15 January 2010
New contract to build an anaerobic plant
The municipal wastewater treatment plant Bitterfeld-Wolfen awards STULZ-PLANAQUA with the implementation of this trendsetting project.
Greater energy efficiency in view of global climate change – this is the premise that the operator of the municipal wastewater treatment plant Bitterfeld-Wolfen has set forth in the entirely new direction in the design of the expansion of their investment.
If the BIOHOCH® reactor technology implemented since 1994 in the municipal wastewater treatment plant was already aimed at the particularly effective exploitation of the aeration energy, the new wastewater pre-treatment plant will do completely without the energy-intensive injection of air. The exclusion of oxygen, in other words under anaerobic conditions, is used to generate biogas by special micro-organisms from highly polluted industrial wastewater – an energy source that is the latest trend of the times.
After qualifying trials in our own laboratory as well as intensive preparation and evaluation of the tender jointly with the planning agency Prof. Dr. Dr. K.-U. Rudolph GmbH from Witten, the environmental systems engineers STULZ-PLANAQUA from Bremen has been selected as the most competitive company among the European bidders.
The current municipal wastewater treatment plant developed for a capacity of 422,000 PE (population equivalent) purifies in addition to the effluent of about 70,000 inhabitants from the Bitterfeld-Wolfen region, industrial waste water from the surrounding chemical and industrial parks, where on a total of 1,700 ha around 400 companies are located. The main loads come from the 1,200-hectare P-D Chemie Park Bitterfeld Wolfen, who is also the majority shareholder of the treatment plant, the industrial park of Bayer Bitterfeld GmbH and the Technology Park Mitteldeutschland. In addition, the municipal wastewater treatment plant annually treats about 2 million m³ of contaminated groundwater under the Saxony-Anhalt “major ecological project” for rehabilitation of the site.
The expansion of production facilities at the site leads to an increased generation of waste water that is strongly contaminated with oxygen-scavenging organic material. In order to create the appropriate purification capacity in the sewage treatment plant, the existing plant needs to be expanded. The treatment of waste water with the previously proven aerobic technology would have increased the total energy consumption of the system significantly if an additional BIOHOCH® reactor was built. The alternative oxygen-free model however specifically targets the wise use of energy potential in highly concentrated industrial waste water: That biogas generated during the anaerobic decomposition of waste water substances is burned in power stations to generate heat and electricity. This covers a part of the plant’s energy demand. Compared to its current state, the annual CO2 emissions can thus be reduced by up to 4,000 tons. This corresponds to the same volume of CO2 emissions produced annually by about 580 family houses (130 m², central oil-heating systems)*, or about 28 million km travelled by car (fuel consumption: 6 l/100 km)!
The special feature of the anaerobic partial flow to be pre-treated, which creates the innovative nature of the overall project: In addition to the biodegradable organic pollutants, the waste water also contains significant amounts of sodium chloride. So far there is no technically comparable anaerobic plant that operates at such high salt loads. The company STULZ-PLANAQUA faces this task with the high-performance reactor of its sister company AQUATYX. This system has already proven itself in other challenging problems in the field of anaerobic waste water treatment. Two AQUATYX reactors will be installed in the Bitterfeld-Wolfen municipal wastewater treatment plant by 2011, which should be charged daily with an organic load of 20 tons (measured as COD = chemical oxygen demand). The plant is designed so that it can later expand to double the capacity.
The municipal sewage treatment plant invests almost EURO 12.3 million in the first stage of this landmark project. Due to its pilot nature and the contribution to climate protection, the project is funded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety with a 30% share.
With the new anaerobic stage of the municipal sewage treatment plant, STULZ-PLANAQUA is bringing a demonstration project in operation, which effect will reach far beyond central Germany because of its exemplary role for other water treatment plants.
