Application of different techniques to enhance sludge drying paved bed drying process

Abstract

Massive quantities of sludge are being generated with the rise in populace and increase of wastewater produced. Ordinary sand and paved drying beds are still designed within the conventional way. This research focused on creating modern procedures to reduce the drying up duration for the combined sludge produced. This included the use of direct thermal solar heated water pipes, wick vertical drain, and horizontal filtration combined with bottom drainage for three built tanks utilizing freshly combined primary and secondary sludge with initial concentrations ranging from 0.42%−3% for the different filling cycles performed over two stages under changing climatic conditions. In-situ measurements of solid content, temperature and sludge height were taken. For stage one, the solids content reached 8.53% for solar tank, 7.42% for wick vertical drain tank and 17.4% for the conventional paved dry tank after 105 days of operation. For stage two, solids content reached 6.9% and 6.6% for solar and wick vertical drain tanks respectively and 7.93% in the conventional PDB combined with horizontal flow after 35 days of operation. Results are promising and could lead to better operational performance of PDB while decreasing the required time required; hence maximizing and upgrading the existing facilities.