Algae can play a positive role in wastewater treatment by recycling of nutrients, by taking up carbon, nitrogen and phosphorus, by reducing the nutrient load through stripping and precipitation, by producing oxygen for bacterial decomposition of organic matter, by eliminating pathogenic bacteria through bactericide action, and last but not least by solving odor problems. If sufficient insolation, and space are available, intensive algal wastewater treatment-systems proved to be valuable and promising alternatives to conventional treatment systems based on activated sludge or trickling filters. The various technologies developed for algal wastewater treatment are commented in this review. They include simple stabilization-oxidation ponds, as well as more... |