Ultra-Dewatering Bags contain Sediment and Oil pumped out during dewatering operations.Ultra-Dewatering Bag Contains Sediment and Oil Pumped Out During Dewatering Operations Detains both oil and sediment, offering a combination of benefits not available in alternative dewatering bags. Standard and custom sizes available. Accommodates up to 4" discharge hose. Helps comply with NPDES, 40 CFR 122.26 (1999) when used as Best Management Practice in Storm Water Pollution Prevention Plans.