Study of Pollutant Degradation Coefficient in Natural Mangrove Forests

Abstract

Natural mangrove wetlands located at the transition zone between upland and rivers usually act as an effective pollution buffer due to their function in degrading organic pollutants (BOD) in polluted water. The efficiency of mangrove is often reported based on the percentage of pollutant removals but the associated degradation kinetics have received little attention. This study looks at the pollutant degradation coefficient, k, of mangrove wetlands by on-site experiments at the wetland of the Brunei River, which is dominated by Rhizophera Apiculata and Sonneratia Alba. The mangroves experimented on were enclosed with timber and the pool has retained partially treated wastewater. Water samples were collected at the inlet and in the pool and then tested in several runs of experiments. The typical reaction kinetic model was used to estimate k and it was found that k has a mean and median of 0.43 and 0.47 (day-1) respectively. The value of k was further modified for saline water conditions and it was estimated to be 0.28 (day-1) with salinity of up to 20 ppt. These findings provide an insight of the reactions of pollutants in mangroves and can be used in water quality modelling of tropical rivers with mangrove forests.