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Internships Anaerobic Digestion

Netherlands, Overijssel, EnschedeInternships

Job description

For the Anaerobic Digestion engineering department we are looking for interns! The following internships / graduation assignments are available. Apply using the apply button and select the (graduation) internship you are interested in.

Design of a high rate PFR Digester

This research focuses on making a design of a PFR suitable to ferment organic material. An anaerobic digester can be seen as a CSTR; an ideally stirred tank. Organic material is added and converted to biogas. Because it is a CSTR and the residence time is relatively long (45 days), the conditions in the tank are stable, which is favourable for the process. However, with a CSTR you have the problem of leaching: if you add fresh material today, some of that fresh material will flow out again immediately, without being converted.

A PFR (Plug Flow Reactor) does not have this problem, which means that in the end a higher conversion of organic material can be achieved compared to a CSTR. However, in a PFR the conditions change continuously as the material slowly flows from start to finish. Also, digestate from the PFR will have to be actively recirculated to the beginning to start the digestion process.

Your tasks:

Familiarize yourself with all components of a Biomass Plant;

  • Literature study on the use of a PFR type reactor as a digester;
  • Modelling of the substance flows in a PFR, making an analytical mass balance;
  • Determination of the amount and position of the recirculation flow;
  • Drafting of a PID (process and instrumentation diagram) of a PFR;
  • Drafting of a basic design including components of a pilot scale (100 m3) PFR digester.

Mass and Energy Balance of the TDH

HoSt does a lot of research into new technology, such as the capture of CO2 from flue gases, and the blending of CO2 and sustainable gas. HoSt also researches the production of sustainable raw materials, such as methanol from biomass and waste. One of the ongoing researches concerns the thermal treatment of the difficult to ferment fraction after fermentation (TDH), so that more gas can be extracted from the biomass and the phosphates can be disposed of more selectively.

The research concerns: the preparation of mass and energy balances of the TDH for an installation that HoSt wants to build in Waalwijk. This is a relatively complex calculation because flows must be recirculated. It will also have to be determined whether the material must first be fermented and then separated or first separated and only thin fraction fermented. What is the consequence of thin fraction in the fermented lead or is a separate fermenter desirable?

Your tasks:

  • Analysing measurement results;
  • Draw up mass and energy balances of the TDH;
  • Determine gas production in different scenarios, determine size of additional digester;
  • Economic calculation of the best system.

Bacterial heat generation in anaerobic digestion

Suitable only for Master Students

HoSt is one of the largest suppliers of bio-energy installations in Europe. HoSt focuses on the technological development of processing biomass flows and the supply of systems for sustainable energy generation from biomass.

A digester is operated at 40 degrees, typically digesters require heating in wintertime. However for some installations we observe increasing digester temperatures in summer without external heat input. Typical for these digesters is a high feed load, and the nett. Result of the biological reactions is a higher heat generation

Your tasks:

  • Literature research: heat generation as by product in CH4 formation pathways; 
  • Setup heat balance existing digesters;
  • Identification of the specific feedstock parameters influencing Nett Heat generation by microbes;
  • Setup a model for the Heat generation by microbes based on a “theoretical” feeding menu to complete the heat balance;
  • Verify the model on existing digester pants.

Job requirements

Who are you?

  • BSc / MSc in Chemical Engineering / Mechanical Engineering / Sustainable Energy;
  • Interested in sustainable energy technology;
  • Plan-minded and independent worker.

What do we offer?

  • Working at the technology forefront of the energy transition;
  • Groundbreaking tech company in the field of biofuels, carbon capture and thermal conversion;
  • Minimum wage based on 40 hours per week for interns with an EU working license / Monthly fixed fee of € 400 based on 40 hours per week for students without an EU working license. Please note: it depends on your type of internship at HoSt which fee you receive;
  • Lots of responsibility and room for own initiatives;
  • Professional support, guidance and insights;
  • Interesting international environment only a 5-minute walk from the ‘Kennispark’ train station in Enschede;
  • Nice and sustainable welcome gift;
  • A dynamic, energetic, passionate young team;
  • Flexibility in working from home / office.


Go to to apply for this internship. General questions can be addressed to Mariëtte Huis in `t Veld, internship coordinator at For questions and more details about the internship please contact Gijs Olde Loohuis (Hiring Manager) on +31 (0) 53 - 460 90 80.

Netherlands, Overijssel, Enschede

About HoSt Group

Realising the greatest challenge we have ever known: the energy transition. That's what we do at the HoSt Group. With a strong and talented team, a deeply rooted entrepreneurial culture, innovative technologies and the many international successes and milestones, we are making this transition possible. Our team of over 375 employees, spread across 7 countries and with offices in the US and Europe, is committed to technological solutions and innovations for renewable energy worldwide and is dedicated to achieving sustainability ambitions.

HoSt Group is a large family company and came into existence in 1991 as a result of the joint-venture between Holec Projects and Stork, two well-established suppliers of energy systems. HoSt has grown into a global industry-leader in the field of technology to transform waste into bioenergy and valuable end-products. We engineer, build, and maintain bioenergy systems producing sustainable energy and valuable end-products from residual streams, striving to a zero-waste society.