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Summer 2012 Blog - Ramya Prathuri

Ramya Prathuri is spending eight weeks at the Indian Institute of Technology, Kharagpur.

August 17, 2012

After two whole months in India, coming back home to the South Bay is bittersweet.  I miss Kharagpur with all my heart – from my lab co-workers and project work to my residence hall staff.  The last few weeks went by in a whirlwind. Exactly one week ago, I and the other four interns from Berkeley gave presentations about our project work in front of an audience containing our professors, labs, and friends. I never expected the crowd to be so large! It struck me then how many people I had met and how many people I’d formed long lasting relationships with at IIT Kharagpur. All of our presentations went very well, and we then joined the audience in seeing presentations from our IIT counterparts – the five Kharagpur students who spent two months in UC Berkeley. It was very interesting to meet them after all of the presentations were over. It was as though whatever cultural gap may have existed prior our experiences was bridged by their knowledge of Berkeley and our new knowledge of IIT Kharagpur. We had dinner with them and exchanged memories… hearing them talk about Berkeley made us miss the place so much. Thankfully, I only have a few more days before I arrive on campus once again.

ramya_iit_team

IIT Kharagpur team

My project work wrapped up nicely as well. I finished collecting all of my data the week prior to the end of the program. Subsequent care of my microbial fuel cell was left to my supervisor. In the final weeks of my project, I compared the performance of an air cathode MFC to that of an aqueous MFC. These were the two MFCs I was monitoring. While the air cathode MFC has passive oxygen acting as an electron acceptor at the cathode, the aqueous MFC uses dissolved oxygen in water. Given the limited solubility of oxygen in water, the power output of the aqueous MFC is always limited by the presence of oxygen and the cathodic reaction. I compared their voltage generation and power output when given distillery wastewater as substrate. Currently, my supervisor and I are working on a technical write-up of this work, and as I mentioned, I am continuing to put together a review paper. I am glad for this, as it helps me keep in touch with my friends in Kharagpur!

These past two months have been surreal. The amount that I’ve learned seems impossible for the relatively short duration of the program. Thank you, Cal Energy Corp for this opportunity.  I hope that more Cal Energy Corps students in the future can experience IIT Kharagpur.

August 2, 2012

My work in lab has been moving along smoothly since my last post. And, with only a week and a half remaining, I’m starting to wrap things up! Both of my microbial fuel cells have stabilized over a week and a half ago, operating consistently on a feed of distillery wastewater. The bacterial biofilm appears to be as resilient as ever, withstanding days without additional organic feed, and producing a steady operating voltage. Since my last post, I’ve been doing basic daily monitoring of my MFCs in both the Civil and Biotech labs such as measuring pH, chemical oxygen demand (COD), total dissolved solids (TDS), conductivity, etc. Additionally, I’ve been studying new parameters to test my wastewater including alkalinity, total kejdhal nitrogen (TKN), phosphate content, ammonia content, etc. These tests will help me collect the final pieces of information regarding my fuel cells’ performance, when given distillery wastewater. Last week, I performed polarization tests with both of my reactors. By hooking up my reactors to a changing external resistance and monitoring the corresponding changes in voltage, I gained a great deal of information about the MFC performance including its current density, power density, internal resistance, and coulombic efficiency at various resistances. I’m currently organizing this data and processing it to further optimize my system.

In addition to my lab work, another undergraduate intern in the Civil Engineering lab and I have been working together with our supervisor on a short review paper. While this is endeavor is only in its early stages, I found that I enjoy reading technical papers and extracting the relevant information. Also, this type of work seems like a good skill to have in a future engineer’s arsenal. Given the time crunch before the program ends, we’re going to try our best to finish as much as possible. On top of this work, all of us interns are giving a presentation about our work in Kharagpur before we leave here – so we are all working hard putting the finishing touches on our projects!

After more than a month here in Kharagpur, I’ve grown much closer to the other members of my lab. It will be very difficult to part with them when the time comes… but until then I’ll be sure to make the most of my last nine days here!

July 16, 2012

Hello again! Lab work is in full swing this week, and with it comes lots to report!

Since my last blog post, I’ve spent some time with my supervisor narrowing my objective. There are two different applications of MFCs that I’m working with now. One of my set-ups employs a conventional MFC with a proton exchange membrane (PEM). It consists of a single plastic chamber containing a steel mesh and carbon cloth anode.  The cathode in this case is simply a conductive material exposed to the open air to allow the reduction reaction discussed earlier to water.

I set up my second reactor in a Civil Engineering Lab exploring the use of earthen pots as a replacement for the plastic chambers used in the Biotechnology lab. The earthen pots can do without the expensive PEM used in traditional MFC setups, and the use of common pottery makes this design cost efficient and feasible in poorer countries. The is coated in on the outside with a conductive material and used as the cathode.

My goal is to compare performances of both of these setups in terms of converting organic material into electricity. The problem arose when my earthen MFC began to lose water rapidly a week into my experiment, killing the electrogenic bacteria responsible for converting the organic material into electricity. Even before this incident, my MFC was not performing up to the usual standards given the type of inoculum and substrate I used. So, it was back to the drawing boards last week, and I began anew. So far, my new earthen MFC is performing as expected… we’ll see!

Outside of lab, the other interns and I have been trying to explore as much of Kharagpur’s surroundings as possible. And this meant visiting Kolkata as soon as the weekend rolled around. Here are some pictures from Kolkata and Digha Beach!

 

June 24, 2012

ramya_campus

Some of my colleagues on the IIT Kharagpur campus

Before discussing my project, here’s a short post about my first impressions of my new surroundings.

A geography lesson: Kharagpur is in West Bengal, India, about three hours west of Kolkata by car. Its people speak the local tongue, Bengali, a North Indian language with the same Indo-Aryan roots as Hindi (which people speak as well). English is expected at a university like IIT, but outside of the college community, English won’t get you very far.

The humidity: Having grown up on the East and then attending college in the Bay Area, I can’t say I’ve suffered too much from extreme humidity or mind-blowing heat. Kolkata graciously welcomed me with both. The blast of hot, humid air upon getting off of the plane was just a taste of what is to be my constant companion throughout West Bengal’s monsoon season. My mom, another intern, and I took a taxi on the three-hour journey to Kharagpur from Kolkata and began settling into our new rooms.

And so began our first night at IIT Kharagpur. It was illuminating. Literally, since the furious thunderstorms outside lit up the room through the curtains and made it difficult to sleep. But little did we know that with rain came crickets. Lots of crickets.

The wildlife here is pretty rich. I mean, the heat and humidity allow so many species to flourish. But it is the insects that thrive the most. That second night as we made our way back from dinner, I saw the largest gathering of crickets that I’ve ever seen in my life! Since then, we’ve taken all necessary precautions: taping up cracks in walls, covering the AC vent with a porous cloth (I saw a cricket zoom through there like some sort of cannonball), spraying down our rooms with questionable carcinogenic substances.

I’ll spend the next two months in Professor Debabrata Das’s Biotechnology lab at IIT Kharagpur, a lab that focuses on biofermentation (i.e the production of hydrogen via microorganism catabolism of organic material). Hydrogen is already an established alternative energy source, and the prospect of using recycled wastewater, a replenishable organic matter, for fuel is extremely attractive. The lab’s objective is to streamline this process to extract the greatest amount of energy from biofermentation, and to investigate the possibilities of scaling-up for use in factories.

There are many different biological pathways that facilitate hydrogen production; you can use algae, photosynthetic bacteria, or what I’m concerned with, fermentative bacteria. After the fermentative bacteria’s enzymes finish producing ethanol and hydrogen, there remains the “spent media” that still contains some unprocessed organic compounds.

ramya_microbial_fuelcell

Microbial fuel cell

Here’s where I come in. My job is to initially characterize a particular type of spent media — distillery wastewater — and then use a new and upcoming technology to process the wastewater further and extract more energy, a technology called a Microbial Fuel Cell (MFC).

A second objective of this lab is to investigate and streamline MFC technologies. An MFC is a highly promising electrolysis cell that can use organic matter to produce electricity. The theory is simple enough: microbacteria present in the anode chamber consume carbohydrate wastewater and release protons and electrons. The electrons travel through the electrode into the cathode chamber, generating an electric potential like a battery. The protons pass through a selective membrane into the cathode chamber and combine with the passed electrons and oxygen at the electrode to form the single, non-polluting product of water. Cool huh?

My goal is to generate data regarding the efficiency of my MFC by periodically taking samples of my wastewater and characterizing it. Characterization is just another way of saying that I’ll be measuring my samples along parameters including pH, Conductivity, Chemical Oxygen Demand, Salinity, and about a dozen more. You’d think I didn’t have enough to do in two months. . .

I’m sure I missed something and I’ll probably be posting a lot more specifics about my lab activity soon. There has been loads to observe here in Kharagpur — especially the colossal differences in lab etiquette and expectations. . . Until next time!

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