Assessment of groundnut (Arachis hypogaea) as a natural coagulant for water treatment

Abstract

Natural coagulants can be an alternative solution to minimise the environmental pollution and health risks caused by the use of chemical coagulants. The main objective of this research was to evaluate the performance of groundnut extract for turbidity removal from water. For this, the active coagulant agents were extracted from the deshelled nuts and used in a series of water treatment tests performed at low, medium, and high turbidity levels using synthetic turbid water. The groundnut extract showed good coagulative abilities, close to those of Al2(SO4)3. The best performance was obtained at medium turbidity (150 NTU), where the extract removed 89% of the turbidity using a 500 mg/L dosage. However, it was not as efficient as Al2(SO4)3, whose coagulation was better at every turbidity level. The use of the groundnut extract does not modify the water's pH significantly and the floc size decreases as turbidity increases, although they are bigger than those produced by Al2(SO4)3. Its flocculation and sedimentation processes are also quick (each less than 10 min) and quicker than those with Al2(SO4)3. Hence, the groundnut extract is a viable alternative to chemical coagulants. HIGHLIGHTS Groundnut extract can be used efficiently to treat water at any turbidity level.; Its application does not modify the pH of water significantly.; The treatment process is quick, less than 15 min.;

Keywords

• aluminium sulphate
• groundnuts
• natural coagulant
• synthetic turbid water
• turbidity removal
• water treatment