October 24, 2011
Kurita Develops and Begins Sales of the Biosaver™ TK, a Carrier-Type Anaerobic Water Treatment System Applicable for Low-Concentration Wastewater
-- A Biotreatment Technology Enabling Energy Conservation and Waste Reduction in Wastewater Treatment --
Kurita Water Industries Ltd. (Head Office: Shinjuku-ku, Tokyo; President: Toshiyuki Nakai) has developed and commenced selling the Biosaver™ TK. A new biological treatment technology, the Biosaver™ TK purifies low-concentration organic wastewater, which would be difficult to treat with conventional anaerobic biological treatment systems(*),using carriers with anaerobic microorganisms attached.
An anaerobic treatment method using granules (bacterial granules) has been widely used as a method for treating organic wastewater, mainly in food and beer factories. However, this method had a shortcoming: the granules are difficult to maintain in wastewater with low concentrations of organic matter or wastewater consisting of a single composition, such as methanol or acetic acid, which makes stable operations difficult and application of anaerobic treatment impossible.
The latest anaerobic treatment technology from Kurita features use of new carriers, which enable the technology to be used for the treatment of low-concentration wastewater, too. This permits energy conservation and waste reduction in wastewater treatment.
This method also has advantages over aerobic treatment(*), which has been widely used for organic wastewater, including: 1) a smaller reaction tank, at one-third to one-fifth, or even less, the size of those used for aerobic treatment; 2) halving of power costs; 3) reduction in surplus sludge to less than a quarter, and; 4) ability to reuse as fuel the methane gas generated in the treatment process.
- (*)Microorganisms are commonly used for treating organic matter contained in wastewater. There are two types of treatment methods. One is aerobic treatment, which has microorganisms decompose organic matter in the presence of oxygen. The other is anaerobic treatment, which decomposes organic matter without any oxygen. The method used depends on the type of microorganism. Anaerobic treatment has advantages over aerobic treatment, including lower power consumption, the generation of reduced surplus sludge, the reusability of methane gas generated in the process, the potential for high-load treatment, and compact reaction tanks.
Supporting Data: About the Biosaver™ TK
- 1)Anaerobic treatment has traditionally been unsuitable for use in treating low-concentration wastewater or wastewater consisting of a single composition, such as methanol or acetic acid, because of a technical problem: granules become difficult to maintain in low-concentration wastewater, making stable treatment difficult.
Consequently, anaerobic treatment has been used only for medium- and high-concentration wastewater. A technology that would permit widespread application of this method, including use with organic wastewater, while ensuring stable operation was needed.
- 2)Anaerobic treatment has been used mainly for food factories, beer breweries, and other sites that continuously generate high-concentration wastewater. However, with rapidly growing needs for energy conservation and waste reduction, demand for anaerobic treatment systems has also been growing in markets and industries where anaerobic treatment had not been used before.
2. Measures of Kurita
Kurita is a leader in Japan in biological treatment technologies for treating wastewater. The Company has also delivered a large number of anaerobic treatment systems, mainly to domestic customers.
To broaden the range of application of anaerobic treatment and expand its market, Kurita has leveraged its technologies and know-how in system operations to develop and launch the Biosaver™ TK, an anaerobic treatment system that can be used for treating low-concentration wastewater as well.
3. Biosaver™ TK, a Carrier-Type Anaerobic Water Treatment System
In this system, the reaction tank is filled with flowable carriers for anaerobic treatment and anaerobic microorganisms are attached to the carrier surfaces. This permits high-load, stable treatment of wastewater with low concentrations of organic matter or wastewater consisting of a single composition and highly efficient elimination of organic matters (with elimination efficiency at 80% or higher).
The system can also be used in diverse conditions (concentrations, components, and temperatures) and is highly resistant to load fluctuations. As well as organic wastewater from food factories, where Kurita systems have a proven track record, the Biosaver™ TK can be used for wastewater with a broad range of properties, including organic wastewater from chemical plants, paper mills, and liquid crystal and semiconductor factories.
Moreover, the system permits a significant reduction in operating costs with its advantages over aerobic treatment, including: 1) a smaller reaction tank, at one-third to one-fifth, or even less, the size of those used for aerobic treatment; 2) halving of power costs; 3) reduction in surplus sludge to less than a quarter, and; 4) ability to reuse as fuel the methane gas generated in the treatment process.
<Features of the Carrier for Anaerobic Treatment>
The new carrier is made of resin and comes in a structure with a layer of microorganisms formed on the surface. The carriers move slowly in the tank as they treat wastewater, and their structure prevents microorganism dissolution and leakage.
The carrier has the following features:
- 1)The irregular surface holds a large amount of microorganisms.
- 2)It is heavier than water so its sinking velocity is high.
- 3)The structure permits biogas to be released easily.
4. Future Development
It is expected that demand for anaerobic treatment, which contributes to energy conservation and waste reduction, will increase in the future, leading to growing demand for the Biosaver™ TK. Kurita will use this latest system for new water treatment facilities and for enhancing existing facilities, aiming to apply anaerobic treatment across broader industrial fields.
Kurita will also continue its efforts to strengthen the biological treatment technologies it has developed, including those for aerobic treatment, and to enhance the competitiveness of its products. In doing so, the Company will strive to expand its businesses in the field of industrial wastewater treatment, not only in Japan but also in overseas markets where demand for clean water has been growing rapidly.
- *Biosaver™ is a trademark of Kurita Water Industries Ltd.