Chemical Engineering and Clean Water
IntroductionHello, I’m Emily, a second year PhD student in Chemical Engineering at the University of Manchester. I have always been a keen scientist studying Chemistry, Biology and Maths at A-level before coming to the University of Manchester in 2010 to study Chemical Engineering. I completed my four year Integrated Master’s degree before continuing on with my studies by beginning a PhD in September 2014.
My research focuses on the development of fuel cells, in particular Microbial Fuel Cell which uses bacteria found in waste water to clean wastewater whilst generating small quantities of electricity. The main purpose of this research is to identify and develop a system of cleaning waste water which is less harmful to the environment compared with methods currently used.
Every day we use water. To drink, to cook, to clean, etc. We are very lucky that when we turn on our taps at home the water that comes out is clean and safe to use. However, when the water leaves our homes it is contaminated and cannot be used again unless it’s cleaned. So, how do we clean this water?
Current methods of treating wastewater are expensive as they either require large quantities of air to be pumped through the system (activated sludge reactors) or large areas of land for large reactors (trickle filter bed). They also produce large quantities of waste sludge which requires further treatment. The quantity of energy required for pumping, the damage to large areas of land and the production of sludge also makes this technology damaging to the environment highlighting a further need for a better method of cleaning water. An alternative is the use of microbial fuel cells.
Microbial fuel cells use the bacteria found in wastewater and starve it of oxygen. This prevents the bacteria from breathing and forces them to ferment, break down organic materials in water, in order to gain energy and survive. As the organic materials are broken down protons and electrons are formed. This occurs on one side of a fuel cell called an anode. These newly formed ions are forced to travel from the anode side of the fuel cell to the other side, called the cathode, following two separate routes routes. In between the sides of the fuel cell is a proton exchange membrane, this allows the movement of protons from one side to the other but blocks the movement of electrons. Meanwhile the electrons flow through wires externally of the fuel cell from one side to the other. The ions are then able to re-join on the cathode side; here they are mixed with oxygen to produce clean water.
This movement of ions is able to generate small quantities of electricity. The anaerobic nature of the anode greatly reduces the quantity of sludge produced which reduces the amount of further treatment required. The reduction of waste sludge, reduction of energy needs and the production of electricity make microbial fuel cells an ideal alternative to current wastewater treatment systems. As well as its use as an alternative wastewater treatment system, other research is ongoing which uses this technology specifically for power production or as bio-sensors.
This is a great website for general information on what it’s like to be a chemical engineer and how to become one: http://www.whynotchemeng.com/
This is the official blog by students in the School of Chemical Engineering and Analytical Science; it highlights work by both staff and students: http://www.mub.eps.manchester.ac.uk/ceasblog/
This blog highlights work being done in fuel cell technology and is run by the Governments Office of Energy, Efficiency and Renewable Energy: http://energy.gov/eere/hydrogen-fuel-cells-blog
Another blog about different types of Microbial Fuel Cells and how they work: http://www.sciencebuddies.org/blog/2014/03/microbial-fuel-cells-on-the-hunt-for-renewable-energy.php
A short video explaining microbial fuel cells by Bruce Logan, a world leader in this research: https://www.youtube.com/watch?v=ZotwUJAb8R4