Currently, most tapioca processing companies in South Vietnam treat their wastewater using pond systems. A study conducted in Tay Ninh Province found that all large-scale tapioca production processes in the area are treated using a biological wastewater system that includes anaerobic, facultative, and polishing ponds. The Tan Chau Tapioca Company’s treatment system consists of eight stabilization ponds that occupy 7.4 ha and can treat 1,200 m3/d of wastewater. Similarly, the Tay Ninh Tapioca Company uses twelve stabilization ponds that cover 15.8 ha and can treat 1,500 m3/d of wastewater.
The stabilization ponds installed by the companies do not meet Vietnamese industrial wastewater discharge standards. This is partly due to poor design and maintenance of the systems, as well as a lack of understanding. An ARRPET study in 2005 showed that the effluent from the pond systems in Tay Ninh Province fluctuates widely and has high concentrations of COD and BOD, with levels ranging from 88-312 mg/L and 40-174 mg/L. Additionally, anaerobic ponds fed with high organic concentrations often cause unpleasant odors, mosquito breeding, and groundwater pollution.
The Phuoc Long Tapioca Company in Binh Phuoc Province uses a treatment system that combines the UASB process with a pond system and (micro) aerobic post-treatment to treat wastewater. This system produces effluent that can be used for irrigation and fertilization of the company’s cassava fields with minimal environmental impact.
Household-scale tapioca processing units in South Vietnam typically dispose of their wastewater in city sewers or earth ponds without any pre-treatment. A study found that factories in Dong Nai Province release wastewater without pre-treatment, while those in Ho Chi Minh City discharge directly into the city’s sewage system. In Tay Ninh Province, most household-scale factories discharge their wastewater into earth ponds without any lining to prevent groundwater pollution, and many prefer to use a “no discharge” system with deep ponds.
In summary, tapioca processing wastewater in Vietnam is causing significant harm to the environment due to its high pollution levels and large volume. Many tapioca factories are located near rivers or lakes and discharge their wastewater into these bodies of water, posing a serious threat to rural areas. Since 1998, companies have been required to treat their wastewater, and many have used artificial ponds due to available land. However, this treatment is not effective enough to meet effluent discharge standards, and heavy pollution persists.
Currently, every new tapioca factory in Vietnam must provide a report on how their operations will affect the environment, and must install an appropriate wastewater treatment system. This means that the situation will significantly improve in the coming years.