Manganese Detection and Removal from Surface Water: A case study from Mengkubau Water Treatment Plant

Abstract

The study of water contamination, especially in developing countries, has become more crucial in recent years as the demand for clean, drinkable water has increased. Brunei Darussalam’s primary water supply comes from surface waters, and each year, BND $ 9 to 10 million is spent on chemicals for water treatment. Recently, the Mengkubau dam, which supplies water to the Brunei Muara District, has been upgraded in terms of its height to meet the increased demand. Because of this, the amount of manganese in raw water went up, especially during the rainy season. This caused problems for the Mengkubau Water Treatment Plant (MWTP). So, a study was done to find out where the extra manganese was coming from and how it could be stopped to help solve the problems in a more cost-effective and long-term way. Rock samples from the dam and rainfall data, as well as the data for manganese concentration in the raw water, were collected to understand the source of manganese. The results showed that the rocks contributed to the manganese concentration in the raw water, which increased by almost nine folds. Furthermore, rainfall influences manganese concentration because concentration is higher in the rainy season compared to the dry season. Also, an experiment was done to see if water lettuce, or Pistia stratiotes, could be used as a sustainable and cost-effective treatment. The efficiency of manganese removal through water lettuce varies depending on the exposed weather condition. The highest removal efficiency of 97% was achieved when the water lettuce was placed in the shade.