The yellow water issue often occur after prolonged rain, causing flooding at several raw water catchment areas of Tutong River. This is followed by less rainfall that led stagnant water from the flood to flow back into the river.
This will cause raw water colour to turn darker from minerals namely manganese as well as soil flow via surface runoff. Manganese can be naturally found on water surfaces or in the soil. This year, manganese content in river waters especially at Tutong River has drastically increased, exceeding JASTRe's content limit standards for river water.
The drastic increase is due to several factors namely upstream rain water that starts to flow into the river; development, excavation activities and others. After raw water is treated at the plant, the processed water will be delivered to tanks. Due to high manganese content in the water, there is chemical reaction in the delivery process, leading to a change in the water's colour.
The Public Works Department, Ministry of Development is monitoring water quality at water treatment plants, water tanks and water samples. The department also introduced a temporary chemical dosing system aimed at neutralising the manganese content in raw water.
The department also slows down the water treatment process to enable optimal chemical mixing; make optimal chemical coordination to neutralise manganese content in raw water; introduced aeration system to assist in reducing manganese content in raw water; make detailed study on manganese content in river water by identifying river pollution site; and conduct flushing in pipe systems as well as take water samples at affected areas.
In this regard, the public is advised to make sure that their water tanks and filters are clean by carrying out flushing and backwashing, and call Talian Darussalam 123 for water quality complaint. Manganese in the water will cause water colouration and produce sediments in the long term. The public can turn on the pipe and let the water flow until it loses colouration, and to boil the water first before consumption.
Source: Radio Television Brunei