Sludge is probably something you’d rather not think about, but if you have wastewater treatment done on-site, you’re bound to have to deal with the residual sludge, too. This can create its own set of logistical problems and, if mishandled, undo your efforts at minimizing environmental impact. If you’re smart about it, though, not only can you effectively deal with sludge buildup, you can also make use of it.
Can’t You Just Dispose of It?
Following water treatment, the various waste materials removed from the water get collected into a wet slurry that is known as sludge. Though you’ve successfully restored the water to a potable state, you still have to handle the accumulated sludge left behind. Disposing of sludge is not a trivial matter, though. Transporting it is often difficult without reducing the volume of sludge, for one. On top of that, the hazardous materials in the wastewater are now concentrated, and improper disposal will simply release them into the environment anyway.
What Must Be Done
Treatment of sludge is a multi-step process, combining chemical, biological and physical processes to make the sludge more feasible to handle and transport. First, organic solids are decomposed into safer compounds via anaerobic digestion by bacteria, sometimes accompanied by heating or the addition of enzymes to encourage the breakdown of larger molecules. Afterward, the sludge is thickened and dewatered to reduce its volume and solidify it. Primary treatment may use sedimentation, dissolved-air flotation or centrifuges to separate solids. The thickened sludge can then be mechanically pressed or filtered with sludge dewatering equipment.
Better Options Than Disposal
Typically, stabilized and dewatered sludge is taken to a landfill for burial. Depending on the sludge’s composition, though, it may be put to use in other ways. Stabilized sludge can be a means of recovering resources, commonly through use as fertilizer or biofuels. Doing so both reduces the facility’s ecological footprint and utilizes what would otherwise be thrown away for better efficiency. Proper sludge treatment makes this possible.