The treatment of wastewater using activated sludge can be straight forward producing excellent final effluent. Why then do plants run into problems? Activated sludge plants that have problems are unable to achieve the required standard of treatment. This leads to huge discharge problems, what do you do with the poor quality effluent that is not within consent limits? Often companies are facing court cases for breaches of discharge consent...

The problems can be many and varied including overloading, bulking sludge, toxic shock, poor management plus many others. In an attempt to highlight some of the common problems two case studies are examined and solutions offered.