Enhanced Biogas Production From Anaerobic Co-digestion of Lignocellulosic Biomass and Poultry Feces Using Source Separated Human Urine as Buffering Agent

Abstract

Effect of source separated human urine as buffering agent compared to sodium bicarbonate and water in anaerobic co-digestion of lignocellulosic biomass and poultry feces was evaluated in laboratory scale reactor for 180 days at 37 ± 2 • C. Mean biogas volume ranged from 37 ± 8 to 101 ± 18 mL gVS −1 in the urine buffered reactors which was 1-5 times higher than the bicarbonate and water buffered reactors and the difference was significant at p = 0. 05. Total volatile fatty acids (VFA) concentration ranged between 396 and 1,400 mg L −1 with a pH of 6.9 ± 0.3 and 7.8 ± 0.1, respectively. In contrast, VFA concentration ranged between 386 and 3,109 mg L −1 (pH 7.6 ± 0.2 and 4.8 ± 0.4) in sodium bicarbonate buffered digestate and control (water) respectively. The result indicates buffering capacity of urine on anaerobic co-digestion with positive effect on biogas production. The Archaeal isoprenoids included markers of aceticlastic and hydrogenotrophic methanogens with a relative abundance that ranged between 0.71-18, 3-55, and 2-59 µg g −1 dry matter in the water (control), bicarbonate and urine buffered digestate, respectively. The Archaeal abundance was 1.12 and 6 times higher in the combined female/male urine than the bicarbonate buffered digestate and the control, and the difference was significant at p = 0.05. Overall, this study demonstrates that human urine with no pharmaceutical loadings as a wetting and buffering agent is a promising option for anaerobic co-digestion with competitive edge over sodium bicarbonate on lignocellulosic biomass saccharification for enhanced biogas production. HIGHLIGHTS-Source separated human urine served as buffer in anaerobic co-digestion process.-Combined female/male urine exerted an additive effect on biogas production. -Competitive edge offered by the combined female/male urine over sodium bicarbonate buffer in relation to biogas produced. -Evidence of synergy for enhanced biogas production from high C/N ratio lignocellulosic biomass combined with low C/N ratio poultry feces.

Anaerobic co-digestion of spent coconut copra with cow urine for enhanced biogas production

“…The experimental design of Alrawi et al (2011) was adopted with some modifications in incubation temperature, retention time and reactor design. Four sets of laboratory-scale reactors described elsewhere (Eduok et al, 2018) with a capacity of 100 ml and a working volume of 80 ml were fed with varying proportions of the waste mixtures in duplicate and labelled A to D as follows: A = 75 g SCC + 5 ml CU; B = 70 g SCC + 10 ml CU; C = 65 g SCC + 15 ml CU; and D (control) = 80 g SCC. To each digester, 5 g of ADS (inoculum) was added and operated at 45 ± 2°C in a thermostatic water bath maintained over a hydraulic retention time (HRT) of 42 days until no significant biogas production was achieved.…”

Improved biofertilizer properties of digestate from codigestion of brewer’s spent grain and palm oil mill effluent by manure supplementation

“…The AD was performed in a lab-scale batch system using amber borosilicate glass serum bottles (100 mL capacity) (Wheaton 223,766, USA) and 20 mm aluminium crimp seal with PTFE/Butyl septa for headspace vial (Wheaton W224224, USA) as reactors [12]. The experimental design of Cater et al [20] was adopted for the anaerobic codigestion and manure supplementation assay.…”

“…Since the AD process is very complex involving different groups of microorganisms with various environmental requirements, any adjustment in one or more of these operating conditions will influence the growth and performance of the microorganisms and hence the yield and quality of the biogas and digestate [9]. Certain waste/residues with complementary properties can be codigested anaerobically to achieve elevated biogas yields [10][11][12]. The biogas generated from AD processes has been utilized as a source of renewable energy in many developed countries with potentials for heating, electricity and vehicle fuel.…”

Enhanced Biogas Production from Anaerobic Codigestion of Lignocellulosic Waste for Efficient Bioenergy Utilization in Heating and Combustion Engine

“…The lignocellulosic biomass was subjected to wet anaerobic digestion with free moisture from wash water as a wetting agent in 100 ml amber serum bottles bioreactors (amber borosilicate glass serum bottles, Wheaton 223766, USA) with 20 mm aluminum cap with PTFE/Butyl septa vial headspace (Wheaton W224224, USA)for biogas accumulation. The biogas assay was set up in a batch condition whereby the mixture of feedstock and inoculum were charged once into the bioreactors [14]. The experimental design and initial reactor composition are presented in Fig.…”

“…The set-ups were incubated at 45ºC ± 2ºC in a thermostatically regulated water bath with 5 minutes of daily manual agitation for 25 days until no biogas was detected from the reactors. At 3 days interval, the evolved gas was determined by volumetric method by connecting each reactor to a cylinder device at reverse position and liquid displacement was measured and biogas volume was calculated using the expression [14]:…”