Residuals” refers to liquids that contain a high concentration of solids and are left over after industrial processes including wastewater treatment, drinking water treatment, mining operations, and petroleum extraction.  In this context, the term “residuals” is somewhat interchangeable with the term “sludge.”  Although sludges are typically thought of as problematic waste materials, they may contain valuable constituents like nutrients, metals, and energy content.  A sludge treatment expert will assist in finding the most environmentally and economically advantageous methods to recover those valuable constituents for the beneficial reuse of the materials.

Biological sludges from wastewater treatment contain the beneficial microorganisms that actually performed the treatment.  These “biosolids” can be returned to the earth as soil amendments or landfill cover materials, if health-based regulatory quality limits for 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 can be extracted for reuse.  Some sludges, however, need to be treated as hazardous waste.

Biological sludges are typically treated by heating, aeration, or adjustment of their 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.  The excess methane may be burned to generate electricity for the treatment plant or upgraded to renewable natural gas (RNG) standards for vehicle fueling or injection into the local natural gas piping network. Prior to the reuse or disposal, sludges are often thickened within the sludge treatment process and then dewatered to reduce the sludge volume and weight and the transportation and disposition costs.

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.

For over 25 years, Lee Enterprises Consulting has been assisting companies and investors with bioenergy, biofuels, biomaterials and chemicals, biotechnologies, and feedstock matters.   With over 150 consultants, we have the diverse expertise and geographical reach to assist in virtually any bioeconomy project worldwide. These seasoned professionals average over 30 years of industry experience.  Our ability to assemble these professionals into multidisciplinary teams allows us to fully integrate the technical, scientific, and regulatory aspects of a project, and combine them with years of hands-on experience.  Take a look at our experts and the services we provide.  You will note that most of our experts are also available for ancillary engagements and advice, for specialty engagements like serving as expert witnesses in litigation matters.  Call us at 1+ (501) 833-8511 or email us for more information.