Supercritical water oxidation improvements through chemical reactors energy integration

Supercritical Water Gasification of Municipal Sludge: A Novel Approach to Waste Treatment and Energy Recovery

“…Most contemporary thermal options are prohibitively costly due to high capital investment and increasingly stringent, air-quality permitting and compliance standards (Chun et al, 2011;Fytili & Zabaniotou, 2008). Thermal destruction also meets with considerable, unfavorable public opinion due to the air-borne release of metal emissions and harmful gases (Abbas et al, 1996;Adegoroye et al, 2004;Lavric et al, 2006). Intense public protests of new permits alone have derailed some incinerator permitting efforts (Sloan et al, 2008;Weismantel, 1996).…”

“…Transpiring-wall reactors provide a nuanced use of liquid water to flush salt from the system (Bermejo & Cocero, 2006a;Lavric et al, 2006). A more common method, however, is a brute-force approach using high fluid velocities in tubular reactors such as AquaCat ® and AquaCritox ® processes developed by Chematur (Bermejo & Cocero, 2006b;Marrone et al, 2004).…”

“…Until a sustainable sludge destruction solution is found, the sludge disposal problem will continue to grow with increasing population, rather than dissipate (Lavric et al, 2006). Application of sewage sludge on agricultural land has become socially unacceptable due to the fact that it is increasingly regarded as an unsafe and insecure handling route (Eriksson et al, 2008;Fytili & Zabaniotou, 2008;Harrison et al, 2006;Mathney, 2011;McBride, 2003;Snyder, 2005;USEPA, , 2002b.…”

“…Ocean dumping was a preferred sludge disposal method for the last couple of centuries (Chun et al, 2011;Snyder, 2005), but it was banned in the 1990s by both U.S. and international law due to the high level of harmful pollutants in the sludge and the adverse effect on marine organisms (Abbas et al, 1996;Costello & Read, 1994;Harrison et al, 2006;Snyder, 2005). The loss of ocean-dumping drove most municipalities to embrace either agricultural land application or thermal destruction (viz., incineration) as their primary sludge-disposal routes, with a small percentage using landfilling or composting (Lavric et al, 2006). Current sludge disposal methods, and associated regulations, are outgrowths of the need for municipalities to find a viable solution for treating or disposing large amounts of concentrated harmful pollutants resulting from wastewater treatment.…”

“…Transpiring-wall reactors are recent developments designed to avoid high temperatures near the walls and flush away corrosive salts with a thin film of subcritical water (Lavric et al, 2006). The reaction chamber consists of a porous inner wall through which clean water continuously flows, creating a thin film of subcritical water (Figure 3).…”