Team:Charlottesville RS/Project/Applications

From 2014hs.igem.org

Moores Creek Wastewater Treatement Plant

The Moores Creek Wastewater Treatment Plant (WWTP) is managed by the Rivanna Water & Sewer Authority. The purpose of the water treatment plant is to use bacteria to purify waste water so it can be released into Moores Creek. Bacteria are used to process the waste and purify the water. However, these bacteria require nourishment, so every year the plant purchases $250,000 worth of glycerine in order to feed these bacteria. Our idea is to use genetically modified E. coli to produce a bioplastic called PHB, which the bacteria that purify the waste water could consume for energy, and thus save the city up to $250,000 on the Moores Creek WWTP and potentially apply to other WWTPs as well.

How Wastewater Treatment Plants Work

1) Anoxic: Polyphosphate-accumulating organism (PAO’s) are able consume simple carbon compounds without the presence of an external electron acceptor, such as NO3 and O2. The bacteria in this step are deprived of NO3 and O2 to give the PAO’s a competitive advantage. This is done to enhance the removal of phosphorus.

2) Anaerobic: Denitrifying bacteria are supplied with NO3 from step 3 but are denied O2. The bacteria can separate the NO3 into N2 and O2 and then use the O2. (2NO3→N2+3O2) The nitrogen is now a harmless gas that evaporates out of the wastewater.

3) Aerobic: Aerators supply O2 and the bacteria convert NH3 from the wastewater into NO3 and H2. The NO3 is recycled to step 2.

4) Anaerobic: Any leftover NO3 is processed by denitrifying bacteria, but the food supply has been largely depleted and is supplemented with glycerin.

5) Aerobic: Any remaining organic material is consumed by the bacteria.

Sequencing Batch Reactor

Since we do not have as much space as the Moores Creek Wastewater Treatment Plant, so we used a sequencing batch reactor, where instead of the water flowing from step to step, the water remains in the same location and aerators are turned on and off to alternate between aerobic and anaerobic zones. Instead of just two aerobic and anaerobic zones, we used sixteen.