In developing countries with increased industrialization, much research is carried out in order to recover the maximum ammonium from the environment. One of the methods to recover ammonium is Bipolar Membrane Electrodialysis (BPMED), a chemical-free technology that enables recovery and purification of the corresponding acid and base by the application of electrical energy. This thesis aims to evaluate five different BPMED cell configurations using the ammonium sulfate ((NH4)2SO4) salt. Experiments are based on evaluating operational parameters including flow rate, feed volume, base volume, and current density to achieve the maximum ammonium recovery using ammonium sulfate salt with efficient electrochemical energy consumption. Additionally, the optimum experiment was carried out with the best results of operational parameters to understand the overall impact on ammonium recovery and electrochemical energy consumption.

Removal of ammonium from simulated ammonium salt solutions was done using bipolar membrane electrodialysis (BPMED), without the use of chemicals. The effect of spacer thickness and open area on the overall energy consumption of BPMED to transport ammonium from the diluate was assessed in batch experiments. The electrochemical energy consumption decreased from 28 MJ/Kg-NH4+ to 16 MJ/Kg-NH4+ when the spacer thickness decreased from 750 μm to 140 μm.
The removal efficiencies of ammonium from the diluate increased from 77% to 85% when the spacer thickness decreased from 750 μm to 140 μm. These results show that with the increasing spacer thickness, the open area and porosity also increase, which accounts for higher resistance on the membrane stack. However, besides open area and porosity, it is the thickness of the spacer that plays a major role in higher energy consumption. This study demonstrated the energy-efficient application of BPMED for the removal of ammonium from simulated ammonium salt solutions.1