Dieu (2003) found that Vietnam’s fast industrialization and urbanization are harming the environment and depleting natural resources. This is causing issues such as water and air pollution, land degradation, soil erosion, natural resource depletion, and ecosystem damage. Poor management and outdated technology in industrial production and waste treatment are among the leading causes of pollution in the country (Vietnam News, June 17, 2005).
Vietnam aims to achieve a GDP growth rate of 7.5% by 2010, while Ho chi minh City’s target is 12%. But as GDP doubles, environmental pollution may triple or quadruple. The food-processing industry is a major contributor to Vietnam’s environmental pollution, according to the Worker Newspaper in May 2005.
Below are specific categories of environmental problems in the tapioca processing industry.
Tapioca processing requires a lot of water, which is used for washing and extraction processes. This generates a large amount of wastewater that can reach up to 15 cubic meters per ton of fresh cassava root. This wastewater must be treated before it is released into the environment. The amount of water used to produce 1 ton of starch ranges from 10-30 cubic meters, and using more water for washing can improve the starch quality.
After the tapioca starch is extracted, it needs to be dried by hot air to remove water, which uses a lot of energy from sources like coal, petroleum, gas, and electricity. Producing 1 kg of tapioca starch requires about 0.320-0.939 MJ of electrical energy and 1.141-2.749 MJ of thermal energy, with 25% from electrical energy and 75% from thermal energy. (Sriroth et al., 2000a)
The tapioca processing industry produces a large amount of wastewater, which is highly polluted with organic matter. The wastewater mainly comes from the washing and extraction processes, and it is discharged into the environment after treatment. Studies have shown that the wastewater contains high levels of chemical oxygen demand (COD), suspended solids (SS), and other contaminants, which can cause significant environmental damage. In some regions of Vietnam, pollution from tapioca processing has visibly impacted wells, springs, and rivers.
A study conducted by Peter et al. (2000) in several villages of Ha Tay Province found that the processing of 1 ton of cassava roots generates 10.7 m3 of wastewater containing high concentrations of organic matter and suspended solids. Residents in these villages reported that the drinking water was cleaner during the off-season. In Tra Co village (Dong Nai Province), wastewater from tapioca processing households was found to be highly acidic and contain high levels of organic matter. The discharge of tapioca wastewater has heavily polluted Dia Spring, with high levels of BOD5, COD, ammonia, organic nitrogen, and total phosphate. During the cassava harvesting season, more than 2000 m3 of wastewater per day is generated from Tra Co village, which causes serious problems for local surface water resources.
Cassava contains cyanide, which can be harmful to the environment and living organisms. Regulations in Switzerland and Germany limit cyanide discharge in surface water to 0.01 ppm and 0.5 ppm in sewers. Fish can tolerate up to 0.1 ppm, while most micro-organisms stop functioning at 0.3 ppm. Processing cassava produces cyanide-containing wastewater that needs detoxification before discharge. A factory producing 100 tons of starch daily releases 10-40 mg of cyanide per liter of wastewater. However, high temperatures or enzyme activity can easily degrade cyanoglucosides in cassava. Groundwater sources near cassava processing factories have shown cyanogen concentrations exceeding acceptable levels. No solutions to the cyanide problem from tapioca/sago starch processing industries have been found yet.
When cassava starch is processed, the solid waste includes root skins and fibrous residues, which account for about 2-3% and 15-20% of the weight of raw cassava roots, respectively. The cassava pulp that is left still contains a lot of starch (about 50% by weight) and moisture (65-75%), so it is dried to remove the moisture and can be used as animal feed. For a factory that processes 400 tons of fresh cassava roots, about 80 tons of solid waste is generated daily. If the process is not managed well, fermentation may occur during drying and storage, leading to bad odors. Some of the solid waste is disposed of by dumping or composting, which can cause local environmental pollution and unpleasant smells.
So far, researchers have mainly explored using fibrous residues from tapioca processing to recover starch and produce food. Some studies have investigated using enzymes to extract starch from cassava pulp, and partially hydrolysed cassava solid waste has been found to have digestive function properties that could be used as food. A few researchers have also attempted to convert waste peels to reducing sugars and enriching them with microbial protein, but success has been limited.
Air pollution is mainly caused by burning fuel. A factory producing 100 tons of starch product uses about 3,500 liters of fossil oil (FO) fuel daily, which emits approximately 71 kg of SOx, 35 kg of NOx, and 9.9 kg of dust each day. To address this, factories must install an air treatment system for their boiler. Pollution also results from dust during drying, sieving, and packing, as well as unpleasant odors from storing cassava pulp. Greenhouse gases, like methane and carbon dioxide, released from the degradation of solid waste and wastewater treatment plants, also contribute to air pollution and require attention.
In recent years, other countries have helped Vietnam prevent environmental pollution. Japan’s Ministry of Economy, Trade, and Industry offered the Green Aid Program to six Asian countries, including Vietnam. The program provided necessary techniques to prevent pollution.
In May 2002, Vietnam and Sweden signed an agreement in Hanoi to cooperate on improving land and environmental management until 2009. The Swedish International Development Agency (SIDA), the Ministry of Natural Resources and Environment, and the Ministry of Industry of Vietnam agreed to provide annual financial contributions for programs related to safe chemical use, technical assistance, and environmental impact assessments. The goal is to improve policy-making capacity and law enforcement, as well as human resource development, to enhance land and environmental management at both central and grassroots levels.
SIDA is a program that supports the ARRPET project in two phases between 2001 and 2007. The project aims to research environmental issues in Asia, including wastewater, solid waste, air pollution, and hazardous waste. In phase 1 of the project, the focus was on developing a sustainable treatment method for tapioca processing wastewater in South Vietnam, and in phase 2, the aim is to promote sustainable development of the tapioca processing industry in Vietnam by using industrial ecology. Vietnam is responsible for the tapioca starch industry field, and is developing waste treatment and management methods that are robust, easy to operate, and suitable for Asian conditions. The project is exploring water reuse and recycling as alternative solutions to meet growing water demands, reduce water scarcity, and improve the quality of the environment.