentation of highly inhibitory lignocellulosic hydrolysate


Thursday, February 21, 2019

PhD thesis: New plates and films from apple pomace and citrus wastes

Do you like orange or apple juice? Do you know while making those juices, half of the apple or orange weight is ended in the wastes? There are some research about these materials to convert it to e.g. ethanol or biogas. On the other hand, there is large global problem with plastics in the world.  Therefore, Veronika Batori tried to produce some replacement for plastics from citrus wastes and apple pomace, and she worked to make new materials and biofilms out of them in her PhD thesis that has title "Fruit wastes to biomaterials: Development of biofilms and 3D objects in a circular economy system". She published several papers is defending her thesis tomorrow. We wish her good luck!

The papers are about:

  1. Production of pectin-cellulose biofilms: A new approach for citrus waste recycling
  2. Synthesis and characterization of maleic anhydride-grafted orange waste for potential use in biocomposites
  3. Anaerobic degradation of bioplastics: a review
  4. The effect of glycerol, sugar and maleic anhydride on the mechanical properties of pectin-cellulose based biofilms produced from orange waste
  5. Development of Bio-Based Films and 3D Objects from Apple Pomace

Sunday, January 6, 2019

Flaring natural gas and producing biogas?

Russia, Iraq, Iran and USA flared (or just burned) natural gas in one year 19.9, 17.8, 17.7 and 9.5 billion m3, respectively. It means these four countries burned 2058 m3 natural gas every second. It results in 127 million tons of CO2 per year that goes to atmosphere and its energy content that is lost is 714 TWh or 61 million tones oil equivalent (mtoe). These numbers can be compared with the total energy production from biofuels and wastes in the world that is ca 132 mtoe after all the efforts in the world. It is a disappointing fact where politicians put political disputes before environmental disasters  and human life.