Presence of water during biodiesel production and purification processes, storage and use in compression
ignition (diesel) engines causes problems that cannot be ignored. These problems include: difficulties
in biodiesel processing especially during alkali-catalyzed transesterification process, deterioration of
biodiesel quality, decrease in heat of combustion, corrosion of fuel system components, and acceleration
of hydrolytic reaction. Beside use of water during biodiesel purification results in wastewater discharges
which causes environmental effects, due to high contents of chemical oxygen demand, biological oxygen
demand, and higher pH values. Thus, this study critically analyzed and examined the effects of water on
biodiesel production and the refining of crude biodiesel. Furthermore the effects of water on the quality
of biodiesel were also examined.