scholarly journals Anaerobic Co-Digestion of Tannery and Slaughterhouse Wastewater for Solids Reduction and Resource Recovery: Effect of Sulfate Concentration and Inoculum to Substrate Ratio

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2491
Author(s):  
Ashton B. Mpofu ◽  
Victoria A. Kibangou ◽  
Walusungu M. Kaira ◽  
Oluwaseun O. Oyekola ◽  
Pamela J. Welz
Keyword(s):  
Dry Mass ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Tannery Effluent ◽  
Biochemical Methane Potential ◽  
Slaughterhouse Wastewater ◽  
Methanogenic Activity ◽  
Methane Potential ◽  
Efficient Processing ◽  
High Concentrations

Anaerobic digestion is considered unsuitable for the bioremediation of tannery effluent due to process inhibition, mainly due to high concentrations of sulfur species, and the accumulation of H2S and/or NH3. This study using the standardized biochemical methane potential protocol showed that efficient processing is possible with slaughterhouse wastewater, provided sufficient functional biomass is present at the start of the process and the SO42− concentration is below inhibition threshold. Methanogenic activity (K = 13.4–17.5 and µm = 0.15–0.27) and CH4 yields were high when reactors were operated ISR ≥ 3 and/or lower SO42− ≤ 710 mg/L while high SO42− ≥ 1960 mg/L and ISR < 3.0 caused almost complete inhibition regardless of corresponding ISR and SO42−. The theoretical optimum operating conditions (922 mg/L SO42−, ISR = 3.72) are expected to generate 361 mL biogas/gVS, 235 mL CH4/gVS with reduction efficiencies of 27.5% VS, 27.4% TS, 75.1% TOC, 75.6% SO42−, and 41.1% COD. This implies that tannery sludge will be reduced by about 27% (dry mass) and SO42− by 76%, with a fraction of it recovered as S0. The models displayed a perfect fit to the cumulative CH4 yields with high precision in the order Logistic > Cone > modified Gompertz > first order.

scholarly journals Bioenergy Production through Mono and Co-Digestion of Tomato Residues

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5563
Author(s):  
Patrícia V. Almeida ◽  
Rafaela P. Rodrigues ◽  
Leonor M. Teixeira ◽  
Andreia F. Santos ◽  
Rui C. Martins ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Operating Conditions ◽  
Fractional Factorial ◽  
Optimum Operating ◽  
Solids Concentration ◽  
Volatile Solids ◽  
Working Volume ◽  
Substrate To Inoculum Ratio ◽  
Methane Potential ◽  
High Concentrations

The agro-industry of tomato generates three types of residues: ripe rotten tomato (unfit for consumption) (RT), green (unripe) tomato (GT), and tomato branches including leaves and stems (TB). These materials are commonly wasted or used as feed for livestock. Energy production through anaerobic digestion is an alternative way to manage and simultaneously valorise these materials. Initially, the operating conditions of mono anaerobic digestion were investigated using RT. Thus, a design of experiments based on a two-level fractional factorial design with resolution V was performed to determine the factors that affect biochemical methane potential (BMP). The substrate to inoculum ratio (SIR), total volatile solids concentration (VSt), working volume (WV), presence of nutrients (Nu), and the pre-incubation of the inoculum (Inc) were investigated. The results showed that SIR is the most important factor. The maximum BMP for RT was 297 NmLCH4/gVS with SIR = 0.5; tVS = 20 g/L; WV = 20%; no pre-incubation and the presence of nutrients. Using these optimum operating conditions, co-digestion was investigated through a mixture design approach. The substrates RT and GT presented similar BMP values, whereas TB led to a significantly lower BMP. Indeed, when high concentrations of TB were used, a significant decrease in methane production was observed. Nonetheless, the highest BMP was achieved with a mixture of 63% RT + 20% GT + 17% TB, with a production of 324 NmLCH4/gVS, corresponding to a synergetic co-digestion performance index of about 1.20. In general, although the substrate RT generates the highest BMP, the mixture with GT did not impair the methane yield. Overall, the co-digestion of tomato residues must be conducted with SIR close to 0.5 and the content of tomato branches in the reaction mixture should be kept low (up to 20%).

scholarly journals A Novel Nitrogen Removal Technology Pre-Treating Chicken Manure, Prior to Anaerobic Digestion

2020 ◽  
Vol 12 (18) ◽  
pp. 7463
Author(s):  
Marie E. Kirby ◽  
Muhammad W. Mirza ◽  
James Davies ◽  
Shane Ward ◽  
Michael K. Theodorou
Keyword(s):  
Anaerobic Digestion ◽  
Nitrogen Removal ◽  
Recovery Process ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Chicken Manure ◽  
Nitrogen Recovery ◽  
Biochemical Methane Potential ◽  
Removal Technology ◽  
Methane Potential

Chicken manure is an agricultural by-product that is a problematic feedstock for anaerobic digestion due to its high nitrogen content inhibiting methane yields. This research examines a novel pilot-scale method of ammonia stripping, the nitrogen recovery process (NRP) developed by Alchemy Utilities Ltd. The NRP was designed to remove and recover nitrogen from chicken manure and two different operating conditions were examined. Both operating conditions demonstrated successful nitrogen removal and recovery. The biochemical methane potential assays were used to compare the digestibility of the NRP-treated chicken manures to that of a fresh chicken manure control. Overall, the biochemical methane potential assays demonstrated that some NRP-treated chicken manure treatments produced significantly more methane compared to untreated manure, with no inhibition occurring in relation to ammonium. However, some of the NRP-treated chicken manures produced similar or lower methane yields compared to fresh chicken manure. The NRP requires further development to improve the efficiency of the pilot-scale unit for commercial-scale operation and longer-term continuous anaerobic digestion trials are required to determine longer-term methane yield and ammonium inhibition effects. However, these initial results clearly demonstrate the technology’s potential and novel application for decentralised, on-farm nitrogen recovery and subsequent anaerobic digestion of chicken manure.

scholarly journals Biochemical Methane Potential (BMP) from sugarcane biorefinery residues: maximizing their use by co-digestion

2021 ◽  
Author(s):  
Maria Paula. C. Volpi ◽  
Livia B. Brenelli ◽  
Gustavo Mockaitis ◽  
Sarita C. Rabelo ◽  
Telma T. Franco ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Filter Cake ◽  
Biogas Production ◽  
Economic Advantage ◽  
Small Scale ◽  
Biochemical Methane Potential ◽  
Production Potential ◽  
Methanogenic Activity ◽  
Positive Effects ◽  
Methane Potential

ABSTRACTThis work evaluated the methane (CH4) production potential from residues of integrated 1st (vinasse and filter cake) and 2nd (deacetylation pretreatment liquor from straw) generation (1G2G) sugarcane biorefinery. The small-scale study provided fundamentals for basing the optimization of co-digestion by assessing the best co-substrates synergistic conditions. Biochemical Methane Potential (BMP) tests showed co-digestion enhanced CH4 yield of isolated substrates, reaching 605 NmLCH4 gVS−1. Vinasse and deacetylation liquor as the only co-substrates increased the BMP by 37.72%, indicating that the association of these two residues provided positive effects for co-digestion by nutritionaly benefeting the methanogenic activity. The filter cake had the lowest BMP (260 NmLCH4 gVS−1) and digestibility (≤40%), being the stirring required to improve the mass transfer of biochemical reactions. The alkaline characteristic of the liquor (pH-prevented alkalinizers from being added to the co-digestion, which could be a relevant economic advantage for the implementation of the process in an industrial scale. The co-digestion system has proven to efficiently maximize waste management in the 1G2G sugarcane biorefineries and potentially enhance their energy generation (by at least in 18%), providing experimental elements for placing the biogas production as the hub of the bioeconomy in the agroindustrial sector.

scholarly journals Simultaneous Synergy in CH4 Yield and Kinetics: Criteria for Selecting the Best Mixtures during Co-Digestion of Wastewater and Manure from a Bovine Slaughterhouse

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 384
Author(s):  
Zamir Sánchez ◽  
Davide Poggio ◽  
Liliana Castro ◽  
Humberto Escalante
Keyword(s):  
Anaerobic Digestion ◽  
Binary Mixtures ◽  
Synergistic Effects ◽  
Physicochemical Characteristics ◽  
High Potential ◽  
Multicomponent Mixtures ◽  
Biochemical Methane Potential ◽  
Slaughterhouse Wastewater ◽  
Methane Potential ◽  
Better Than

Usually, slaughterhouse wastewater has been considered as a single substrate whose anaerobic digestion can lead to inhibition problems and low biodegradability. However, the bovine slaughter process generates different wastewater streams with particular physicochemical characteristics: slaughter wastewater (SWW), offal wastewater (OWW) and paunch wastewater (PWW). Therefore, this research aims to assess the anaerobic co-digestion (AcoD) of SWW, OWW, PWW and bovine manure (BM) through biochemical methane potential tests in order to reduce inhibition risk and increase biodegradability. A model-based methodology was developed to assess the synergistic effects considering CH4 yield and kinetics simultaneously. The AcoD of PWW and BM with OWW and SWW enhanced the extent of degradation (0.64–0.77) above both PWW (0.34) and BM (0.46) mono-digestion. SWW Mono-digestion showed inhibition risk by NH3, which was reduced by AcoD with PWW and OWW. The combination of low CH4 potential streams (PWW and BM) with high potential streams (OWW and SWW) presented stronger synergistic effects than BM-PWW and SWW-OWW mixtures. Likewise, the multicomponent mixtures performed overall better than binary mixtures. Furthermore, the methodology developed allowed to select the best mixtures, which also demonstrated energy and economic advantages compared to mono-digestions.

INFLUENCE OF FREEZING/THAWING AND DRYING/MILLING ON BIOCHEMICAL METHANE POTENTIAL

2016 ◽  
Vol 15 (7) ◽  
pp. 1533-1536
Author(s):  
Jin Mi Triolo ◽  
Sven Gjedde Sommer ◽  
Lene Pedersen
Keyword(s):  
Biochemical Methane Potential ◽  
Methane Potential

Vacuum Operation for Overloaded Anaerobic Treatment Systems

1989 ◽  
Vol 21 (4-5) ◽  
pp. 87-95
Author(s):  
J. De Santis ◽  
A. A. Friedman
Keyword(s):  
Volatile Fatty Acids ◽  
Loading Rate ◽  
Anaerobic Treatment ◽  
Optimum Operating ◽  
Operating Pressure ◽  
Simple Modification ◽  
Anaerobic Reactors ◽  
Fixed Film ◽  
Solids Retention ◽  
High Concentrations

Overloaded anaerobic treatment systems are characterized by high concentrations of volatile fatty acids and molecular hydrogen and poor conversion of primary substrates to methane. Previous experiments with fixed–film reactors indicated that operation with reduced headspace pressures enhanced anaerobic treatment. For these studies, four suspended culture, anaerobic reactors were operated with headspace pressures maintained between 0.5 and 1.0 atm and a solids retention time of 15 days. For lightly loaded systems (0.4 g SCOD/g VSS-day) vacuum operation provided minor treatment improvements. For shock organic loads, vacuum operation proved to be more stable and to support quicker recovery from upset conditions. Based on these studies and a companion set of bioassay tests, it was concluded that: (a) a loading rate of about 1.0 g SCOD/g VSS-day represents a practical loading limit for successful anaerobic treatment, (b) a headspace pressure of approximately 0.75 atm appears to be an optimum operating pressure for anaerobic systems and (c) simple modification to existing systems may provide relief for organically overloaded systems.

scholarly journals Batch Anaerobic Co-Digestion and Biochemical Methane Potential Analysis of Goat Manure and Food Waste

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1952
Author(s):  
Ayobami Orangun ◽  
Harjinder Kaur ◽  
Raghava R. Kommalapati
Keyword(s):  
Food Waste ◽  
Gompertz Model ◽  
Water Displacement ◽  
Biochemical Methane Potential ◽  
Greenhouse Gasses ◽  
Nonlinear Regression Models ◽  
The Us ◽  
Methane Potential ◽  
Goat Manure ◽  
Modified Gompertz Model

The improper management of goat manure from concentrated goat feeding operations and food waste leads to the emission of greenhouse gasses and water pollution in the US. The wastes were collected from the International Goat Research Center and a dining facility at Prairie View A&M University. The biochemical methane potential of these two substrates in mono and co-digestion at varied proportions was determined in triplicates and processes were evaluated using two nonlinear regression models. The experiments were conducted at 36 ± 1 °C with an inoculum to substrate ratio of 2.0. The biomethane was measured by water displacement method (pH 10:30), absorbing carbon dioxide. The cumulative yields in goat manure and food waste mono-digestions were 169.7 and 206.0 mL/gVS, respectively. Among co-digestion, 60% goat manure achieved the highest biomethane yields of 380.5 mL/gVS. The biodegradabilities of 33.5 and 65.7% were observed in goat manure and food waste mono-digestions, while 97.4% were observed in the co-digestion having 60% goat manure. The modified Gompertz model is an excellent fit in simulating the anaerobic digestion of food waste and goat manure substrates. These findings provide useful insights into the co-digestion of these substrates.

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