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Solar Energy


Low Temperature Sludge Dryers

Solar Panels - The Solar Sludge Drying Solution

USA Sludge’s high tech solar sludge drying creates a much smaller solar footprint, as our system uses solar electric panels that we install at the site of the dryer, which reduces installation costs and increases efficiency.  The closed cabinet dryer with a low temperature heat pump requires less electricity to operate because the heat pump cycle utilizes all of the waste heat to dry the sludge which makes this process three times more efficient than a standard solar dryer.  When the dryer is not in use, the electricity from the solar panels at the dryer site, is redistributed to the treatment plant, therefore the solar energy never goes to waste.  Maintenance is a breeze as there are no moving parts, less labor costs, and no buildings to maintain.  Odor control issues and burn permits are eliminated.

Our solar sludge drying solution accepts non stabilized sludge at 1% solids and can dewater and dry the sludge to 90% solids.  The bio-solids are then automatically bagged and ready for shipment, resulting in lower costs, is odor free with effective results.  The drying time for our solar dryer is ONLY TWO HOURS compared with standard solar dryers that take 10 DAYS.  This high tech system is sustainable and saves industries and companies valuable time and money, allowing for future growth, all while exceeding the EPA 503 quality requirements for Class A bio-solids.


The Dilemma of Using Current Solar Sludge Drying Systems

Today’s solar sludge dryers require the sludge to be dewatered before entering the dryer.  Current solar dryers have a very large footprint, because buildings have to be constructed to absorb infrared solar heat.  The suns thermal energy is then used to evaporate water from the top layer of a makeshift sludge lagoon housed inside the building.  Using these current solar drying systems, the sludge then needs to be turned with a robotic vehicle mechanism that aerates and mixes the sludge inside the drying chamber.  Expensive odor control equipment needs to be installed with costly filters that need to be maintained.  The solar dryers are expensive to build as they need a waste heat source or in most installs, a natural gas boiler to maintain the temperature of the solar lagoon when the sun is not shining.  This also means the dryers need a supply of natural gas and requires 10 DAYS to dry the sludge, including emissions monitoring and permits, thus significantly increasing the cost of sludge drying.

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