Dating back to the 19th century, people began purifying used water prior to sending it back into the environment when it became clear that wastewater treatment was a necessity to improve quality of life and protect the environment. Today, access to clean water is a basic necessity and is essential to sustain and provide for the continued development of the world’s population and its economic growth. An urgent concern is to have a sufficient supply of clean water to meet and sustain the constantly growing demand. The role that wastewater treatment plants plays in meeting our demands for clean water is vital, therefore, it’s important for the professionals in the wastewater industry to have the knowledge and resources to support the efficient and reliable operation of the treatment plants. To support these professionals, the Hydraulic Institute published its first edition of Wastewater Treatment Plant Pump: Guidelines for Selection, Application, and Operation, a comprehensive application guide for the selection of pumps used in a typical aerobic wastewater treatment plant employing conventional activated sludge process.
The purposes of wastewater treatment system operations are to provide controlled removal and/or decomposition of wastewater constituents so that odor nuisances will not arise, and pollution of valuable water resources and hazards to the community’s health will be reduced. According to the 2021 Infrastructure Report Card, an estimated 22.8 trillion gallons of wastewater is consumed in the United States per year, and an estimated 16,000 publicly-owned treatment plants provide wastewater collection, treatment, and disposal services to more than 250 million people. The treatment process is guided by extensive engineering and technological development, which continues to refine the process. Concurrently, in today’s energy-efficiency conscious world, reducing the energy required to complete the treatment process and water recovery activities is critical. Nearly 2% of total U.S. electricity consumption goes towards moving and treating water and wastewater. The pumping systems employed at wastewater treatment plants account for 62% of all wastewater motor-driven electricity consumption. Thus, poor application of the pumps, flow control, and motors can lead to inefficiency and wasted energy consumption.
Wastewater Treatment Plant Pump: Guidelines for Selection, Application, and Operation is intended to assist in understanding the general layout, components, and operation of a typical wastewater treatment plant, and provide the guidance necessary to select pump types and define pump materials to perform effectively efficiently, and reliably in the various plant operations. In addition to pump selection criteria, this document also addresses auxiliary components that are required to operate a pump, including the driver, couplings, and control methods. This single resource yields the practical information for those that are new to defining treatment plant pumping systems and equipment, and for those that are experienced in the field but desire to enhance their knowledgebase of these systems. The basic process operations used in a typical aerobic wastewater treatment plant are discussed in this guideline, as are the application and operation of rotodynamic and positive displacement pumps for the various processes. A brief description of the particular process operation and the recommended type of pump, including materials of construction and pump sealing recommendations, to be applied to that particular process is covered. For example, if the wastewater treatment plant is built above the influent sewers, the wastewater has to be pumped up to the plant headworks. An influent lift station is required to allow the wastewater to flow by gravity through the treatment process (see Figure 1).
Figure 1: Influent pump station arrangement
The pumps used in an influent lift station needs to accept and pass solids that may include household and commercial solids, large solids, stringy material (such as rags and hair), sanitary waste, plastic scraps, food waste, sticks, leaves, and abrasive materials (such as sand, grit, stones, and pieces of metal), and other inorganic and organic solids. For this part of the process, solids-handling pumps are required since they are specifically designed to reduce the risk of clogging from large solids and stringy material. Similar recommendations are provided for the other process operations in a wastewater treatment plant.
The Wastewater Treatment Plant Pump: Guidelines for Selection, Application, and Operation guidebook is a comprehensive reference for engineering designers, manufacturers, and operators involved in the design and operation of wastewater treatment plants. It provides the reader with an overview of the typical fluid characteristics and the type of pump and materials commonly used and recommended for each unit process. With the collective knowledge of numerous pump and wastewater design industry experts, who collective process hundreds of years of practical experience, readers can be assured that the information presented in this easy to follow guideline will serve as a resourceful guide for many years to come.