GEA environmental Decanter prime: Tailored, efficient wastewater treatment that generates resources for municipalities, industry and agriculture. GEA varipond® – a success story: Fully automatic control system to simplify and optimize sludge treatment
The IFAT Environmental Trade Fair 2018 will see GEA present the environmental Decanter prime: a solution to generate energy and recover resources from wastewater, sludge, manure and fermentation residues that can be tailored to each individual client’s requirements. The prime line boasts seven machine sizes with throughput capacities of 15 m³/h to 300 m³/h. As a result, the system is ideally suited for large volumes. Due to the increased focus in technical development on rising costs and growing public environmental awareness of energy consumption, the specialists at GEA have also closely re-examined the system’s energy balance. On the basis of over 125 years’ experience with centrifugal separation technology, they successfully applied a unique machine design to optimize the prime line’s energy efficiency – so much so that the line’s energy balance represents savings of up to 50% compared to earlier generations. This was made possible, among other factors, by the decanter bowl’s deep-pond design. The prime line thus facilitates optimized flow behavior in the bowl through the high hydrostatic pressure, an improved treatment effect and lower energy consumption in product discharge. The GEA varipond®, a patented, fully automated control system with variable pond depth ensures energy-saving and resource-efficient decanter start-up and shut-down, without any liquids overflowing to the solids side.
GEA varipond®: The patented control system for the prime line
GEA varipond® stands for “variable pond depth” while the decanter centrifuge is running.
In wastewater treatment plants, a precise, reliable process flow must be ensured, including in widely varying conditions. Such processes include dewatering and thickening of primary and secondary sludge. GEA varipond® adjusts to changing requirements at lightning speed; its variable pond depth ensures solids are discharged at a stable rate while the decanter is running. Optical sensors measure the solid content of thickened sludge and compare this with the configured set point, while the control system keeps the concentration constant – with everything done automatically. This enables unsupervised operation even overnight and at weekends.
The GEA varipond®: How it works
The point where the clarified liquid is discharged from the decanter bowl features an axially adjustable throttle disc which determines the width of the outlet aperture. A small gap means greater resistance, while a larger gap allows lower water discharge and a higher liquid level. Intelligent sensor technology automatically adjusts the aperture width according to the desired liquid level in the decanter bowl by moving the throttle disc into the optimal position while the machine is running.
The GEA varipond® reduces decanter energy consumption by up to 30%
The energy consumption of a decanter centrifuge is determined, among other factors, by the power required to discharge the clarified liquid. This can represent up to 50% of the decanter’s overall energy consumption. In order to achieve optimal separation performance when dewatering and thickening, specific G-values are required within a defined range, depending on the sludge characteristics and flow volume. This means that continuously maintaining the maximum G-value is often not necessary: a special control circuit in the GEA varipond® uses a sensor to identify unnecessarily high bowl speeds and optimizes them by constantly maintaining the required discharge concentration. The rotor geometry also provides additional energy savings. The design of the bowls in the GEA deep-pond design ensures optimized flow behavior and enhanced clarification effect, and means less energy is required to discharge the product. In short, this means that energy consumption can be reduced by up to 30%.
GEA varipond®: All benefits at a glance
- Automatic pond depth control while machine is running
- Simplified infrastructure with no solids valve
- Energy-saving and resource-efficient start-up and shut-down without liquids overflowing to the solids side
- Simple, precise dewatering and thickening processes with stable discharge concentration
- Accuracy ± 0.3% dry substance (DS), infinitely adjustable
- Thickening without polymers possible
- Highest possible decanter throughput
- Energy savings of up to 30%
- Optimization of all downstream processes
- Minimal wear and tear, long service life
- Unsupervised operation possible overnight and at weekends
- Can be retrofitted economically at any time