WASTEWATER

By Rick Lallish

What color is the waste gas burner on a properly operating anaerobic digester with an approximate mixture of methane 68% and carbon dioxide 32%?

A. Red

B. Orange

C. Blue

D. Green

Answer: C. Anaerobic digestion uses waste gas burners to burn excess gases from the system. It has a continuously burning pilot flame to perform this action safely. Methane-rich gases burn with a blue flame, and gases rich in carbon dioxide burn orange. This is a quick way to visually check your gas content in the anaerobic digester. It is also a safety device to help prevent explosive conditions that arise with volatile gases such as methane. More information may be found in the WEF textbook, Wastewater Treatment Fundamentals II – Solids Handling and Support Systems, Chapter 4.

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DRINKING WATER

By Drew Hoelscher

What tool and setting would an operator use to identify a blown fuse?

A. Megger/voltage

B. Megger/amperage

C. Volt-ohm-meter/amperage

D. Volt-ohm-meter/continuity

Answer: D. A volt-ohm-meter (or multimeter) is a handheld device that can measure several functions within an electrical circuit. The multimeter is a common tool operators use to identify faults during field maintenance work. For example, the multimeter positioned in the continuity setting will give an audible alarm when a complete path for current is detected. This helps operators identify a blown fuse, bad switch or any other electrical connection/component problem.

About the authors

Rick Lallish is water pollution control program director and Drew Hoelscher is program director of drinking water operations at the Environmental Resources Training Center of Southern Illinois University Edwardsville.