Abstract:
In coffee - producing countries, the uncontrolled disposal of coffee wastewater effluent is
a significant concern because it shows a high concentration of suspended solids, organics,
organic and inorganic matter, nitrate, phosphate and produces adverse effects on the
receiving bodies of water. This causes many serious health problems among residents of
nearby areas, such as spinning feeling, eye, ear, and skin irritation, stomach pain, nausea,
breathing problems, and forms eutrophication on freshwater zone. This study conducted to
investigate the coffee processing wastewater effluent potential treatment of selected natural
coagulants Acanthus stem, Aloe Vera, and Moringa stenopetala individually and in the
blend form within the framework of central composite design- response surface
methodology (CCD-RSM) for the optimization process. Grap/hand sampling technique
used, and Jar test conducted to evaluate coagulation ability by varying design parameters
such as pH (3.0, 7.0, and 11.0), coagulant dosage (0.75,1.25, and 1.75g), stirring speed
(40,80,120rpm), and stirring time (15, 30 and 45 min). Coagulation - flocculation process
experiment conducted to analyze and investigate the coffee processing wastewater
potential treatment of selected natural coagulants in terms of color, turbidity, COD,
𝑁𝑂3,and 𝑃𝑂4
3_
removal. Design expert (11.1.02) was used for statistically analyzing the
experimental data with ANOVA and to evaluate the optimum condition or value of both
process factors with respective responses. Optimum conditions and responses from the
numerical and experimental optimization system for pH, coagulant dosage, agitation
speed, and agitation time were studied. Therefore, according to the experimentally
analyzed result, the optimum conditions obtained from the numerical optimization system
for coagulant dosage, pH, agitation speed, and agitation time were 0.750g, 8.76, 80.73rpm
and 19.23min respectively when the blended form of the three coagulants namely, Acanthus
stem, Moringa powder, and Aloe-vera used as a natural coagulant. Under these optimum
responses from numerical optimization, about 99.99%,98.70%, 98.41%, 99.12% and
99.63% for Color, Turbidity, COD, 𝑁𝑂3 ,and 𝑃𝑂4
3_
removal efficiency was obtained
respectively. Even if all coagulants are best, the more effective result was found using the
blended form of coagulant for coffee effluent treatment over the individual.
