A solution contains an abundance (i.e., a lot) of organic carbon (in the form of acetate, CH 3 COO- ), with COD that far exceeds the concentration of all electron acceptors in solution. In addition to ammonium and micronutrients needed for growth, the solution also contains the following dissolved species: sulfate, chloride, oxygen, nitrate, and phosphate. The solution is completely mixed in a closed reactor (with no oxygen in the headspace), and biomass is added to the reactor. The biomass does not contain nitrifiers or polyphosphate accumulating organisms. All other types of microorganisms relevant to wastewater treatment can be assumed to be present. Draw a line graph showing the change over time for each of the six compounds below. An example of an answer is shown on the right.

 

Total CH4 Produced Phosphate [mg-L-1] Nitrate [mg L-1] Oxygen [mg L-1] Chloride [mg L-1] Sulfate [mg L-1] [L] Time [hours] Compound X [units] Example Answer Time [hours]