Comparative use of lime and moringa oleifera in removal of suspended solids from coffee processing effluent

Abstract

In Kenya, coffee grows in only a small part of 20% of the whole country which is arable land. It grows well between 1200 m and 2100 m above sea level and an annual rainfall of more than 1000 mm. Besides that, coffee does well in areas with red roam soil which is deep and selfdraining. It is grown by two economic sectors namely the small holder who are in cooperative societies and in small, medium and large estates. It has been identified with occasional environmental pollution threat in particular during the peak season. Such pollution has been attributed to the coffee processing wastes in particular the voluminous effluent. However, the final grading effluent which constitutes the largest component of the effluent has been recommended for recycling back to the pulping and washing operations. The washing effluent is also preferably mixed with the pulp which can subsequently be composted for agricultural use. Therefore, the pulping effluent remains as the only component in need of serious concern. Recent studies found minimization of water used for processing followed by treatment as the most practical solution towards alleviation of pollution from coffee pulping effluent. One of the postulated forms of treatment targets the removal of the suspended solids from the effluent prior to its discharge to the percolation disposal pits.