Maintaining Wastewater Equipment

Lesson 1: Pumping Stations

Topics

Collection Systems; Pumping Stations; Pumping Station Components; Pump Operation; Pump Types; Pump Maintenance; Pump Drive Units; Piping System; Ventilation System; Control System; Level Detection; Station Start-Up and Shutdown; Station Operation and Maintenance; Safety Considerations

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.

Lesson 2: Screening and Grinding Equipment

Topics

Hand-Cleaned Bar Screens; Mechanically Cleaned Bar Screens; Grinders; Rotating Drum Comminutors; Stationary Screen Comminutors; Barminutors

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.

Lesson 3: Grit Removal Systems

Topics

The Nature of Grit; Hand-Cleaned Grit Chambers; Maintaining Hand-Cleaned Grit Chambers; Detritus Tanks; Maintaining Detritus Tanks; Chain and Flight Grit Collectors; Maintaining Chain and Flight Grit Collectors; Aerated Grit Chambers and Cyclone Separators; Maintaining Aerated Grit Chambers

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 hand-cleaned 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.

Lesson 4: Sludge- and Scum-Collection Apparatus

Topics

Sedimentation; Rectangular Clarifiers; Scum Removal; Circular Clarifiers; Pre-Operational Checks; Daily Maintenance Activities; Sludge Removal; Laboratory Testing; Troubleshooting; Safety Considerations

Objectives

• List the five major components common to all clarifiers.
• Describe the operation of slotted pipe 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.

Lesson 5: Flow Measurement Devices

Topics

Properties of Flowing Liquids; Flow Measurement Methods; Flow Measurement in Batch Processes; Flow Measurement in Open Channels; Measuring Flow from Freely Discharging Pipes; Methods of Depth Measurement; Flow Measurement in Completely Filled Pipes; Methods of Pressure Measurement; Maintenance of Flow Measurement Devices

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.