RESIDUALS MANAGEMENT: AN INNOVATIVE APPROACH

摘要

Historically, water treatment plants have used low-technology approaches to treat and dispose of spent backwash water and sedimentation residuals such as utilizing onsite lagoons, and discharging to sewer systems and natural waterways. These approaches have been a low cost means to residuals management. However, many utilities are now evaluating and implementing relatively complex residuals management systems because of regulatory limitations imposed on drinking water treatment and wastewater discharges. In addition, treatment plants are finding that as solids production increases due to the more stringent water treatment regulations and due to increasing water demands, there is limited availability onsite for lagoon or drying bed disposal and there is less time available to attend to the labor-intensive disposal methods.rnThis paper identifies the technologies considered by the City of Bloomington [Indiana] Utilities (CBU) for residuals processing, and presents CBU's approach to residuals management using an innovative process based on proven technologies.rnCBU has used lagoons and drying beds to dewater and dispose of the sedimentation basin residuals and has returned backwash water to the head of the process at the Monroe Water Treatment Plant for many years. In 1998, after inadvertently discharging solids to Lake Monroe, CBU signed an Agreed Order with the Indiana Department of Environmental Management to implement a residuals management program. After careful consideration, CBU decided to use a pressure filter press with drying, in a single process. This approach to residuals management