Silica sand mining plant operator explains cause of blackish water
KOTA KINABALU: The dark coloured stream near the silica sand mining and processing plant in Sikuati, Kudat is a result of the decomposition of plants present in the drain channel and dead plants washed by tides to the waterway.
There was a high content of organic materials in the stream resulting in the ‘blackish’ coloured water.
According to SBH Kibing Silicon Materials Sdn Bhd’s Inhouse Environmental Advisor Elin Empau, based on a water analysis they conducted, oil and grease concentration from the baseline until January 2024 has never been over the permissible level (O&G <1).
“Excess in TSS were attributed to the rainy season, causing soil and other pollutants from the surrounding area to be washed into the waterway during rainfall events. Sediments could also be transported to the waterway by tides.
“The excess of Nitrate (NH3) and FCC content results may be linked to the upstream water containing animal wastes such as chickens and pollutants from non-point sources transported by tides. Note that the FCC baseline result had readily exceeded the limit.
“There was no sewage discharged from the project site as septic tanks were provided for the sanitary facilities onsite. The decomposition of plants present in the drain channel and dead plants washed by tides to the waterway may also produce high levels of NH,” she said.
Elin added that the environmental protection equipment and facilities in the processing plant are operating normally and are being monitored by the appointed environmental consultant, and stressed that there have been no instances of illegal discharge of pollutants from the mining and processing operation.
SBH Kibing Silicon Materials Sdn Bhd operates the silica sand mining and processing plant in Sikuati.
Recently, NGOs under the Indigenous People Network Malaysia expressed concern about a stream that has emerged, with dark water flowing into the beach.
The company’s Public Relations Manager Fred Nee during a media inspection trip to the plant on Monday explained that it has a water recycling system and does not discharge any water to the sea in the area.
“As a large volume of water is required to pump the mined sand to the processing plant as part of daily operation, there is no intention of water release. The water recycling system sees sand transported from the mining area to the processing plant via a slurry pipeline using a large volume of water,” he said.
The water that was pumped along with the sand, will be recycled to be used by other buildings in the processing plant for operation, he said, adding that wastewater will be directed to the thickener tank for sedimentation, then to the sedimentation pond (formerly known as the Emergency Response Pool).
The water will then be pumped to either the buildings in the processing plant or the mining area, depending on the specific requirements of each location, he disclosed.
The company, he added, had taken note of the villagers’ concern and in response, repaired all water canal embankments, and taken steps to block any potential overflow from the constructed water canal that could potentially contribute to the release of blackish water to the sea.
They will also ensure continuous improvement of the sedimentation pond, he said adding, “construction of trenches and reservoirs is in the planning. These trenches act as a sedimentation pond in which water is circulated, and filtered, enabling sediments to settle along the trenches.”
Auditor for Integrated Quality, Environment, Occupational Health and Safety Management Systems, Dr Raymond Alfred who also attended the briefing, said he concurred with Elin’s findings on why the water was dark in colour.
Dr Raymond in his report explained that sulphidic sediments commonly occur in environments with reducing conditions, decaying organic matter and a sufficient availability of iron and sulphur.
Sediments settling in sheltered estuarine waters commonly contain a significant amount of pyrite transported from elsewhere in the marine environment.
“Brackish tidewater contains dissolved sulphate and in sheltered waters lush vegetation quickly colonises soft muds, fuelling sulphate reduction. The highest sulphide contents are found in this environment.
“Drainage and floodwaters often provide the first indications of sulphidic alluvium or suphidic peat soils, for example, water draining from this area (i) periodically black or dark brown (looks like tea), (ii) Periodically milky, (iii) Periodically red, carrying an oily sheen or scum or depositing gelatinous or curdy ochre,” he said.
A family who lives in Kampung Andap Jawa which is within the mining area, said that the water in the streams there has always been dark in colour.
Saridah Zakaria, 63, and her daughter Lina Maidal have lived in the village for almost 18 years and said that the situation with the dark coloured water was not unusual to them.
“The land here is not suitable for agriculture,” she said, adding that attempts to cultivate crops were not successful.
Meanwhile in response to allegations by the villagers that public access to Pantai Bangau has been closed off, Nee explained that it only involved the area where the jetty is being constructed due to safety reasons.
An alternative route has been built for the villagers to use, he said.
In his report, Dr Raymond noted that the jetty is constructed crossing the beach landscape.
“However, according to the management, the beach still can be accessed by the public. The main confusion is with the current road previously utilised by the public to access the beach landscape.
“Therefore, it is recommended that the management of SBH Kibing Silicon Material (M) Sdn Bhd inform the surrounding community that the beach can be accessed for any activities,” he stressed.