Assessment of mobility and bioavailability of mercury compounds in sewage sludge and composts.

Content of heavy metals, including mercury, determines the method of management and disposal of sewage sludge. Excessive concentration of mercury in composts used as organic fertilizer may lead to accumulation of this element in soil and plant material. Fractionation of mercury in sewage sludge and composts provides a better understanding of the extent of mobility and bioavailability of the different mercury species and helps in more informed decision making on the application of sludge for agricultural purposes.

Two composting phases running in different process conditions timing relationship.

This research work pertained to establishment of timing relationship for two sludge composting phases proceeding in different conditions. The first phase was performed in a dynamical reactor and the second - in periodically turned windrows. The research was carried out in three independent repetitions with five test series cycles in each varying in the hot phase timing.