Residuals” is a general term for liquids, with a high solids content, that remain after some sort of industrial process such as wastewater treatment, drinking water treatment, mining operations, petroleum extraction, etc. The term “residuals” is more or less interchangeable with the term “sludge.”
Although sludges are typically thought of as problematic waste materials, they may contain valuable constituents including nutrients, metals, and energy content. A sludge treatment expert will seek to find the most environmentally and economically advantageous methods to recover those valuable constituents, in beneficial reuse of the materials. Biological sludges from wastewater treatment contain the beneficial microorganisms that performed treatment. These “biosolids” can be returned to the earth as soil amendment or landfill cover material, if health-based regulatory quality limits on disease-causing organisms and trace contaminants are not exceeded. Other, chemical sludges are not suitable for land application, but may contain metals or other constituents that could be extracted for reuse. Some sludges may need to be treated as hazardous waste.
Biological sludges are typically treated by heating, or aeration, or adjustment of alkalinity, to reduce infectious viruses and bacteria. During anaerobic digestion of biological sludges, in the absence of oxygen, biogas containing flammable methane is produced. Some of that biogas is burned to heat the anaerobic digester complex, and the excess methane may be burned to generate electricity for treatment plant needs, or upgraded to renewable natural gas (RNG) standards, for vehicle fueling, or injection into the local natural gas piping network.
Sludges are often thickened within the sludge treatment train, and then dewatered to reduce sludge volume and weight, and transportation and disposition costs, prior to ultimate reuse or disposal.
Experts in wastewater, sewage, and sludge treatment are typically engineers and chemical experts with experience including anaerobic digestion and fermentation. Large renewable energy and biochemical consulting firms certainly have experts in biotechnologies, as well as the more common areas like bio and renewable fuels, biomass and biomass power, feedstocks, biomaterials, and biochemicals. These larger groups will also have expertise in other technologies like agitation systems, beverage fermentation, bio-oil extraction, bioreactors, carbon capture, carbon storage, carbonization, catalysis, cellulosic ethanol, cleantech, combined heat and power, direct combustion, , enzyme technologies, fermentation, Fischer-Tropsch, gasification, genetic engineering, hydrothermal, nanotechnology, organosynthesis, power generation, pyrolysis, renewable technology due diligence, synthetic biology, thermochemical conversion, torrefaction, water treatment, and waste management.
Lee Enterprises Consulting is the world’s premier bioeconomy consulting group, with over 100 highly qualified experts serving in all these areas. Take a look at our experts and the services we provide. Most of our experts are also available to advise and serve as expert witnesses in bioeconomy litigation matters. For the larger projects, we specialize in putting together full service, interdisciplinary teams with one point of contact. Call us at 1+ (501) 833-8511 or email us for more information.