Article thumbnail

Biological sulfate removal from gypsum contaminated construction and demolition debris

By P. Kijjanapanich, A. P. Annachhatre, G. Esposito, E. D. van Hullebusch and P. N. L. Lens

Abstract

Construction and demolition debris (CDD) contains high levels of sulfate that can cause detrimental environmental impacts when disposed without adequate treatment. In landfills, sulfate can be converted to hydrogen sulfide under anaerobic conditions. CDD can thus cause health impacts or odor problems to landfill employees and surrounding residents. Reduction of the sulfate content of CDD is an option to overcome these problems. This study aimed at developing a biological sulfate removal system to reduce the sulfate content of gypsum contaminated CDD in order to decrease the amount of solid waste, to improve the quality of CDD waste for recycling purposes and to recover sulfur from CDD. The treatment leached out the gypsum contained in CDD by water in a leaching column. The sulfate loaded leachate was then treated in a biological sulfate reducing Upflow Anaerobic Sludge Blanket (UASB) reactor to convert the sulfate to sulfide. The UASB reactor was operated at 23±3°C with a hydraulic retention time and upflow velocity of 15.5h and 0.1mh-1, respectively while ethanol was added as electron donor at a final organic loading rate of 3.46gCODL-1reactord-1. The CDD leachate had a pH of 8-9 and sulfate dissolution rates of 526.4 and 609.8mgL-1d-1 were achieved in CDD gypsum and CDD sand, respectively. Besides, it was observed that the gypsum dissolution was the rate limiting step for the biological treatment of CDD. The sulfate removal efficiency of the system stabilized at around 85%, enabling the reuse of the UASB effluent for the leaching step, proving the versatility of the bioreactor for practical applications

Topics: Construction and demolition debris, Gypsum contaminated waste, Leaching, Solid sulfate, Sulfate reducing bacteria, UASB
Publisher: 'Elsevier BV'
Year: 2013
DOI identifier: 10.1016/j.jenvman.2013.09.025
OAI identifier: oai:www.iris.unina.it:11588/738397
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://hdl.handle.net/11588/73... (external link)
  • Suggested articles


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.