The rapid infiltration wastewater treatment and disposal option would cost more because it requires about $5 mill ion to purchase land needed for the ground water seepage basins.
Both wastewater treatment alternatives the city is looking at to answer its growing pains would have the same treatment process.
Each alternative would treat waste water to a higher degree than the current plant. The difference is in how the treated wastewater would be disposed.
Rapid infiltration would dispose the wastewater in basins that allow the water to seep into the ground.
In order to do so, the city would need to purchase land that has the proper soils to allow the process to work.
The city's contract engineer, CH2M Hill, was operating on an estimate of $50,000 per acre as a possible cost for land. In addition, the rapid infiltration option would also require a pipeline to transport the treated wastewater to the basins.
The additional parts of the plant would cost the city about $5.1 million in the first phase and an additional $740,000 over the last two phases of the 20-year plan.
The city would also have to do other projects to satisfy state and federal regulators to reduce the phosphorus entering the North Fork of the Payette River watershed.
To do that, the city can manage its storm water drainage better, pave gravel streets, or pay area farmers to limit the amount of phosphorus that enters the watershed from agricultural sources.
The rapid infiltration option also comes with a higher operating cost than the surface water discharge option.
In the first phase of the plan between 2013 and 2017, it would cost about $150,000 more per year to operate a rapid infiltration plant. The additional operating costs are largely a function of operating the pipeline and seepage basins that account for $149,000 additional operating costs in the alternative.
Rapid infiltration would cost the city an estimated $695,000 per year initially, compared to $546,800 per year initially for a surface water discharge plant.
The operating costs increase in each phase. From 2018 to 2023 the cost would be $740,800 compared to $587,300 in the river discharge option.
In the final phase, 2024 to 2033, the operating cost per year would rise to $908,300 in the rapid infiltration option, compared to $717,800 in the river discharge option.
Major costs associated with the rapid infiltration alternative include:
• Four aeration basins at about $40 million.
• Two fine screens, two vortex grit removal devices at $7.4 million.
-Aerobic digester and one belt filter press at $7 million.
• Expanded administrative and support facilities at $4.2 million.
• Eight rapid infiltration basins at about $3.7 million.
• Dewatering belt filter press at $3.7 million.
• Expanded disinfectant generation at $2.5 million.
• New pump station at $2.4 million.
• Pipeline to rapid infiltration basins at about $2.1 million.
• Phosphorus offsets at $2 million.
J-Ditch pipe & pond would be kept with infiltration
The city of McCall would still use its J-Ditch pond and pipeline if it decides to choose rapid infiltration to meet future wastewater treatment and disposal needs, city engineer Betsy Roberts said.
"McCall will continue to direct its treated wastewater to the J-Ditch Pipeline irrigation system through the end of year 2016 in accordance with the agreements between the city, the J-Ditch Pipeline Association, and the Lake Irrigation District," Roberts said.
"Both the winter storage pond and the pipeline to the J-Ditch irrigation system will be fully utilized during this period," she said.
The city has a $6 million judgment against it to pay back a contractor and his bonding agency for work done to build the city's storage pond in 2001.
The city has yet to come up with a plan or time frame to pay St. Clair Contractors of Boise or its bonding agency, Employers Insurance of Wausau.
There is concern that the city could scrap the J-Ditch infrastructure as it moves toward a new wastewater treatment facility.
City Manager Lindley Kirk Patrick said that would not happen. The city would use the infrastructure in some capacity in the future, Kirkpatrick said. "Beyond 2016, the city, the J-Ditch Pipeline Association, and the Lake Irrigation District are required to meet in good faith and discuss their mutual interests regarding continuation of the irrigation arrangements in accordance with their agreements," Roberts said.
The parties could agree to continue the irrigation plan under new agreements, she said.
"If the parties agree to discontinue irrigation arrangements beyond year 2016, then the city would not supply treated wastewater to the J-Ditch Pipeline Association, and the pipeline to the J-Ditch system would not be utilized," Roberts said.
"The winter-time storage pond would be integrated into the treatment plant and utilized to provide storage of effluent for either discharge alternative," she said.
Engineers would also look at the J-Ditch pipeline to see if any of it could be used as part of the pipeline that moves treated wastewater from the plant to the proposed rapid infiltration basins, she said.
