Abstract: A clarifier for treatment of water and other liquids including a housing having a generally channel shaped member having an inlet arm and an outlet arm. The inlet arm forms a flocculation zone and the outlet arm forms a settling zone.The inlet arm may be provided with means for causing influent to travel a tortuous or serpentine flow path and the settling zone may include settling means so as to increase the effective surface area of the settling zone. Suitably both the inlet arm and outlet arm are substantially parallel to each other with the inlet arm being spaced from and located upwardly of the outlet arm.A sludge collection zone may be provided at the junction of the inlet arm and the outlet arm and may have associated therewith one or more sludge removal conduits.