Mixture Of Cow Dung Research Articles

Enhancing Biogas Production Through the Co-Digestion of Fish Waste (FW) and Water Hyacinth (WH) Using Cow Dung as an Inoculum: Effect of FW/WH Ratio

The current investigation explores biogas production from water hyacinth (WH) and fish waste (FW) with cow dung (CD) as an inoculum source in two scenarios. In the first scenario, the optimization of mono-digestion was performed where the effect of WH/FW (substrates) with CD (inoculum) in varied ratios of 1:1, 1:2, 2:1, and 3:1 was observed to enhance the biogas production. In the second scenario, the optimization of co-digestion using both FW and WH as substrates in different ratios (1:1, 1:2, and 2:1) with a fixed amount of inoculum was studied. The experiments were conducted in 500 mL digesters in duplicate under mesophilic conditions. Under mono-digestion conditions for FW, the digester operating with FW/CD in a 1:2 ratio demonstrated the highest biogas yield of 970 ± 14.1 mL/g VS, containing 610 CH4 mL/g VS, while in WH, the WH/CD ratio of 1:1 exhibited the highest biogas yield of 925 ± 49.4 mL/g VS, with a methane content of 440 CH4 mL/g VS. The co-digestion of the WH/FW ratio (1:1) showcased the highest biogas production of 1655 ± 91.92 mL/g VS, accompanied by 890 ± 70.7 CH4 mL/g VS. This was followed by the 1:2 and 2:1 ratio, yielding 1400 ± 56.5 and 1140 ± 169.7 mL/g VS. of biogas and 775 and 585 CH4 mL/g VS, respectively. The CD and WH mixture at a 1:1 ratio demonstrated the most significant decrease in chemical oxygen demand (COD), reaching 91.68%. COD reductions over 80% in all combinations were observed in all instances. Anaerobic digestion (AD) simulations were validated using the Gompertz model, with high correlation coefficient values (R-squared) above 0.99 for all of the studied ratios, depicting a significant correlation between experimental data and model predictions. The propionic to acetic acid ratio did not cross the threshold level, indicating no inhibition of methane production. ANOVA analysis of biogas production between the co-digestion and mono-digestion of substrates showed non-significant results (p > 0.310 and p > 0.824, respectively), while overall digestion was significant (p < 0.024), indicating efficiency variations among substrates. Paired sample t-tests revealed substantial differences between co-digestion ratios, which were also significant.

Assessing the potential of cow dung and carpet grass as feedstock for biogas production to power a generator

This study investigates the potential of cow dung and carpet grass as feedstock for biogas production, aiming to provide a sustainable energy source for powering generators. A digester was fabricated to produce biogas from a mixture of cow dung and carpet grass under controlled anaerobic digestion conditions. The composition and energy content of the biogas were analyzed, and the biogas yield was measured over a 30-day period. Key parameters such as pH, system temperature, and total dissolved solids (TDS) were monitored to understand their influence on biogas production. Results showed that the pH values ranged from 4.1 to 5.2, which is lower than the optimal range for methanogenesis, yet biogas production was still feasible, peaking at pH 5.0. System temperature ranged from 28°C to 36.8°C, with the highest biogas yield observed at the upper end of this range. TDS levels fluctuated between 1,331 ppm and 3,060 ppm, indicating variations in the feedstock composition and microbial activity. The purified biogas successfully powered a 2.5 KVA generator for 30 minutes, demonstrating its practical application as an alternative energy source. This study highlights the potential of using cow dung and carpet grass for biogas production, contributing to sustainable energy solutions and waste management strategies.

Selection and evaluation of optimal medium for Eisenia fetida in sustainable waste recycling

Present study explored the optimal medium for survival, growth, and reproductive performance of Eisenia fetida using kitchen waste, cow dung mixtures, and rice straw in a volume of 3834. Experimental setups involved various combinations of different experimental set such as set I:kitchen waste alone (3 kg); set II kitchen waste:dung (2 kg:1 kg); set III kitchen waste:dung (1 kg:2 kg) set IV Kitchen waste: Dung: Rice straw (1 kg:1 kg:1 kg) and set V:dung alone (3 kg) to evaluate earthworm survival rates. Eisenia fetida were introduced three days after setup initiation, with temperatures maintained between 20 °C–28 °C and moisture levels at 50–60%. Jute cloth covers prevented external intrusion and earthworm escape. The study monitored earthworm weight, cocoon production, hatchlings, and waste in a 90 day experiment, collecting adult earthworms, cocoons, and juveniles for observation. Results revealed that specific ratios of kitchen waste and cow dung significantly influenced earthworm survival, reproduction and vermicompost quality. The study highlights the significance of optimizing waste recycling processes using earthworms and emphasizes the need for suitable mediums to improve waste conversion efficiency and vermicompost quality.

Rhizostimulation of Hydrocarbon Degrading Microorganisms Using Chrysopogon zizanioides and Eucalyptus camaldulensis Species During Bioattenuation of Hydrocarbon Polluted Soils

Background: This study was carried out to compare the rhizostimulation potentials of C. zizanioides and E. camaldulensis on microorganisms cfu during the phytoremediation of hydrocarbon contaminated potted soils. The objectives were to: i). determine the best treatment for the rhizostimulation of the microbial population in soils during the bioattenuation process. ii). examine the most efficient plant species in the Phytostimulation of hydrocarbon degrading microorganisms during the bioattenuation of hydrocarbon contaminated soils. iii). identify the various bacterial and fungal colonies associated with the bioattenuation of hydrocarbon. Materials and Method: The design was the Split-Split Plot experiment (4 x 4 x 2). The main plot factors were the crude oil contamination (4 levels), the sub-Plot factors were the soil amendments (4 levels) while the subsub-Plot factors were the plant species (2 levels). Results: Results indicated that there were significant differences (p < 0.05) in rhizostimulation potentials of the plant species in different crude oil contamination levels and in the different soil amendments for both bacteria and fungi. Although E. camaldulensis species was involved in biostimulation of microbial cfu, C. zizanioides was found better efficient (16.13 x 106 soil bacteria cfu g g -1 at 9 WAT and 10.04 x 106 soil fungal cfu g g -1 at 12 WAT respectively. Microorganisms found involved in bioattenuation of hydrocarbon include Bascillus spp., Staphylococcus spp., and Streptococcus spp for bacteria and Aspergillus spp., Rhizopus spp., and Penicillium spp for fungi. The most frequently occurred genus of microorganisms were Bacillus and Rhizopus. Conclusion: In conclusion, C. zizanioides was recommended as efficient rhizostimulating plant species. It was concluded that the mixture of both the grass and woody plant species are required for optimum growth and stimulation of hydrocarbon degrading microorganisms during phytoremediation procedure in the field. Additionally, bacterial and fungal cfu was observed to have increased with increasing hydrocarbon concentration under the influence of the two plant species and the applied landfarming treatments of a mixture of NPK (g g-1) and Cowdung (3:1 v/v) fertilizer. The most frequently occurred genus of microorganisms were Bacillus and Rhizopus.

IMPLEMENTATION OF BIOGAS EQUIPMENT USING ARDUINO MEGA 2560 WITH SENSOR MQ-4

The biogas in the research that the authors do is a mixture of cow dung with 1: 2 water, where the biogas in this study is carried out by anaerobic fermentation or without air, a mixture of cow dung and water is put into the reactor and the fermentation process is carried out for 12 days to prove whether biogas In this study, gas will be stored in storage (biogas bag 1 and biogas bag 2. The research method used, namely conducting literature studies, exploration, determining equipment specifications, designing and implementing and testing. In designing this tool, it is able to produce gas from the biogas fermentation process, namely methane gas which can be detected by a functioning methane gas sensor. Where there is an increase in PPM testing between the first MQ-4 sensor from 5246.36 and the second MQ-4 sensor detected at 5667.23 PPM with the adjusted difference of 420.87 PPM, so the methane gas is tested with a stove and a lighter. The MQ-4 sensor measurement error results reached 5.63%. Keywords: Reaktor fixed dome, MQ-4, Gas Metana, Monitoring

Design Analysis and Production of Biogas Using Local Feedstock “Elephant Grass”

The study was aimed at constructing a biodigester and determining the efficiency of using a mixture of cow dung and elephant grass as feedstock for biogas production. The volume of the biodigester was 126 litres (0.126m3) and it was constructed using mild steel with a thickness of 5mm and a maximum allowable stress of 1.74 N/mm2 to withstand high pressures that could be generated within the digester. 6 kg of elephant grass was mixed with 6 kg of cow dung and 12 litres of water and poured in the biodigester and left for a period of 21 days with a temperature range of 35°C - 44°C. Graphs of temperature (°C) against retention period (days) and daily biogas produced (litres) against retention period (days) were obtained. The daily biogas yield was measured by calculating the volume increase of the storage device which is a car tyre tube in this case. Elephant grass serves as an effective substrate for biogas production. To enhance its efficiency in the digester, it is recommended to mechanically pre-treat the grass by breaking it into smaller particles.

Integrated microcontroller mq sensors for monitoring biogas: Advancements in methane and hydrogen sulfide detection

Recent technological advances in microcontroller systems enable novel biogas monitoring capabilities. This study investigates microcontroller-based quantification of methane and hydrogen sulfide concentrations in biogas derived from anaerobic digestion. Anaerobic digesters were fed either 100% cow dung substrates or a 50:50 mixture of cow dung with municipal solid waste (MSW). Methane levels were monitored using an MQ-4 sensor, hydrogen sulfide via an MQ-136 sensor, and temperature with a K-type thermocouple, all integrated with an ATmega 2560 microcontroller system. The 100% cow dung digester produced biogas with maximum methane concentrations of 3488 ppm at 21 days, indicating improved methane production compared to the 50:50 mixture of cow dung with MSW. Hydrogen sulfide reached 195 ppm and 192 ppm for the 100% cow dung and mixed digesters. Mesophilic temperature conditions were maintained throughout the digestion process. Real-time quantification of biogas composition demonstrates the capabilities of microcontroller-based anaerobic digester monitoring to provide precise methane and hydrogen sulfide measurements.

Thermal Insulation of “akassa” Hot Preservation Baskets Using Cow Dung Coatings

The use of eco-materials for thermal insulation is becoming more and more recommended compared with synthetic materials. They have the advantage of being biodegradable and sometimes less expensive. To this end, the use of packaging with the function of hot preservatives but made from local and biodegradable materials is a very interesting alternative to synthetic enclosures. This work involved formulating eco-materials made from cow dung coatings and a mixture of cow dung coatings with a framework of fibres extracted from the stalks of oil palm leaves. In addition, to monitor the temperature rise in the various eco-materials manufactured and characterise them using the hot ribbon method to determine their effusivity and thermal conductivity. The pair of materials exposed to heating showed a gradual rise in temperature within the materials when the resistor was energised. A slightly faster rise was observed in the first fifty minutes. The results obtained indicate that the cow dung has a higher effusivity (E = 517.32 J.m<sup>-2</sup>. °C<sup>-1</sup>. s<sup>-1/2</sup>) than its composite (E = 501.20 J.m<sup>-2</sup>. °C<sup>-1</sup>. s<sup>-1/2</sup>). The thermal conductivity values obtained indicate that the cow dung has a higher thermal conductivity (λ'=0.19 W.m^(-1).K^(-1)) than that of the composite structure (λ=0.15 W.m^(-1).K^(-1)). From the above, the presence of the fibre frame has the effect of reducing thermal conductivity because it absorbs more energy. The materials produced therefore have proven insulating properties, which are improved when the framework is made from fibres extracted from the stalks of oil palm leaves. Using oil palm fibres in combination with cow dung as eco-materials for thermal insulation is an excellent alternative to synthetic insulation.

Assessment of Effects of Amended Bioremediation of Toxic Metal-polluted Soil using Organic Composites and Bacillus sp on Plant Growth Parameters

It has become pertinent to develop improved bioremediation techniques, to avert the deleterious effects of heavy metal pollution on agricultural productivity, and safety of its produce. In this study, cow dung, poultry wastes and their composites used as organic amendments were collected and processed, while Bacillus sp used as plant growth promoting rhizosphere was isolated and identified. Then 24 kg of fertile soil was polluted by introducing 20 mL of 0.1M lead acetate solution, before bagging 5 kg of polluted soil into ten perforated nylons. Soil sample was then analyzed before and after treatment. After mixing with Bacillus sp suspension, two of the pot experiments were amended with each of 0.5 kg cow dung only, 0.5 kg poultry wastes only and 1:1 ratio of their composites. Control samples were set up without amendment, and they were bioremediated for 25 days. Following germination of sown corn seedlings, heights of their shoots and number of leaves were monitored on day 4, weeks 2, 4 and 7, before harvesting for analysis together with soil samples. Results obtained revealed that seedlings grown on treated samples as well as properties of treatment of soil were generally better than those of control samples. Highest percentage increase in organic matter content of soil was recorded in treatment with mixture of cow dung only and Bacillus sp, with 9.28% and 7.63% increase at 33.75 mg/kg and 52.55 mg/kg of lead (Pb) pollution. Seedlings grown on samples treated with poultry wastes only, recorded the highest protein content of 161.25±5.5 mg/g, 104.99±4.95 mg/g and 79.75±3.2 mg/g protein contents, at 32.75 mg/kg, 42.02 mg/kg and 52.44 mg/kg levels of Pb pollution, respectively. The amendments also reduced bioaccumulation of Pb in corn seedlings, which was in the order; stem<leaf<root. Therefore, these amendments can be exploited for improved bioremediation of heavy metals.

Analysis of Anaerobic Digestion Installation Testing for Tofu Liquid Waste Utilization into Biogas with the Addition of Cow Manure Variations

The purpose of this study is to convert tofu wastewater into biogas using an anaerobic digester with varying cow dung mixtures (10%, 15%, and 20%). The study method entails creating digesters including independent, dependent, and controlled variables. Variations in pH, temperature, biogas pressure, and biogas volume were detected throughout the course of a 15-day fermentation. The data show that in the 10% fluctuation, the greatest pH was on day 7 (7), whereas the highest temperature was 32°C on days 6 and 7. Biogas pressure emerged on day 6 (89.2 cmHg), resulting in a volume of 90 liters by day 15. In the 15% variation, the highest pH (7.2) occurred on day 8, with the highest temperature (34°C) on days 9 and 10. Biogas pressure began on day 5 (89.9 cmHg), with a biogas volume of 95 liters on day 15. The 20% variance resulted in the highest pH (7.4) on day 8 and the highest temperature of 35°C from days 9-11. Biogas pressure began on day 5 (90.7 cmHg), resulting in a biogas volume of 100 liters on day 15. This study sheds light on how to manage tofu waste into biogas with varying degrees of effectiveness and efficiency.

Biogas Production in a Variety of Sawdust and Cow Dung Mixtures Using the Intermittent Mixing Method

Cow dung is livestock waste that is very useful for renewable energy sources. The acceleration of the gas rate in cow dung biogas fermentation can be accelerated by the addition of secondary material, sawdust is one of the organic materials that can accelerate the rate of gas production in the formation of cow dung biogas. This study used a mixture composition: (B1) 675 g cow dung and 0 g sawdust, (B2) 472.5 g cow dung and 202.5 sawdust, (B3) 450 g cow dung and 225 g sawdust, and (B4) 427.5 g cow dung and 247.5 g of sawdust by fermentation for 20 days. In the research process, measurements of pH at the beginning and at the end of the study, gas pressure, gas volume, biodigester temperature, production rate, methane gas content, and flame test were carried out. In this study, the pH values ranged from 7-7.5 and the biodigester temperature was 27.5-31°C. The results of this study indicate that an organic mixture with a mixture of sawdust can accelerate production faster than without organic sawdust. Optimal results are found in the variation of the organic mixture of sawdust with a mixture of 450 g cow dung and 250 g sawdust having the highest production rate of 281.72 ml/day.

Laboratory Investigation of Biogas Production Using Cow Dungs and Kitchen Wastes Otta

Laboratory Investigation of Biogas Production Using Cow Dungs and Kitchen Wastes Otta

Assessment of The Bioremediation Potential of Selected Bacterial Species Isolated from the Textile Printing Wastewater Inoculated with Cow Dung

This study was conducted to isolate and identify bacteria from the wastewater of the textile printing industry inoculated with a mixture of cow dung, jaggery, and urea to assess the bioremediation potential of isolated bacterial species for reducing color and other polluting parameters of the wastewater. Based on colony characteristics, we were able to isolate nine types of bacteria (Pri 1 to 9), capable of thriving in textile printing wastewater. Out of the nine isolates examined, four (Pri 3, Pri 4, Pri 8, and Pri 9) significantly reduced the color and values of other physicochemical parameters of the wastewater. Isolated bacterial cultures were identified using various biochemical tests, antibiotic sensitivity tests, and rRNA sequence analysis. At the end of a 24-h incubation period at room temperature under shaking conditions at 100 rpm on an orbital shaker, isolate Pri 3 was identified as Alcaligenes aquatilis LMG 22996 (T), capable of reducing color by 86.13%, biological oxygen demand (BOD) by 70.44%, chemical oxygen demand (COD) by 80.65%, total dissolved solids (TDS) by 47.31%, total suspended solids (TSS) by 56.56%, and ammoniacal nitrogen by 75.95%; isolate Pri 4 as Priestia aryabhattai B8W22(T), capable of reducing color by 78.35%, BOD by 66.35%, COD by 74.92%, TDS by 34.94%, TSS by 31.66%, and ammoniacal nitrogen by 71.14%; isolate Pri 8 as Citrobacter werkmanii NBRC 105721(T), capable of reducing color by 90.37%, BOD by 82.13%, COD by 85.06%, TDS by 54.83%, TSS by 61.97%, and ammoniacal nitrogen by 80.76%; and isolate Pri 9 as Shewanella chilikensis JC5(T), capable of reducing color by 90.17%, BOD by 84.68%, COD by 83.46%, TDS by 59.13%, TSS by 62.45%, and ammoniacal nitrogen by 90.37%.

Vermitechnology transforms hazardous red mud into benign organic input for agriculture: Insights on earthworm-microbe interaction, metal removal, and soil-crop improvement

Bioremediation of hazardous bauxite residues, red mud (RM), through vermicomposting has yet to be attempted. Therefore, the valorization potential of Eisenia fetida in various RM and cow dung (CD) mixtures was compared to aerobic composting. Earthworm fecundity and biomass growth were hindered in RM + CD (1:1) feedstock but enhanced in RM + CD (1:3). The pH of highly alkaline RM-feedstocks sharply reduced (>17%) due to vermicomposting. N, P, and K availability increased dramatically with Ca and Na reduction under vermicomposting. Additionally, ∼40–60% bioavailable metal fractions were transformed to obstinate (organic matter and residual bound) forms upon vermicomposting. Consequently, the total metal concentrations were significantly reduced with considerably high earthworm bioaccumulation. Microbial growth and enzyme activity were more significant under vermicomposting than composting. Correlation statistics revealed that microbial augmentation significantly facilitated a metal reduction in RM-vermibeds. Eventually, RM-vermicompost stimulated sesame growth and improved soil health with the least heavy metal contamination to soil and crop.

High-value crops' embedded groundnut-based production systems vis-à-vis system-mode integrated nutrient management: long-term impacts on system productivity, system profitability, and soil bio-fertility indicators in semi-arid climate.

The current study identified two new climate-resilient groundnut-based cropping systems (GBCSs), viz., groundnut-fenugreek cropping system (GFCS) and groundnut-marigold cropping system (GMCS), with appropriate system-mode bio-compost embedded nutrient management schedules (SBINMSs) for semi-arid South Asia. This 5-year field study revealed that the GMCS along with leaf compost (LC) + 50% recommended dose of fertilizers (RDF50) in wet-season crop (groundnut) and 100% RDF (RDF100) in winter-season crop (marigold) exhibited the highest system productivity (5.13-5.99 t/ha), system profits (US$ 1,767-2,688/ha), and soil fertility (available NPK). Among SBINMSs, the application of 5 t/ha leaf and cow dung mixture compost (LCMC) with RDF50 showed the highest increase (0.41%) in soil organic carbon (SOC) followed by LC at 5 t/ha with RDF50 and RDF100. Legume-legume rotation (GFCS) had significantly higher soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) than legume-non-legume rotations (groundnut-wheat cropping system (GWCS) and GMCS). Among SBINMSs, the highest SMBC (201 µg/g dry soil) and SMBN (27.9 µg/g dry soil) were obtained when LCMC+RDF50 was applied to groundnut. The SMBC : SMBN ratio was the highest in the GWCS. LC+RDF50 exhibited the highest SMBC : SOC ratio (51.6). The largest increase in soil enzymatic activities was observed under LCMC+RDF50. Overall, the GMCS with LC+RDF50 in the wet season and RDF100 in the winter season proved highly productive and remunerative with better soil bio-fertility. SBINMSs saved chemical fertilizers by ~25%' in addition to enhanced system productivity and system profits across GBCSs in semi-arid regions of South Asia. Future research needs to focus on studying the potential of diversified production systems on water and environmental footprints, carbon dynamics, and energy productivity under semi-arid ecologies.

Production of biomethane, biohydrogen, and volatile fatty acids from Nordic phytoplankton biomass grown in blended wastewater

Upgrading carbon-negative microalgal biomass to biofuels and value-added products presents a three-pronged solution for waste treatment, carbon capture, and economically viable bioenergy production. Acidogenesis and methanogenesis are versatile processes at the core of anaerobic digestion systems, facilitating the conversion of diverse biogenic substrates into energy and a wide range of biobased products. The present study was conducted to integrate acidogenesis and methanogenesis for coproduction of biohydrogen, biomethane, and volatile fatty acids from Nordic phytoplankton consortia. For this purpose, microalgal consortia was cultivated in a raceway pond equipped with high surface area structures. Harvested microalgal biomass was subjected to thermoalkaline (2% NaOH solution at 121 °C) and enzymatic (cellulase) pretreatments. The hydrolysates of the pretreated biomass were inoculated with thermally treated sludge for acidogenic fermentation and with mixture of untreated sludge and cow dung (1:1 v/v ratio) for anerobic digestion. The acidogenic process produced a significant amount of biohydrogen (maximum 164.8 mL bioH2/VSload) along with volatile fatty acids (maximum 7.9 g COD/L), while methanogenesis resulted in biomethane production of maximum 210.7 mL bioCH4/VSload, accompanied by an ammonium recovery of 1278 mg NH4+/L. These maximum yields were all achieved by enzymatic pretreatment of the biomass fraction harvested from high surface area brush head structures inserted in the raceway pond. These results have important implications for designing phytoplankton cultivation systems and upstream pathways to optimize energy production from carbon-negative phytoplankton biomass.

Humifloc™: An improved solid waste responsible for sustainable aquaculture

The present experiment intended to find out the alternative usages of solid wastes, left aside due to their non-usage for the benefit of animals. Among the different types of solid wastes, organic bio-degradable solid wastes from the municipal area comprising non-hazardous properties had been considered for enhancing aquaculture productivity. Organic solid wastes along with the vermicast, produced by certain epigeic earthworms (Eisenia fetida, Eudrilus eugeniae,Perionyx excavatus) from the mixture of raw cow dung (added externally), certain beneficial herbs (Neem: Azadirachta indica, Indian-Almond: Terminalia catappa, Kule Khara: Hygrophila auriculata, and Ashwagandha: Withania somnifera), turmeric (Curcuma longa), and whole banana tree (Musa paradisiaca) were the basic ingredients to represent the ‘improved solid wastes’(Trade named: Humifloc™), produced through a series of natural procedures finally to act as a supplement. Periodical [start-up dose: 10 kg acre−1 (single time); maintenance dose: 05 kg acre−1 fortnightly up to 90 days] direct administration of Humifloc™ was done into the experimental ponds reared with teleostean fishes [Catla (Catla catla), Rahu (Labeo rohita), Magur (Clarias batrachus), and Koi (Anabas testudineus) 2:5:1:1] up to 90 days in the dry season (November to January) and were fed with farm-prepared farm-made-aqua-feed or ‘farm-feed’. Three ponds [(one control (C farm-feed only): and two treatments (T: P1 & P2 farm-feed plus Humifloc™)] were considered while observing the growth performances and alteration in tissue biochemistry of the experimental fish species. A comprehensive study based on growth and biochemical parameters of various tissues indicated a quadratic response. Under Humifloc™ exposure, pond water depicted an equilibrium in water parameters like in pH, ammonia, and nitrate, while the fishes depicted faster metabolic rate, higher digestibility, balancing of glucose homeostasis, and higher brain signalling which might finally result in elevation of growth performances with higher productivity, directly affecting to the profitability of the poor fish farmers.

Biohythane Production from Domestic Wastewater Sludge and Cow Dung Mixture Using Two-Step Anaerobic Fermentation Process

The current study explored bioenergy, particularly biohythane (a combination of biohydrogen (bioH2) and biomethane (bioCH4)), production from cow dung and untreated domestic wastewater sludge to valorize the waste into a value-added product. The experimental study consisted of a two-step process: dark fermentation (DF) and anaerobic digestion (AD) with a range of processing conditions varying the temperature and pH (acidic, neutral, and basic). The study maintained thermophilic conditions (55 °C) for bioH2 production and mesophilic conditions (35 °C) for bioCH4 production. The highest yields of bioH2 and bioCH4 were obtained at a pH of 5.5 (108.04 mL H2/g VS) and a pH of 7.5 (768.54 mL CH4/g VS), respectively. Microorganisms, such as Lactobacillus brevis and Clostridium butyricum, in the wastewater sludge accelerated the conversion reaction resulting in the highest bioH2 yield for an acidic environment, while Clostridium and Bacilli enhanced bioCH4 yield in basic conditions. The maximum cumulative yield of biohythane was obtained under basic pH conditions (pH 7.5) through DF and AD, resulting in 811.12 mL/g VS and a higher volumetric energy density of 3.316 MJ/L as compared to other reaction conditions. The experimental data were modelled using a modified Gompertz’s model at a 95% confidence interval and showed the best-fitting data from experimental and simulation results for biohythane production. The regression coefficient R2 value was highly significant at 0.995 and 0.992 for bioH2 and bioCH4 with the change in pH during biohythane production. Thus, this study presented an effective pathway to utilize untreated domestic wastewater sludge as an inoculum, showcasing the potential of biohythane production and the generation of valuable metabolic end-products across a broad range of pH conditions.

Study on Process Parameters in Hydrothermal Liquefaction of Rice Straw and Cow Dung: Product Distribution and Application of Biochar in Wastewater Treatment

In this study, rice straw (RS) and cow dung (CD) waste were hydrothermally processed for the recovery of bio-oil and biochar. The hydrothermal experiments were performed in a 5 L capacity reactor under the following process conditions: temperature (240–340 °C), solvent to biomass ratios of 1:1, 1:2, 2:1, 1:3 and 3:1, a time of 1 h and a pressure of 15 bar. The HTL products were characterized via FTIR, SEM and GC–MS (gas chromatography mass spectrometry). It was seen that the maximum bio-oil yield was 32.5 wt% and the biochar yield was 18.5 wt% for the 2:1 RS:CD mixture at a temperature of 320 °C. The bio-oil contained hexadecane, heptadecane, octadecane and other hydrocarbons, and their presence was confirmed by GC–MS. The biochar was analyzed, and it was used in wastewater treatment to remove the colorants. The biochar also showed some promising results in the colorants removal study, with an efficiency of more than 76%.

Utilization of Biogas in Generators to Generate Electricity

Agricultural and livestock biomass waste is a potential source of basic materials in producing biogas because the organic content it has is quite high so it needs to be used in generators as engine fuel mixtures. The purpose of the research is to get the best treatment by looking at the time the generator operates and the highest electrical power produced. This research was conducted using an experimental method with 3 treatments with 3 replications, namely using a mixture of cow dung with rice straw (P1), cow dung with corn cobs (P2), and cow dung with water hyacinth (P3), and the use of biogas and LPG as generator fuel with biogas levels of 5, 10, and 15% and LPG 95, 90, and 85%. The results showed that the best biogas yield was obtained from a mixture of cow dung and rice straw (P1) with a level of 5%. Biogas with a level of 5% can turn on the generator for longer. The generator can operate for 10.10 minutes by producing 946 watts of electrical power.