If approved during the Laramie City Council regular meeting today, Laramie’s wastewater rates could be adjusted in 2018 to reflect the actual costs of treating the city’s wastewater, city documents state.
“It’s a revenue neutral move that will adjust the rates and simplify the (wastewater) customer class system,” Laramie Public Works Director Earl Smith said.
“We won’t be making money on the rate change or losing it.”
Treating Laramie’s wastewater is all about cultivating “bugs,” microscopic organisms that consume organic waste, which require dissolved oxygen to survive, Laramie Wastewater Treatment Plant Supervisor Chris Claymore said.
“The wastewater has a demand for (dissolved) oxygen,” Smith said. “If one waste stream requires too much oxygen, it won’t leave enough oxygen for the other streams.”
Without the right amount of dissolved oxygen present in the wastewater, the bugs start dying by the millions and rebuilding the population could take longer than a month, during which, the untreated wastewater would need to be released back into the water systems around Laramie, Claymore said.
Not only would that incur fines from the U.S. Environmental Protection Agency, but it could be devastating to the Laramie River, so keeping the bugs alive is a top priority at the treatment facility, he said.
The universal method of measuring the amount of oxygen needed for the bugs’ survival is biochemical oxygen demand, Claymore said.
“The bugs use the dissolved oxygen to remove the (biochemical oxygen demand),” he said.
To correct for the demand, the treatment facility uses large blowers to add dissolved oxygen to the oxidation ditch, which holds hold 4 million gallons of bug-infused wastewater at all times, city documents state.
While Laramie treats an average of 3.5 million gallons of wastewater per day, the number can fluctuate with big events in the city such as University of Wyoming football games or Laramie Jubilee Days, Claymore said.
“The energy cost to treat the waste is huge,” Smith said.
Previously the city used regional averages to determine the biochemical oxygen demand of certain streams of wastewater in an effort to accurately gauge wastewater rates for each of the city’s 11 customer classes. But about two years ago, the treatment facility started measuring biochemical oxygen demand on site, Claymore said.
This summer, city staff measured wastewater streams from five locations in each of the 11 classes to determine if Laramie’s wastewater rates were accurate. The study revealed that while some of Laramie’s customer classes’ biochemical oxygen demand were within the regional average, others were not, prompting City Council to review how wastewater customers are charged.
As a result of the data collection earlier this year and a sewer cost of service study conducted by Raftelis Financial Consultants, one way the rates could change is reducing the city’s number of wastewater customer classes from 11 to two.
If the council approves the third and final reading of the proposed rate-change ordinance, the two customer classes would be residential and nonresidential.
Residential wastewater rates are based on January, February and March water reads from the previous year of usage for the residence, according to city documents. The average of the three months of consumption is currently multiplied by $4.05 per 1,000 gallons.
City Council approved a wastewater rate increase earlier this year, which would have increased residential wastewater rates to $4.21 per 1,000 gallons, but if council approves the final reading of the proposed wastewater rate ordinance today, residents could pay $4.41 per 1,000 gallons starting in 2018.
Non-residential wastewater rates are based on the water consumption for the billing period, according to city documents. The figure of the water consumption is multiplied by the sewer rate that is designated by the treatment plant.
Current non-residential wastewater rates range from $3.97-$7.92. While all of the non-residential customer classes were scheduled to receive a wastewater water rate increase, the proposed ordinance would set non-residential customer classes at a flat rate of $4.60, which would be a small increase for some current customer classes and significant decrease for others.