Activated sludge is the most widely used biological wastewater treatment process globally to date, although its high energy demand makes it a major contributor of greenhouse gas emissions. Over recent decades it has been constantly modified and retrofitted to treat ever higher loads or improve effluent standards which have often resulted in even greater carbon emissions. Conventional activated sludge treatment is at a crossroads where new sustainable solutions are required if we are to protect the quality of our rivers and meet net-zero carbon targets.The book details current operation and...