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Composting of olive processing wastes and tomato stalks together with sewage sludge or dairy manure
Şevik, F.; Tosun, İ. & Ekinci, K.
Abstract
In this study, composting of olive pomace from
three-phase oil production system, sewage sludge, dairy
manure, and tomato stalks were carried out. The effects of
carbon/nitrogen ratio on decomposition rate of composting
were investigated with constant free air spaces of composting
mixtures. Composting process was carried out in
the aerobic reactors made of stainless steel which were
monitored for 32 days. Temperature-controlled feedback
system was operated based on the Rutgers strategy. Temperature,
moisture, organic matter, pH, electrical conductivity
total carbon, total nitrogen, ammonium nitrogen and
nitrate nitrogen, total phosphorus as well as potassium were
monitored during the composting process. In addition,
mass and volume changes of the mixtures were determined.
The highest degree of decomposition was determined for
the mixture (carbon/nitrogen ratio of 20) based on the dry
matter loss where the maximum amount of sewage sludge
was used. On the other hand, maximum decomposition
occurred at a carbon/nitrogen ratio of 23 for mixtures
containing dairy manure. The increase in the use of olive
pomace in mixtures had adverse effects on the decomposition
process. The stabilization process in the mixture
containing dairy manure lasted shorter than the mixtures
containing sewage sludge.
Keywords
C/N ratio; Free air space; Heavy metal; Mass loss; Olive stone structure; Rutgers strategy
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