Drying systems and evaporation processes are major energy consumers. To minimize energy usage, the focus should be on optimizing the upstream mechanical dewatering process. Mechanical dewatering separates water from solid waste using force like screw presses, centrifuges, or a simple filter bag. Private contractors have reported significant savings on transport costs and disposal fees compared to other methods.
Less Energy Intensive
Dewatering equipment, like vacuum or centrifugal motion, separates water from solids by force. This saves money on solids handling or disposal expenses charged on a weight basis since the percentage of water in landfill-bound solids or raw wastewater sludge can double or triple the cost. In addition, mechanical dewatering equipment can be less energy intensive than dryers or evaporators that utilize heat to remove moisture from products. However, properly instrumentation of a dewatering system’s product flow and moisture levels is necessary to minimize energy consumption.
Unlike other dewatering methods that can leave behind contaminants, mechanical dewatering helps eliminate harmful materials from the water. This can protect expensive construction equipment and help prevent project delays due to excess moisture. In addition, it can reduce the risk of erosion and make job sites safer and more environmentally friendly by removing toxic materials from the standing water.
The process works by separating the sludge into its solid and liquid parts. This can be done with various techniques, including chamber filter presses, centrifuges, and sludge lagoon systems. The resulting dry product is easier to transport, less costly to dispose of, and can be used as fill, topsoil, or landfill cover. It’s also much more convenient than relying on siphoning or using large machinery buckets to drain the water, which can leave behind contaminated materials and waste that can be difficult to remove.
Mechanical dewatering separates sludge (residual sludge from wastewater treatment plants or fecal sludge from on-site sanitation) into liquid and solid parts. Depending on the method, it uses pressure, acoustic, electric, or chemical force. However, it does not treat the sludge, so it still contains pathogens and pollutants.
This high water content sludge is typically used as a landfill (often with further mechanical dewatering) or ad-mixed to conventional fuels such as coal for incineration and gasification. However, if a chemical/mechanical dewatering process is implemented, these high percentages of water in the sludge can be reduced significantly.
By using hybrid chemical/mechanical dewatering at a construction site, the contractor can save on water removal and waste disposal costs. In addition, excess moisture on a construction site can cause damage to equipment and create unsafe conditions for workers. By using dewatering bags, contractors can avoid these costly expenses and keep their projects on schedule and under budget.
Traditional mechanical dewatering techniques such as belt filter presses and centrifuges separate sludge (residual sludge from wastewater treatment plants or fecal sludge from on-site sanitation) into liquid and solid parts. Due to their bulk, these sludges often have high water content and are difficult to transport, store, or landfill. They also cannot be used for composting or incineration at smaller facilities because they need more independent fuel value and must be mixed with conventional fuels before burning.