aerobic secondary treatment
- Good secondary treatment plants remove 90 percent of measured BOD.
- For irrigational purposes, recycled water may be used after secondary treatment.
- Public treatment works were required to adopt secondary treatment by 1977, and "best practicable waste treatment over the life of the works" by 1983.
- EPA analyzed POTW costs and established a figure of $1.15 per pound as the appropriate marginal cost of advanced secondary treatment at a POTW.