Oil and Grit Separators are suitable as pre-treatment to other downstream treatment systems such as ponds or LID features. Cost effective application of OGS as [[pretreatment]] to a downstream LID practice typically requires that the practice have a single [[inlet]] with a drainage area larger than 0.2 ha. | Oil and Grit Separators are suitable as pre-treatment to other downstream treatment systems such as ponds or LID features. Cost effective application of OGS as [[pretreatment]] to a downstream LID practice typically requires that the practice have a single [[inlet]] with a drainage area larger than 0.2 ha. |