How Many Trains in Boston?

When all Boston service-area wastewater received secondary treatment the amounts of solids produced would increase. An investigation to assess whether the four trains of the treatment plant drying and pelletizing facility would be sufficient for higher production is presented. Each train in the drying and pelletizing facility converted biosolids cake to a fertilizer product. The capability and reliability of each dryer train was determined by the dryer's evaporative capacity and the solids handling and conveying equipment's capacity. A typical analysis approach to allow for one or more units to be out of service and to determine the number of active units is presented. Analysis indicated that six trains should be provided and if available capacity was less that that required for a long period then alternative biosolids disposal methods would be required.