Santa Rosa's BoDean asphalt plant takes steps to reduce noise

The company that operates an asphalt plant near downtown Santa Rosa has outlined how it intends to comply with city noise rules it currently violates.

Following noise complaints from several neighbors over the summer, the BoDean Co. performed a sound study that confirmed its Maxwell Drive plant exceeds permissible noise levels, especially at night.

The company recently submitted a plan for how it intends over the next six months to reduce the racket created by heavy machinery that heats sand and gravel, mixes it with oily binder and dumps loads of hot, goopy asphalt into awaiting trucks.

“It’s going to be a significant investment,” said Bill Williams, general manager of BoDean. “This equipment is older equipment, so that’s one reason it’s so noisy.”

After a neighborhood group that wants greater restrictions on the plant paid for a sound study, the company conducted its own. That analysis found the plant exceeded the noise limits by up to 7 decibels during the daytime and 13 decibels at night. While the findings didn’t perfectly match neighbors’, the figures were close.

The company proposed a three-phase plan to muffle the noise. The first phase would be to build a noise-dampening wall around a large piece of equipment called a baghouse, which Williams likened to a large vacuum cleaner.

The 40-foot-long structure collects and filters dust from the hot air forced into the drying drum, where sand and gravel is heated before it is mixed with the binder. The baghouse is raised above the ground, and the company’s short-term plan is to enclose the bottom of it with a noise-dampening barrier, Williams said.

That work could be done in a couple of months if no permits are needed. The company is meeting with city officials Tuesday to discuss what permits, if any, are required. Williams said he doubts the barrier will need special permits because it will not be visible from the street.

The second phase will involve several upgrades to the existing equipment designed to reduce the noise. This includes replacing the burner, which Williams likened to a jet engine, and its fan, with a quieter model. The burner heats the air that dries the sand and gravel.

Another fix is to upgrade the drying drum with a more efficient, insulated version. The insulation is meant to save energy, but has the added benefit of making the drum quieter when the material is tumbling around in it, Williams said. The energy savings could be on the order of 10 percent, he said.

Other upgrades include a quieter exhaust fan and blower on the baghouse.

The work will be completed by May 15, after which a new sound study will be conducted to see if city noise rules have been met at nearby residential locations across the railroad tracks from the site.

It’s possible the upgrades will suffice to bring the plant into compliance, but it’s by no means certain.

“I cannot say definitively this will take care of the issue,” Williams said.

If it doesn’t, then the company will look at other solutions yet to be identified, he said.

Allen Thomas, the West End resident leading the opposition to the plant, said he was disappointed that the city hasn’t issued a notice of violation against the plant even though the company’s own study confirms the problem.

He accused the city of giving the company “special VIP treatment” that others violating city ordinances would not enjoy.

David Gouin, director of the city’s Housing and Community Services Department, said the purpose of such notices is to alert a property owner who is out of compliance. Because BoDean’s own study confirmed the noise issue and the company began taking steps to fix it, he said there was little reason to formally notify company officials of the problem.

You can reach Staff Writer Kevin McCallum at 521-5207 or kevin.mccallum@pressdemocrat.com. ?On Twitter @srcitybeat.