Cellulose and microcrystalline cellulose (MCC) were isolated from waste Leucaena leucocephala seeds (LLS) by using acid hydrolysis method. Waste LLS are unused residues after extraction of oil for conversion to biodiesel. Cellulose from LLS (LLS-cellulose) has been isolated by using 80% acetic acid and 65% nitric acid to yield 33% cellulose. MCC was further prepared from the LLS-cellulose via the acid hydrolysis method and yield 71%. The obtained LLS-cellulose and LLS-MCC samples were comparatively investigated by Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy technique (FESEM). FTIR second derivative showed the presence of minor amounts of bound hemicellulose and relatively free of lignin compound. The crystallinity index of LLS-cellulose is higher than LLS-MCC, indicating higher crystallize size and thermal decomposition. FESEM image also showed that there is smooth surface of raw LLS after hot boiling extraction for 2 hours. Thus, this study revealed that the lignin and hemicelluloses can be removed efficiently by using hot water treatment. In addition, cellulose components produced from waste LLS could be used as precursors of other industrial applications.

Incineration is one of the options available to dispose municipal solid wastes (MSW) as it is capable of breaking down hazardous non-metallic wastes besides destroying bacteria and viruses. In terms of volume of wastes, incineration can reduce almost instantaneously by 90 %. In 1998, the government of Malaysia embarked on a pilot project to use incinerators to dispose MSW in four popular resort islands to see the effectiveness of this technique of waste disposal. Seven units of mini incinerators were installed on the islands and the local municipals were made responsible to manage and maintain.This project looked into the problems arises when incineration is used for MSW disposal on these islands. Data collected revealed that the plants were not properly managed and maintained. This was due to the lack of funds available for effective and smooth operation and the absence of highly expert personnel required to maintain the plant. Other factors that contribute to the inefficiency are inadequate air pollution control facilities and the infrastructure which do not condon the foul odour. Further research work need to be done to monitor the operation of these incinerators in order to explore its potential to dispose waste safely, effectively and cleanly.

The waste seeds of Leucaena leucocephala (LLS) used in this study were unused residues obtained after oil and polysaccharides extraction. The microcrystalline cellulose (MCC) was isolated from LLS by acid treatment. MCC produced was, then, further converted to glucose by using sulphuric acid at 121 °C by varying the acid concentration and reaction time. The sugar composition was analyzed by using the phenol-sulfuric acid method and pre-column derivatization HPLC technique. The yield of glucose ranging from 70–85% could be obtained from MCC hydrolyzates, depending on the hydrolysis factors, which corresponding to around 57-75% of the percentage conversion of MCC to glucose.Cellulose isolated from LLS was, therefore, potentially suitable to be utilized in liquid biofuels and other value-added chemicals such as bioethanol, 5-hydroxymethylfurfural(HMF), and levulinic acid.

Investigation on the thermal degradation characteristics and other properties of Jatropha Curcas L. (JCL), sewage sludge and their combination was carried out to assess their viability for bio-oil production. Proximate and ultimate analysis was conducted on all the samples. Volatile matter content for sewage sludge was in the range of 23 to 40 weight percent while JCL was more than 85%. The volatile matter fraction of sewage sludge was enhanced up to 65 to 75% by mixing the sewage sludge with JCL, at a ratio of 30:70. Thermogravimetric (TG) analysis revealed the volatile matter content of the different samples increased proportionally to the bio-oil yield. JCL decomposed from 200 °C-550 °C whereas sewage sludge from 190 °C-550 °C. The combination feeds decomposed from 210 °C-600 °C.Production of bio-oil through pyrolysis is an interesting method since the majority of feedstock was made up of non-food resources and thus eliminating competition against food commodities. The groups of compounds detected were aromatics, ketones, amines, aldehydes and most importantly alkanes, alkenes which could be converted into valuable fuel as replacement for transportation fuel. Results indicated that a higher content of bio-oil could be produced from the combination feedstock and also produced low char compared to the individual sewage sludge sample.