Taiwanese industries have, for the past 50 years, been concentrating on developing production and economic growth. This has led to a transformation of the society, but some issues, like environmental ones, have not attracted the same amount of attention during this period. This development forced the Taiwanese government to regulate industrial effluent treatment, and these days the companies have a new awareness of the importance of a balance between economic growth and environmental protection.
Environmental protection
At the Kuan Yuan paper mill, in Taiwan, a lot of effort was put into building an effective wastewater system when their mill in Taichung was built in 1984. Many other plants have learned from their example.
"Principally, enough space is the rule of thumb for good effluent treatment," says the vice president of the mill, David Hsieh. "The total area of Kuan Yuan's effluent treatment plant is almost one third of the mill area."
Efficient treatment process
All the reject from the cleaner plants and the screening plants is treated with separate thickening, filtering and dewatering equipment. The polymer mixing and flocculent system was tailor-made by ABS, using SCABA® agitators which mix the raw effluent with polymer to obtain optimum flocculation. The agitation gives very good pre-sedimentation; suspended solids after pre-sedimentation are reported at less than 30 mg/1.
No chemicals needed
Kuan Yuan has, in the past few years, installed 21 ABS TA aerators in its effluent treatment plant. The TA is a self-aspirating submersible aerator for wastewater and water treatment. Thanks to optimum aeration, no chemical treatment (e.g. chemical precipitation for removing residual chemicals) is needed after bio treatment. The ABS aerators give the pre-treated effluent the optimum COD (Chemical Oxygen Demand) and BOD (Biochemical Oxygen Demand).
The Taichung mill produces an average of 420 tonnes per day of coated duplex board. Raw materials used are 50% local waste paper and 50% European and American waste paper.
National awards
The efforts have paid off. "Today, the wastewater from Kuan Yuan's effluent plant is clean enough for raising carp!" David Hsieh adds. As a confirmation of its progress, Kuan Yuan Mfg. has received several national awards from the government for its water treatment and environmental protection.
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