Sustained Shockwave Plasma (SSP) Destruction of Sewage Sludge – A Rapid Oxidation Process

Abstract

Sewage sludge is destroyed and neutralized in an environmentally safe way by rapid, plasma-assisted oxidation. The material is rendered inert where it is being produced, leaving behind a benign and useful solid oxidation byproduct and producing a clean off-gas. The solid product can be used as a cement or aggregate. The process is based on oxidation enhancement by employment of sustained Shockwave plasma and controlled oxidation to provide an off-gas which can effectively be handled by gas cleaning systems to provide a degree of purity required by the most stringent air quality standards. The process is very compact, owing to very rapid throughput and near-stoichiometric air requirements. It is entirely enclosed. The Neutrail SSP process comprises three main steps; drying, oxidation and gas cleaning. The oxidation step consists of three distinct sections. It is designed to completely destroy all organic structures, limit acid gas formation and to retain a maximum amount of all volatile heavy metals in the solid residue in a non-leachable form, thereby making it possible to devise a gas cleaning system which can deliver a clean off-gas economically.