Environ Sci Pollut Res DOI 10.1007/s11356-014-3054-x
WETLAND SYSTEMS: ECOLOGY, FUNCTIONS AND MANAGEMENT
Organic matter and pollutants monitoring in reed bed systems for sludge stabilization: a case study Eleonora Peruzzi & Cristina Macci & Serena Doni & Maurizio Volpi & Grazia Masciandaro
Received: 14 December 2013 / Accepted: 16 May 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract In this study, results about sludge stabilization and pollutant monitoring in a reed bed system (RBSs) situated in Central Italy (Colle di Compito, 4,000 p.e.) were presented. In order to evaluate the process of sludge stabilization, parameters that highlighted the biochemical, chemical and chemicostructural properties of organic sludge matter have been followed during the entire period of operation (7 years). Moreover, the trend of heavy metals (bioavailable fractions and total content) and toxic organic compounds (LAS, NPE and DEHP) was monitored during all the period. The trend of all parameters related clearly demonstrated that sludge stabilization successfully proceeded in RBS. Moreover, through statistical analysis modelling, it is possible to determine how the stabilization process proceeded in terms of organic matter mineralization and humification, and how these processes influenced the content of pollutant compounds present in the stabilized sludges. Keywords Pyrolysis . Heavy metal fractionation . Mineralization . Humification . Toxic organic compounds . Sludge treatment wetland
Introduction
where sludge is frequently applied. The sludge–plant–microorganism system established within the beds is effective in sludge stabilization, also considering the pathogen abatement (Nielsen 2007). Since the late 1980s, RBSs have represented a valid technology for sludge treatment for their low construction costs, minimal daily maintenance, water reduction content and good stabilization of biosolids (Burgoon et al. 1997; Nielsen 2003). Several studies clearly demonstrated that this technology is able to dewater and stabilize sludge, improving the organic matter quality (Uggetti et al. 2010; Peruzzi et al. 2011a). In the last recent years, some authors proposed mathematical models about the performances of RBSs, mainly focused on sludge dewatering and short-term dynamics (Giraldi and Iannelli 2009; Giraldi et al. 2009; Vincent et al. 2011; Stefanakis and Tsihrintzis 2011; Uggetti et al. 2012; Iannelli et al. 2013). However, there are few studies, which reported data about long-term dynamics for sludge stabilization, with particular attention to mineralization and humification processes occurring in RBSs (Peruzzi et al. 2011a; Nielsen et al. 2014). The objective of this research is to quantitatively evaluate the stabilization process occurring in the RBS, fitting a logistic model to parameters related to sludge organic matter stabilization processes.
Reed beds systems (RBSs) for sludge treatment are a combination of a traditional sludge drying bed and natural wetland. Phragmites australis is directly planted in the drying beds,
Materials and methods
Responsible editor: Philippe Garrigues
Reed bed system
E. Peruzzi (*) : C. Macci : S. Doni : G. Masciandaro National Research Council - Institute of Ecosystem Study (CNR-ISE), Pisa 56124, Italy e-mail: [email protected] M. Volpi ACQUE SPA, Pisa, Italy
In this paper, results about the quality of the stabilized sludges within a reed bed system during the operational phases of loading and resting periods (7 years) are reported (Table 1). Sludge stabilization was investigated in one urban wastewater treatment plant of Acque S.p.A. (Tuscany, Italy), Colle
1.6±0.3
pH; total solids (TS, g/L); volatile solids (VS, %); total nitrogen (TN, % dw); total organic carbon (TOC, % dw); heavy metal total content (mg/kg dw); Di-2-ethylhexyl-phthalate (DEHP, mg/kg dw); Linear alkyl benzene sulfonate (LAS, mg/kg dw); nonylphenol and nonylphenol ethoxylates with 1 or 2 ethoxy groups (NPE, mg/kg dw)
41.1±15.3 693±121 35.0±7.3 905±203 143±26
WETLAND SYSTEMS: ECOLOGY, FUNCTIONS AND MANAGEMENT
Organic matter and pollutants monitoring in reed bed systems for sludge stabilization: a case study Eleonora Peruzzi & Cristina Macci & Serena Doni & Maurizio Volpi & Grazia Masciandaro
Received: 14 December 2013 / Accepted: 16 May 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract In this study, results about sludge stabilization and pollutant monitoring in a reed bed system (RBSs) situated in Central Italy (Colle di Compito, 4,000 p.e.) were presented. In order to evaluate the process of sludge stabilization, parameters that highlighted the biochemical, chemical and chemicostructural properties of organic sludge matter have been followed during the entire period of operation (7 years). Moreover, the trend of heavy metals (bioavailable fractions and total content) and toxic organic compounds (LAS, NPE and DEHP) was monitored during all the period. The trend of all parameters related clearly demonstrated that sludge stabilization successfully proceeded in RBS. Moreover, through statistical analysis modelling, it is possible to determine how the stabilization process proceeded in terms of organic matter mineralization and humification, and how these processes influenced the content of pollutant compounds present in the stabilized sludges. Keywords Pyrolysis . Heavy metal fractionation . Mineralization . Humification . Toxic organic compounds . Sludge treatment wetland
Introduction
where sludge is frequently applied. The sludge–plant–microorganism system established within the beds is effective in sludge stabilization, also considering the pathogen abatement (Nielsen 2007). Since the late 1980s, RBSs have represented a valid technology for sludge treatment for their low construction costs, minimal daily maintenance, water reduction content and good stabilization of biosolids (Burgoon et al. 1997; Nielsen 2003). Several studies clearly demonstrated that this technology is able to dewater and stabilize sludge, improving the organic matter quality (Uggetti et al. 2010; Peruzzi et al. 2011a). In the last recent years, some authors proposed mathematical models about the performances of RBSs, mainly focused on sludge dewatering and short-term dynamics (Giraldi and Iannelli 2009; Giraldi et al. 2009; Vincent et al. 2011; Stefanakis and Tsihrintzis 2011; Uggetti et al. 2012; Iannelli et al. 2013). However, there are few studies, which reported data about long-term dynamics for sludge stabilization, with particular attention to mineralization and humification processes occurring in RBSs (Peruzzi et al. 2011a; Nielsen et al. 2014). The objective of this research is to quantitatively evaluate the stabilization process occurring in the RBS, fitting a logistic model to parameters related to sludge organic matter stabilization processes.
Reed beds systems (RBSs) for sludge treatment are a combination of a traditional sludge drying bed and natural wetland. Phragmites australis is directly planted in the drying beds,
Materials and methods
Responsible editor: Philippe Garrigues
Reed bed system
E. Peruzzi (*) : C. Macci : S. Doni : G. Masciandaro National Research Council - Institute of Ecosystem Study (CNR-ISE), Pisa 56124, Italy e-mail: [email protected] M. Volpi ACQUE SPA, Pisa, Italy
In this paper, results about the quality of the stabilized sludges within a reed bed system during the operational phases of loading and resting periods (7 years) are reported (Table 1). Sludge stabilization was investigated in one urban wastewater treatment plant of Acque S.p.A. (Tuscany, Italy), Colle
1.6±0.3
pH; total solids (TS, g/L); volatile solids (VS, %); total nitrogen (TN, % dw); total organic carbon (TOC, % dw); heavy metal total content (mg/kg dw); Di-2-ethylhexyl-phthalate (DEHP, mg/kg dw); Linear alkyl benzene sulfonate (LAS, mg/kg dw); nonylphenol and nonylphenol ethoxylates with 1 or 2 ethoxy groups (NPE, mg/kg dw)
41.1±15.3 693±121 35.0±7.3 905±203 143±26
