Valorisation of Starch Wastewater by Anaerobic Fermentation

Starch production is mainly focused on feedstocks such as corn, wheat and potato in the EU, whereas cassava, rice, and other feedstocks are utilised worldwide. In starch production, a high amount of wastewater is generated, which accumulates from different process steps such as washing, steeping, starch refining, saccharification and derivatisation. Valorisation of these wastewaters can help to improve the environmental impact as well as the economics of starch production. Anaerobic fermentation is a promising approach, and this review gives an overview of the different utilisation concepts outlined in the literature and the state of the technology. Among bioenergy recovery processes, biogas technology is widely applied at the industrial scale, whereas biohydrogen production is used at the research stage. Starch wastewater can also be used for the production of bulk chemicals such as acetone, ethanol, butanol or lactic acids by anaerobic microbes.

Pembuatan nata de cassava dari limbah cair tapioka dengan menggunakan sumber nitrogen alami yang berbeda

Liquid waste from processing cassava into tapioca starch is carbohydrate-rich waste and can be used as a growth medium for the Acetobacter xylinum, which is useful in producing one of the fermentation products, i.e. nata. Several factors influence the production of nata, one of them is the addition of nutrients in the form of nitrogen in the fermentation medium. The nitrogen source used is usually from inorganic fertilizers, such as urea and ammonium sulfate. In this study, fermentation of tapioca starch wastewater was developed, using a natural sources of nitrogen derived from soybean and green bean sprouts extract. Nata was made by treating various concentrations of soybean and green bean sprouts extract (3%, 4%, 5%) and fermentation time (6 days, 7 days, 8 days, 9 days and 10 days). The characteristics of the nata product were seen from the thickness and yield of the nata. The nata de cassava product's optimum results were tested for thickness, yield, and moisture content. The results showed that the best type of natural nitrogen source was soybean sprouts extract 5%, fermentation time of 10 days with a thickness of 0.55 cm, the water content of 97.58%, and yield of 63.09%

An analysis of performance of an anaerobic fixed film biofilter (AnF2B) reactor in treatment of cassava wastewater

The cassava starch wastewater contains organic materials (as BOD, COD) in high concentrations so it has the potential to cause pollution in the aquatic environment. Several methods of cassava starch wastewater treatment have been used to reduce the concentration of organic matter (pollutants) in cassava starch wastewater, including Activated Sludge, Stabilization Pond, Anaerobic-Aerobic filter process. However, various studies continue to be carried out to get higher processing efficiency on the factors that influence it. Several factors influence the efficiency of wastewater treatment processes, including the type and origin of decomposing microorganisms, hydraulic residence time (HRT), organic load rate (OLR), process design, pH, and temperature. The research aimed to evaluate the performance of the AnF2B reactor in treating cassava starch wastewater, in which the reactor performance is shown by changes in organic matter removal (COD removal) and biogas production. The research is conducted using 3 types of AnF2B reactors wherein each AnF2B reactor contains a bee nest-shaped bio-filter as a growth medium for the consortium of indigenous bacteria. The AnF2B reactor operates in anaerobic conditions with a set temperature of 29–30 °C and a pH of 4.5–7. In each AnF2B reactor, cassava starch wastewater is fed with different OLR so that each reactor has an HRT of 5, 6, and 7 days. The concentration of COD at the influent and effluent of the reactor was measured and the biogas was produced using the APHA standard method. The results showed that the AnF2B reactor had a satisfactory performance in COD removal and biogas production, which at HRT: 6 days and OLR of 1.72 g/L·day found that the maximum COD removal was 98 % and the volume of biogas of 4.8 L/L·day was produced on the 12th day