Methodology
​The following steps were followed during the experimentation phase of this thesis:​
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- Decide on a population size (136 500 people) and the average daily wastewater contributions per person
- Decide on an appropriate diurnal flow pattern to be modelled in the wastewater treatment plant software (shown in 'Figure a' on the right)
- Perform computer-aided diurnal (daily-fluctuating) simulations of different levels of urine separation in UCTPHO simulation software (shown in 'Figure b' on the right).
- Run two sets of simulations at each urine separation level: one where the WWTP is left unchanged and one where the WWTP is optimised for Nitrogen Removal
- Show the steady-state, maximum and minimum daily effluent concentrations for Ammonia, Nitrogen and Phosphorous
- Show the gains in capacity (gains in capacity come from a reduced organic load on the bioreactors with increasing urine separation) for the unoptimised and optimised setups
Figure a
Figure b
Objectives
The objectives of this thesis were to:

- Through the use of computer-aided modelling, show the impact of urine separation on the effluent Ammonia, Nitrate and Phosphorous concentrations, for both an unchanged (unoptimised) and optimised WWTP setup.
- Investigate the impacts of increasing levels of urine separation on the size, capacity and operational complexity of both an unchanged (unoptimised) and optimised WWTP setup.
- Investigate at what level (if this level exists) of urine separation Nitrification will no longer need to be sustained to facilitate full N removal (i.e. all N will be removed by bacteria growth).
- Show the potential benefits and drawbacks of using this technology by focussing on the impacts at WWTPs and commenting on the broader impacts to society.
EXPERIMENTATION
Hypothesis
Because urine separation was applied to two different WWTP setups (unoptimised and optimised), there were different hypotheses for each setup.

For the unoptimised setup, it was expected that the capacity increases would be relatively low but the improvements in effluent quality would be greater. For the optimised setup, it was expected to see lower improvements in effluent quality but larger increases in capacity. The reason for this was because the optimised setup was designed to be 'on the edge' with respect to nutrient removal, in order to facilitate the larger gains in capacity.