External filtering device for use in a local containment area for removing oil and other contaminants from storm drain effluent as it exits storm water systems; Filters for air conditioning; Purification installations for sewage; Waste water purification apparatus, installations and tanks; Water filtration and purification units and replacement cartridges and filters therefor; Water purification units; Water purification, sedimentation and filtration apparatus for clarification, thickening an...