Potential Co-substrate Research Articles

Correction: Chow et al. Anaerobic Co-Digestion of Wastewater Sludge: A Review of Potential Co-Substrates and Operating Factors for Improved Methane Yield. Processes 2020, 8, 39

The journal is publishing this correction to update the name of the Academic Editor listed on this published paper [...]

Optimization of hydrolases production by Penicillium crustosum in submerged fermentation using agro-waste residues as cosubstrate

This study aimed to enhance the production of exo-polygalacturonases (exo-PG), xylanases, and endoglucanases using Penicillium crustosum through submerged fermentation. Lemon peel (LP) and wheat bran (WB) were examined as potential cosubstrate for hydrolase production. The highest exo-PG and endoglucanase activities were observed with LP, whereas xylanase activity showed improvement with the addition of WB. To optimize exo-PG and endoglucanase production, a 23 Face-Centered Central Composite Design (FCCCD) was employed, varying crucial physicochemical factors. Similarly, a 24 FCCCD was utilized to optimize xylanase production by varying temperature, pH, MnSO4 concentration as a cofactor, and the PDB culture medium. Under optimized conditions, exo-PG production reached 1427.99 ± 27.41 U/mL, marking a 45% increase compared to initial fermentation conditions. Endoglucanase production peaked at 62.68 ± 9.65 U/mL under conditions of 45 °C, pH 5.5, and 2.5 g/L MnSO4. Xylanase production reached 271.77 ± 8.50 U/mL under optimal conditions (37.5 °C, pH 5.5, 2.5 g/L MnSO4, and 62.5% PDB). The optimized simultaneous production of the hydrolytic cocktail occurred at 45 °C, pH 5.5, and 2.5 g/L MnSO4 with LP, yielding maximum activities of 959.74 U/mL for exo-PG, 61.98 U/mL for endoglucanases, and 65.60 U/mL for xylanases as determined by FCCCD. In conclusion, Penicillium crustosum shows promise as a hydrolase producer, and the utilization of agro-wastes as cosubstrate enhances the yield of enzymes with industrial relevance.

Synergistic Impacts of Wheat Straw on Coal Bio‐Methanation: Insights Into Microbial Community Dynamics Toward Nontargeted Metabolomics

Biogenic methane (BM) production from coal is quite limited due to its complex chemical nature, which makes the responsible microbes sensitive to its denaturation. In the current investigation, wheat straw (WS) at different concentrations as a cosubstrate were used with coal to augment methane generation from coal. Results revealed that the codigestion approach significantly enhanced the cumulative methane generation in CS1 (17.25 mmol) (coal:straw, 75:25), which was 59.52%–256.47% higher than the CS2 (coal:straw, 85:15), and WS single digestion, respectively. Moreover, the lowest methane yield (0.295 mmol/g) was achieved from single coal digestion. Particularly, the highest methane content, 68.37% in the collected biogas, was observed in CS1, followed by CS2 (49.53%), WS (44.92%), and coal (3.53%). Microbial community analysis illustrates that Methanobacteriaceae (51.33%) and Methanosarcinaceae (48.66%) were the leading archaeal communities at the peak methanogenic stage in CS1. While the abundant bacteria at this stage were Hungateiclostridiaceae (40.18%), Rhodobacteriaceae (21.40%), and Lentimicrobiaceae (19.20%) in CS1. According to scanning electron microscopy (SEM) analysis, several microbes were seen to be attached to the coal surface in CS1 and CS2. Moreover, the nontargeted metabolomic results showed that aromatics, aliphatic, long‐chain fatty acids, and alkane (C19–C36) compounds were found to be highly expressed in only coal, CS1, and CS2 reactors compared to WS. In addition, volatile fatty acids (VFAs) analysis showed that acetic acids were abundantly present in CS1 (2,190,175 ng/ml), followed by WS (1,543,492.88 ng/ml), CS2 (1,159,050 ng/ml), and coal (50,998.31 ng/ml). These results promote the significance of using WS as a cosubstrate with coal to enhance methane production, which can be used as a fuel in power plants. Further studies are required to investigate the potential cosubstrate with coal to enhance methane production and identify the specific metabolic pathways involved.

Agricultural Plant Residues as Potential Co-Substrates for Biogas Production

Plant biomass can be used in many directions for bioenergy production. Biogas can be produced from a most diverse group of substrates compared to liquid or solid biofuels. The choice of substrates and technologies is crucial because it will allow getting the expected results. Not without significance is also the price and availability of substrates. Therefore, waste and residues are increasingly being used. Accordingly, the aim of the review was to analyze the potential of biogas production from agricultural plant residues and the effectiveness of using this feedstock as a co-substrate in anaerobic digestion. In this article, selected agricultural plant residues are collected, and their advantages and disadvantages as substrates for biogas production are described. Moreover, the effective technology of biogas production by anaerobic digestion on an industrial scale and calculations to obtain biogas and methane efficiency of the substrates are also included. In addition, the summarized biogas efficiency of selected plant agricultural waste under mesophilic conditions studied by many researchers is shown. On the basis of the analyzed results of this research, it can be concluded that agricultural plant residues have great potential as co-substrates for biogas production. It is important to experimentally determine both the biogas and the methane efficiency of the substrate, representing a potential raw material for the production of gaseous biofuels. The use of artificial neural networks in the prediction of biogas emission is future-proof and should facilitate the management of biogas plants. The use of waste from the cultivation and processing of plant raw materials will not only help to manage this waste rationally, but also contribute to the increase in production of renewable energy sources. Accordingly, the circular economy in terms of the management of agricultural plant residues to produce biogas will have a multi-faceted, positive impact on the environment. On the basis of this review, it can be concluded that numerous agricultural plant residues can be used as potential co-substrates for biogas production.

Physico-chemical characterization of selected feedstocks as co-substrates for household biogas generation in Ghana

ABSTRACT Substituting biogas for Liquefied Petroleum Gas (LPG) in households is a long-awaited sustainable solution for the increasing cost of energy and large amounts of household human-generated waste. Nevertheless, a study of the characteristics of feedstocks is essential to maximise their energy potential. Consequently, this study examined the physico-chemical properties of Human Excreta (HE), Food Leftovers (FLO), Kitchen Residue (KR) and Cow Dung (CD) of Ghanaian origin adhering to recommended standards. Results for volatile to total solid ratios (VS/TS) were 0.81 ± 0.001, 0.97 ± 0.001,0.89 ± 0.001 and 0.85 ± 0.001 for HE, FLO, KR and CD, respectively. The results showed that all feedstocks had high biodegradable content, making them desirable for biogas production. The carbon-to-nitrogen (C/N) ratios determined from the elemental compositions were 8.29 ± 0.09, 22.14 ± 0.26, 23.34 ± 0.25 and 26.19 ± 0.47 for HE, FLO, KR and CD, respectively. Although the C/N ratios for FLO, KR and CD were within the optimal range, that of HE was significantly low. With a mean alkalinity of 1219.67 ± 1.53, 630.00 ± 0.58, 590.00 ± 2.08 and 15,730.00 ± 6.00 mg CaCO3 eq./L for HE, FLO, KR and CD, it was observed that only CD has the optimal alkalinity value for anaerobic digestion. This brings into perspective the need for co-digestion and the choice of potential co-substrates for household biogas production.

Recent advances in anaerobic digestion of lipid-rich waste: Challenges and potential of seaweeds to mitigate the inhibitory effect

• Lipid-rich waste (LRWs) represents a potential feedstock for biogas production. • Microbial structure and activity play a significant role in LRWs digestion and biogas yield. • Foaming, fatty acids accumulation, and nutrients imbalance are the main challenges. • Seaweeds provide a complementary co-substrate and a synergistic action to mitigate the effect. • Co-digestion of LRWs and seaweeds enhance the economic feasibility up to 18.9-times. Considerable attention has been devoted towards anaerobic digestion of lipid-rich waste (LRWs) due to their higher energy content comparing to other waste rich in carbohydrates and proteins. However, there are still many challenges for LRWs anaerobic digestion which are mainly attributed to floatation, foaming, long-chain fatty acids (LCFAs) accumulation, and nutrients imbalance resulting in reactor instability and failure. The present review aims to report the recent progress in LRWs production, with a special focus on the main challenges for anaerobic digestion and the recent advances to enhance the digestion process including pretreatment, microbial acclimatization, dosing of trace elements, carrier addition, and co-digestion. Regarding the later, main characteristics and potential of seaweeds to mitigate the toxic effect of LRWs towards enhanced anaerobic digestion through cascading approach was discussed. Considering the low nitrogen content in LRWs and moderate nitrogen content in seaweeds with very low lipid content and negligible lignin, seaweeds could be a potential co-substrate for anaerobic digestion with LRWs. Co-digestion of seaweeds with LRWs results in synergistic action leading to nutrient balance and enhanced anaerobic performance. In addition, developing a cascading approach for high bioenergy recovery from LRWs through co-digestion with seaweeds/residues could further provide optimum conditions for enhanced biogas production and economic feasibility. The economic analysis estimated US$ 15.27 million annual net profit from co-digestion of LRWs and seaweeds, which was 1.0- and 18.9-times higher than that from mono-digestion of LRWs or seaweeds, respectively. The present article suggests a new perspective for efficient anaerobic digestion of LRWs towards enhanced energy recovery through integrated cascading approaches.

Biomass immobilization in hydrolyzed lignocellulosic material can enhance biohydrogen production from cassava residues?

This study evaluated cassava stems (CS) as support material and a potential co-substrate in dark fermentation. Pre-tests were carried out with cell immobilization in CS without hydrolysis and submitted to acid and steam hydrolysis. Subsequently, hydrogen production was evaluated in an anaerobic sequencing batch biofilm reactor inoculated with biomass immobilized in CS, using cassava starch wastewater as substrate (OLR of 11 and 15 gCarb L−1d−1). The reactor was run for 180 cycles with maximum volumetric hydrogen productivity and a yield of 1.48 LH2 L−1d−1 and 1.98 molH2 kg−1Carb (OLR 15 gCarb L−1d−1). The carbohydrate conversion remained above 97% in both assays, with a predominance of the acetate-ethanol route. During the assays, the Food/Microorganisms ratio remained between 0.8 and 1.0 gCarb gTVSd−1, promoting the biomass control in the reactor. The structural characterization of CS before and after fermentation indicates that the cellulose, hemicellulose, and lignin content in the stems were changed after hydrolysis and fermentation, confirming the material degradation. In addition, the hydrolysis increased the CS surface area and favored cell immobilization of hydrogen-producing microorganisms such as bacteria of the genus Clostridium and Hydrogenispora, demonstrating that CS can be an alternative support material and co-substrate to be explored in dark fermentation.

Oyster shell waste as potential co-substrate for enhancing methanogenesis of starch wastewater at low inoculation ratio

This study evaluated the effect of oyster shells on the methanogenesis of starch wastewater subjected to over-acidification (pH < 4.5) at low inoculum/substrate ratios, and revealed that oyster shells could be used as co-substrates for methane production. The methane yield was improved by approximate 86-folds with optimal dose when compared with that in control. Oyster shells conditioning synchronously improved the acidogenesis and hydrogenotrophic methanogenesis steps, resulting in high methane production. These improvements were attributed to the fact that the oyster shells served as the neutralizing reagent and buffered the sharp pH drop. Carbon dioxide was also released during this process, which was subsequently converted into methane and contributed 17% of the total methane yield. Furthermore, some spheroid and rod microcolonies were observed on the surfaces of the oyster shells. Along with the remarkable enrichment of acetotrophic and methylotrophic methanogens, these microbes benefitted the successful methanogenesis of starch wastewater.

Mechanisms Driving Microbial Community Composition in Anaerobic Co-Digestion of Waste-Activated Sewage Sludge.

Anaerobic co-digestion (Co-AD) is used to increase the effectiveness of anaerobic digestion (AD) using local “wastes”, adding economic and environmental benefits. Since system stability is of existential importance for the operation of wastewater treatment plants, thorough testing of potential co-substrates and their effects on the respective community and system performance is crucial for understanding and utilizing Co-AD to its best capacity. Food waste (FW) and canola lecithin (CL) were tested in mesophilic, lab-scale, semi-continuous reactors over a duration of 120 days with stepwise increased substrate addition. Key performance indicators (biogas, total/volatile solids, fatty acids) were monitored and combined with 16S-rRNA amplicon sequencing to assess the impact of co-substrate addition on reactor performance and microbial community composition (MCC). Additionally, the latter was then compared with natural shifts occurring in the wastewater treatment plant (WWTP, source) at the same time. An almost linear increase in biogas production with both co-substrates at an approximate 1:1 ratio with the organic loading rate (OLR) was observed. The MCCs in both experiments were mostly stable, but also prone to drift over time. The FW experiment MCC more closely resembled the original WWTP community and the observed shifts indicated high levels of functional redundancy. Exclusive to the CL co-substrate, a clear selection for a few operational taxonomic units (OTUs) was observed. There was little evidence for a persistent invasion and establishment of microorganisms from typical primary substrates into the stable resident community of the reactors, which is in line with earlier findings that suggested that the inoculum and history mostly define the MCC. However, external factors may still tip the scales in favor of a few r-strategists (e.g., Prolixibacter) in an environment that otherwise favors K-strategists, which may in fact also be recruited from the primary substrate (Trichococcus). In our study, specialization and diversity loss were also observed in response to the addition of the highly specialized CL, which in turn, may have adverse effects on the system’s stability and reduced resilience and recovery.

Addressing Nutrient Depletion in Tanzanian Sisal Fiber Production Using Life Cycle Assessment and Circular Economy Principles, with Bioenergy Co-Production

Nutrient depletion in Tanzanian sisal production has led to yield decreases over time. We use nutrient mass balances embedded within a life cycle assessment to quantify the extent of nutrient depletion for different production systems, and then used circular economy principles to identify potential cosubstrates from within the Tanzanian economy to anaerobically digest with sisal wastes. The biogas produced was then used to generate bioelectricity and the digestate residual can be used as a fertilizer to address the nutrient depletion. Life cycle assessment was used in a gate-to-gate assessment of the anaerobic digestion options with different cosubstrates. If no current beneficial use of the cosubstrate was assumed, then beef manure and marine fish processing waste were the best cosubstrates. If agricultural wastes were assumed to have a current beneficial use as fertilizer, then marine fish processing waste and human urine were the best cosubstrates. The largest reduction in environmental impacts resulted from bioelectricity replacing electricity from fossil fuels in the national electricity grid and improved onsite waste management practices. There is significant potential to revitalize Tanzanian sisal production by applying circular economy principles to sisal waste management to address soil nutrient depletion and co-produce bioenergy.

Exploring the biogas production and microbial community from co-digestion of sewage sludge with municipal solid waste incineration fresh leachate

Fresh leachate (FL) rich in organic matter is a potential co-substrate for anaerobic treatment of sewage sludge (SS); however, the understanding of how sludge–leachate matrix affects the biogas production and microbial community remains incomplete. This study investigated the mesophilic co-digestion of SS with different proportions of FL (0, 5%, 15%, and 30%). The results showed that the total biogas production from co-digestion was enhanced by 17.7–66.3%. Further analysis suggested that co-digestion with 5% (R2) and 15% (R3) FL had positive effects on organic removal and methane conversion, while R4 with 30% FL imposed negative effects. Kinetic analysis indicated that both FL dosage and digestion time should be considered to determine the maximum predicted biogas production. Moreover, the microbial community analysis confirmed that the bacteria related to the degradation of complex organic matter showed high relative abundance. Firmicutes were enriched from 6.44% to 22.06% as the FL dosage increased; Bacteroidetes and Chloroflexi presented high relative abundance of 20.69–25.69% and 11.77–21.21% in all bioreactors. The methanogens were influenced by free ammonia, and the dominant methanogens shifted from Methanosaeta (R1–R3) to Methanobacterium (R4). This study demonstrated that FL could serve as co-substrate to improve the biogas production from anaerobic co-digestion of SS.

Natural Communities of Microalgae and Cyanobacteria from Eutrophicated Waters as Potential Co-substrates for Small-scale Biogas Production.

The purpose of this study was to determine the biogas potential of biomass produced by microbiotic communities developed under natural conditions in freshwater systems such as ponds incorporated into agricultural landscapes. Natural communities of microalgae were collected from a small eutrophicated pond where dominant species were euglenoids (Lepocinclis species). Cyanobacterial communities dominated by Lyngbya species were taken from a domestic aquarium and cultivated under makeshift conditions. Experiments were done using dairy cow manure (DCM) for codigestion with natural communities of microalgae (MDM) and cyanobacteria (CDM) and conducted during 42 days in thermophilic regime. The total biogas yields were 421.40 and 383.34 mL/g volatile solids (VS), while the average methane contents were 63.97 and 64.06% for MDM and CDM, respectively. Our results indicate that the natural communities of microalgae and cyanobacteria used in this study possess the potential for biogas production, which is, in comparison with particular algal and cyanobacterial strains cultivated under strictly controlled cultivation conditions, more promising. Therefore, this study aims to motivate further investigations into the diverse natural communities of microalgae and cyanobacteria and pretreatments that are environmentally friendly and cost-effective and will eventually enhance small-scale biogas production on agricultural farms.

Anaerobic Co-Digestion of Wastewater Sludge: A Review of Potential Co-Substrates and Operating Factors for Improved Methane Yield

Anaerobic digestion has been widely employed in waste treatment for its ability to capture methane gas released as a product during the digestion. Certain wastes, however, cannot be easily digested due to their low nutrient level insufficient for anaerobic digestion, thus co-digestion is a viable option. Numerous studies have shown that using co-substrates in anaerobic digestion systems improve methane yields as positive synergisms are established in the digestion medium, and the supply of missing nutrients are introduced by the co-substrates. Nevertheless, large-scale implementation of co-digestion technology is limited by inherent process limitations and operational concerns. This review summarizes the results from numerous laboratory, pilot, and full-scale anaerobic co-digestion (ACD) studies of wastewater sludge with the co-substrates of organic fraction of municipal solid waste, food waste, crude glycerol, agricultural waste, and fat, oil and grease. The critical factors that influence the ACD operation are also discussed. The ultimate aim of this review is to identify the best potential co-substrate for wastewater sludge anaerobic co-digestion and provide a recommendation for future reference. By adding co-substrates, a gain ranging from 13 to 176% in the methane yield was accomplished compared to the mono-digestions.

Enhancement of methane production and wastewater treatment from algae

In this study, the synergy between wastewater treatment and anaerobic co-digestion (AC) was evaluated. To fulfill this objective, urban wastewater and pig effluents were treated by means of microalgae and macroalgae sampled from Limay River, Neuquen-Argentina. Comparison between macroalgae, aquatic and terrestrial plants as best co-substrate in AC process was performed using Biochemical Methane Potential (BMP) method. To understand their contributions to methane production, Biological Nutrient Removal Model N°2 (BNRM2) was used to represent dynamic data of BMP assays. Results indicate high performance of organic matter removal by algae (63.8 ± 0.5%COD) with high biomass production. BMP assays showed macroalgae as the high methane potential cosubstrate (157.2 ± 66.1 ml CH4/g VS). BNRM2 implementation showed good fit of dynamic data and reveals that the more methane produced, the higher the hydrolysis rate. In conclusion, algae could be used as a link point between wastewater depuration and anaerobic co-digestion processes.

Enhancement of methane production and wastewater treatment from algae

In this study, the synergy between wastewater treatment and anaerobic co-digestion (AC) was evaluated. To fulfill this objective, urban wastewater and pig effluents were treated by means of microalgae and macroalgae sampled from Limay River, Neuquén-Argentina. Comparison between macroalgae, aquatic and terrestrial plants as best co-substrate in AC process was performed using Biochemical Methane Potential (BMP) method. To understand their contributions to methane production, Biological Nutrient Removal Model N°2 (BNRM2) was used to represent dynamic data of BMP assays. Results indicate high performance of organic matter removal by algae (63.8 ± 0.5%COD) with high biomass production. BMP assays showed macroalgae as the high methane potential cosubstrate (157.2 ± 66.1 ml CH4/g VS). BNRM2 implementation showed good fit of dynamic data and reveals that the more methane produced, the higher the hydrolysis rate. In conclusion, algae could be used as a link point between wastewater depuration and anaerobic co-digestion processes.

A Multi-criteria Decision Analysis of Co-substrate Selection to Improve Biowaste Composting: a Mathematical Model Applied to Colombia

Several physicochemical properties of biowaste can limit its composting. The incorporation of bulking agents (BA) and amendment materials (AM) is the most frequently applied operational approach to overcome such substrate limitations. This work proposes a decision model to optimally select bulking agents and amendment materials by applying a multicriteria analysis. The main objective of this study was to present a methodology to rank the co-substrates needed to compost biowaste. To accomplish this aim, an integrated hierarchy-based model was used that accounted for technical and environmental criteria. In particular, Analytical Hierarchy Process (AHP) and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) were used to rank the potential co-substrates. The co-substrate ranking that was achieved with AHP and TOPSIS was then complemented by a cost analysis. The results of this study demonstrated the importance and the significant weight of the technical criteria, such as nutrients, porosity and biodegradability. The methodology was applied to a small town in Colombia that operates a biowaste composting facility. The results of the application of the tool in the above case study revealed that the most suitable materials for biowaste composting were sugarcane filter cake and star grass.

Anaerobic co-digestion of catering food waste utilizing Parthenium hysterophorus as co-substrate for biogas production

Catering food waste is a constant concern both at home and in the restaurant kitchens. Advances in the catering industry are generating a significant amount of catering waste, which poses a significant risk to public health and the environment. The anaerobic digestion technology used to produce biogas from various substrates has attracted worldwide attention for its economics and ease of use. This study evaluated the potential of pretreated parthenium weed (as co-substrate) in anaerobic co-digestion of catering food waste in lab scale bioreactors using different mixing ratios (0:100, 20:80, 60:40, 40:60, 80:20, and 100:0 TS basis) for biogas production. The performance parameters of the bioprocess were evaluated using COD, C/N ratio, solids content, pH and the biogas potential. The results showed that the maximum biogas production rate (559 ml L−1 d−1) and accumulative biogas (5532 ml L−1) was achieved in the PCP2 co-digestion reactor, where 60% catering food waste and 40% parthenium weed (pre-treated) was used under static incubation at 30 ± 1 °C. Furthermore, in response to pretreatment conditions, a steady decrease in volatile solids (VS), total solids (TS), C/N ratio, and organic content were observed. The highest removal efficiency of organic matter (38.9%) was achieved by the PCP2 co-digestion reactor with a maximum reduction of 79% of iCOD in 60 process days. The present findings suggest the suitability and application of the pretreated parthenium weed as a potential co-substrate for biogas production in the anaerobic digestion of catering food waste.

Analysis and optimization processes of goat dung as a potential co-substrate in bioremediation

The present study investigates the analysis and optimization processes of crushed Goat Dung (GD) as a potential co substrate in bioremediation of crude oil contaminated soil (COCS). The first order crude oil (CO) degradation kinetics and biological half-life with the effects of process parameters (pH and initial CO concentration) were also investigated. Results obtained from the effects of process parameters showed that 70 and 75% of CO were degraded at pH 7 and initial CO concentration of 130 g/l. The first order CO degradation kinetics and half-life indicated that the highest CO degradation rate constant and lowest half-life was obtained at 130 g/l. The optimum values of the independent variables as indicated by response surface methodology (RSM) were pH (6.8), temperature (39.5 °C) and CO concentration (85.2 g/l). Good relation between the R2 (98.60%), adjusted R2 (97.05%) and predicted R2 (90.88%) indicated the satisfactory performance of the second order quadratic model. The findings of this present work suggest that GD could be an effective CO substrate in bioremediation of COCS.

Production of more toxic hexa-brominated diphenyl ether from rapid biotransformation of decabromodiphenyl ether in anaerobic granular sludge

Decabromodiphenyl ether (BDE-209) is used widely as a flame retardant and deserves more attention due to its potential danger to environment. Previous studies generally considered that BDE-209 degraded slowly in environment. Herein, a rapid reductive debromination of BDE-209 to BDE-154 was demonstrated with simultaneous stoichiometric bromide recovery (45%) in 10 h driven by the anaerobic granules. Debromination occurred in anaerobic granules when they were spiked with BDE-209 dissolved in the solvent dimethyl sulfoxide (DMSO), which was proved a potential cosubstrate for stimulating PBDE debromination. Moreover, the solvent DMSO enhanced the penetration of BDE-209 across cell membranes and forced the dominant phylum in anaerobic granules to change from Bacteroidetes to Euryarchaeota. Thus, the amended culture could better raise the functional genera Ralstonia and Pseudomonas, accounting for the rapid degradation of BDE-209. This is the first report that BDE-209 could be quickly debrominated to BDE-154 in anaerobic granules. Given the high cytotoxicity of BDE-154 produced from BDE-209, the fate of BDE-209 in the wastewater treatment plants should be paid more attention.

Tea powder waste as a potential co-substrate for enhancing the methane production in Anaerobic Digestion of carbon-rich organic waste

Anaerobic co-digestion of solid wastes with activated sludge for biogas production is an alternative and effective cleaner process of energy production from waste matter. This study comprehensively evaluated the suitability of Tea Powder Waste as an alternative co-substrate for higher biogas production. Biochemical Methane Potential analyses were performed on the anaerobic co-digestion of carbon-rich organic solid waste and Tea Powder Waste with the presence of Methanogens in activated sludge. The process parameters for the co-digestion of organic waste with Tea Powder Waste were optimized in order to achieve higher biogas production. Biogas producing reactors, with the organic wastes and methanogens activated sludge, were maintained under a mesophilic temperature (35 ± 2 °C) for 60 days retention period. The influence of various process parameters on the production of biomethane were analyzed. The optimized feed ratio of 1:2:1 (FFV: TPW: MAS) showed higher methane yield. Nitrogenous compounds present in Tea Powder Waste increased the methane production by four folds. The co-digestion of wastes showed 65% yield when compared to 40% yield as in mono-digestion of wastes.