WASTEWATERBy Rick LallishWhich of the following pumps would be the least effective for pumping heavy sludges?A. Progressing cavityB. Rotary lobeC. CentrifugalD. DiaphragmAnswer: C. Progressive cavity pumps are well suited for pumping sludges, especially for dewatering or thickening processes. Of the choices, a centrifugal pump is least suited for this operation. Understanding the different types of pumps and what types of flows they can pump is important for the operator’s knowledge of plant operations. Pumps and pumping questions are included in most states certification examinations. More information can be found in the Water Environment Federation, Operation of Water Resource Recovery Facilities, Manual of Practice No.
