Microbial and chemical profile of a ponds system for the treatment of landfill leachate Heloísa Fernandes a , Aline Viancelli b , Claudia L. Martins a , Regina V. Antonio c , Rejane H.R. Costa a,⇑ a Department of Sanitary and Environmental Engineering, Federal University of Santa Catarina, Florianópolis, Brazil b Department of Ecology, Federal University of Santa Catarina, Florianópolis, Brazil c Department of Biochemistry, Federal University of Santa Catarina, Florianópolis, Brazil article info Article history: Received 17 July 2012 Accepted 30 October 2012 Available online 1 December 2012 Keywords: Stabilization ponds Microbial dynamics Phytoplankton community Landfill Leachate abstract The present study describes the behavior of spatio-temporal variation of parameters and microbial profile of a pilot stabilization ponds system, consisted of three serial ponds, for the treatment of landfill leachate. Bacterial diversity was determined through molecular techniques (FISH, PCR and phylogenic analysis), while the phytoplankton community was evaluated through optical microscopy and quantified by the Sedgewick–Rafter chamber. Physicochemical parameters were also evaluated. The ponds system pre- sented the following removal efficiency: 56% for TCOD; 83% for SBOD 5 and 82% for N—NH þ 4 . Moreover, the analysis of chlorophyll a and DO showed stratification in the mass of water by the vertical profile. The analysis of the phytoplankton community showed a low number of species, with a predominance of Chlamydomonas sp. and presence of Cryptomonas sp. in lower density. The bacterial diversity analysis showed the presence of Planctomycetales, Verrucomicrobiales, some Desulfovibionaceae sulfate- reducing bacteria and Pseudomonas sp. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction The landfill is the most common method for the disposal of mu- nicipal solid residues in undeveloped countries (Olivero-Verbel et al., 2008). The landfill leachate consists of wastewater that is re- leased from sanitary landfills. Wastewater normally contains high concentrations of pollutants being the main groups: dissolved or- ganic matter, inorganic macro components (including nutrients), heavy metals and xenobiotic organic compounds, which, if not cor- rectly collected and treated, can cause serious problems to water bodies and groundwater sources (Modin et al., 2011). For removing pollutants contained in the leachate a number of options for the treatment can be applied however the degree of treatment required is dependent upon the nature and strength of the leachate, according Ding et al. (2001). The most widely used method in reducing the polluting load of landfill leachate is by the utilization of biological wastewater treatment (Mehmood et al., 2009). The stabilization pond is one of the most important methods for the treatment of wastewater and has been used in all Brazilian re- gions to treat landfill leachate (Castilhos et al., 2009). The practical application and simplicity in terms of design and operation are important advantages of the pond treatment (Altinbas ß, 2009). In these systems the treatment is carried out through biological and physicochemical processes regulated by microbial communities sufficiently adaptable to breaking down complex organic com- pounds in waste streams from a wide range of processes, allowing recycling of nutrient and natural organic matter (Calli et al., 2006). The knowledge on the microbiology and ecology of microorgan- isms involved in landfill leachate depuration becomes relevant for the control and efficiency of the treatment because it allows the evaluation of the microorganisms’ interaction with the environ- ment and other organisms. Metabolically, photoautotrophic organisms transform organic matter into simple molecular compounds, such as oxygen, which is important in the process of organic matter decomposition. Het- erotrophic organisms use the organic matter and oxygen generated for both oxidation and the release of the required energy (Pearson, 2005). The diversity and density of the microorganisms are, therefore, directly related to their organic load and nutrient availability and also subject to the action of climatic factors, showing mechanisms of horizontal and vertical specific movement. Depending on the al- gal concentration (high = 10 4 –10 6 ind/mL), an increase on organic N and P can occur in the effluent, resulting in differences in micro- biological characteristics and physicochemical properties in accor- dance with the operating conditions of the system (Kargi and Pamukoglu, 2003). The aim of this work was to evaluate a stabilization ponds system for the treatment of landfill leachate, characterizing the microbial dynamics through FISH and phylogenetic analysis. 0956-053X/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.wasman.2012.10.024 ⇑ Corresponding author. Tel.: +55 (48) 3721 7738. E-mail address: rejane@ens.ufsc.br (R.H.R. Costa). Waste Management 33 (2013) 2123–2128 Contents lists available at SciVerse ScienceDirect Waste Management journal homepage: www.elsevier.com/locate/wasman