Sludges from cold regions lagoons: Fid-Bau Portal

Sludges from cold regions lagoons

Schneiter, R. Wane / Middlebrooks, E. Joe / Sletten, Robert S. / Reed, Sherwood C.

ABSTRACT:  Accumulated solids associated with the operation of aerated and facultative lagoons in cold climates were investigated to determine (1) the rate and extent of solids accumulation, (2) the characteristics of the accumulated solids, (3) the potential for in situ stabilization of the accumulated solids, and (4) the effect of lime treatment upon the pathogenic population and subsequent solids drying on sand and soil beds. Accumulated sludges from the Logan and Corinne, Utah, facultative lagoons and the Palmer and Galena, Alaska, partial‐mix aerated lagoons were studied. The rates of accumulation, determined by in situ measurement of the sludge layer in each lagoon, were found to vary with lagoon type and specific operational and environmental conditions. The solids characteristics, determined for samples upon collection and for samples in cold storage over time, were found to be generally comparable to those of conventional primary sludges. Sludge samples were stored for an extended period at temperatures that model winter conditions at the lagoon bottom and were periodically tested to determine if changes were occurring in basic sludge characteristics. With the exception of bacterial concentration reduction, no significant changes were observed, indicating that in situ stabilization of the sludge is probably not occurring in the actual lagoons under low‐temperature conditions. Lime treatment of the lagoon sludges was evaluated by dosing the sludges with lime and applying the limed sludges to bench‐scale sand and soil drying beds. Lime addition produced high pathogen kill levels. The limed sludges readily dewatered on both sand and soil beds.