In July, I returned to Europe for a five and a half month research stint in The Netherlands. I had previously visited the Netherlands for a week, however, the only places I saw were Amsterdam and other train stations I stopped in on the way to Germany. I knew that Amsterdam was a very atypical city for The Netherlands in many ways, but the only other information I had about the country was the stereotypes about Dutch people and their country: the people are very hard working, industrious, always punctual, socially progressive and accepting of others. Most of these things turned out to be very true, which was a great thing.

I spent my time in the Netherlands living and working in the city of Wageningen, which is located in the center of the Netherlands. The town has a population about the size of the University of Arizona, and about half of those people are students. Needless to say, Wageningen is a rather small town, which had its advantages and disadvantages. One thing that was great is that I was able to bike from the two farthest points of the city in about 15 minutes, so transportation was no problem. One disadvantage to the size of the city was that all of the stores closed at 5 pm everyday, except for Friday, and absolutely nothing was open on Sundays. This proved to be quite annoying when one gets out of the lab after 5 pm on a daily basis! I worked in the Environmental Technology Department of Wageningen University and Research Center, which was located at the top of the “Mountain,” as some students referred to it. The mountain was hardly what I would call a hill, but it is a huge geographic anomaly when it is placed in the flattest country in the world. One advantage of the flat landscape was that there was quite an impressive view from the seventh floor, where my lab was located: on a clear day you could just see forever.

Dr. Piet Lens headed the research project I worked on in Wageningen, and I worked most closely with one of his PhD students, Sonia Lopes. We investigated sulfate reduction at low pH under thermophilic conditions by a consortium of anaerobic bacteria gathered from a wastewater treatment plant in The Netherlands. Sulfate rich wastewaters are produced by many industries, such as food processing and the pulp and paper industry. When sulfate rich wastewaters find there way to the sea, bacteria can then use sulfate as a form of oxygen for its metabolic pathways, and in this process reduced sulfate reacts with hydrogen to produce hydrogen sulfide, which is toxic to aquatic life in very small concentrations. When there are algae blooms in the sea, this phenomenon creates dead zones, like those seen in the Black Sea and the Gulf of Mexico, that kill aquatic life on a large scale. One option for the removal of sulfate in industrial wastewaters is biological treatment, which can be substantially cheaper than traditional physical or chemical treatment. In this process, sulfate reducing bacteria (SRB) use organic waste as an electron donor to create energy and reproduce, thus removing the organic waste and producing carbon dioxide and hydrogen sulfide as byproducts. Although the hydrogen sulfide formed in this process can be very harmful, research shows that hydrogen sulfide can be used as an electron donor in a biological process to remove mutanogenic phenolic compounds from wastewater and to form precipitates to remove heavy metals from microprocessor waste waters. So, the hydrogen sulfide produced in sulfate reduction can be put to a good use in a controlled environment.

Temperature and pH have been found to have a large effect on cell growth and sulfate reduction rates. SRB strains have been found to live and operate between a temperature range of 9 to 60°C and a pH range of 3 to 9. Depending on the microbial population, the optimal conditions for sulfate removal can lie anywhere in these ranges. The economical feasibility of SRB industrial applications may also be heavily influenced by the operating pH and temperature of the system. Since many waste streams are discharged at thermophilic temperatures and acidic pH’s, it would make SRB applications more economically viable if they could be operated at the discharge conditions and costly basic solutions and stream cooling could be avoided. At low pH’s many metals needed for growth and utilized in enzymatic pathways become soluble and can be washed out. For these reasons, the aim of this project was to investigate the effect of metal dosing on sulfate reduction and acidification at a pH of 5 under thermophilic conditions (55oC).

Due to some setbacks, such as the failure of pH controllers, a power outage, and a blown fuse, I was not able to complete all of the research goals that I had set forth in my research proposal. I did, on the other hand, get to realize all of my goals for living in a foreign country and experiencing a different culture. The presence of the university in Wageningen makes it a very international town. WUR draws students from all over Europe, the Middle East, South America, and Africa. The common language that everyone speaks is English, which made it very easy for me to communicate with people! This diverse environment the university creates enabled me not only to experience the Dutch culture, but also many others from all over the world .

A great advantage of being in the middle of The Netherlands is that it makes it very easy to travel. Public transportation being as it is in The Netherlands, incredibly efficient that is, made it easy to take trains all over The Netherlands. So, I was able to spend my weekends visiting Den Haag, Leiden, Utrech, Arnhem, Den Bosch, Nijmegen, Maastricht, and of course Amsterdam. I also got to add a very new experience to my life: the freezing cold! During the winter it was often –3oC and very windy, which made riding a bike very difficult. One of the things that I will never forget is the morning I woke up in Amsterdam to see the canals frozen! I hope I never feel that cold again in my life.

I am very grateful for all of the experiences I had in The Netherlands, whether pleasant or not. So, I must thank Drs. Jim Field and Reyes Sierra at the University of Arizona who co-sponsored my trip and connected me with the folks at Wageningen University. Thank you to Dr. Piet Lens and, soon to be Dr. Sonia Lopes for sponsoring my research at WUR. Also, a big thank you to Carol Bender and Genevieve Kenney for making my BRAVO experience possible.

Pieter Rowlette, UBRPer in Dr. James Field’s lab, Chemical & Environmental Engineering