Assessment of a submerged membrane bioreactor with composite ceramic filters for cassava wastewater treatment

Abstract

Cassava processing activity is characterised by the generation of an enormous quantity of toxic wastewater with detrimental effects on the environment if disposed of without adequate treatment. To alleviate this concern, lab-scaled cylindrical-shaped composite ceramic filters produced from rice husk and clay mixed with equal proportions of activated carbon, kaolin and sherd powder were produced and assessed in a membrane bioreactor. The permeate obtained from the filter with 2.39% rice husks, 0.95% activated carbon, 0.80% kaolin, 0.40% sherd powder and 95.47% clay gave the optimum pollutant removal efficiency. The average removal efficiencies of the chemical oxygen demand (COD), biochemical oxygen demand (BOD), turbidity and hydrogen cyanide (HCN) were 98.32, 78.93, 37.81 and 56.52%, respectively. The pH increased from 3.8 to a maximum value of 6.5. The flux ranges from 0.005 [m3.(m2.d-1)] to a maximum value of 0.108 [m3.(m2.d-1)] obtained for the filter with 1.45% rice husks. The availability of low-cost construction materials and the ease of operation makes the concept a promising option for treating cassava wastewater, however, an optimisation study is required to improve the filter performance and enhance the field applications.

Keywords

• rice husk
• environment
• clay
• environmental pollution
• activated carbon