Maintaining Wastewater Equipment

Table of Contents

Chapter 1: Pumping Stations

Topics: Pump stations; Pump types, operation, and maintenance; Drive units; Piping; Controls; Level detection; Safety

Learning Objectives:

• Describe a typical collection system layout.
• Name the three types of pumping stations currently in use and explain how they differ.
• List seven basic components of wet-well and dry-well stations.
• Use the following terms in an explanation of pump operation: impeller, shroud, volute case, stuffing box, shaft sleeve, wearing ring.
• Name the important elements of a good preventive maintenance program for pumps.
• Explain the importance of a pump station ventilation system.
• Demonstrate the necessary procedures to follow before pump start-up.

Chapter 2: Screening and Grinding Equipment

Topics: Bar screens; Grinders; Rotating drum comminutors; Stationary screen comminutors with oscillating cutters; Barminutors

Learning Objectives:

• Name the two basic parts of a hand-cleaned bar screen and explain their functions.
• Describe the operation of a mechanically cleaned bar screen.
• Explain why grinders are used and how they are maintained.
• Compare and contrast a rotating drum comminutor and a stationary screen comminutor with an oscillating cutter.
• Explain how a Barminutor combines the functions of a bar screen and a comminutor.
• Give examples of important safety rules to follow when working with screening and grinding equipment.

Chapter 3: Grit Removal Systems

Topics: Grit chambers; Detritus tanks; Chain and flight grit collectors; Aerated grit chambers; Cyclone separators

Learning Objectives:

• Tell why grit removal is important.
• Name the three phases of the grit removal process.
• Explain the functions of slide gates and dewatering drains in handcleaned grit chambers.
• Describe the action of a reciprocating rake and explain its purpose.
• List several maintenance checks to make on chain and flight grit collectors.
• Explain how an aerated grit chamber works and how to tell if it is not working correctly.
• Describe the operation of a cyclone grit separator.

Chapter 4: Sludge- and Scum-Collection Apparatus

Topics: Sedimentation; Clarifiers; Scum and sludge removal; Lab testing; Maintenance; Troubleshooting; Safety

Learning Objectives:

• Describe the operation of slottedpipe and helical-type skimmers.
• Name the two flow patterns possible in circular clarifiers.
• Discuss the daily maintenance requirements of clarifiers.
• Explain the importance of laboratory testing on the contents of a clarifier.
• Identify possible safety hazards associated with clarifier operation.

Chapter 5: Flow Measurement Devices

Topics: Flow measurement in batch processes, filled pipes, open channels, and freely discharging pipes; Depth and pressure measurement

Learning Objectives:

• Define flow and differentiate between flow rate and total flow.
• List the three basic types of flow systems.
• Distinguish between direct and indirect flow measurements, and between primary and secondary devices.
• Give a brief description of a current meter, a pitot tube, a weir, and a flume, and tell how each functions in open channels.
• Describe several methods of measuring flow from freely discharging pipes.
• Name at least five level detection devices and explain their operation.
• Describe the following flow measurement devices as they are used in completely filled pipes: orifice, venturi, flow nozzle, rotameter, magnetic flowmeter, and ultrasonic flowmeter.

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