Electro-dewatering of activated sludge of sewage treatment plants, Ternopol

The sewage sludge formed at wastewater treatment plants constitutes a small percentage of the volume of treated wastewater. However, the costs associated with sludge treatment and disposal account for the lion's share of the operational expenses of wastewater treatment plants. The sludge contains harmful and toxic substances. On the other hand, sludge is a source of carbon, nutrients, and trace elements, meaning it can be effectively utilized. An important stage in sludge disposal is its dewatering, particularly with the use of electric current. The study investigated the electro-dewatering of activated sludge with a moisture content of 98% from secondary clarifiers at the Ternopil wastewater treatment plant using direct electric current. Experiments were conducted on a laboratory setup with a U-shaped glass tube and carbon rod anode and cathode. The effect of the electric field was observed during the fading period, when, after a significant amount of water had been separated from the sludge, the electro-dewatering process slowed down. The obtained results were compared with those from the electro-dewatering of activated sludge with a moisture content of 98% from secondary clarifiers at the Ternopil wastewater treatment plant on a setup with a graphite rod anode and a flat cathode, as reported by other researchers. Electro-dewatering of activated sludge on both setups produced practically the same effect. It was confirmed that sludge dewatering using direct electric current can be applied on sludge drying beds at wastewater treatment plants.