HUBER Sludge Turner SOLSTICE® The innovative, season-independent solar sludge dryer

HUBER SRT system for solar sewage sludge drying

The HUBER Sludge Turner SOLSTICE® has two motors: one drive moves the machine longitudinally to the drying area, the second turns the double shovel during forward travel in order to tip the sludge over its axis back into the sludge bed.

• The extensive mixing of the sludge minimizes odor-producing processes in the sludge and intensifies drying.
• The rotary motion within the shovel creates round, mechanically stable granules, enhancing the quality and handling of the dried sludge.
• As the machine travels forwards from one end to the other with the rotating double shovel, the sludge is completely restacked.

The HUBER Sludge Turner SOLSTICE® can optionally use its double shovel to transport dried sludge. The machine can transport dry sludge back to the sludge feeding area and mix it into the freshly dewatered sludge, which results in the following advantages:

• Back mixing of dry sludge reduces odor-generating biological processes within the sludge due to the reduced water content.
• Pasty sludge becomes easier to handle – less force is needed to move the sludge.
• Quicker sludge drying – dry sludge increases the surface due to the open-porous structure.

Optionally, the machine can be equipped with a blade that adjusts to the level of the sludge bed during sludge turning. A motor raises or lowers the blade depending on the measured sludge bed level. Larger sludge lumps are cut into small pieces between the rotating shovel and the blade, and the height and dry residue of the sludge bed can also be precisely controlled.

Feeding of wet sludge and discharge of dry material

The drying hall can be filled all at once; however, continuous feeding of the drying plant is the preferred method for optimal operation

• No shock loads for exhaust air
• The drying system is always ready to receive sludge.
• If sludge is fed in by wheel loader, this is done in daily to weekly batches.
• Automation of sludge feeding via screw conveyors in the roof of the drying hall
• The sludge dewatering system can deliver sludge without intermediate storage – fully automated, unmanned operation of the entire sludge treatment system.

On-site dry sludge removal can be adjusted depending on the application:

• The dry granulate can be stored in depressions accessible for a wheel loader to empty these into trucks or dumpers.
• The sludge is transported directly into containers by screw conveyors embedded in the ground.
• The dry granulate can be removed or stored either on the same gable side where the wet sludge is fed or on the opposite gable side.

Machine safety

The safety system of the HUBER SRT process protects operators from crushing hazards that might be caused by the self-acting, automatically starting HUBER Sludge Turner SOLSTICE®.

• The maintenance doors and seldom used gates on the dry sludge removal side are equipped with electronic non-contact safety switches.
• A special light grid can be installed at frequently used access doors on the sludge feeding side. Unobstructed viewing is guaranteed.
• Operators can monitor the HUBER Sludge Turner SOLSTICE® from the touch panel location outside the operating area of the machine and start individual drives in manual mode or set the plant into automatic mode.
• An enabling button is available for maintenance diagnosis if close inspection is necessary.

HUBER climate control system

The HUBER climate control system calculates water evaporation based on various ventilation system settings, selecting the scenario that achieves the optimal balance between evaporation efficiency and energy consumption. The following values are considered in the calculation:

• Global radiation, temperature and humidity outside the greenhouse, measured with a weather station
• Air humidity and temperature inside the greenhouse, measured with robust sensor technology
• The turbulence of the air on the sludge bed generated by ventilators, determined by measurement campaigns

The fans in the roof of the greenhouse also provide air movement longitudinally through the greenhouse. The air streams in at the weather protection gratings in the dry sludge area. Even if moisture is still absorbed at that point, the drying potential of the air increases due to the greenhouse effect. As the air moves through the dryer, it progressively absorbs moisture as it nears the wet sludge bed. Ultimately, the air, now saturated with water vapor, is extracted by ventilators installed at the gable front.

Depending on the specific requirements, we develop a tailored plant concept for the customer and can offer the following services upon request:

• Calculation of the required drying surface and process-engineering options
• Recommended arrangement of the dryer on the given available space
• Forecast values for the potential odor through analysis of specific sludge samples in our own laboratory
• Budget prices and operating costs for all plant components

Our 20 years of experience and more than 250 dryer lines sold on every continent are proof of the high quality of the HUBER system and its suitability for applications worldwide.