A symposium presented at two Achema Meetings: 1967, 1970 Frankfurt Germany - Contents - Preface - Clean Water in the Chemical Industries - On the Shear Strength of Floes -Aeration in Effluent Treatment -Biological Problems in the Handling of Organic Pollution in Industrial Effluents -Updraft Impellers in Activated Sludge Processes -Purification of Oil-bearing Effluents by Gas Flotation -The Treatment of Fluid Industrial Wastes by Combustion - Recovery of Nitrogen Oxides from Industrial Emissions by Means of Countercurrent Adsorption - Removal of Industrial Emissions by Electrochemical Means, Using a Novel Double-Layer Electrode - Simultaneous Recovery of Carbon Disulfide and Removal of Hydrogen Sulfide Purity Requirements for Viscose Plant Emissions - Practical Testing of Dryer Exhausts in Surface Coating Operations - On the Size Distribution of Aerosols In the Atmosphere - Developments in Clean Room Techniques - Bacteriological Contamination and Decontamination - Elutriation in the Production of Aerosols - New Knowledge of UItrafine Aerosols -A Novel Ventilation System for Operating Rooms - Applications of Clean Rooms in Manufacturing 167Supervision of Clean Rooms by the 40-1 Particle Counter -Potable Water from Sea and Brackish Waters State of-the-Art Report -Problems in the Removal of Inorganic Industrial Slurries - Problems in the Operation of Electrostatic Filters -Catalytic and Thermic Combustion of Industrial Waste Gases -Novel Honeycomb Type Catalyzers for Gas Purification -Desulfurization of Waste Gases by Adsorption and Catalysis on Activated Carbon -Control of Air Pollution by Vehicular Exhaust Testing Methods and Expectable Results -Removal of S02 from Waste Gases -Pollution in Industry -Decontamnination of Effluents by Percolating Filters With Plastic Packing -Continuous Ion Exchange in a Novel Counterflow Process -Intensive Fractionation-A Novel Approach in Ion Exchange Technology -Novel Developments in the Regeneration of Acid Pickling Liquors and Other Chloride Bearing Solutions -Water Purification in Sludge Blanket Clarifiers. The Influence of the Suspension Load -Making Potable Water from Surface Waters -Supervision and Control of Large Biological Clarifiers for Industry Effluents - Automatic Sampling of Domestic Effluents -Atomic Absorption Spectrophotometry in the Investigation of Waste and Interceptor Waters -Disposal of Industrial Wastes -Industrial and Domestic Sewage-A Total Treatment with Fly Ash and Polyelectrolytes -A Chemist's View of Garbage Disposal Methods -A Novel Method for Continuous Determination of Chlorine Ions in Liquids and Chlorinated Hydrocarbons in Air -Reverse Osmosis and Ultrafiltration -Where Do We Stand Today? -Index -