Modelling and Evaluation of CO2 Supply and Utilisation in Algal Ponds

A mathematical model was constructed to simulate the behaviour of an open algal pond particularly with respect to CO2 supply and utilisation. The algal pond considered takes wastewater as feed, which provides substrate for aerobic bacteria and also nutrients for the algal-bacterial consortium. CO2containing gas such as flue gas or biogas is considered as additional source of CO2 to support the growth of algae which at the same time also serves the purpose of CO2 abatement. A number of simulation studies were carried out to evaluate the performance of the system in terms of the production of algae, treatment of wastewater, and CO2 fixation and removal. Important design and operating parameters were considered, including pond depth, hydraulic retention time, composition of the feed wastewater, flowrate and CO2 fraction of the supplied gas flow, and the area utilised for gas flow induction. Several useful observations were made based on the simulation results, with the potential to provide guidance to the future practical development of multi-functional algal ponds.