In the summer of 2015 the DSPUD in concert with the Sierra Lakes County Water District inaugurated a new $25 million sewer plant. 

The impetus behind the project was State mandates and a sewer system that was not working properly and the old plant had reached capacity.  

The Joint Facilities Committee of the two districts along with the engineers had  a number of goals in designing the new plant: accommodating growth in the two districts so that those owning vacant lots will be able to connect,  protecting the Yuba River, meeting current and forseeable

State Regulations, and being responsible to the Ratepayers.  DSPUD general manager, Tom Skjelstad, called those last three his  3 R’s.

The new plant’s capacity is enough to meet the foreseeable demands due to growth in the two districts.

The new plant uses proven technology, Membrane Bio-Reactors, and incorporates procedures to meet the unique challenges of Donner Summit.   

The area is mostly a second home community which means that sewage processing may be very high some heavy weekends and almost nothing in the off-season.  Sewage is processed by having bacteria digest it.   The bacteria do not like being on a “feast or famine” regimen and take exception by dying.   Then there are not enough “bugs” to process heavy flows.  To solve that problem the new plant has large storage tanks.  The sewage flow into the plant can then be at a consistent level.  The “bugs” are then happy.

Second, the inflow during winter can be very cold.  Bacteria do not like very cold temperatures and take exception by not processing things optimally.  To solve that problem influent to the new plant is heated just a bit.

The new plant replaces the old plant’s final step of chlorine disinfection with UV (ultra-violet) disinfection.  That step kills any remaining pathogenic organisms but had another benefit too. Although not required now, the State will probably institute requirements to remove pharmaceuticals and cosmetics from wastewater.  UV disinfection can do that.

Here is a link to a PDF schematic (3.5 meg download size, reduced size below) of the flow through the new plant.  It can be printed on a normal letterhead sized piece of paper if you choose.