Opportunities and challenges in sustainable treatment and resource reuse of sewage sludge: A review

Sludge or waste activated sludge (WAS) generated from wastewater treatment plants may be considered a nuisance. It is a key source for secondary environmental contamination on account of the presence of diverse pollutants (polycyclic aromatic hydrocarbons, dioxins, furans, heavy metals, etc.). Innovative and cost-effective sludge treatment pathways are a prerequisite for the safe and environment-friendly disposal of WAS. This article delivers an assessment of the leading disposal (volume reduction) and energy recovery routes such as anaerobic digestion, incineration, pyrolysis, gasification and enhanced digestion using microbial fuel cell along with their comparative evaluation, to measure their suitability for different sludge compositions and resources availability. Furthermore, the authors shed light on the bio-refinery and resource recovery approaches to extract value added products and nutrients from WAS, and control options for metal elements and micro-pollutants in sewage sludge. Recovery of enzymes, bio-plastics, bio-pesticides, proteins and phosphorus are discussed as a means to visualize sludge as a potential opportunity instead of a nuisance

Adsorption of Bisphenol A on KOHactivated tyre pyrolysis char

International audienceAn activated carbon (AC) with a specific surface area of 700 m 2 g-1 was prepared by KOH activation of tyre pyrolysis char (TPC) and tested to remove Bisphenol A (BPA) from aqueous solutions. BPA adsorption on this AC was evaluated by studying both the adsorption isotherms at three different temperatures and the decrease of BPA concentration with time, in order to determine the thermodynamic and the kinetic parameters, respectively. The results were compared with those obtained with pristine TPC and with a multipurpose commercial activated carbon (CAC) recommended for BPA adsorption. The present KOH-activated TPC showed a great potential to adsorb BPA with a monolayer capacity as high as 123 mg g-1 , higher than that of the CAC used as a reference. BPA adsorption equilibrium data were fitted using different isotherm models with two or three parameters, and the best fitting models were those of Langmuir and Radke-Prausnitz. BPA adsorption was an exothermic process, and the adsorption capacity decreased with increasing temperature. The adsorption kinetics of BPA was adequately described by a pseudo-second order model