Performance of a Small-Scale, Variable Temperature Fixed Dome Digester in a Temperate Climate

Abstract

Small-scale digesters, similar to popular Chinese designs, have the potential to address the energy needs of smaller dairy farmers in temperate U.S. climates. To assess this potential, a 1.14 m 3 (300 gallon) modified fixed-dome digester was installed and operated, at variable temperatures (5.3 to 27.9 °C) typical of the Midwestern United States, from March 2010 to March 2011 (363 days). Temperature, gas production, and other variables were recorded. The system was fed with dilute dairy manure with 6% volatile solids (VS) and an organic loading rate (OLR) ranging from 0.83 to 2.43 kg volatile solids (VS)/m 3 /day. The system was loaded with no interruption and exhibited no signs of inhibition from July 2010 to mid-November 2010 (129 days). During this period the digester temperature was over 20 °C with an average daily biogas production of 842 ± 69 L/day, a methane yield of 0.168 m 3 /kg VS added, and a Volatile Solids reduction of 36%. After the temperature dropped below 20 °C, the digester showed signs of inhibition and soured. These findings suggest that an ambient temperature, modified fixed dome digester could operate without temperature inhibition for approximately six months (169 days) a year in a temperate climate when digester temperatures exceed 20 °C. However, during colder months the digester temperature must maintained above 20 °C for viable gas production year round.

Seasonal variation in biogas production in reinforced concrete dome biogas plants with buffalo dung in Pakistan

“…In addition, little information is available on how changes in ambient temperature affect the temperature of the full-scale anaerobic digestion process. Castano et al [30] and Ihara et al [31] found an improvement in biogas production through an increase in ambient temperature in the field-scale digester. Kalia et al [32] examined the performance of the dome biogas plant under seasonal temperature fluctuations and found that declining temperatures from summer to winter results in lowering digester temperatures.…”

An Innovative Solid-State Micro-Anaerobic Digestion Process to Valorize Food Waste: Technical Development Constraints and Consequences on Biological Performances

“…Micro-scale AD development and study started during the 1970s in China and India [9] where about 30 million anaerobic digesters are nowadays installed to meet basic energy needs of rural farm families [10,11]. Depending on climate conditions, geographical situation and type of waste treated, three main technologies are used: the fixed dome digester, the floating drum digester and the plug flow or tubular digester [12].…”

“…However, after improving the above listed technical and environmental weaknesses, the development of simple and affordable micro-scale AD processes may have potential to contribute meeting the energy needs of urban areas in temperate countries. A first example was performed in Midwestern United States, where a modified and completely buried fixed-dome digester was installed inside a greenhouse [10]. Results showed that the ambient and digester temperatures ranged between − 13.5 to 35 °C and 5.3 to 27.9 °C respectively along a year, which highlights the positive effect of burying the digester to limit temperature variations of the process.…”

Effects of Seasonal Temperature Variation on Slurry Temperature and Biogas Composition of a Commercial Fixed-Dome Anaerobic Digester Used in Bangladesh

“…22 to 13 • C. Ihara et al [23] observed improvement in biogas production with an increase in ambient temperature in a field-scale digester in Japan. Castano et al [24] evaluated the performance of a small-scale fixed-dome digester in a temperate U.S. climate for 363 days. They observed that the digester temperature below 20 • C produced less biogas than expected.…”

“…Besides these studies, the knowledge of seasonal temperature effect on commercial-scale digesters in Bangladesh context to date is insufficient. Moreover, studies devoted to poultry manure as a feedstock are even scarcer, with very few previous studies [22,24] reporting the performance of digesters treating cattle manure only. To address this research gap, the aim of the current work was to investigate the effect of seasonal temperature variations on the digester temperature and biogas quality by using a fixed-dome biogas digester treating local poultry litter in Bangladesh conditions.…”