Siti Nurjaliah Muhammad

Hybrid off-river augmentation system as an alternative raw water resource: the hydrogeochemistry of abandoned mining ponds

The use of water from abandoned mining ponds under a hybrid off-river augmentation system (HORAS) has been initiated as an alternative water resource for raw water. However, it raises the questions over the safety of the use of such waters. In this study, the hydrogeochemical analysis of the waters is presented to assess the degree to which the water has been contaminated. Comparisons were made between sampling sites, i.e. abandoned mining ponds, active sand mining ponds and the receiving streams within Bestari Jaya, Selangor River basin. The aqueous geochemistry analysis showed different hydrochemical signatures of major elements between sites, indicating different sources of minerals in the water. Discharges from the sand mining ponds were found to contain elevated availability of dissolved concentrations of iron, manganese, lead, copper and zinc, among others. However, the quality of the water (from the main river) that is supplied for potable water consumption is at a satisfactory level despite being partly sourced from the abandoned mining ponds. In fact, all the metal concentrations detected were well below the Malaysia Ministry of Health guideline limits for untreated raw water. In addition, the results of the geochemical index analysis (i.e. geoaccumulation index, enrichment factor and modified contamination factor) showed that the rivers and abandoned mining ponds were generally unpolluted with respect to the metals found in sediments.

Integrated River Basin Management: incorporating the use of abandoned mining pool and implication on water quality status

AbstractExploring alternative water resource has been an option in an Integrated River Basin Management approach for Selangor River Basin, Malaysia. This includes the use of abandoned mining pool water as additional raw water resource to downstream water treatment plants. Monitoring of water quality along Selangor River was performed at selected locations within the river basin including active (sand mining) and abandoned mining pools to evaluate on current water quality status of the river for raw water supply. Measured variables were compared with the recommended acceptable value by the Ministry of Health (MOH) for guideline compliance. Generally, the abandoned mining pools were classified as Class II according to Water Quality Index sufficient to be used as alternative water resource in terms of water quality and have metal contents below the recommended acceptable values. The water intake point of the water treatment plant downstream the river basin indicated satisfactory water quality level and in co...

Passive bioremediation technology incorporating lignocellulosic spent mushroom compost and limestone for metal- and sulfate-rich acid mine drainage

ABSTRACT Passive bioremediation of metal- and sulfate-containing acid mine drainage (AMD) has been investigated in a batch study. Multiple substrates were used in the AMD remediation using spent mushroom compost (SMC), limestone, activated sludge (AS), and woodchips (WC) under anoxic conditions suitable for bacterial sulfate reduction (BSR). Limestones used were of crushed limestone (CLS) and uncrushed limestone, provided at two different ratios in mixed substrates treatment and varied by the proportion of SMC and limestone. The SMC greatly assisted the removals of sulfate and metals and also acted as an essential carbon source for BSR. The mixed substrate composed of 40% CLS, 30% SMC, 20% AS, and 10% WC was found to be effective for metal removal. Mn, Cu, Pb, and Zn were greatly removed (89–100%) in the mixed substrates treatment, while Fe was only removed at 65%. Mn was found to be removed at a greatly higher rate than Fe, suggesting important Mn adsorption onto organic materials, that is, greater sorption affinity to the SMC. Complementary with multiple treatment media was the main mechanism assisting the AMD treatment through microbial metal reduction reactions.

Coupled physicochemical and bacterial reduction mechanisms for passive remediation of sulfate- and metal-rich acid mine drainage

Treatment of acid mine drainage (AMD) highly rich in sulfate and multiple metal elements has been investigated in a continuous flow column experiment using organic and inorganic reactive media. Treatment substrates that composed of spent mushroom compost (SMC), limestone, activated sludge and woodchips were incorporated into bacterial sulfate reduction (BSR) treatment for AMD. SMC greatly assisted the removals of sulfate and metals and acted as essential carbon source for sulfate-reducing bacteria (SRB). Alkalinity produced by dissolution of limestone and metabolism of SRB has provided acidity neutralization capacity for AMD where pH was maintained at neutral state, thus aiding the removal of sulfate. Fe, Pb, Cu, Zn and Al were effectively removed (87–100%); however, Mn was not successfully removed despite initial Mn reduction during early phase due to interference with Fe. The first half of the treatment was an essential phase for removal of most metals where contaminants were primarily removed by the BSR in addition to carbonate dissolution function. The importance of BSR in the presence of organic materials was also supported by metal fraction analysis that primary metal accumulation occurs mainly through metal adsorption onto the organic matter, e.g., as sulfides and onto Fe/Mn oxides surfaces.