Interaction effects of organic load and cycle time in an AsBr applied to a personal care industry wastewater treatment Ricardo Polisaitis Oliveira a , Suzana Maria Ratusznei a , José Alberto Domingues Rodrigues a, * , Marcelo Zaiat b , Eugenio Foresti b a Escola de Engenharia Mauá (EEM), Instituto Mauá de Tecnologia (IMT), Praça Mauá 1, CEP 09.580-900, São Caetano do Sul, SP, Brazil b Departamento de Hidráulica e Saneamento (SHS), Escola de Engenharia de São Carlos (EESC), Universidade de São Paulo (USP), Av. Trabalhador São-Carlense 400, CEP 13.566-590, São Carlos, SP, Brazil article info Article history: Received 5 February 2010 Received in revised form 5 July 2010 Accepted 6 July 2010 Available online 1 August 2010 Keywords: ASBR Personal care industry effluent Sodium lauryl sulfate Organic load Feed time Influent concentration abstract A mechanically stirred anaerobic sequencing batch reactor (ASBR) containing granular biomass was applied to the treatment of a wastewater simulating the effluent from a personal care industry. The ASBR was operated with cycle lengths (t C ) of 8, 12 and 24 h and applied volumetric organic loads (AVOL) of 0.75, 0.50 and 0.25 gCOD/L.d, treating 2.0 L liquid medium per cycle. Stirring frequency was 150 rpm and the reactor was kept in an isothermal chamber at 30  C. Increase in t C resulted in efficiency increase at constant AVOL, reaching 77% at t C of 24 h versus 69% at t C of 8 h. However, efficiency decreased when AVOL decreased as a function of increasing t C , due to the lack of substrate in the reaction medium. Moreover, replacing part of the wastewater by a chemically balanced synthetic one did not yield the expected effect and system efficiency dropped. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Anaerobic sequencing batch reactors were proposed as an alternative to continuous systems, because they promoted good solids retention in the system and improved process control (Dague et al., 1992). Despite the advances observed since the first works, complete utilization of these systems still depends on insight into fundamental and technological aspects (Zaiat et al., 2001). One of the applications of anaerobic sequencing batch reactors is the treatment of wastewaters containing toxic or recalcitrant compounds, such as surfactants. The relationship between chemical structure, physicochemical properties, biodegradability and the impact caused by these substances has still not been very well elucidated. The role of these compounds in the environment seems to be ambiguous, since on one hand they may have toxic effects on living organisms and on the other hand may promote the decomposition of organic pollutants from the environment (Cserháti et al., 2002). Baumann and Müller (1997) investigated the degradation of sodium lauryl sulfate, with no addition of any other compound, in an up-flow anaerobic continuous fixed-bed reactor. Media con- tained 350 mgCOD/L in addition to salts and were autoclaved at 121  C. At a hydraulic retention time (HRT) of 1 h, methane production was only 15% of that which could be theoretically obtained. The justification of the authors was that sodium lauryl sulfate had been partially degraded to dodecanol by sulfate reducing bacteria and since consumption was very slow accumu- lation occurred in the reaction medium, which might have caused inhibition to the microorganisms. Also using an up-flow anaerobic continuous fixed-bed reactor, Patel and Madamwar (1998) studied the effect of different surfac- tants in the treatment of cheese whey. Addition of 200 mg/L sodium lauryl sulfate resulted in a 70% increase in the production of biogas as well as an increase from 69% to 77% of methane molar fraction in the biogas. Moreover, under that condition total volatile acids concentration was at its lowest, confirming system stability during operation. The treatment of different wastewaters has been on the agenda of many research groups including Feitkenhauer and Meyer (2002), Ndegwa et al. (2005), Li and Mulligan (2005), Mohan et al. (2005, 2007), Damasceno et al. (2007), Oliveira et al. (2008), Bezerra et al. (2007) and Canto et al. (2008). One of the explanations is that the compositions of these wastewaters interfere directly with * Corresponding author. E-mail address: rodrigues@maua.br (J.A.D. Rodrigues). Contents lists available at ScienceDirect Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman 0301-4797/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.jenvman.2010.07.015 Journal of Environmental Management 91 (2010) 2499e2504