Siemens has built a nitrification plant for industrial wastewater treatment in China on order of Degussa

In 2004, Degussa decided to transfer the production for producing the amino acid L-methionine for the pharmaceutical industry to Wuming, near Nanning the capital of the Guangxi Zhuang autonomous region, and to construct a plant with a production capacity of over 300 tonnes. L-methionine is used for example as active ingredient in infusion solution or in preparations for treating infections. The new production plant came into operation in the same year, and is the largest plant of its type in the world.

The manufacture of L-methionine and other products produces various types of wastewater containing carbon and nitrogen compounds. The existing wastewater treatment plant had to be adapted to match the changed production conditions. The process engineering solution chosen takes into account the reaction conditions in a subtropical climate, ease of operation, and the cost-effectiveness of the process. The plant treats some 300,000 cubic meters of wastewater per year, has no difficulty meeting the officially required discharge standards, and also has potential for future expansion of production at the Wuming chemicals site.

The concept for expanding the plant is based on a flexible two lane, cascaded bioreactor that can be connected in parallel or series, and can be run with variable gassing zones. The secondary clarification to separate the biomass from the purified wastewater has been implemented in the form of vertical flow round separators, and there is also a special facility for aerating the wastewater with fine bubbles. The excess sludge produced by the biological purification is homogenized, concentrated, and physico-chemically conditioned to enhance the dewatering characteristics of the sludge suspension. This is then maximally mechanically dewatered in a chamber filter press. The dewatered sewage sludge is then alkalinized with caustic lime to prevent further biological activity, and made ready in the storage area to be taken away for disposal.

Fuliang Xia, general manager of Degussa Rexim (Nanning) Pharmaceuticals, Co., Ltd. in Wuming, said, “We place extreme importance on wastewater treatment at our Wuming location, and we have emphasized this importance by selecting Siemens' state-of-the-art technology for the expansion of the existing wastewater treatment plant.”

Increasing attention is being paid to environmental protection in China, and in particular to the protection of water resources. There is an enormous backlog demand for the construction of industrial wastewater treatment plants. The new, central wastewater treatment plant in Wuming represents another milestone for Siemens Water Technologies' wastewater activities in the industrial sector. After the construction of a physico-chemical/thermal plant in Taizhou, the Wuming project has brought an industrial plant with biochemical nitrogen removal into operation in China.

Degussa Rexim (Nanning) Pharmaceutical Co. Ltd. is a wholly-owned subsidiary of Degussa (China) Co. Ltd., and was founded in April 2005. This company was set up in 2001 as a result of a Chinese-German joint venture between the Degussa Group and the Nanning Only-Time Pharmaceutical Co. Ltd. Some 300 people are employed at the Wuming location.

Siemens Water Technologies delivers cost-effective, reliable water and wastewater treatment systems and services to municipal, industrial, commercial and institutional customers worldwide. The division “Water Technologies” is part of Siemens' Industrial Solutions and Services Group (I&S) which is a system and solution provider for industrial and infrastructure facilities and global service provider for the plant and projects business covering planning, installation, operation and the entire life cycle. In fiscal 2006 (to September 30), I&S employed a total of 36,200 people worldwide and achieved total sales of EUR 8.819 billion.


For further information:
Siemens AG
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Mr Franz Friese
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