Originally Posted by cgaengineer
Not around here...not that I'm aware of. Sludge goes to the local landfill. The water used in the treatment process is land applied...that I do know.
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Composting: Dalton Utilities Putting Your Waste to Beneficial Reuse
You’ve heard of taking lemons and making lemonade? Well, Dalton Utilities is doing something similar with the byproducts of wastewater treatment! Dalton Utilities is partnering with Harvest Farms to take the solids (or sludge) from our wastewater system and put it to work to improve the environment. Why? We think a cleaner river and invigorated soil are good reasons. That is recycling in its highest form! It’s incredible to think that the wastewater produced today by homes and businesses in our community is not only being treated in such a fashion that it does not HARM the environment, but it is also being processed further in a manner that actually IMPROVES the environment! That’s what we call a win-win situation.
While the Utility is proud to be putting this waste product to beneficial reuse, it is a double benefit that we are able to reduce our cost of the disposal of sludge, resulting in an annual cost savings of over $400,000.
How is this done? In the wastewater treatment process, solids (or sludge) are pulled from the wastewater in several of the treatment stages. This sludge is then sent to a special digester for treatment. At our sludge handling facility, the final treatment stage involves adding a polymer or “caking” agent to the dewatered sludge which is then sent through a high-speed centrifuge to remove any remaining moisture.
At this point, the sludge is mixed with organic material, like tree bark and wood chips. The mixture is then composted in large containers where it must be kept above 131 degrees Fahrenheit for three consecutive days and average 114 degrees Fahrenheit for a total of 14 days. No special heating is required as the composting process produces its own heat. During this heating process, any pathogens in the sludge/organic matter combination are eliminated. The compost is then placed in windrows (long rows of heaped compost in an open field) on our Land Application System facility to complete the decay process for an additional four to six months.
But is it safe? The initial treatment process and the final composting process consume the contaminants from the organic matter. In fact, the composting process is closely regulated by the Georgia Environmental Protection Division (EPD) to ensure the safety of the product. According to Gerry Harstine, president of Harvest Farms, “All soil is made up of things that have decayed, but the end product of composted sludge is safer and cleaner than any soil you might dig up in your front yard.”