ABSTRACT

A three–variable Box–Behnken design (BBD)  in combination  with  response  surface  methodology  (RSM)  was  utilized  to optimize  and  evaluate  the  effect of  adsorbent dose,  contact time  and  pH level  on percentage  reduction of  BOD,  COD  and  TDS in brewery  effluent.  Adsorbent was prepared from coconut shell, which was carbonized at temperature of 500oC for 1 hour and thereafter activated.  The effluent was treated with the adsorbent by varying three variables: adsorbent dosage(1–5  g), contact time  (40–180)  and pH

  (2–8).  Statistical analysis of the results  showed  that all  the  factors,  except the  contact time, had least significant effect  on the responses of Linear and Quadratic models were developed for percentage reduction of (biological oxygen demand) BOD,  chemical  oxygen  demand  (COD)  and  total  dissolved  solids (TDS).  The models  were  significant  with  p  <  0.0001  and  showed a  good fit to  the  experimental  data.  The percentage  reduction of  BOD,  COD  and  TDS  were  positively  influenced  by  adsorbent dose and  contact time.  The  contact time  range  used  for  this  study  did  not have  so  much effect on the  responses.  The optimum conditions for BOD,  COD and TDS  reduction of 81.7%, 83.8% and 94.2%  respectively  were  adsorbent  dosage of 5g, contact  time of  102.41 minutes  and  pH of 8.