Co-Digestion of Palm Oil Mill Effluent and Refined Glycerin Wash Water for Chemical Oxygen Demand Removal and Methane Production

Problem statement: Refined Glycerin Wash Water (RGWW) from the oleochemical industry contains high Chemical Oxygen Demand (COD) and requires proper treatment before disposal. Unfortunately the wash water also contains high concentration of sodium chloride (NaCl) that could cause inhibition to the normal biological treatment process. However, there is feasibility of co-digesting the RGWW and Palm Oil Mill Effluent (POME) for its treatment and methane recovery.Approach: A large 500 m3 semi-commercial closed digester tank was used to study the effect of co-digesting POME and RGWW under mesophilic condition at different RGWW percentage. The digester performance in terms of COD removal efficiency and methane production rate and stability based on total Volatile Fatty Acids (VFA) accumulation, Mixed Liquor Volatile Suspended Solid (MLVSS) and pH were evaluated.Results: At 1.0% of RGWW co-digested, both COD removal efficiency and methane production rate showed satisfactory results with higher than 90% and 505 m3 day-1, respectively. However, once the percentage was increased to a maximum of 5.25%, COD removal efficiency remains high but the methane production rate reduced significantly down to 307 m3 day-1. At this stage, the digester was already unstable with high total VFA recorded of 913 mg L-1 and low cells concentration of 8.58 g L-1. This was probably due to the effect of plasmolysis on the methanogens at high concentration of NaCl in the digester of nearly 4000 mg L-1.Conclusion: Co-digesting of RGWW with high NaCl content and POME is satisfactory for COD removal but not for increasing the methane production

An ionic liquid treatment and fractionation of cellulose, hemicellulose and lignin from oil palm empty fruit bunch

This work reports on a complete isolation and characterization of lignocellulosic compounds from oil palm empty fruit bunch (OPEFB) by ionic liquid (IL) treatment and alkaline treatment processes. The fractionated lignocellulosic compounds were confirmed by FTIR and CP/MAS 13CNMR analyses. The yield of the cellulose, hemicellulose and lignin fractions was 52.72 ± 1.50% wt., 27.17 ± 1.68% wt. and 16.82 ± 1.15% wt. with molecular weight of 1869 g/mol, 1736 g/mol and 2695 g/mol, and degradation temperature of 325.65 °C, 236.25 °C, and 201.40 °C, respectively. The SEM image illustrates the bundle-like fiber of cellulose fraction and smaller particle size of hemicellulose and lignin fractions with inconsistent shape. The XRD patterns depict the crystalline cellulose, amorphous lignin and partially amorphous hemicellulose fractions property. The IL could be recovered and reused with an overall recovery of 48% wt. after the fourth cycle

Optimization of coag-flocculation processes of a newly synthesized quaternized oil palm empty fruit bunch cellulose by response surface methodology toward drinking water treatment process application

An optimization of coagulation and flocculation of kaolin suspension by a newly synthesized quaternized oil palm empty fruit bunch cellulose denoted as a 9QC was investigated using the central composite design of the response surface methodology. The influences of coag-flocculant dosage, pH, and kaolin suspension on turbidity removal efficiency and sludge volume index responses were studied and assessed according to a 23full factorial design. The developed quadratic models revealed that the overall optimum values to obtain the highest performance of the responses were 62.5�mg/L of coag-flocculant dosage, pH 7, and 1400�mg/L of kaolin concentration. The predicted optimum responses were found to be in close proximity to the observed responses. The coag-flocculating of river water using 9QC carried out at the optimum values showed encouraging results as compared to alum which is commonly used in drinking water treatment process

Developing rigor with critical discourse analysis to examine educators' transition toward active learning

This article discusses the Focus Group Discussion (FGD) in the context of the research project investigating educators' transition traditional teaching to active learning. Engineering education researchers are increasingly interested in qualitative data analysis to study social phenomenon on teaching and learning. We describe the research design in phases that show the pragmatic approach to conduct FGD. This study employed FGD using Critical Discourse Analysis (CDA) as the methodology to develop an interview protocol. We present an analysis of a two-hour interview conducted with a group of lecturers at one of the university in Malaysia using a set of interview protocol. The interview protocol was developed following the principle of CDA to provide answers on the aspect of social practices surrounding the implementation of active learning. With CDA, the FGD interview focused on the issues, obstacles to solve the issues, role of issues in the broader context and ways for the issues to be solved. The findings revealed that FGD enables the data collection and analysis to investigate complex belief on the concept and implementation of active learning. The educators responded positively to interactive active learning activities as a medium for instruction. In addition, the analyses indicate that educators' resistance emerged from the conflicting imposter syndrome among resistance educators. Uncomfortable with the transition from teacher-centred to student-centred learning, many of them have self-doubt on what is meant by active learning. CDA shows that they have developed a feeling of competence despite evidence of being incompetent in active learning. Further to this, we begin to identify educators' epistemic knowledge on active learning which leads to the imposter syndrome

Extraction and characterization of lignin from oil palm biomass via ionic liquid dissolution and non-toxic aluminium potassium sulfate dodecahydrate precipitation processes

The objective of this study is to extract and characterize lignin from oil palm biomass (OPB) by dissolution in 1-butyl-3-methylimidazolium chloride ([bmim][Cl]), followed by the lignin extraction through the CO2 gas purging prior to addition of aluminum potassium sulfate dodecahydrate (AlK(SO4)2·12H2O). The lignin yield, YL (%wt.) was found to be dependent of the types of OPB observed for all precipitation methods used. The lignin recovery, RL (%wt.) obtained from CO2-AlK(SO4)2·12H2O precipitation was, however dependent on the types of OPB, which contradicted to that of the acidified H2SO4 and HCl solutions of pH 0.7 and 2 precipitations. Only about 54% of lignin was recovered from the OPB. The FTIR results indicate that the monodispersed lignin was successfully extracted from the OPT, OPF and OPEFB having a molecular weight (MW) of 1331, 1263 and 1473g/mol, and degradation temperature of 215, 207.5 and 272°C, respectivel