Respiration and enzymatic activities as indicators of stabilization of sewage sludge composting.
The objective of this work was to study the evolution of physico-chemical and microbial parameters in the composting process of sewage sludge (SS) with pruning wastes (PW) in order to compare these parameters with respect to their applicability in the evaluation of organic matter (OM) stabilization. To evaluate the composting process and organic matter stability, different microbial activities were compared during composting of anaerobically digested SS with two volumetric ratios, 1:1 and 3:1 of PW:SS and two aeration techniques including aerated static piles (ASP) and turned windrows (TW). Dehydrogenase activity, fluorescein diacetate hydrolysis, and specific oxygen uptake rate (SOUR) were used as microbial activity indices. These indices were compared with traditional parameters, including temperature, pH, moisture content, organic matter, and C/N ratio. The results showed that the TW method and 3:1 (PW:SS) proportion was superior to the ASP method and 1:1 proportion, since the former accelerate the composting process by catalyzing the OM stabilization. Enzymatic activities and SOUR, which reflect microbial activity, correlated well with temperature fluctuations. Based on these results it appears that SOUR and the enzymatic activities are useful parameters to monitor the stabilization of SS compost.
Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran. Electronic address: nikaeen@hlth.mui.ac.ir.
Mahnaz
M
Nikaeen
Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Environmental Health Engineering, School of Health, Kermanshah University of Medical Sciences, Kermanshah, Iran. Electronic address: nafez.amirhossein@gmail.com.
Amir Hossein
AH
Nafez
Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
Bijan
B
Bina
Department of Environmental Health Engineering, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
BiBi Fatemeh
BF
Nabavi
Department of Statistic and Epidemiology, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran.
Akbar
A
Hassanzadeh
D000332:Aerobiosis; D029779:Cupressaceae / Q000737:chemistry; D064307:Microbiota; D028223:Pinus / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry*; D018547:Plant Stems / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D014197:Trees / Q000737:chemistry; D018505:Waste Management / Q000379:methods*
D012722:Sewage
Composting; Enzymatic activity; Organic matter stabilization; Respiratory activity; Sewage sludge