title: Optimization of process parameters for pilot-scale liquid-state bioconversion of sewage sludge by mixed fungal inoculation.
abstract: Liquid-state bioconversion (LSB) technique has great potential for application in bioremediation of sewage sludge. The purpose of this study is to determine the optimum level of LSB process of sewage sludge treatment by mixed fungal (Aspergillus niger and Penicillium corylophilum) inoculation in a pilot-scale bioreactor. The optimization of process factors was investigated using response surface methodology based on Box-Behnken design considering hydraulic retention time (HRT) and substrate influent concentration (S0) on nine responses for optimizing and fitted to the regression model. The optimum region was successfully depicted by optimized conditions, which was identified as the best fit for convenient multiple responses. The results from process verification were in close agreement with those obtained through predictions. Considering five runs of different conditions of HRT (low, medium and high 3.62, 6.13 and 8.27 days, respectively) with the range of S0 value (the highest 12.56 and the lowest 7.85 g L(-1)), it was monitored as the lower HRT was considered as the best option because it required minimum days of treatment than the others with influent concentration around 10 g L(-1). Therefore, optimum process factors of 3.62 days for HRT and 10.12 g L(-1) for S0 were identified as the best fit for LSB process and its performance was deviated by less than 5% in most of the cases compared to the predicted values. The recorded optimized results address a dynamic development in commercial-scale biological treatment of wastewater for safe and environment-friendly disposal in near future.
authors.affiliation: a Department of Chemical and Environmental Engineering , Universiti Putra Malaysia , 43400 UPM Serdang , Selangor DE , Malaysia.|b Department of Bioprocess Engineering , Universiti Teknologi Malaysia , 81310 Skudai , Johor , Malaysia.
authors.forename: Roshanida A
authors.initials: RA
authors.lastname: Rahman
authors.affiliation: a Department of Chemical and Environmental Engineering , Universiti Putra Malaysia , 43400 UPM Serdang , Selangor DE , Malaysia.|c Department of Environmental Science , Bangabandhu Sheikh Mujibur Rahman Agricultural University , Gazipur 1706 , Bangladesh.
authors.forename: Abul Hossain
authors.initials: AH
authors.lastname: Molla
authors.affiliation: a Department of Chemical and Environmental Engineering , Universiti Putra Malaysia , 43400 UPM Serdang , Selangor DE , Malaysia.|d Department of Engineering , College of Applied Sciences-Sohar , P.O. Box 135, Sohar , Sultanate of Oman.
authors.forename: Hind F A
authors.initials: HF
authors.lastname: Barghash
authors.affiliation: a Department of Chemical and Environmental Engineering , Universiti Putra Malaysia , 43400 UPM Serdang , Selangor DE , Malaysia.
authors.forename: Ahmadun
authors.initials: A
authors.lastname: Fakhru'l-Razi
mesh_terms: D001234:Aspergillus niger / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D008962:Models, Theoretical; D010407:Penicillium / Q000378:metabolism*; D010865:Pilot Projects; D012722:Sewage / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis
chemical_list: D012722:Sewage; D062065:Wastewater
keywords: bioconversion; hydraulic retention time; mixed fungal inoculation; optimization; sewage sludge