Carbon capture and storage (CCS) system is a technology that has been developed to reduce the carbon emission in carbon-intensive industries. Although CCS is a sustainable option for power plants, it still produces contaminants in the form of its wastewater stream. The CCS wastewater contains several contaminants that could affect both environmental and human health. This study will focus on the biological treatment of two contaminants: amines and sulfates. The main objective of this study is to design and develop an effective biological system to treat CCS wastewater to a quality that can be recycled back to the CCS process economically. The two biological treatment systems used were the Sequencing Batch Reactor (SBR) and the Sulfate Reduction, Autotrophic Denitrification, and Nitrification Integrated (SANI) system. These systems were further modified with the addition of another bioreactor containing Bacillus benzoevorans. The influent and effluent water quality was evaluated in terms of the chemical oxygen demand (COD), total nitrogen (TN), total Kjeldahl nitrogen (TKN), ammonia, and sulfate. From the first experiment, the following removal efficiency for COD, TN, TKN, ammonia, and sulfate were achieved: 95%, 62%, 88%, > 99%, and 11%, and 96%, 38%, 47%, 89%, > 99%, and 18% for SBR and SANI, respectively at low substrate concentration; 95%, 88%, 88%, > 99%, and 10%, and 97%, 79%, 85% > 99%, and 16% for SBR and SANI, respectively at high substrate concentration. Both SBR and SANI exhibited equivalent removal efficiency for COD removal. The SBR at both low and high substrate concentration exhibited greater removal efficiency in TN, TKN, and ammonia. In contrast, the SANI at both low and high substrate concentration exhibited better sulfate removal efficiency. The removal efficiency of COD, TN, TKN, ammonia, and sulfate through the addition of the B. benzoevorans resulted in 96%, 89%, 88%, > 99%, and 39%, and 97%, 81%, 94%,

99%, and 25% in SBR and SANI, respectively. The modification of the systems shows that SBR has greater or equivalent removal efficiency for all contaminants. The addition of the B. benzoevorans also exhibited an improvement in sulfate removal for both systems.