Water quality characteristic of the National Hydraulic Research Institute of Malaysia (NAHRIM) lake undergoing remediation by the constructed wetlands: a baseline study

This study was conducted to determine the baseline water quality characteristics of a contaminated NAHRIM lake undergoing remediation by the constructed wetlands, based on the physico-chemical and biological parameters. The sampling was conducted for six months (May-October) in 2016 from 5 stations of the lake and analysed using APHA standard methods for water and wastewater analysis, while Malaysian water quality index (WQI) was used to calculate quality of the lake. The results showed that, the Conductivity, Dissolved Oxygen, NO3-N, NO2-N, PO4, Temperature, Turbidity, TDS, TSS, and Zn were under class I, while pH, B and COD were categorized under class II. NH3-N, BOD, Fe, Escherichia coli, Total coliform and Mn were categorized as class III. Moreover, Al was not given any classification under NWQS but their concentration did not exceed EPA guidelines. Furthermore, as compared to the water samples from the constructed wetlands that reported a class III WQI, the lake was observed to show an overall class II WQI. This is suggestive of the retaining and remedial role of the constructed wetlands being the first point of contact for the contaminants going to the lake. Thus the lake is suitable for recreational activities

Moringa oleifera prepared via supercritical fluid extraction as an alternative coagulant for water treatment / Muhammad Azroie Mohamed Yusoff

The removal of turbidity is vital in water treatment plant operation, and is usually carried out by chemical coagulants e.g. aluminium sulphate (alum). In this study, supercritical fluid extraction (SFE) was used to prepare Moringa oleifera (M. oleifera) powder as a coagulant or bioflocculant for water treatment was studied. Relative to chemical coagulants, this bioflocculant will not cause adverse side effects towards human health and the environment. By using SFE, it can also eliminate hazardous chemicals that are used as solvents in the conventional extraction method. From 1 kg of raw M. oleifera, it produced 42% of pure M. oleifera powder, 30% of extracted oil and 28% of discarded husks. It was found that 0.01 g of M. oleifera coagulant was able to reduce more than 95% of turbidity and also reduced up to 60% in bacterial population in 1 litre of river water. In this study, we found that SFE could be used to produce coagulant from M. oleifera. The coagulant performed well and has the potential to replace alum as a main coagulant in water treatment plants. Sludge produced from these plants will be hazardous free and also will not fall in the category of scheduled waste

Analysis of Water Treatment by Moringa oleifera Bioflocculant Prepared Via Supercritical Fluid Extraction

In this study, we used supercritical fluid extraction to prepare Moringa oleifera as a bioflocculant and studied its efficacy in water treatment. Relative to the conventional solvent extraction method, supercritical fluid extraction produced 42% more bioflocculant and was a more efficient method with both time (about seven hours less) and cost savings (about USD30 less). The bioflocculant produced via supercritical fluid extraction was also smaller (18±5 µm) and more similar in size (Coefficient of Variation, CV = 28%) as opposed to conventional solvent extraction (23±8 µm, CV = 35%). It was able to reduce more than 95% of turbidity and up to 60% bacterial population. Its performance in reducing selected heavy metals from water samples was also generally better than aluminium sulfate or alum. Our study showed that with the exception of cost restrictions, M. oleifera bioflocculant produced via supercritical fluid extraction has the potential to replace alum in water treatment plants