Technical, economic and environmental assessment of sludge treatment wetlands.

Sludge treatment wetlands (STW) emerge as a promising sustainable technology with low energy requirements and operational costs. In this study, technical, economic and environmental aspects of STW are investigated and compared with other alternatives for sludge management in small communities (<2000 population equivalent). The performance of full-scale STW was characterised during 2 years. Sludge dewatering increased total solids (TS) concentration by 25%, while sludge biodegradation lead to volatile solids around 45% TS and DRI(24h) between 1.1 and 1.4 gO(2)/kgTS h, suggesting a partial stabilisation of biosolids. In the economic and environmental assessment, four scenarios were considered for comparison: 1) STW with direct land application of biosolids, 2) STW with compost post-treatment, 3) centrifuge with compost post-treatment and 4) sludge transport to an intensive wastewater treatment plant. According to the results, STW with direct land application is the most cost-effective scenario, which is also characterised by the lowest environmental impact. The life cycle assessment highlights that global warming is a significant impact category in all scenarios, which is attributed to fossil fuel and electricity consumption; while greenhouse gas emissions from STW are insignificant. As a conclusion, STW are the most appropriate alternative for decentralised sludge management in small communities.

[1]  H. Obarska-Pempkowiak,et al.  Polish experience with sewage sludge utilization in reed beds , 2000 .

[2]  Morgan Fröling,et al.  Environmental assessment of supercritical water oxidation of sewage sludge , 2004 .

[3]  H. W. Campbell,et al.  Sludge management – future issues and trends , 2000 .

[4]  S. Molander,et al.  Life cycle assessment of wastewater systems : Influence of system boundaries and scale on calculated environmental loads , 2000 .

[5]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[6]  Esther Llorens,et al.  Sludge treatment wetlands: a review on the state of the art. , 2010, Bioresource technology.

[7]  Patrizia Buttol,et al.  An environmental LCA of alternative scenarios of urban sewage sludge treatment and disposal , 2007 .

[8]  Jinglan Hong,et al.  Environmental and economic life cycle assessment for sewage sludge treatment processes in Japan. , 2009, Waste management.

[9]  Ujjaini Sarkar,et al.  Landfill odour: assessment of emissions by the flux footprint method , 2003, Environ. Model. Softw..

[10]  Fabrizio Adani,et al.  Determination of Biological Stability by Oxygen Uptake on Municipal Solid Waste and Derived Products , 2001 .

[11]  A. Hospido,et al.  Environmental Evaluation of Different Treatment Processes for Sludge from Urban Wastewater Treatments: Anaerobic Digestion versus Thermal Processes (10 pp) , 2005 .

[12]  Mattias Olofsson,et al.  Environmental and economic assessment of sewage sludge handling options. , 2004 .

[13]  Albert Germain,et al.  Life Cycle Assessment of Water: From the pumping station to the wastewater treatment plant (9 pp) , 2007 .

[14]  Xavier Font,et al.  Ammonia emissions from the composting of different organic wastes. Dependency on process temperature. , 2006, Chemosphere.

[15]  Teresa Gea,et al.  Comparison of aerobic and anaerobic stability indices through a MSW biological treatment process. , 2008, Waste management.

[16]  Patrick Rousseaux,et al.  An LCA of alternative wastewater sludge treatment scenarios , 2002 .

[17]  Arpad Horvath,et al.  Hybrid life-cycle environmental and cost inventory of sewage sludge treatment and end-use scenarios: a case study from China. , 2008, Environmental science & technology.

[18]  Esther Llorens,et al.  Sludge dewatering and stabilization in drying reed beds: characterization of three full-scale systems in Catalonia, Spain. , 2009, Bioresource technology.

[19]  Anastasia Zabaniotou,et al.  Utilization of sewage sludge in EU application of old and new methods--A review , 2008 .

[20]  Xavier Font,et al.  Long term operation of a thermophilic anaerobic reactor: process stability and efficiency at decreasing sludge retention time. , 2010, Bioresource technology.

[21]  Didier Lecomte,et al.  Life Cycle Assessment (LCA) Applied to the Design of an Innovative Drying Process for Sewage Sludge , 2006 .

[22]  E. Bertrán,et al.  Composting winery waste: sludges and grape stalks. , 2004, Bioresource technology.

[23]  A. Hospido,et al.  Environmental performance of wastewater treatment plants for small populations , 2008 .

[24]  Fabrizio Adani,et al.  In search of a reliable technique for the determination of the biological stability of the organic matter in the mechanical-biological treated waste. , 2009, Journal of hazardous materials.

[25]  R. Singh,et al.  Potential benefits and risks of land application of sewage sludge. , 2008, Waste management.

[26]  Barbara Scaglia,et al.  An index for quantifying the aerobic reactivity of municipal solid wastes and derived waste products. , 2008, The Science of the total environment.

[27]  Katia Lasaridi,et al.  A simple respirometric technique for assessing compost stability , 1998 .

[28]  Eliot Epstein,et al.  Evaluating Risks and Benefits of Soil Amendments Used in Agriculture , 2002 .

[29]  Klaus Fricke,et al.  Biodegradation of Organic Matter During Mechanical Biological Treatment of MSW , 1998 .

[30]  Fu Yang Wang,et al.  Sewage Sludge Technologies , 2008 .

[31]  Steen Nielsen,et al.  SLUDGE TREATMENT AND DRYING REED BED SYSTEMS IN DENMARK , 2005 .

[32]  Olivier Jolliet,et al.  Life cycle assessment of processes for the treatment of wastewater urban sludge: energy and global warming analysis , 2005 .