Skip to main content


May contain: machine and lathe
1. Roto-strainer - removes roots, rags, plastics, and other coarse debris from the incoming wastewater.

GCSD is responsible for Wastewater Collection for approximately 1,500 residents of the Groveland and Big Oak Flat communities. The Wastewater Collection System includes 16 sewerage lift stations, 35 miles of gravity mains, 7 miles of force mains, a recycled water treatment plant, 2 surface storage reservoirs, and approximately 15 acres of spray fields.


Snow blower
2. Pellet maker - coarse materials
are dewatered and compressed
into pellets.



May contain: hot tub, tub, and jacuzzi
3. Equalization basin - wastewater then flows into the E-basin where it is aerated. The addition of air freshens the wastewater, removes gasses, adds oxygen, promotes the flotation of grease and oil, and aids in coagulation.
May contain: roof rack
4. Contact basin - wastewater is then introduced into the treatment plant where it is oxygenated and fed to a thriving population of naturally occurring organisms. These organisms feed on organic materials in the wastewater, breaking them down into gasses, liquids, or to a more stable solid form.




May contain: machine
5. Return activated sludge pump - used to either return settled materials and microorganisms into the treatment process, or to pump them into the aerobic digestion chamber.
May contain: water, bridge, building, and outdoors
6. Aerobic digestion chamber - reduced solids are pumped into the digestion chamber where they are thickened with chemical coagulants.



May contain: countryside, outdoors, shelter, building, nature, and rural
7. Thickened sludge is then pumped into covered drying beds.
May contain: person, human, bridge, building, and architecture
8. Wiers - after the settling, the liquid portion of the wastewater flows over wiers and into the chlorine contact basin.


May contain: water
9. Chlorine contact basin - liquid chlorine is used to kill any remaining organism in the plant effluent.
May contain: water, nature, outdoors, shoreline, and river
10. Holding reservoir - disinfected liquid is pumped to a holding reservoir.


May contain: outdoors, field, nature, machine, and grassland
11. Irrigation fields - during warm and dry months, the disinfected wastewater is sprayed onto irrigation fields or sent to the PMLA golf course for irrigation.