There are various substances in our water resources that could cause to harmful effects upon human consumption. Suspended solids (e.g. SiO2 particles) and dissolved organic matters (e.g. humic acid) are two of the common contaminants that significantly affect the water quality. The present work aims to investigate the feasibility of using poly (diallydimethylammonium chloride) (PDDA), a cationic flocculant, to purify water contaminated with SiO2 particles and humic acid via flocculation and precipitation process. Various concentrations (0.1 ppm – 1000 ppm) and molecular weights of PDDA were tested for their contaminant removal efficiency. Results showed that a mild amount of PDDA (0.1 ppm) is sufficient to completely separate 300 mg/L of SiO2 particles from its suspension (100 % removal). At this optimum concentration, the effect of PDDA molecular weight on the removal efficiency is rather insignificant. However, excess amount of PDDA reduced the removal efficiency as the PDDA may re-stabilize the SiO2 particles. The same PDDAs were tested for humic acid removal. In this case, it was found that 10 ppm of PDDA is needed to achieve effective removal of humic acid. Similarly, adding excess amount of PDDA (i.e. > 10 ppm) reduced the humic acid removal efficiency. Worth to highlight that the removal kinetic profiles appear to be vastly different for both SiO2 and humic acid, owing to the different physical natures of these two contaminants

A literature review is presented in the subject of optimization solution to solve renewable energy (RE) in the green building rating system (GBRS) to: delineate the variables in optimization; consider its significant contribution to the green innovation effort; and provides competitive advantage (CA) in green building development. The paper aims to close the gap in knowledge, by using the right methodologies in optimization as a mechanism to portray how research themes can be utilized for desired CA, and to suggest future analysis for research direction. A thematic review of RE optimization literature is undertaken for disaggregating variables towards potential CA consequences in green building development. The study has reconstructed variables in RE optimization towards appropriate CA where optimization is being identified as an antecedent of green innovation while CA as a consequence of green innovation. In this regard, green innovation would serve as a conceptual bridge between optimization approach towards gaining CA. These can be achieved since various RE optimization case studies have been presented and overcome with the improvement impact on the test system, in term of power loss reduction, increased efficiency and optimal cost outcome which also obtained as key variables for the end focus. A new framework comprises of RE optimization, green innovation, and CA is proposed and linked with some of the previous optimization reviews in recent literature.