The Stadtwerke Halle (Halle Municipal Utilities) is not only a reliable and economical local utilities supplier and waste disposal company, it has also proven its ability to innovate by using intelligent solutions. The companies in the city utilities group point the way to the future with such projects as the process for needs-based chemical dosing to combat unpleasant odours from a sewer or the continuation of the plantation short rotation project.
Intelligent solutions to combat unpleasant sewer odours
If a sewer emits unpleasant odours, this can usually be combated by conventional means such as chemicals, which are added to the water, or by bio-filters, which can be applied in the cover.
Both procedures are cost-intensive but Hallesche Wasser und Abwasser GmbH, a subsidiary of Halle City Utilities, relies on the use of chemicals. However, the problem is how these can be mixed economically into the waste water stream as required without harming the environment. The company is working on this question together with water scientists from Halle at ECH Elektrochemie Halle GmbH and the IFT Institut für Fluidtechnologien Halle GmbH in an attempt to find the optimal chemical dose and thereby solve the problem. The scientists developed a new type of analytical procedure and the corresponding measuring techniques.
For the first time, hydrogen sulphide is being recorded here as an indicator of sewer odours, both in waste water and the atmosphere. This is the “new” aspect of the “SULPHOX-4 Method” and in fact, the analyser measures already minute traces of hydrogen sulphide.
There had always been unpleasant odours at the transfer point of pressure pipes to the non-pressure sewer, so a ferric salt solution is now being added to the inlet to the building and into the atmosphere. The result will be analysed by a hydrogen sulphide measurement. The data-logger gives a signal via a control programme to a dose-pumping machine for the reactive chemical, which results in the ferric salt solution being added precisely. Overdoses, which often occurred during rainfalls, can now be avoided. Since the use of intelligent dosing has started, there have been no more unpleasant odours, treatments costs can be considerably reduced and damage to the building from biogenous sulphuric acid can be avoided.
Obtaining renewable energies
The Stadtwirtschaft Halle, a subsidiary of the Halle Utilities Company, together with Hallesche Wohnungsgesellschaft mbH (Halle’s Housing Company) and Bau- und Wohnungsgenossenschaft Halle-Merseburg e. G. (construction and housing cooperative) erected what is now the third plantation short rotation project at Silberhöhe, a suburb on the south edge of Halle. This so-called “energy forest” consists of fast-growing trees which are cut down after only a few years and then processed into biomass. In this way, renewable energy or heat can be generated. In addition, the plantations of trees make the living environment at Silberhöhe greener and do not complete with food production since the tree plantations in Halle are on land that used to be the former site of prefabricated high-rise apartment blocks as opposed to farmland. This project is an integral part of the beginnings of core biomass competence in the Halle and Saale County regions.
The fact that fossil fuels such as coal or natural gas are only available in limited quantities is general knowledge, which is why the focus on the production of renewable resources will be a principal task for the next few decades. The Halle Municipal Utilities is confronting this issue in the field of biomass as well as eco-power, solar and water power. The Stadtwirtschaft Halle is using and conducting research into these energy carriers and is continuing the successful “plantation short rotation” work.
Already in 2007 and 2008, the Halle Municipal Utilities established two “energy forests” in Halle-Neustadt near Lüneburger Bogen and Osnabrücker Straße. The first plantation was planted with 18,000 balsam poplar seedlings, which have now reached a height of 1.5 to 3.5 metres and could be harvested in the 2009/2010 winter. The second plantation has been planted with 9,000 balsam poplar seedlings and 1,000 robinia seedlings. The seedlings are currently at knee-height and given their current rate of growth, could be harvested in winter 2011/2012 at the earliest.
With the experience gained from these projects, the third short rotation forestry plantation will be operated on a 9,000-square-metre-large former housing property with 8,000 seedlings.
In future, the Halle Municipal Utilities intends to use biomass in increasing amounts in order to make energy recycling with other materials more effective. For the housing companies, the implementation of energy forests of this nature is of enormous significance in the designing of tracts of land at the edge of a large residential area.
The author has been chairman of the management team at the Stadtwerke Halle GmbH since 2005. He is general manager of the subsidiary Hallesche Wasser und Abwasser GmbH and of Abfallwirtschaft GmbH Halle-Lochau. Klose studied water management at the Dresden Technical University and, from 1966 to 1989, worked as a graduate engineer in various areas of the former East German VEB WAB Halle.
The author is general manager of Stadtwerke Halle GmbH and commercial manager of Stadtwirtschaft GmbH Halle. With a degree in commerce, he was previously group controlling manager and head of division at Stadtwerke Halle GmbH. After completing his studies at the University of Göttingen, he was a business field manager at the auditing company Rödl & Partner in Nuremberg.