TITLE:
Semiconductor Wastewater Treatment Using Tapioca Starch as a Natural Coagulant
AUTHORS:
Mohd Omar Fatehah, Sohrab Hossain, Tjoon Tow Teng
KEYWORDS:
Chemical Oxygen Demand; Natural Coagulant; Response Surface Methodology; Semiconductor; Tapioca; Turbidity
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.5 No.11,
November
27,
2013
ABSTRACT: The efficiency of using tapioca
starch as a natural coagulant on semiconductor wastewater treatment was
investigated. The silica content in the wastewater was pH dependent and it was found that the reduction of COD and turbidity occurred
at pH between 12 and 14 with measurements below 100 mg/L and 100 NTU
respectively. A three-level factorial design
experiment in the Response Surface Methodology (RSM) was applied to determine
the influence of retention time and dosage of the tapioca starch. The
parameters studied were chemical oxygen demand (COD), turbidity and total
suspended solids (TSS). The R2 for turbidity, COD and TSS were 0.92,
0.92 and 0.77 respectively. Results indicate that the dosage of the tapioca
starch has a higher influence on COD and turbidity reduction. Tapioca starch as
a natural coagulant has shown that the optimum turbidity reduction was 99% at a
settling time of 30 minutes with dosage of 0.1 g/L. The COD reduction was
achieved at 87% after 60 min of retention time and 0.1 g/L of dosage while
higher coagulant dosages reduced the TSS concentration to 10.9 mg/L at
retention time between 50 to 60 minutes.