Journal of Hazardous Materials 269 (2014) 38–44 Contents lists available at ScienceDirect Journal of Hazardous Materials jo ur nal ho me p ag e: www.elsevier.com/locate/jhazmat Biological sulfate removal from construction and demolition debris leachate: Effect of bioreactor configuration Pimluck Kijjanapanich a,∗ , Anh Tien Do b , Ajit P. Annachhatre c , Giovanni Esposito d , Daniel H. Yeh b , Piet N.L. Lens a a Pollution Prevention and Resource Recovery Chair Group, UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands b Civil and Environmental Engineering, University of South Florida, Tampa, FL 33620, USA c Environmental Engineering and Management, Asian Institute of Technology, PO Box 4, Klongluang, Pathumthani 12120, Thailand d Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino (FR), Italy h i g h l i g h t s • Novel biological technique for gypsum removal from CDD. • CDDS leachate treatment performed using different sulfate reducing bioreactors. • Gypsum in CDD can be used as a source of sulfate for sulfate reducing bacteria. • High calcium concentration (1000 mg L -1 ) did not affect the bioreactor performance. a r t i c l e i n f o Article history: Received 19 August 2013 Received in revised form 6 October 2013 Accepted 7 October 2013 Available online 15 October 2013 Keywords: Construction and demolition debris Sulfate reduction UASB Inversed fluidized bed reactor Gas lift anaerobic membrane bioreactor a b s t r a c t Due to the contamination of construction and demolition debris (CDD) by gypsum drywall, especially, its sand fraction (CDD sand, CDDS), the sulfate content in CDDS exceeds the posed limit of the maximum amount of sulfate present in building sand (1.73 g sulfate per kg of sand for the Netherlands). Therefore, the CDDS cannot be reused for construction. The CDDS has to be washed in order to remove most of the impurities and to obtain the right sulfate content, thus generating a leachate, containing high sulfate and calcium concentrations. This study aimed at developing a biological sulfate reduction system for CDDS leachate treatment and compared three different reactor configurations for the sulfate reduction step: the upflow anaerobic sludge blanket (UASB) reactor, inverse fluidized bed (IFB) reactor and gas lift anaerobic membrane bioreactor (GL-AnMBR). This investigation demonstrated that all three systems can be applied for the treatment of CDDS leachate. The highest sulfate removal efficiency of 75–85% was achieved at a hydraulic retention time (HRT) of 15.5 h. A high calcium concentration up to 1000 mg L -1 did not give any adverse effect on the sulfate removal efficiency of the IFB and GL-AnMBR systems. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Construction and demolition debris (CDD) originates from building, demolition and renovation of buildings. Due to insuffi- cient source separation, CDD becomes a mixed material which is difficult to recycle [1]. The composition of CDD is affected by numer- ous factors, including the raw materials used, architectural tech- niques, local construction and demolition practices [2]. The main ingredients present in the CDD are soil, ballast, concrete, asphalt, bricks, tiles, masonry, wood, metals, paper, plastics and gypsum drywall [2–4]. Moreover, toxic wastes, like asbestos and heavy met- als, are not always separated from the rest of the CDD. Although ∗ Corresponding author. Tel.: +31 649539640. E-mail address: som cheng00@hotmail.com (P. Kijjanapanich). their quantity is relatively small, their presence can significantly affect the recycled materials or can contaminate landfills [2]. According to several characterization studies of CDD in the US, gypsum drywall accounts for 21–27% of the mass of debris generated during the construction and renovation of residential structures [3]. On an average, 0.9 metric tons of waste gypsum is generated from the construction of a typical single family home or 4.9 kg m -2 of the structure [5]. Nearly 40% of the total mass of CDD is construction and demolition debris sand (CDDS), which con- sists mainly of sand [6], due to its weight and extensive usage in modern building techniques. Moreover, most of the gypsum is con- centrated in the sand fraction (52.4% of total gypsum) [1,7], whereas the organic matter is distributed mainly in the large-sized fractions of CDD [1]. Reuse options have been proposed for CDDS, including soil amendment, alternative daily landfill cover, and fill material in 0304-3894/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jhazmat.2013.10.015