Biogas Formation Research Articles

Methane production by Methanothrix thermoacetophila via direct interspecies electron transfer with Geobacter metallireducens.

Methanothrix is widely distributed in natural and artificial anoxic environments and plays a major role in global methane emissions. It is one of only two genera that can form methane from acetate dismutation and through participation in direct interspecies electron transfer (DIET) with exoelectrogens. Although Methanothrix is a significant member of many methanogenic communities, little is known about its physiology. In this study, transcriptomics helped to identify potential routes of electron transfer during DIET between Geobacter metallireducens and Methanothrix thermoacetophila. Additions of magnetite to cultures significantly enhanced growth by acetoclastic methanogenesis and by DIET, while granular activated carbon (GAC) amendments impaired growth. Transcriptomics suggested that the OmaF-OmbF-OmcF porin complex and the octaheme outer membrane c-type cytochrome encoded by Gmet_0930, were important for electron transport across the outer membrane of G. metallireducens during DIET with Mx. thermoacetophila. Clear differences in the metabolism of Mx. thermoacetophila when grown via DIET or acetate dismutation were not apparent. However, genes coding for proteins involved in carbon fixation, the sheath fiber protein MspA, and a surface-associated quinoprotein, SqpA, were highly expressed in all conditions. Expression of gas vesicle genes was significantly lower in DIET- than acetate-grown cells, possibly to facilitate better contact between membrane-associated redox proteins during DIET. These studies reveal potential electron transfer mechanisms utilized by both Geobacter and Methanothrix during DIET and provide important insights into the physiology of Methanothrix in anoxic environments. IMPORTANCE Methanothrix is a significant methane producer in a variety of methanogenic environments including soils and sediments as well as anaerobic digesters. Its abundance in these anoxic environments has mostly been attributed to its high affinity for acetate and its ability to grow by acetoclastic methanogenesis. However, Methanothrix species can also generate methane by directly accepting electrons from exoelectrogenic bacteria through direct interspecies electron transfer (DIET). Methane production through DIET is likely to further increase their contribution to methane production in natural and artificial environments. Therefore, acquiring a better understanding of DIET with Methanothrix will help shed light on ways to (i) minimize microbial methane production in natural terrestrial environments and (ii) maximize biogas formation by anaerobic digesters treating waste.

INVESTIGATION OF INITIATING ADDITIVE EFFECT ON BIOGAS FORMATION DURING SOLID HOUSEHOLD AND MUNICIPAL WASTE DECOMPOSITION

The article is devoted to the problem of the biogas formation process during solid household and municipal waste decomposition. It is noted the necessity to ensure a constant temperature regime of biodegradation at landfills under natural conditions of waste disposal, as well as the intensification of the process itself. The results of experimental studies on the production of biogas during the decomposition of model mixtures from solid household and municipal waste in laboratory conditions in the presence of initiating additives are presented.
 The aim of the work is to study the effect of initiating additives on biogas formation during the biodegradation of solid household and municipal waste with the defining of the best intensifier.
 As a result of the research, the authors obtained results indicating the effect of dietary supplements on the formation of biogas during the organic waste decomposition. The factors that affect the process of mixtures biodegradation are revealed, proving the validity of the use of initiating additives, as well as the use of landfills of solid household and municipal waste of a new design.

Gases in the near-surface zone of the reclaimed Barycz municipal waste landfill – a case study from southern Poland

The formation of biogas at municipal landfills and the significant emission of greenhouse gases from these facilities into the environment were the main reasons for analyzing the molecular composition of soil gas in the near-surface zone at the reclaimed part of the Barycz municipal waste landfill. The relations between the studied components (methane, carbon dioxide, light hydrocarbons and non-hydrocarbon components) and impact of the magnitude of recorded concentrations of methane and carbon dioxide on their emission to the atmosphere were evaluated. Two profiles were determined, along which 41 soil and landfill gas samples were taken at 20-meter intervals. At the same time, emissions were measured at each sampling point using a static chamber with a portable fluxometer. Chromatographic analysis showed that the concentrations of methane and carbon dioxide fluctuated in the ranges: 2.1 ppm – 76 vol% and 0.04 ppm – 11 vol%, respectively. Relatively high concentrations of these gases were determined at many of the measurement points, and this was particularly evident at the A-A’ profile, indicating stronger biochemical processes in this part of the landfill, or lateral migration of methane from the neighbouring stage II of the landfill, where biogas extraction is currently taking place. In addition, significant correlations between methane, carbon dioxide, and oxygen were demonstrated, indicating ongoing methane fermentation processes. Based on the study, it can be concluded that the southern part of the A-A’ profile is an optimal place to locate a degassing well from which biogas production could be used. However, the research is only preliminary and, it will be necessary to extend the soil gas tests before the final decision on the location of the well is made. Moreover, it has been shown that the concentrations of methane and carbon dioxide measured at points located outside the landfill were low. This means that generated biogas probably does not migrate beyond the boundaries of reclaimed waste landfill, but this will need to be confirmed by performing additional soil gas tests inside and outside the landfill area. The preliminary assessment of the effectiveness of the reclamation carried out was confirmed by the negligible values of the measured methane and carbon dioxide emissions on the surface.

Production and Kinetic Study of Biogas Formation from Cow Dung and Utilization of Biogas Effluent as Bio-Fertilizer

Biogas is an alternative and eco-friendly renewable power source and biogas effluent is used as a bio-fertilizer. In this research, the kinetic of biogas formation was studied and also the acceptance of biogas effluent as a bio-fertilizer was evaluated. 8000 g of cow dung and 600 ml of inoculum were fed to the digester. The volume of biogas production was observed for 50 days by using Orsat Apparatus and gas chromatography was used to analyze the gas. From the data, it was found that the formation of methane gas didn’t depend upon the concentration of cow-dung hydrocarbon and it followed the mechanism of the zero-order reaction. On the other hand, the elementary analysis of biogas effluent by AAS ensured the property of effluent as a bio-fertilizer. Utilization of Miscanthus fuscus with E. coli and S. aureus ensured a higher degree of biodegradation.

Mesophilic anaerobic digestion of waste activated sludge in an intermittent mixing reactor: Effect of hydraulic retention time and organic loading rate

An anaerobic digester was operated at mesophilic temperature and with intermittent mixing conditions to treat waste activated sludge. The organic loading rate (OLR) was increased by decreasing the hydraulic retention time (HRT), and the effect on process performance, digestate characteristics and inactivation of pathogens was investigated. The removal efficiency of total volatile solids (TVS) was also measured by biogas formation. The HRT varied from 50 to 7 days, corresponding to OLR from 0.38 to 2.31 kgTVS.m−3.d−1. The acidity/alkalinity ratio remained within stable limits (lower than 0.6) at 50-, 25- and 17-day HRT; due to an imbalance between the production and consumption of volatile fatty acids, the ratio increased to 0.7 ± 0.2 at HRT of 9 days and 7 days. The highest TVS removal efficiencies were 16, 12 and 9%, which were obtained at 50-, 25- and 17 day-HRT, respectively. Intermittent mixing provided solids sedimentation greater than 30% for almost all HRT tested. The highest methane yields (0.10–0.05 m3.kgTVSfed−1.d−1) were obtained when the reactor was operated at a higher HRT (50-17 days). At lower HRT, methanogenic reactions were likely limited. Zinc and copper were the main heavy metals found in the digestate, while the most probable number (MPN) of coliform bacteria remained below 106 MPN.g TVS−1. Neither Salmonella nor viable Ascaris eggs were found in the digestate. In general, increasing the OLR by decreasing the HRT to 17 days under intermittent mixing conditions provided an attractive alternative to treat sewage sludge despite some limitations due to biogas and methane yields.

Anaerobic Co-Digestion of Sewage Sludge and Trade Wastes: Beneficial and Inhibitory Effects of Individual Constituents

Anaerobic digestion (AD) of sewage sludge can be optimised by adding trade wastes (TWs) because of their nutrient content and boost in biogas formation if non-inhibitory. However, some components in TWs might have an inhibitory impact, such as nitrogen compounds, sulphate, heavy metals, metalloids, halogens and organic pollutants (e.g., phenol). This study aimed to understand the impact of TWs on the co-digestion with sewage sludge to identify appropriate TW loads for sustainable AD operation. The composition of 160 TWs was evaluated and the constituents with potential to cause inhibition or toxicity were tested in bio-methane potential (BMP) tests. The compounds studied in BMP tests included ammonia, zinc, copper, aluminium, mercury, arsenic, chloride, sulphate and nitrate. An improvement was observed at concentrations 2–746 mg Zn/L, 1066–2821 mg Cl/L as zinc sulphate and sodium chloride in biogas production, and 2–746 mg Zn/L, 162 mg SO4/L, 25 mg Hg/L as zinc sulphate, sodium chloride and mercury sulphate in methane production, respectively. Considering the TWs characterised and the results of the BMP tests, a volumetric ratio of 10/90 of TWs and sewage sludge is proposed as a suitable feedstock for co-digestion.

TECHNICAL AND TECHNOLOGICAL ASPECTS OF BIOLOGICAL RECLAMATION USING ANTHROPOGENIC ORGANIC WASTE IN COMPOSITION WITH SEWAGE SLUDGE

A systematic modern analysis of the state of waste management in the country encourages the search for more rational, efficient and cost-effective ways of processing and recycling solid waste. The inclusion of sewage sludge as a raw material in technologies for processing substrates makes it possible to solve the problems of accumulation and negative environmental impact of this hazardous waste, in addition to the problems of recycling. Promising strategies for the use of sewage sludge in combination with other components for reclamation purposes are considered: the production of substrates by direct mixing without any physical and chemical transformation of the substrate before application for reclamation purposes; composting to obtain reclamation compost; preliminary anaerobic biodegradation with the formation of biogas and subsequent use of digestate for reclamation purposes. The conditions for the application of the strategies, their advantages and disadvantages are analyzed.

Effect of addition of certain substances during slurry preparation to optimize biogas production

Biogas from anaerobic digestion of organic substance has become the available replacement for the fossil fuel. This research was carried out to investigate the effect of certain substances added during slurry preparation to enhance biogas formation. The biodigester was locally fabricated using plastic container of 25liter capacity. The slurry was prepared by adding Calcium Sulphate, Chopped plantain leaf, and pretreated substrate. After 15 days of anaerobic fermentation, the slurry with CaSO4 gave more biogas of 0.403kg followed by the pretreated which gave 0.270kg. The one with plantain leaf gave the least biogas. This is as a result of inhibition of enzyme activity by certain chemical substance from the leaf. Also, the amount of Calcium sulphate to be added should not exceed 200g to 1kg of substrate to be used for slurry preparation.

Comparative study of biogas formation using different locally sourced substrate

Co-digestion method of biogas production has proved to enhance the quantity of biogas produced. Co-digestion simply means the combination of two or more substrates together in anaerobic fermentation. For containers 1, 2, 3 and 4; there is a reasonable amount of gas production for container 4 which is for co-digested substrates. The ratio of the 4 containers at day 15 shows 0.10: 0.11: 0.12: 0.16: and 0.20. This shows that containers which represent cow dungs, poultry dungs and sewage for day 3, 6, 9, 12 and 15 are in the percentage of 14.49%, 15.94%, 17.39%, 23.19% and 28.99%. The 28.99% explains why co-digestion produces more biogas.

Construction of Magnetic Z-Scheme P-Doped Biobr/CoFe<sub>2</sub>O<sub>4</sub> Nanocomposite for Expeditious Visible Light Photocatalytic Palm Oil Mill Effluent Degradation via the Assistance of IO<sub>4</sub><sup>-</sup> and S<sub>2</sub>O<sub>8</sub><sup>2-</sup>

P-BiOBr/CoFe2O4 nanocomposite was fabricated through a surfactant-free hydrothermal route and combined with electron acceptors (IO4- and S2O82-) for the first time to examine the palm oil mill effluent (POME) degradation and concurrently evaluated the biogas formation under visible light irradiation. The POME degradation efficiency reached 100% in 120 min over P-BiOBr/CoFe2O4/IO4-, which was much higher than the P-BiOBr/CoFe2O4/S2O82- (80.6%). Interestingly, the evaluation of the biogas production demonstrated that the P-BiOBr/CoFe2O4/IO4- photocatalysis generated greater amount of biogas (CH4 + CO2) compared to other systems. The great photocatalytic enhancement was due to the efficient charge carrier separation thanks to the Z-scheme heterojunction between P-BiOBr and CoFe2O4, and the electron trapping by IO4-. The hydroxyl radicals and photogenerated holes contributed majorly to POME degradation. Ultimately, the P-BiOBr/CoFe2O4 with IO4- and S2O82- assisting under visible light provided an effective and feasible method to degrade POME.

Review: Biogas Production from Rice Straw

Rice straw is a rice plant whose fruit (grain) has been removed, so only the stems and leaves are left. Rice straw is the largest among rice plant waste and has not been utilized as well. Utilization of rice straw waste is not optimal because its usually used for cattle feed and as organic fertilizer. Apart from being used as cattle feed and organic fertilizer, methane gas can still be used for alternative renewable energy sources such as biogas. Rice straw has a carbon-to-nitrogen (C/N) ratio content between 50-70. However, to achieve the optimum biogas formation, the substrate requires a C/N ratio of 20-30, therefore a combination of other waste mixtures, such as cow dung or waste that has a low C/N ratio content is usually carried out.

The involvement of organic acids in soil fertility, plant health and environment sustainability.

Increasing demand for safe food by an ever-growing human population emphasizes the urgency for increasing crop yields and reducing the losses caused by abiotic and biotic stresses; a partial solution to this problem is to develop a better understanding of plant-microbe interactions. Plant roots continuously release a wide range of compounds including organic acids in root exudates. These root exudates stimulate growth of specific microbial communities in the rhizosphere, which affect complex biological and physico-chemical interactions occurring between plant roots and the surrounding soil environment. In addition, organic acids are also released by different microbes and during decomposition of organic matter and plant residues in the soil. Interestingly, the available organic acids in the rhizosphere play crucial roles in various physio-chemical processes including the chemoattraction of microbes (both beneficial and pathogenic), mineralization and solubilization of complex minerals (P, K and Zn), biocontrol of phytopathogens, induction of systemic resistance, biogas formation, mitigation of abiotic stresses and, detoxification of metals and residual pesticides. Thus, organic acids play a significant role in the sustainable management of the soil ecosystem and in environmental sustainability. This review discusses the role of organic acids in the stimulation or enrichment of specific root-associated microbial communities and their effect on plant-microbe interactions at the root surface. In addition, the potential for root microbiome modification to enhance nutrient cycling and nutrient acquisition, and in amelioration of environmental stresses for increasing food production is discussed.

Pembentukan Biogas pada Media Eceng Gondok dengan Starter Kotoran Ternak

Animal manure and water hyacinth become waste if not used. One of its uses is as raw material for biogas. The purpose of this study was to determine the effect of the type of manure on the formation of biogas from water hyacinth as seen from: 1) the rate of biogas formation, 2) the temperature of the slurry, 3) the pH of the slurry, and 4) the weight of the biogas produced. Research with Completely Randomized Design (CRD) consisted of five treatments (P); P1: cow dung + water hyacinth + water, P2: buffalo dung + water hyacinth + water, P3: goat dung + water hyacinth + water, P4: horse dung + water hyacinth + water, and P5: broiler chicken dung + water hyacinth + water . Each treatment was repeated 4 times to obtain 20 experimental units. The composition of the raw material mixture consists of 8 kg of water hyacinth chopped 2 cm + 3 kg of livestock manure + 2 liters of water. Parameters observed were: rate of gas formation, slurry pH, slurry temperature, and weight of biogas produced. The research was conducted at the Biology Education Laboratory, Faculty of Teacher Training and Education, Kapuas Sintang University. Data were analyzed by ANOVA at 5% significance level using SPSS 16.0 and BNT test if there was a significant difference between treatments. The results showed that the type of manure only had a significant effect on the weight of biogas formed, but had no significant effect on the rate of biogas formation, slurry pH, and slurry temperature. Thus the five types of manure can be used as a starter in the manufacture of biogas made from water hyacinth.

Pretreatment of lignocellulosic biogas substrates by filamentous fungi

Decomposition of lignocellulosic plant biomass by four filamentous fungi was carried out to facilitate subsequent anaerobic degradation and biogas formation. Agricultural side products, wheat straw and corn stover and forestry energy plant willow chips were selected as plant biomass sources. The substrates were confronted by pure cultures of Penicillium aurantiogriseum (new isolate from rumen), Trichoderma reesei (DSM768), Gilbertella persicaria (SZMC11086) and Rhizomucor miehei (SZMC11005). In addition to total cellulolytic filter paper degradation activity, the production of endoglucanase, cellobiohydrolase, β-glucosidase enzymes were followed during the pretreatment period, which lasted for 10 days at 37 °C. The products of pretreatments were subsequently tested for mesophilic biogas production in batch reactors. All 4 strains effectively pretreated the lignocellulosic substrates albeit in varying degrees, which was related to the level of the tested hydrolytic enzyme activities. Penicillium aurantiogriseum showed outstanding hydrolytic enzyme production and highest biogas yield from the partially degraded substrates. Corn stover was the best substrate for biomass decomposition and biogas production. Scanning electron microscopy confirmed the deep penetration of fungal hyphae into the lignocellulosic substrate in all cases.

Biodigestion of Mixed Substrates of Cow Manure-Delignified Spent Coffee Ground (DSCG) using Microorganism Enhancer for Biogas Production and Its Kinetic Study

Environmentally benign energy strategies have been implemented to cope with the rapidly increased global energy needs. Indonesia’s coffee consumption has triggered an increase in the generation of spent coffee ground (SCG) that can be used as a biogas raw material. The novelty that we offer in this research effort is to reduce the premature formation of biogas, so that we can extend the biogas production period during the digestion of spent coffee ground by adjusting the right pH and digestion time. This study aimed to produce biogas from an organic substrate mixture containing cow manure and SCG with a 25:1 C/N ratio by employing effective microorganisms-4 (EM-4). The process began with delignification of SCG using sodium hydroxide solution to obtain delignified SCG (DSCG). The biodegradation of the substrate was performed in an anaerobic batch digestion (AD) system at ambient temperature by varying pH (5, 7, and 9) and EM-4 concentration (6%, 9%, and 12%). The biogas product and chemical oxygen demand measurements were carried out every two days for 60 days of digestion. The results showed that the increase in EM-4 concentration induced earlier initial biogas production enhanced the volume, and extended the production time. The pH 7 level and 9% EM-4 loading gave the ideal digestion substrate condition containing cow manure and SCG with a 25:1 C/N ratio to obtain 11.28 mL of biogas/g COD with 100.2% production enhancement. The modified Gompertz equation fitted the experimental data very well as indicated by a high value of the coefficient of determination (R2 > 0.95).

Assessment of solar emissions in the climate of Iraq for efficient multifunctional disposal

The concept of solar-hydrogen energy today provides optimal solutions in light of the climate agenda for all geographic areas of the globe.Iraq's geographical location and climate conditions predetermine ample opportunities for renewable sources, namely solar energy. High air temperatures, the prevailing number of sunny days recorded annually in the region, create a favorable technical platform for the implementation of thermal processes based on the utilization of incoming research. Therefore, for the design of solar plants and in the future, a reliable estimate of solar energy resources is required to determine the generated power depending on seasonal changes. Theoretical methods of calculating the incoming radiation flow for a particular area do not have the required accuracy for a number of reasons, the main of which is the permanent state of cloud cover. Only taking into account the actual climatic conditions for the construction areas under consideration on the basis of long-term actinometric observations gives a fairly accurate distribution of solar energy. The absence of such information in full implies forecasting of resource availability, including for areas not covered by observation systems. Given these limitations, an analysis of the average monthly daily solar radiation revenues for densely populated areas of Iraq is provided. On the basis of actinometric information of many years of observations, dependencies were obtained to determine the solar energy coming at statistical clouds per day per 1 m2 of horizontal surface of the area, taking into account its latitude and serial number of the month of the year. The equations allow to fulfill the forecast of the area irradiation for the design of solar plants, to justify the subsequent efficiency of the alternative system, as well as the level of possible replacement of traditional resources and the degree of reduction of their consumption. On the basis of the calculated data, it is possible to justify the most expedient scheme of solar energy utilization depending on the available resources and to select the structures of radiation sensing devices required for climatic conditions for the solved tasks. In view of the analysis of solar energy distributions and average monthly outdoor air temperatures in Iraq, two types of thermal solar plants have been recommended for use, which may have additional circuits for generating electricity and cold. In addition, the fixed irradiation potential of the territories makes it possible to carry out an effective passive transmission to maintain the thermophilic mode of anaerobic fermentation of organic waste. In this case, environmentally friendly utilization of carbon-containing substrates is accompanied by an increase in the rate of formation of biogas, and therefore hydrogen, without the use of traditional heat supply to reactors.

Effect of Cow Manure on Biogas Production Based on Rice Husk Waste in SSAD Conditions

The development of biogas technology is currently very fast along with the increasing need for energy and expensive costs used to buy fossil energy. Rice husk-based biogas has begun to be widely developed because of the high potential that can be utilized from the biomass. The aim of this study was to study the effect of the addition cow manure combined with rice husks for biogas production under SSAD conditions. Variable comparison of rice husk and cow manure as follows: 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, and 1:4. The study was carried out in duplicate on laboratory scale with C/N ratio 35, 27% total solids and rumen fluid as a source of methanogenic bacteria. Biogas is observed every two days until its productivity decreases. It was found that the best biogas productivity was in the 2:1 variable range, namely 39.49 mL/grTS followed by 1:1 21.91 mL/grTS, 3:1 13.80 mL/grTS, 1:2 13.31 mL/grTS, 1:3 10.90 mL/grTS, 1:4 82 mL/grTS and 4:1 9.41 mL/grTS. After calculating the biogas production rate constant with Gompertz, the highest productivity was obtained at 1:1 variable, with maximum biogas (A): 65.69 mL/grTS, daily biogas production (U): 0.37 mL/grTS.day, and minimal time for biogas formation (\U0001d706): 25th day.

Strategies for variable regulation of methanogenesis efficiency and velocity.

Combinations of various strategic approaches to the suppression of methanogenesis and the formation of biogas with a simultaneous decrease in the ratio of methane in its composition were investigated. Introduction of methanogenesis suppressors such as redox derivatives of humic acids, potassium persulfate (K2S2O8), possessing oxidizing and electron acceptor properties, enzyme hexahistidine-containing organophosphorus hydrolase with high lactonase activity and polypeptide antimicrobial agent bacitracin into the media with anaerobic consortia were studied. The effect of these substances was directed at various participants of the natural methanogenic consortium, as well as on the biochemical processes carried out by them. The use of K2S2O8 together with bacitracin provided maximum and almost complete suppression of CH4 production. The measured concentration of intracellular adenosine triphosphate has shown that viability of cells in the consortium remained almost the same, whereas their metabolic activity decreased. Various combinations of the above-mentioned suppressors provided different degrees of methanogenesis suppression, but redox agents played a key role in all the cases studied. Based on the accumulated data, combining suppressors in different concentrations can be used to manage the methanogenesis (efficiency and velocity of its decrease) in media with anaerobic consortia. KEY POINTS: • Various strategies for suppression of the methanogenesis were combined. • The enzyme His6-OPH was firstly used for quorum quenching in methanogenic consortium. • Velocity of methanogenesis decrease can be managed by combinations of suppressors.

Utilization of Livestock Dung as A Biogas Starter from Water Hyacinth to Suppress Water Weeds

Animal manure and water hyacinth will become waste in the environment if not utilized. One form of utilization of both is to make it as raw material for biogas. The aims of this study were: to determine the effect of the type of manure on the process of forming biogas from water hyacinth, which is related to: 1) the speed of biogas formation, 2) the temperature of the slurry , 3) the pH of the slurry , and 4) the volume of biogas produced. This study was designed with a completely randomized design (CRD), consisting of five (5) treatments, namely Treatment 1 (P 1 ) cow dung + water hyacinth + water, (P 2 ) buffalo dung + water hyacinth + water, (P 3 ) manure goat + water hyacinth + water, (P 4 ) horse manure + water hyacinth + water, and (P 5 ) broiler chicken manure + water hyacinth + water. Each treatment was repeated 4 times to obtain 20 experimental units. In this study, the composition of the mixture of raw materials was used as follows: 8 kg of chopped water hyacinth (2 cm) + 3 kg of animal dung + 2 liters of water. This is based on the results of research by Sari et al. (2014) which showed that the composition was good enough to produce biogas made from water hyacinth. The composition of the raw material mixture is as follows: 8 kg of chopped water hyacinth (2 cm) + 3 kg of animal dung + 2 liters of water. The variables observed in this study were: the rate of gas formation, slurry pH, slurry temperature, and the volume of gas produced. The research was conducted at the Biology Science Education Laboratory, Faculty of Tarbiyah and Teacher Training, UIN Mataram. The time of research was carried out from March to October 2018. The results showed that the type of manure only had a significant effect on the amount of biogas formed, but did not significantly affect the time of gas formation, slurry pH, and slurry temperature. Thus, the five types of manure can be used as a starter in the manufacture of biogas made from water hyacinth.

OPTIMALISASI BIOGAS DARI KOTORAN SAPI DENGAN PENAMBAHAN BAHAN ORGANIK DARI LIMBAH PERTANIAN DAN PASAR

Cow farm waste is one type of raw material that is commonly used in biogas formation technology. According to 1 Wahyuni (2013), a cow can produce fresh waste between 20 to 29 kg/day. According to 2 Kaharudin and Sukmawati (2010), biogas on a household scale with a number of livestock of 2-4 cows or a supply of dung of approximately 25 kg/day is sufficient to use a reactor tube with a capacity of 2500-5000 liters which can produce biogas equivalent to 2 liters of oil. land/day and is able to meet the energy needs of one rural household with 6 family members. The higher the organic matter content in biogas technology, in a suitable environment, the biogas production will increase. This causes the need for the addition of mixed organic matter so that biogas production is maximized. The type of organic material used is a very important factor. Grass, rice straw or vegetable waste can be used as a source of organic matter in the biogas production process.