Down in the depths and under the water filters of the 78-year-old Moffat Treatment Plant in Lakewood, Colorado, a team of Denver Water mechanics did some heavy lifting in December — very heavy lifting. The crew replaced 20 large valves that regulate the flow of water in and out of the plant’s water filters. The largest valves weigh 1,850 pounds and are roughly the size of semi-truck tires.

The valves, installed in the 1980s, were showing their age.

“We had to replace them because they were leaking and seizing up,” said Randy Slocum, assistant treatment plant supervisor. “When the valves fail, the plant loses its full capacity to treat water.”

Replacing a valve that weighs nearly 1 ton is no easy task. The work involves disconnecting each valve from the large pipe that carries water into the plant’s filters, and then carefully lowering the valve to the ground with a system of pulleys and chains.

Mechanic Matt Abeyta and his team did the heavy lifting. “It’s fun and it’s challenging work,” he said.

The process required careful planning and teamwork to ensure the valve didn’t fall. After removing the old valves, the mechanics installed 20 new ones.

The new valves and supporting equipment cost $184,000 and will make the plant more reliable. This is the last major improvement project for the Moffat plant, which will be replaced with a new plant in 2023.