The high calcium concentration in the wastewater of the existing wastewater treatment plant had caused significant operational problems. The higher wastewater load required a modernization of the processing plant. H+E was awarded the contract.
Germany 2009
Plant Modernization at a German Paper Mill
This paper factory manufactures hygiene towels made from 100 percent recycled paper. Three paper machines deliver 105,000 tons of tissue paper per year, from colored crepe to bright white tissue. The high calcium concentration in the wastewater of the existing wastewater treatment plant had caused significant operational problems. The shift to high-quality tissue products and the correspondingly higher wastewater load required modernization of the processing plant. In addition, the high operating costs needed to be reduced, system stability had to be improved, and an environmentally friendly treatment of the wastewater had to be ensured. Since early 2009, the restructured plant has been in successful continuous operation.
Developed Solution
In 2007 H + E was awarded the contract for the wastewater treatment plant modernization. An anaerobic stage ANAFIT® with waste air treatment was constructed. The new biogas line consists of a gas storage, a biological and chemical desulfurization, a packaged cogeneration unit, and an emergency flare. The decalcification stage DECAFIT reduces the calcium content to prevent lime scale and blockages. The activated sludge plant was turned into a nitrogen elimination.
Applied Process Combination
In order to reliably prevent lime precipitation after the anaerobic stage, a decalcification stage DECAFIT has been installed. Initially, the lime / carbonic acid equilibrium is pushed towards lime precipitation in an aerated reactor and calcium crystallization is promoted. In the following flocculation, sedimentation, and thickening stage FLOCOPAC, the decalcifying process is completed. Lime mud with up to 20% of dry matter can be drawn off for disposal.
Zahlen & Fakten:
- Reduction of operating costs by 35%
- Stable system operation
- Environmentally friendly treatment
- Economical due to energy recovery of biogases
- Reduction of chemicals used