A Comparative Study of Biogas Production from Cattle Slaughterhouse Wastewater Using Conventional and Modified Upflow Anaerobic Sludge Blanket (UASB) Reactors

Abstract

Cattle slaughterhouses generate wastewater that is rich in organic contaminant and nutrients, which is considered as high strength wastewater with a high potential for energy recovery. Work was undertaken to evaluate the efficiency of the 12 L laboratory scale conventional and a modified upflow anaerobic sludge blanket (UASB) reactors (conventional, R1 and modified, R2), for treatment of cattle slaughterhouse wastewater (CSWW) under mesophilic condition (35 ± 1 °C). Both reactors were acclimated with synthetic wastewater for 30 days, then continuous study with real CSWW proceeds. The reactors were subjected to the same loading condition of OLR, starting from 1.75, 3, 5 10, 14, and 16 g L−1d−1, corresponding to 3.5, 6, 10, 20, 28, and 32 g COD/L at constant hydraulic retention time (HRT) of 24 h. The performance of the R1 reactor drastically dropped at OLR 10 g L−1d−1, and this significantly affected the subsequent stages. The steady-state performance of the R2 reactor under the same loading condition as the R1 reactor revealed a high COD removal efficiency of 94% and biogas and methane productions were 27 L/d and 89%. The SMP was 0.21 LCH4/gCOD added, whereas the NH3-N alkalinity ratio stood at 651 mg/L and 0.2. SEM showed that the R2 reactor was dominated by Methanosarcina bacterial species, while the R1 reactor revealed a disturb sludge with insufficient microbial biomass.

Treatment of Cattle Manure by Anaerobic Co-Digestion with Food Waste and Pig Manure: Methane Yield and Synergistic Effect

“…Livestock manure has been traditionally managed by direct application to agricultural land and open composting, causing environmental problems such as soil/groundwater contamination and eutrophication. Anaerobic digestion (AD), which converts organic matter into biogas, is a proven technology to treat high-strength organic wastes, including livestock manure, and has been widely applied [ 3 ]. In Europe, more than 18,000 AD plants are in operation, and they produced a total of 63.5 TWh energy out of biogas in 2018 [ 4 ].…”

Up-Flow Anaerobic Sludge Blanket (UASB) Technology for Energy Recovery: A Review on State-of-the-Art and Recent Technological Advances

“…The presence of support materials in a traditional UASB reactor for methane production triggers the formation of densely packed aggregates and a more consistent presence of large granular sludge (≥0.6 mm), with an increase in EPS production, promotion of VFA degradation and methane yield stimulation, together with stabilized performances [ 93 , 94 ]. Different materials were proposed for packing UASB reactor, including metals, minerals, recycled plastic material, synthetic grass and biochar [ 93 , 94 , 95 , 98 , 99 ]. Biochar, in particular, is a biomass-derived carbonaceous material, obtained from pyrolysis process, with proved capability of enhancing AD process performances, by DIET stimulation, C/N ratio optimization, micro-pollutant adsorption [ 74 ].…”

Assessment of Energy-Positive Wastewater Treatment System Design of Different Industrial Wastewater Streams

“…1 kg COD digested could be converted to 0.25 kg CH4 or 0.35m 3 CH4 theoretically at 0℃ and 1 atm [95] Table 7 lists the data of COD removal and methane production of UASB in treating food processing wastewater. These data were collected from published peer-reviewed papers [109][110][111]. Actual COD removal, unit methane production, and unit energy production at 25 ℃ are 43%-95%, 0.01-0.38 m 3 CH4/kg COD removal, and 0.03-1.30 kWh/kg COD.…”