Effect of nitrogen and phosphorus concentration in the water of stormwater constructed wetland to freshwater phytoplankton distribution (10 years establishment): Case Study in Universiti Sains Malaysia

Syafiq Shaharuddin, Aminuddin Ab. Ghani, Nor Azazi Zakaria, Chang Chun Kiat

Wednesday 1 july 2015

9:15 - 9:30h at Asia (level 0)

Themes: (T) Hydro-environment, (ST) Impacts of pollutants on the water environment

Parallel session: 8G. Environment - Impact

The understanding the implication of biotic component, especially freshwater phytoplankton in the man-made stormwater constructed wetland under tropical climate condition in Malaysia still rare and less documented. Thus, the aim of the this study is to investigate the effect of nitrogen and phosphorus removal (as an important element for freshwater phytoplankton) in the stormwater constructed wetland in Universiti Sains Malaysia (USM), which designed based on Urban Stormwater Management Manual for Malaysia (MSMA) first edition, 2001, to the freshwater phytoplankton communities, as a primary food chain in aquatic life. This paper also will elaborate the detail design of stormwater constructed wetland during the first construction design was being made. Four (4) main nutrients was measured; nitrite, nitrate, ammoniacal nitrogen and orthophosphate, together with other supporting data such as water temperature, total suspended solid, biochemical oxygen demand (BOD), chemical oxygen demand (COD), pH, DO and conductivity. The phytoplankton sampling was conducted at the same time of water quality sampling. The results showed that the concentration of nutrient (especially nitrogen and phosphorus) continuously reduce when enter to throughout the constructed wetland for nitrite (80%), nitrate (61.56%), orthophosphate (60.98%) and NH4-N (51.49%) before it discharge to the outlet. Based on this nutrient concentration reduction pattern, species diversity (H’) measured for phytoplankton showed decreasing in number as well as number of individual species and types of species. The dominance species represented by the dominance group Chlorophyta are Coelastrum microporum, Mougeotia sp and Westella botryoides. The freshwater phytoplankton distribution is strongly correlated with the reduction of nutrient concentration, however, for the other biotic component such as freshwater fish, inverse relationship found with the freshwater phytoplankton due to other factors such as the water depth design and water temperature in this constructed wetland. KEYWORDS: Constructed wetland, Water quality, Biodiversity, Stormwater runoff