City adopts wastewater facilities plan

Sisters City Council has unanimously adopted a wastewater system capital facilities plan with a $1.5 million price tag. Improvements are planned for wastewater collecting, treatment, and effluent disposal.

The current permitted limit of 178 acre-feet of effluent will be exceeded in 2018. One feature of the capital facilities plan includes utilizing new forest land and the Lazy Z property for effluent dispersion (2017/18). Those 49 additional acres will allow for a maximum application rate of 255 acre-feet per year, which is projected to be sufficient until 2031.

Security upgrades are scheduled at the City's treatment facility for 2017/18. An interceptor at Locust Street will hook up to a line running along Black Butte Avenue to pump station No. 1 in 2020. Replacing and increasing the size of aeration equipment at the treatment facility will be needed in 2017/18.

A biosolids management plan for removal and disposal on a portion of the Lazy Z, where it will be watered into the soil is scheduled for 2017. New pumps at station No. 1 will be needed by 2022-25.

A second expansion of effluent dispersion by 2031 (including crop irrigation), which increases the inches per year that can be spread, will allow more acre-feet per year. Different crops and soils have different uptake rates. In Central Oregon, with so few frost-free days, hay works well as a crop and can be used by livestock. The crop management can be contracted out so the City won't have to be in the agriculture business.

The final project, which will be triggered by any eventual development of the Forest Service property at the west end of town, involves the west-side pump station, which would send wastewater along the south side of town directly to the treatment facility in the southeast corner of the city. By diverting west-side wasterwater from pump station No. 1 in the northeast corner of the city, the capacity of No. 1 would be increased.

The comprehensive planning document covers required improvements and additions to the city's wastewater treatment system through the year 2035. Compared to other Central Oregon municipalities, Sisters is in an enviable position from both monetary and planning points of view, according to staff. Paul Bertagna, public works director, Eric Huffman, city engineer, and the public works department staff, created the 200-plus-page plan.