Palm oil is one of the leading agricultural crops in the world, as it dominates 34% of the global vegetable oil market, with approximately 64.6*103 million kgs of production in 2017. However, along with its breakthrough, the generation of palm oil mill effluent (POME) as uncontrolled waste has become a serious matter and requires proper management to reduce its negative effects on the environment. Subsequently, the high organic content of POME makes it possible to convert waste into value-added products, such as biogas. A ratio of 0.5 for biological oxygen demand to chemical oxygen demand (BOD/COD) indicates a high possibility for biological treatment. Recently, the utilisation of POME as a cheap source for biogas production has gained an extraordinary amount of attention, and intensive research has been conducted on the upstream to downstream process. Finding the most suitable and efficient pretreatment technique and reactor configuration are vital parameters for the treatment and conversion of POME to biogas. This review describes existing pretreatment processes for POME and recommends recently manufactured high-rate anaerobic reactors as the most suitable and efficient pretreatment technique for maximising the extraction of biogas from POME.
The current high price of crude oils for bitumen production has led to various studies on the most economical way in replacing or reducing the amount of virgin bitumen as a binder in road pavement while increasing their pavement performance. The aim of this study is to investigate the effect of using bio-oil, particularly waste cooking oil, (WCO) on the engineering properties of bitumen. Both physical and rheological properties of the original bitumen and WCO modified bitumen were measured using penetration, softening point, viscosity, loss on heating and dynamic shear rheometer (DSR) tests. In this study, bitumen 80/100 pen was modified with WCO at different percentages i.e. 1%, 2% and 3% by weight of bitumen. Based on the results, it was found that addition of WCO in virgin bitumen has softened the bitumen, thus increase the temperature susceptibility. In terms of rutting resistance, the addition of WCO up to 2% has produced modified bitumen with performance grade of PG 64 which is comparable to the original bitumen.
Coconut shell is an agricultural waste which is abundant to the environment and also rise the risk to health as well as environment. Currently, most of the researchers are investigate the use of waste material which can reduce the costof construction and increase the strength. Some of thewaste materials are used in construction for instance palm oil fuel ash, rice husk, fly ash slag, sludge, coconut shell and etc. Hence, coconut shellwas selected for this study. Generally, the chemical and physical properties of coconut shell in road construction was highlighted in this paper and compared with others raw materials. In addition, the chemical and physical characteristics of coconut shell was presented according to X-ray Fluorescence (XRF), Scanning Electron Microscopy (SEM),Fourier Transform Infrared Spectroscopy (FTIR) Analysis and X-ray Diffraction (XRD). A review of using coconut shell in asphalt mixture has better potential than others raw materials to constribute in construction field.
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