Early indications are that the plant is costing significantly more in some areas, but expenses in other areas are similar to the old plant or lower than the old plant.
Increased costs at the plant over those of the previous plant’s operation include electricity and chemicals. However, city officials point out that even though it’s been a year there is still no easy way to tell how much more the plant is going to cost until it has another year under its belt because not all aspects of the plant have been operational for a full year.
“We’ll have to look at all the costs,” Plant Manager Carl Jones said. “Until we do an annual analysis of the history, it would be hard to tell. Next year at this time we could probably tell.”
Decreased costs include landfill fees because once the plant’s sludge is certified in the next few months it will become Class A sludge, meaning instead of paying to take it to the landfill the city could actually sell it for use as fertilizer if it chooses.
Also, the plant is operating with less staff. When the city budgeted for the new plant it expected to need two new operators at the plant, but the plant’s efficiency has made that measure unnecessary. In fact, a vacant position was eliminated, bringing the plant’s staff to less than it was a year ago with no plans to create new positions in the future.
One reason the actual cost differences from the first year are so vague compared to previous years at the old plant is a new billing formula the city recently worked out with Georgia Power for electricity. Rather than being billed on a commercial rate, the plant is now under a “real-time” pricing structure for kilowatt hours used, meaning that the prices are based on demand for the hours.
The plant’s first billing cycle for electricity — June 2011 — saw a monthly cost of $3,455.59 for 110579 kilowatt hours at the plant, not including the influent pump which averaged about $1,600 per month. However, that cost increased as the plant’s operation picked up until its 12-month peak of $10,113.43, which included 283,176 kilowatt hours used at the plant and was the first month the new plant’s ATAD (digester system) was in use.
“It almost doubled from when we did not have the digester running,” City Manager Larry Wood said. “It’s taking almost twice the energy to run the plant, just because we’re running the digester system.”
The most recently billing cycle — April 2012 — is the most telling because it includes the newest billing rate and the rate for the influent pump station. The cost last month was about $9,900, including the influent pump station, compared to a bill in April 2011 — the last full month of the old plant’s operation — which was $8,544, including the influent station.
“What we’re being charged now is a completely different rate schedule,” Wood said. “What we were under was the old commercial rate that was dependent on what your base is and what your usage is and if you spike it they push your demand up and that kills you. Under the new rate schedule, in the winter time we’re buying kilowatt power time at three or four cents an hour, but this summer when Georgia Power really needs that power they’ll be charging us like 20 cents an hour in the afternoons some days when they really need the power, so it could get really expensive on a hot summer day.”
Jones agreed that the cost will be higher in the summer with the new rates.
“Those rates at the old West Plant were pretty constant year-round, but the summer rates are going to drive these costs up,” he said.
It is estimated that the electrical cost will be at least $15,000 per month this summer.
Even though it may be more expensive in the summer to run the plant, Wood is confident the new rate structure should save the city per kilowatt hour in the long run.
The city budgeted $320,000 for electricity at the new plant for the fiscal year that ended March 31 and came in nearly $40,000 under budget, though that was because the new plant became operational about two months after the fiscal year began. There is $330,000 budgeted this year for electricity.
“We’ve probably got 10 times more connected power, so we could be anywhere in between where we are and 10 times that much,” Jones said.
The chemicals needed to “dewater” the sludge that come through the plant are also costing more than expected. However, there is really no way around the added costs because the Georgia Environmental Protection Division requirements on the new plant are much more stringent than on the old plant and additional chemicals are required to meet the mandates.
“The new plant has a new permit and requirements are much more stringent,” Jones said. “That alone increases the cost of operating the plant. These were expected costs though.”
Plans to purchase the chemicals in bulk and store them until needed may help defray some of the added costs.
The capacity at the new plant is 2.3 million gallons per day, but only slightly more than 500,000 gallons per day is currently being used due to the lack of new construction in the city. However, when a new east-west sewer line is complete later this summer it will divert another 200,000 to 300,000 gallons per day to the new plant that would have gone to the North Plant near Mirror Lake.
When construction picks up in the city and the capacity used at the West Plant increases, the cost to run the plant will go up as well. However, this operational cost will not increase proportionally, according to Jones, and the increased costs would be offset by additional user fees.
The last part of the new plant’s operation, the belt presses, are only recently up and running. However, since the capacity coming through the plant is less than it was designed for there are modifications that have been made to make it operate efficiently.
Otherwise, Jones reports the plant is operating as it should and there have been no major problems in the first year of operation.
“It’s still going to be a net loss, but long-term, when it’s up to design capacity, it’s less than unit volume to operate,” Jones said. “There weren’t many bugs in the process at all other than a few ‘punch list’ type items. In fact, the process has worked exactly like it was designed.”