Sand Bioreactors for Wastewater Treatment for Ohio Communities, Bulletin 876, Sand Bioreactor System Construction Sand Bioreactors for Wastewater Treatment for Ohio Communities Bulletin 876-99 Sand Bioreactor System Construction Keeping groundwater and surface water out of the sand bioreactor is the single most important goal in construction. Liners, or cast or precast tanks, are required with sand bioreactors to keep out groundwater. Liners and tanks are also used to keep untreated wastewater from entering groundwater. Berms and surface grading must be provided in such a way as to keep surface water from draining into a sand bioreactor.
Liners are an effective way to prevent infiltration of groundwater into the system.
A PVC liner of at least 20 mil is recommended in an earthen basin with provisions for UV protection. As with any liner system, it is important to use as few seams as possible. If an outlet must penetrate the bottom of the liner, great care must be taken at this point to prevent leaks. Precast, or poured in place, concrete tanks are an alternative to lined earthen basins. Small bioreactors have been constructed in the bottom section of precast septic tanks.