A new solids technology train: can 70% volatile solids reduction and class a biosolids be achieved from digestion?
There has been an increase in interest amongst utilities to develop solids technology concept trains that result in solids volume reduction for land application. For example, the Water Environment Research Foundation has recently initiation the OWSO “optimization” program in part to develop concepts that reduce sludge volumes for beneficial reuse or disposal. Another concept that has been receiving increasing attention is the need to produce Class A biosolids for land application. A third concept that is receiving attention is the need to remove nitrogen from the recycle streams from anaerobic digestion. The District of Columbia Water and Sewer Authority has been investigating all these concepts for the past seven years and has recently developed a process train for full-scale implementation at its 370 mgd Blue Plains AWTP. DCWASA was seeking opportunities to improve its solids management process (enhanced VS destruction, improved cake solids and Class A processing), while at the same time minimize the impact of these process recycles on the liquid stream.