title: Methanogenic activity inhibition by increasing the linear alkylbenzene sulfonate (LAS) concentration.
abstract: The effect of the initial concentration of linear alkylbenzene sulfonate (LAS) on specific methanogenic activity (SMA) was investigated in this work. Six anaerobic flasks reactors with 1 L of total volume were inoculated with anaerobic sludge (2 g VSS L(-1)). The reactors were assayed for 42 days, and fed with volatile fatty acids, nutrients, and LAS. The initial LAS concentrations were 0, 10, 30, 50, 75, and 100 mg L(-1) for the treatment flasks T1 (control), T2, T3, T4, T5, and T6, respectively. When compared with T1, T2 exhibited a 30% reduction in maximum SMA and total methane production (TMP). In treatment T3 through T6, the reductions were 44-97% (T3-T6) for SMA, and 30-90% (T3-T6) for TMP. Total LAS removal increased following the increase in the initial LAS concentration (from 36% at T1 to 76% at T6), primarily due to the high degree of sludge adsorption. LAS biodegradation also occurred (32% in all treatments), although this was most likely associated with the formation of non-methane intermediates. Greater removal by adsorption was observed in long-chain homologues, when compared to short-chain homologues (C13 > C10), whereas the opposite occurred for biodegradation (C10 > C13). The C13 homologue was adsorbed to a great extent (in mass) in T4, T5 and T6, and may also have inhibited methane formation in these treatments.
authors.affiliation: a Laboratory of Environmental Sanitation, Department of Civil Engineering, Federal University of Pernambuco , Recife , Brazil.
authors.forename: Luiza F C
authors.initials: LF
authors.lastname: Souza
authors.affiliation: a Laboratory of Environmental Sanitation, Department of Civil Engineering, Federal University of Pernambuco , Recife , Brazil.
authors.forename: Lourdinha
authors.initials: L
authors.lastname: Florencio
authors.affiliation: a Laboratory of Environmental Sanitation, Department of Civil Engineering, Federal University of Pernambuco , Recife , Brazil.
authors.forename: Savia
authors.initials: S
authors.lastname: Gavazza
authors.affiliation: a Laboratory of Environmental Sanitation, Department of Civil Engineering, Federal University of Pernambuco , Recife , Brazil.
authors.forename: Mario T
authors.initials: MT
authors.lastname: Kato
mesh_terms: D017738:Alkanesulfonic Acids / Q000378:metabolism*; D000693:Anaerobiosis; D019149:Bioreactors; D006801:Humans; D008772:Methylococcaceae / Q000378:metabolism*; D012722:Sewage; D013501:Surface-Active Agents / Q000378:metabolism*; D062065:Wastewater; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D017738:Alkanesulfonic Acids; D012722:Sewage; D013501:Surface-Active Agents; D062065:Wastewater; C030641:alkylbenzyl sulfonic acid
keywords: LAS; adsorption; anaerobic digestion; biodegradation; homologues; specific methanogenic activity; toxicity