Effects of Biochar and Clinoptilolite on Composition and Gaseous Emissions during the Storage of Separated Liquid Fraction of Pig Slurry

Abstract

The storage of animal manure is a major source of gaseous emissions. The aim of this study was to evaluate the effects of biochar and clinoptilolite on the composition and gaseous emissions during the storage of separated liquid fraction of pig slurry. The experiment was carried out using containers with 6 L of pig slurry each. The additives biochar and clinoptilolite were added alone and mixed to the pig slurry at a rate of 2.5% each, in a total of four treatments with three replicates including the control. Gaseous emissions were monitored by a photoacoustic multigas monitor, and slurry samples were collected at 0 and 85 days and their composition assessed. Results showed that the addition of biochar could modify the physicochemical properties of the slurry. The addition of biochar did not reduce the E. coli during the experiment while clinoptilolite decreased its prevalence. The addition of biochar or clinoptilolite reduced significantly the NH3 emission during the storage of slurry, but no advantages were gained with their combination. The addition of biochar significantly reduced the CO2 and CH4 emissions relative to clinoptilolite, however N2O emissions and global warming potential did not differ among the additives. We conclude that the biochar and clinoptilolite are recommended as a mitigation measure to reduce gaseous emissions and preserve the fertiliser value at slurry storage.

Effects of the Addition of Different Additives before Mechanical Separation of Pig Slurry on Composition and Gaseous Emissions

“…where AD is the mean value of individual or cumulative gas values from slurries and their fractions with additives, and UN is the mean value of individual or cumulative gas values from untreated slurries. The cumulative emissions of NH 3 , N 2 O, CO 2 and CH 4 were determined by averaging the flux between two sampling occasions and multiplying by the time interval between the measurements [21,22]. Then, cumulative emissions were expressed as % of total N or C applied in each slurry and fraction.…”

“…The sedimentary origin of the clinoptilolite was Turkey (Zeolita Natural NUTRI-Clinoptilolita 1g568, ZeoCat Soluciones Ecológicas S.L.U., Barcelona, Spain), with the following characteristics: particle size < 0.425 mm; mineralogical composition of 915 g kg −1 for clinoptilolite, 35 g kg −1 for montmorillonite, 35 g kg −1 for feldspars, 15 g kg −1 for muscovite and 10 g kg −1 for cristobalite (by XRD analysis); chemical composition of 685 g kg −1 for SiO 2 , 110 g kg −1 for Al 2 O 3 , 29 g kg −1 for K 2 O, 31 g kg −1 for CaO, 11 g kg −1 for MgO, 4.5 g kg −1 for Na 2 O and 0.5 g kg −1 for TiO 2 ; cation exchange capacity (CEC) of 1.7 meq g −1 (by CEC method); apparent porosity of 47.5%; specific surface area of 75 m 2 g −1 (by Brunauer, Emmett and Teller method); pH (H 2 O) of 7.8; bulk density of powder of 750 kg m −3 ; moisture content of 65.7 g kg −1 . The rate of each additive was chosen considering previous studies [20,21], which recommended a maximum dosage of 5% (w/w) due to economic and practical issues.…”

“…The experiment was carried out using a system of twelve Kilner jars (H = 230 mm, Ø = 105 mm, volume = 2.0 L) filled with 1.0 kg (H = 105 mm) of each treatment (with three replications per treatment) along 30 d and at constant airflow rate and temperature (20 • C), such as those used by Pereira et al [21,22]. Briefly, one air inlet and one air outlet were inserted in the jar lid with a Teflon tube (Ø = 3 mm) through one of the septa, with the end kept above the slurry surface (H = 20 mm).…”

Bioengineered biochar as smart candidate for resource recovery toward circular bio-economy: a review

“…A meta-study demonstrated that the application of biochar causes a reduction in CH 4 , N 2 O and NH 3 emissions [ 77 ]. Recently, a study was focused on the analysis of commercial biochar stability in combination with clinoptilolite for the reduction in gas emissions [ 78 ].…”

Effects of Biochar in Soil and Water Remediation: A Review

“…The application of proper amendments such as biochar is a known efficacious and environmentally friendly method for reducing the availability and mobility of potentially toxic elements in contaminated soil via in situ immobilization [3,9]. Biochar is a sensible and robust material for the enhancement of soil fertility and management of contaminated soils for sustainable agriculture and mitigation of climate change [1,10]. Is a carbon-rich material that can be prepared from various organic waste feedstocks [1], like from various biomass, both woody (primarily residues from forestry and trees) and non-woody (agricultural crops and residues, animal waste, urban and industrial solid waste).…”