Search

•EDW has allowed achieving sludge dry solids up to 39.3%.•EDW may require much lower polyelectrolyte dosage than mechanical dewatering.•EDW was more effective on aerobically stabilized sludge, consuming less energy.•EDW led to a maximum saving of 30% of the costs of the sludge management.

Incineration units for sewage sludge disposal require a 40% minimum of dry solid content to obtain an ignitable material for energy recovery. Electro-dewatering (EDW) process could be useful to accelerate and improve the removal of adsorbed/interstitial water from sludge, but this application must be as cheap as possible and, further, the use of noble metals as electrodes to avoid corrosion is not appropriate. With these constraints, the use of an organic conductive coating could be suitable to protect low carbon steel electrodes. In this work, we investigated the chemical, electrical and mechanical characteristics of coatings obtained with epoxy resin/multi-walled carbon nanotube (MWCNT) composites, with the aim to design a protective film. The filler/resin ratio is the main parameter to be considered because at high ratio the electrical conductivity increases and, on the reverse, the physical and mechanical performances worsen. Specimens with different concentrations of carbonaceous filler have been produced and their characteristics have been discussed in relation to the critical pigment volume concentration (CPVC) and to the percolation limit.