Abstract:
Fisheries in Pakistan need to be made more sustainable, due to improper wastewater management
as well as lack of research in aquaculture, fish nutrition, & sustainable consumption. CO2
emissions from combustion processes in industries can be utilized more efficiently instead of being
discharged into the atmosphere causing climate change. Furthermore, there is a need to mitigate
the energy crisis of diminishing fossil fuel reserves through clean energy technologies. The
solution for all these targeted challenges is a photobioreactor (PBR). The study's methodology
involved cultivating microalgae in 9 L capacity PBR under three distinct operating systems. The
initial system employed aeration with air and fishery wastewater obtained from the Capital Biofloc
fish farm in the capital. In the subsequent two systems, Industrial CO2 and synthetic wastewater
with and without organic carbon were introduced. Remarkably, the third operational system
demonstrated exceptional efficiency in nutrient removal, specifically nitrate, phosphate, and
ammonia. Additionally, this system exhibited higher algal growth and lipid production compared
to the other setups. The microalgae generated from these systems were harnessed for lipid
extraction. Subsequently, the residual algal biomass remaining after lipid extraction was examined
to determine its protein content, essential to produce fish feed. The research analyses the feasibility
of constructing a closed system which can produce microalgae for clean energy and fish feed using
fish wastewater as well as treating wastewater simultaneously.
