Wastewater coming from starch factories is one such
type of wastewater, which is treated extensively in
anaerobic ponds. Starch is often produced in many parts
of the world from tapioca. Tapioca roots contain 20–
25% starch. The starch extraction process essentially
involves pre-processing of roots, followed by starch
extraction, separation and drying. The process generates
20–60 m3/ton of wastewater with a low pH in the range
3.8–5.2 (Economic and Social Commission for Asia and
The Pacific, 1982). The wastewater is highly organic in
nature with chemical oxygen demand (COD) up to
25,000 mg/l (Bengtsson and Treit, 1994). The wastewater
consists of high TSS comprising starch granules in the
range 3000–15,000 mg/l, which are highly biodegradable
by nature. Tapioca starch wastewater also has high
cyanide content up to 10–15 mg/l, which is highly toxic