Windrow Composting Research Articles

Open windrow composting of lignocellulosic crop residues and neem litter: Accounting for reactive nitrogen and greenhouse gas emissions

Crop residue management plays a key role in reducing the environmental impact of agriculture, particularly through composting. Compost application to soil replenishes organic matter. A study was conducted to quantify the greenhouse gas emissions (GHG) (carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)) and reactive nitrogen (Nr) losses (ammonia (NH3) and oxides of nitrogen (NOx)) from the open windrow composting of crop residues from three cereal crops (rice, maize and pearl millet) and neem litter. The windrow moisture was maintained between 50 and 60% with mechanical turning every 25 days. Compost maturity was reached after 137 days, indicated by a germination index (GI) > 80% and the ratio of initial to final C/N ratio, which was <0.4. CO2 and N2O emissions increased after turning, while CH4 emissions declined. The global warming potentials of the composts were 169.71, 184.13, 200.15, and 217.3 g CO2 eq. kg⁻1 initial dry matter (DM) for rice straw, maize stover, pearl millet stover, and neem litter, respectively. NH3 emissions ranged from 1.13 to 2.13 mg kg⁻1 initial DM, with neem litter producing more NH3 and less N2O due to its lower C/N ratio and nitrification inhibitory properties. Rice straw emitted the highest NOx (75.48 mg kg⁻1 DM), while maize stover had the lowest (28.39 mg kg⁻1 DM). Nitrogen losses from compost ranged from 8.16% in paddy straw to 0.53% in neem compost, with carbon losses ranging from 82.35% to 85.57%. The study concluded that careful management of moisture and aeration is critical for minimizing gaseous emissions from open windrow composting.

Management of industrial wine residues: physicochemical, bacterial and fungal dynamics during composting processes

To foster a circular bioeconomy throughout the management of industrial solid wine residues in the wine industry, this work presents the physicochemical and microbiological dynamics of the composting process with white grape pomace, stalks and wastewater treatment plant sludge from the same winery. Three composting windrows of 41 m3 were constructed with 0, 10 and 20% sludge addition. Physicochemical parameters were assessed following the Test Method for the Examination of Composting and Compost (TMECC), and the diversity and dynamics of the bacterial and fungal communities involved in the composting process were assessed via a high-throughput sequencing metabarcoding approach. The addition of sludge increased the moisture content, bulk density, and pH after six months of turned windrow composting. No effect of sludge addition on the macronutrient composition of the compost was observed. The Shannon‒Wiener index differed among stages and treatments. Bacterial diversity increased over time, while the fungal community appeared to be highly affected by the thermophilic stage, which led to a reduction in diversity that slightly recovered by the end of the process. Furthermore, the sludge exhibited high bacterial diversity but very low fungal diversity. Consequently, the design of on-site biologically based strategies to better manage wine residues can produce soil amendments, improve fertilization, reclaim damaged soils, and ultimately reduce management costs, making composting an economically attractive and sustainable alternative for waste management in the wine industry.Graphical

Biodegradable Waste Management in Georgia: Problems of the Composting System Introduction

Biodegradable waste management and, in particular, the introduction and implementation of composting systems are among the major problems for Georgia. An increase in the volume of municipal waste has been recorded in the country; therefore, the volume of generated biodegradable waste is also increasing. In accordance with the National Waste Management Strategy 2016-2030 of Georgia, the municipal waste generated in 2021 amounted to 1,104,952 tons. It is worth noting that the largest part of municipal waste is organic waste - 54.7%, while plastic waste is 13.8%, paper and cardboard - 10.6%, textiles - 4.1%, and other wastes. According to various studies, by 2030, waste generation is expected to increase from 0.6% to 1.2% annually, which should be the cause of significant challenges for national and local authorities, especially local municipalities, whose duties include municipal waste collection and transportation as well as the implementation of separate waste collection systems. Biodegradable waste management, including various composting systems, is of particular importance.The study shows that composting, as one of the best approaches for recycling biodegradable waste, is still not properly developed in Georgia. It is possible to name only a few successful experiences. Noteworthy among them is the Kutaisi Composting Center, which was established within the framework of the EU JOP “Black Sea Basin” in Kutaisi, Georgia. The Composting Center is designed for windrow composting of green waste (tree branches, leaves, grass). Its productivity is 2000 tons of compost annually. This Composting Center is one of the first in Georgia. It can bring very tangible benefits. In particular, the amount of municipal waste going to landfill sites was reduced by approximately 10%; the expenditures of the municipalities connected to the maintenance of green facilities (received compost is used) and so on have been reduced.Among the biodegradable waste composting approaches, it is recommended to use systems such as:Centralized composting,Community composting,Home (individual) composting.A centralized composting method can be used in municipalities where a large amount of biodegradable waste is generated. It is especially favorable in regions where the agricultural sector is developed and large amounts of green waste are generated. The Kutaisi Composting Center is a good example of the centralized composting system. As experience shows, such large-scale composting is particularly effective for green waste composting.It is promising for Georgia to introduce community composting approaches that offer an optimal scheme for communities to get the maximum benefits of their potential.Composting is an approach used in the field of biodegradable waste management that has the greatest potential in Georgia and can make a significant contribution to both economic development and the protection of the social and natural environment.

Techno-economic evaluation of biofertilizer production using wastewater biosolids: case study from municipal wastewater treatment plants in northwest region of Russia

The continuous and rapid growth of sewage sludge (biosolids) from wastewater treatment plants (WWTPs) poses both economic and environmental challenges. In many cities of Russia, the situation has exacerbated with time. In this study, three state-of-the-art biosolid management technologies, namely windrow composting (WC), tunnel composting (TC), and lime stabilization (LS), were evaluated for their economic feasibility to produce commercially biofertilizers from WWTP-derived biosolids. Based on an annual discharge of 22,000 m3 of dewatered biosolids from the case WWTP, about 29,785, 22,453, and 35,056 m3 biofertilizers could be produced through WC, TC, and LS, respectively. Analysis showed the selected WC, TC, and LS technological options to be feasible if the selling price of the produced biofertilizer would be maintained at 19 EUR/m3 for WC and LS, and 77 EUR/m3 for TC. The discounted payback period (DPP) of WC, LS, and TC would be 3.1, 18.1, and 25.3 years, respectively, with an IRR (internal rate of return) of 10%. The key characteristics of the treated WWTP-derived biosolids were found to be good enough to meet the existing environmental laws, standards, and regulations in Russia. From an investment perspective, this study is useful in developing WWTP-derived biosolids for biofertilizer production at enterprise level.

Influence of Spent Lubricating Oil Spiked Compost on Microbial Counts and Hydrocarbon Degradation Rate in Soils

This study evaluated the influence of organic fertilizers produced from spent lubricating oil (SLO) spiked aerobic composting technique on hydrocarbon degradation rate in soils. The compost windrows (Ft2 and Ft4), consisting of kitchen and agricultural wastes, were spiked with varying concentrations (2% and 4%) of SLO. The resultant organic fertilizers were employed as amendment in pollution simulated potted soils laid out in a complete randomized block design with three replications for 90 days. Results revealed higher counts of hydrocarbon utilizing microbes (HUB: 4.2±0.02×104cfu/g in Ft2, 3.0±0.02×104cfu/g in Ft4; HUF: 3.9±0.2×104cfu/g in Ft2, 2.5±0.02×104cfu/g in Ft4) in spiked compost compared to the control, Ft0 (HUB: 7.9±0.02×103cfu/g; HUF: 6.0±0.2×103cfu/g). Mean count in amended soils reflected a dose-dependent increase which followed the trend: Ft2 ˃ Ft0 ˃ Ft4 for the 5% (3.7×108 cfu/g), 10% (9.2×107 cfu/g) and 15% (6.9×107 cfu/g) levels of fertilizer treatments respectively. There was a significant (P&lt;0.05) reduction in the TPH content of soils after 90days treatment with organic fertilizers. Generally, remediation efficiency followed the order: Ft2 ˃ Ft0 ˃ Ft4, with the highest (11.51%) achieved at 5% Ft2 application. Spiking technique was responsible for the higher counts of hydrocarbon utilizing microbes and enhanced bioremediation associated with the use of fertilizers Ft2.

Variability of Physiochemical properties of Pig Manure with Added Wood Shavings during Open-Air Dumping and Windrow Composting

Background: Effective composting management practice through monitoring of composting governing parameters is very crucial in ensuring the safety and effectiveness of the composting process and hence the quality of the compost.&#x0D; Aims: To assess the variability of the different physiochemical properties (pH, pile temperature, mass, VS, TS and TOC) during open-air dumping and windrow composting of raw pig manure and shavings amended pig manure with wood.&#x0D; Study Design: Field and laboratory experiment.&#x0D; Place and Duration of Study: Waste-to-resource project site and project laboratory of the Department of Environmental Science of the University of Buea, Cameroon between February and March 2022. &#x0D; Methodology: Two sets of pig manure and wood shavings were mixed in mass ratios of 100%:0% and 90%:10% and placed in four different chambers. One set was dumped in an open-air situation while the other set was left to compost for 40 days. Piles were monitored after every next day for pH, temperature, mass loss, EC, MC, TOC, TS and VS analyses.&#x0D; Results: The highest composting temperature (63.4℃) was experienced in the 90:10 % while the lowest (39.4℃) was experience in the 100%. All 100% treatments had an acidic starting pH (5.04 and 5.58) while 90:10% treatments had a more basic pH (6.76 and 6.82), there was a significant difference in EC between the open-air dumped and windrow compost piles (P = 0.000). Mass significantly reduced by 64% and 75% (100% and90:10% compost respectively), 51% and 56.5% (100% and 90:10%dumping respectively). Significant difference existed in MC (P = 0.010). Both VS and TC decrease across all treatments, the highest VS and TOC were observed in all 100:0% treatments.&#x0D; Conclusion: Open-air dumping and composting of pig manure with woods shavings should be promoted since it enhances physiochemical properties, but more emphasis should be on composting than on open-air dumping.

A Comparative Life Cycle Assessment of Dry and Wet Anaerobic Digestion Technologies for Food Waste Management

Anaerobic digestion (AD) is especially useful in the treatment of organic waste sources, such as food waste (FW) since AD can support the generation of clean energy while preventing the hazards of uncontrolled GHG pollution originating from landfills. However, the potential environmental impacts of dry AD and integrated wet AD treatment are largely unknown, particularly in Malaysia. Thus, this study aimed to compare the potential environmental impacts of four FW treatment technologies in Malaysia: landfill (Sc0), dry anaerobic digestion (Sc1), wet anaerobic digestion combined with windrow composting (Sc2), and wet anaerobic digestion combined with windrow composting and landfill (Sc3). The scenario modelling was performed via GaBi v6.0 software using 1 ton of pre-treated FW as a functional unit, with the analysis of environmental impact scores being based on the ReCiPe (H) v1.07 characterization method. At the midpoint assessment, the Sc1 produced extensive improvements in 12 mid-point impact categories, being the most environmentally favoured FW treatment method compared to the other options in critical categories such as global warming, depletion of fossils and agricultural land occupation. The Sc1 mesophilic conducting reactor in this study used less energy for heating, without generating waste water while requiring a small operating area. Sc3 had the lowest environmental performance since the emissions into the air from windrow composting and landfill were discharged completely without any form of treatment like capturing or flaring. Finally, through the single score analysis, Sc1 was regarded as an appropriate FW treatment technology with the least damaging impact on resource depletion, human health, and ecosystems in comparison to all scenarios. This was accomplished through relatively low power demands for the operation, shorter road transport distances, and a substantial reduction in the amount of waste and electricity generation. These analyses provide a useful framework for understanding the important characteristics of anaerobic treatment despite the divergent challenges faced by the different processes.

Microplastics Release from Conventional Plastics during Real Open Windrow Composting

The recycling of bio-waste plays an important role in a circular economy as it transforms bio-waste into a valuable resource (organic fertilizer). However, even separately collected bio-waste can contain some plastic waste, which is usually separated after composting and not before it. Primary studies have confirmed the degradation of plastic during composting, but the release of microplastics from them has not been studied. This article presents a quantification and comparison of the release of microplastics from commonly used plastics during green waste composting. Microplastics were identified by Nile red staining and examination under a fluorescent microscope. Plastic degradation was assessed by weight loss calculation, scanning electron microscope (SEM), and Fourier-transform infrared spectroscopy (FTIR) analysis. On average, 17 to 52 microplastics’ are released from 5-by-5 cm pieces of conventional plastics during composting. The control polylactic acid sample showed the smallest amount of released microplastics: four particles on average. The number of released microplastics depended on the polymer type and thickness of the samples. The results of the current article can be further used for the prediction of microplastic generation and setting a limit on the plastic content in bio-waste

Environmental impact evaluation of landfill mining of legacy waste with on-site sorting using life cycle assessment.

The present research is aimed at assessing the environmental impacts of landfill mining of soil-like material with on-site sorting for land application using life cycle assessment. The scenario is compared with no-landfill mining (base scenario) and future scenario (including material recycling and incineration). Soil-like material is processed using windrow composting. The impact assessment was performed using the EASETECH™ software tool. ReCipE 2016 midpoint world impact method with eight impact categories was used for assessing the environmental profiles. The functional unit of the assessment was 1 t of recovered waste in India. Overall, the results showed that excavation of landfilled waste with on-site recovery of soil and land application of soil resulted in higher environmental benefits compared to no mining condition in global warming potential (GWP), freshwater eutrophication (FEW), human toxicity (HT), and fossil depletion (FD), while higher impacts were observed in terrestrial acidification (TA), terrestrial ecotoxicity (TE), marine eutrophication (ME), and photochemical oxidation (PCO). After composting, land application of recovered soil contributed to environmental offsets in GWP, HT, and FEW while contributing to TE emissions. Emissions associated with excavation and on-site sorting contributed 55.1% to freshwater toxicity, 25.5% to human toxicity, 16.2% to climate change, and 10.8% to terrestrial acidification. The choice of energy, transportation, and fuel for waste activities affected the performance of alternative scenarios in GWP. Application of recovered metals in the manufacturing process, incineration of plastic, and textile components improved the environmental performance. The outcomes of this research will equip regulatory bodies in the development of guidelines and frameworks on material and energy recovery from the waste components mined from legacy waste.

Effects of different composting methods on Enteromorpha: Maturity, nutrients, and organic carbon transformation

This study investigated the composting performance of Enteromorpha for product maturity and organic carbon transformation under membrane-covered aerobic composting and windrow composting. Meanwhile, the effects of adding mushroom waste as an additive on the Enteromorpha composting process performance were evaluated. Results show that Enteromorpha was highly compostable and had low phytotoxicity under different composting techniques after 60 days. Each method's high temperature (>50 °C) can maintain for more than 5 days during the composting process of Enteromorpha, which meets the Chinese national standard for organic fertilizer production. Moreover, the highest GI (113%) was obtained by the forced ventilation treatment with mushroom waste, which was mainly achieved by adjusting the raw materials of compost. The addition of mushroom waste could improve the polymerization of humic substances and maintain nutrients, while the Enteromorpha alone composting had a serious nutrient loss phenomenon no matter what method was adopted. Regardless of composting conditions, the rapid decline of cellulose, fat, and starch content occurred during the high-temperature period. In addition, the maturity of Enteromorpha compost was mainly related to the degradation of organic matter. Forced ventilation can reduce the phytotoxicity of Enteromorpha composting better than windrow composting. The results can provide theoretical basis and measures for the practical application of Enteromorpha treatment and the directional control of compost maturity.

Examination of compost maturity using reflectance

Composting is one of the most popular recycling processes for organic waste. Composting plays an important role in waste and by-product management and is becoming increasingly important in both sustainable energy management and circular economy. Composting transforms organic matter to produce a safe and stable by-product (compost) that can be applied to arable land in a similar way to fertilizer. Physical, chemical and biological methods can be used to monitor the process and to determine the maturity of the compost, as spectrometric/spectroscopic methods play an important role in the analysis of different environmental samples. Our aim was to (1) non-destructively detect the effects of different additive ratios on the spectral properties of the composting process and the spectral data of different compost mixtures, (2) to find the wavelength ranges of the reflectance curve (inflection points) sensitive to compost maturity, (3) to determine the correlation between the inflection points and the chemical and physical parameters measured in compost by conventional methods. The mixture of broiler and hen manure and zeolite was composted 62 days in windrow composting. In the composting experiment, the moisture content and temperature (°C) were measured every three days and compost samples were taken and in 10% destillated aquaeous suspension were measured the pH and electrical conductivity (mS cm-1). Compost samples dried to mass stability were spectrally analyzed in the wavelength range 400–1000 nm with AvaSpec 2048 spectrometer. Based on the results, the reflectance of mature compost were smaller in the last days of composting than the reflectance values of day 0 samples, thus compost maturity can be detected spectral in the VIS-NIR wavelength range. For the tested compost prisms, the reflectance of each sampling day shows a constant slope, with a significant overlap of the reflectance curves up to 400–700 nm wavelength range, and there was a breakpoint in the 700–750 nm wavelength range which was proved by binary encoding.

Insight to maturity during biogas residue from food waste composting in terms of multivariable interaction.

This study used biogas residue produced by anaerobic fermentation of food waste as the raw material in large-scale windrow composting. The effects of the addition of a microbial consortium on the physical and chemical properties and stability of composting of biogas residue were studied. The maturity of food waste biogas residue during composting was investigated by multivariate interaction of environmental, maturity, and nutrient parameters, using structural equation modeling (SEM). Results showed that the temperature of T2 compost with the microbial consortium increased more rapidly. The pH ranges of T1 (without the microbial consortium) and T2 were 8.75-9.15 and 8.42-9.27, respectively; the electrical conductivity (EC) ranges of T1 and T2 were 2.74-3.95 mS/cm and 2.81-3.85 mS/cm, respectively; the degradation rates of organic matter (OM) in T1 and T2 were 21.74% and 33.62%, respectively; and the total nitrogen (TN) ranges of T1 and T2 were 1.93-3.10% and 1.80-3.21%, respectively. By the end of composting, the germination indices (GI) of T1 and T2 were 20.57% and 64.24%, respectively. The total oxygen consumption after 4days (AT4) was 1.88mg-O2/g and 1.2mg-O2/g in T1 and T2, respectively. SEM of T1 showed that compost temperature and EC were important factors affecting compost maturity. These factors highly significantly affected OM, which in turn affected AT4 of the biogas residue composting. SEM of T2 showed that compost temperature, pH, and EC affected OM, which in turn affected compost maturity. Temperature affected compost maturity by affecting AT4 and GI. Principal component analysis (PCA) showed that the overall score of T2 was higher than that of T1, indicating that the addition of the microbial consortium was beneficial for industrial-scale composting of biogas residue produced by anaerobic digestion of food waste.

Use of Various Organics Substrates and Evolution of Chemical Parameters during Composting of Panicum maximum Jacq and Oriza sativa L. Straw

Aims: The present study was initiated with the objective of evaluating the quality of composts obtained from different organic substrates.&#x0D; Place and Duration of Study: The test was conducted at the research station of the INERA (Institute of Environment and Agricultural Research) of Farako-Bâ in western Burkina Faso.&#x0D; Methodology: Aerobic composting was conducted through use of compost heaps composed of various organic and plant substrates, and physical and chemical parameters were measured during the process. Two types of biomass comprising Oriza sativa and Panicum maximum straw and two types of substrates including cattle manure and poultry manure were subjected to windrow composting. Two treatments were defined with the combination of rice straw + cattle manure (T1) and the combination of Panicum maximum straw + poultry manure (T2).&#x0D; Results: The study showed that the composts from both treatments gave basic pH for water and low C:N ratios (&gt; 20) and were rich in mineral elements. The best quality compost is obtained in T2 with values of total P (0.52%), Ca (2.05%) and Mg (0.62%) higher than those of T1 by 44%, 39% and 39% respectively.&#x0D; Conclusion: This study highlights the possibility of composting these substrates, which may contribute to improving the organic matter requirements of the soil.

Advanced composting technologies promotes environmental benefits and eco-efficiency: A life cycle assessment

Growing demand for intensive animal farms and increased public awareness of environmental friendliness, have led to continuous iteration and refinement of the initially crude composting technology. However, the impact of the composting facility and energy input on eco-efficiency is limited. In this study, a LCA approach was conducted to investigate the eco-efficiency of four widely applied composting strategies: static heaps (SH), windrow composting (WC), membrane-covered composting (MC) and reactor composting (RC). The results showed that the environmental benefits of RC's were decreased by 11.3%, 21.7%, and 6.5% compared to SH, WC, and MC, respectively. Advanced composting technologies didn’t substantially reduce direct economic costs, however, the eco-efficiency of RC was increased by 296.9%, 54.7%, and 87.6% compared to SH, WC, and MC, respectively. Overall, the results demonstrate that RC is a promising solution with high ecological efficiency that can contribute to the sustainable development of intensified livestock production.

LIFE CYCLE ASSESSMENT ANALYZING WITH GABI SOFTWARE FOR FOOD WASTE MANAGEMENT USING WINDROW AND HYBRID COMPOSTING TECHNOLOGIES

The use of composting technologies to treat food waste (FW) now represents an environmentally friendly form of waste treatment, in which organic matter can decompose biologically. However, the damaging emissions of composting technologies for FW treatment vary, thus a life cycle assessment (LCA) approach is often used to certify the quality of the decision-making process. This study quantifies and compares the environmental impact of two scenarios in Malaysia: windrow and hybrid composting (windrow integrated with a landfill) technologies. The scenario modeling was performed via GaBi v6.0 software using 1 ton of pre-treated FW as a functional unit, with the analysis based on the ReCiPe (H) v1.07 characterization method. The midpoint results revealed that windrow composting technology has a lower environmental impact and is an environmentally friendly option compared to hybrid technology. Treating FW in a windrow scenario has relatively low power requirements for operation with the added advantageous properties of compost production, and a substantial reduction in the distances transferred by the road. The hybrid scenario had the largest negative environmental impact in all categories, such as climate change (1.45E+03 kg CO2 eq), and ozone depletion (4.39E-09kg CFC-11 eq) because of the energy-intensive waste collection and treatment activities it needs, and with no landfill gas filtration. Finally, based on the single score synthesis, windrow is considered as an appropriate treatment with the avoidance of Resource Depletion (6.61E+02 Pt).

​Duration of Composting and Changes in Temperature, pH and C/N Ratio during Composting: A Review

Composting is the most viable treatment for biodegradable solid waste. Numerous techniques have been developed by different agencies to carry out composting. The most common method is aerobic bin method carried out on small scale. Compost piles and windrow methods needs larger land area and are mainly carried out by industries. The total time for completion of composting depend upon the type of substrate and the methods employed. Moisture content, temperature, pH and C:N ratio are among the most important factors for carrying out composting. The present review emphasised on the estimation of time taken by different types of substrates under different methods of composting and the changes in temperature, pH and C:N ratio occurring therein.

Decreased Methane Emissions Associated with Methanogenic and Methanotrophic Communities in a Pig Manure Windrow Composting System under Calcium Superphosphate Amendment.

With the rapid growth of livestock breeding, manure composting has evolved to be an important source of atmospheric methane (CH4) which accelerates global warming. Calcium superphosphate (CaSSP), as a commonly used fertilizer, was proposed to be effective in reducing CH4 emissions from manure composting, but the intrinsic biological mechanism remains unknown. Methanogens and methanotrophs both play a key role in mediating CH4 fluxes, therefore we hypothesized that the CaSSP-mediated reduction in CH4 emissions was attributed to the shift of methanogens and methanotrophs, which was regulated by physicochemical parameter changes. To test this hypothesis, a 60-day pig manure windrow composting experiment was conducted to investigate the response of CH4 emissions to CaSSP amendment, with a close linkage to methanogenic and methanotrophic communities. Results showed that CaSSP amendment significantly reduced CH4 emissions by 49.5% compared with the control over the whole composting period. The decreased mcrA gene (encodes the α-subunit of methyl-coenzyme M reductase) abundance in response to CaSSP amendment suggested that the CH4 emissions were reduced primarily due to the suppressed microbial CH4 production. Illumina MiSeq sequencing analysis showed that the overall distribution pattern of methanogenic and methanotrophic communities were significantly affected by CaSSP amendment. Particularly, the relative abundance of Methanosarcina that is known to be a dominant group for CH4 production, significantly decreased by up to 25.3% accompanied with CaSSP addition. Only Type I methanotrophs was detected in our study and Methylocaldum was the dominant methanotrophs in this composting system; in detail, CaSSP amendment increased the relative abundance of OTUs belong to Methylocaldum and Methylobacter. Moreover, the increased SO42− concentration and decreased pH acted as two key factors influencing the methanogenic and methanotrophic composition, with the former has a negative effect on methanogenesis growth and can later promote CH4 oxidation at a low level. This study deepens our understanding of the interaction between abiotic factors, function microbiota and greenhouse gas (GHG) emissions, as well as provides implication for practically reducing composting GHG emissions.

Quality assessment of compost from Centralized windrow composter (CWC) and Source segregate automatic vessel composter (AVC) at Hyderabad city in India

Out of the millions of tons of Municipal Solid Waste (MSW) generated annually in India, only about 75-80% of the waste gets collected and out of this, only 22- 28% is processed and treated, and the remaining is deposited indiscriminately at dump yards. Hyderabad city generates around 5500MT of waste every day. And only 20% of the waste is used for composting using the windrow composting process. MSW composting is a rapidly growing method of solid waste management in Hyderabad and In-Vessel composting is the recent initiative by the Govt. of India to reduce the organic solid waste generated at the source. The present study was aimed to assess the degree of accumulation and contamination of the heavy metals in composts from Centralised Windrow Composter (CWC) and Source Segregated Accelerated Vessel Composter (AVC). Compost Samples from CWC and AVC were analysed for metals concentration using Energy Dispersive X-ray Fluorescence Spectrometers (ED-XRF). CWC samples were found with slightly high concentrations of heavy metals like Zinc (0.51 – 0.66%), Copper (0.36 – 0.45%), Nickel 0.03 – 0.05%), Iron (11.46 – 13.27%), and chromium (0.06 – 0.14%) compared to AVC. AVC samples contained high concentrations of Calcium (14.99 – 64.19%), Potassium (9.13 – 29.59%) and Phosphorous (1.55 – 3.43%) when compared to CWC. The current study does a comparative analysis on the process and nutrients available to assess the quality of the compost from both sources. Considering the above findings source segregated AVC seems to be a better composter than centralised CWC, as the concentrations of Ca, K, and P required by the plant were abundant in AVC. Also, considering the process aspect, there is always scope for cross-contamination if the waste is separated after treatment which is the case in CWC.

Effects of On-Farm Dairy Manure Composting on Tetracycline Content and Nutrient Composition.

This study quantified the potential of farm-scale composting to degrade antibiotics in dairy manure. The compost windrow, consisting of sick cow bedding from a 1000-cow US dairy farm, was managed using the dairy farm’s typical practices and monitored for tetracycline and nutrient composition. Samples were collected over 33 days, which was the time from compost pile formation to land application as fertilizer, and analyzed for solids, antibiotics, and nutrient content. Average tetracycline concentrations at the beginning of the study (452 ng/g DW) were lower than at the end of composting (689 ng/g DW), illustrating that antibiotic degradation was not greater than degradation of the compost solids. Total Kjeldahl nitrogen (TKN) increased from 15.3 to 18.4 g/kg during the composting period due to decreases in solids and likely inhibition of N-mineralization due to the presence of antibiotics. The results indicated that antibiotics were not completely degraded when using the farm’s compost pile management techniques, with antibiotics possibly impacting nitrogen transformation in the compost, which should be considered in nutrient management when using sick cow bedding. Additionally, the results showed that antibiotic degradation during farm-scale composting can vary from reported laboratory-scale due to differences in management, composting duration, and temporal conditions, illustrating the need for more extensive on-farm research including common farm practices and real-world conditions.

English

Composting livestock manure still remains one of the best waste-to-resource technologies practiced in the world. There is however, limited information on composting of livestock manure and wood shavings in Cameroon.&nbsp; This research, carried out in South West Region of Cameroon assesses the variability of physiochemical properties: pH, pile temperature, mass, volatile solids contents (VS), total solids (TS) and total organic carbon (TOC) of livestock manure with added wood shavings during windrow composting. Different proportions of cow manure (CM), pig manure (PM), fowl manure (FM) and wood shavings (WS) were used in the research over a period of 25 days during the dry season in 2020. The mass and temperature were determined everyday while pH, VS and TOC were measured every three days. Comparing different livestock manure amended with wood shavings to its corresponding raw manure during windrow composting showed that, there was an insignificant difference in the VS and TOC and a significant mass reduction. Similarly, there was a significant difference in temperature between FM+WS and FM and an insignificant difference in temperature in both CM+WS and CM as well as in PM+WS and PM. When comparing only amended livestock manures with wood shavings during windrow composting, it was observed that, in all the amended livestock manure combinations, only temperature and pH had a significant change while mass and VS had an insignificant change. Composting of livestock manure with woods shavings should be promoted since it enhances some physiochemical properties. &nbsp; Key words: Livestock manure, wood shavings, composting, physicochemical properties.