Once established the processing conditions of fly ash, pilot trials have been carried out to optimize prototype adsorption conditions, in terms of contact time between sludge and adsorbent (cycle length), and silt cycles.

<p style="text-align: justify;"> Results show a residence time of 3 hours as convenient to achieve good adsorption results of heavy metals.</p> <p style="text-align: justify;"> Regarding silt ash trials results show that from three whole adsorption cycles, there are no differences in heavy metals reduction and adsorbent change is necessary.</p> <p style="text-align: justify;"> &nbsp;</p> <p style="text-align: justify;"> &nbsp;</p> <p style="text-align: center;"> <img alt="" src="https://www.ctaex.com/icirbus/ficheros/imagenes/2018_01/17-12-duracion-ciclo-y-colmatacion-cenizas3.jpg" style="text-align: justify; width: 500px; height: 328px;" /></p> <div> &nbsp;</div>