International Journal of Recycling of Organic Waste in Agriculture
Volume:11 Issue: 2, Spring 2022

Purpose This study aims to characterize the compost produced under low input conditions in thirty days of composting from food wastes applying the hot composting Berkeley method (HCBM) by 13C NMR CP/MAS techniques combined with evaluation of chemometric, physical and chemical parameters.Method The composting process from food waste was carried out following the recommendations of the Hot Composting Berkeley method. At 7, 9, 11, 13, 15, 17, 19, 21, 23 and 25 days turning was carried out, totaling eleven turns and the temperature, pH, electrical conductivity, dry density, potential CO2 emission and potential NH3 emission were quantified. The metal content in the compost was determined after 25 days. The structural modifications of compost process were monitored by 13C-NMR CP MAS spectroscopic and chemometrics analysis.Results Composting takes place immediately and continues for 15 days through transformation to more labile lipid, carbohydrate and proteinaceous molecules (CAlkyl-H,R; CAlkyl-O; CAlkyl-O,N) with increasing temperature and pH. After 15 days, there is a CO2 and NH3 emission reduction as well as preservation of recalcitrant molecules with more aromatic and nonpolar characteristics (CAromatic-H,R; CAromatic-O,N).Conclusion The compost obtained at 25 days of composting by applying HCBM has greater hydrophobicity and aromaticity and is rich in mineral elements important for plant nutrition. The application of HCBM to food waste allowed to obtain a stabilized compost in ecological production conditions.

Purpose In India, the global contribution of milk and sugarcane production are 21% and 12 to 15%. Dairy and sugarcane industries produce end products as sludge which is directly dumped in open land which pollute the land and groundwater of the nearby areas. The present study was aimed to utilize the vermicomposting technique to treat the sludge generated from these two industries.Method The dairy sludge, sugarcane press mud were homogenously mixed with cattle manure to form five different proportions of waste mixture M1, M2, M3, M4, and M5. The waste mixtures were kept in reactors for 15 days for pre-composting. Once the pre-composting temperature reached to 25 °C, fifty adults Eisenia fetida earthworms with an average weight of 0.4 to 0.5 gram each was introduced into each reactor.Results The highest production of earthworm cocoons was studied in the combinations of M4 and M5. The higher growth of earthworm was observed in M5 (39%) followed by M3 (34%). The germination index and carbon to nitrogen ratio were found to be 100 to 121% and 9 to 11, respectively, along with the negligible carbon dioxide evolution in every combination that revealed the maturity and stability of vermicomposting.Conclusion The vermicompost obtained from the combination of dairy (milk processing unit) and sugarcane industries press mud sludge was rich in nutrients and suitable to utilize as nutrients (fertilizer) for the crops. Vermicomposting can solve the issue of sludge management from these two industries with the utilization of end products as vermicompost.

Purpose Effluents from machined olive waters are highly polluting. These have high organic load values such as the biological demand of oxygen and the chemical demand of oxygen, salinity, and others, which far exceed current regulations. The objective of this work was to achieve, through bioremediation by native microorganisms, the reduction of effluent contamination.Method Bioremediation was achieved by supplementing the effluent with a source of carbon, nitrogen, and phosphorus in the approximate ratio 100: 5: 1, under aerobic conditions at room temperature (25 ± 1 °C) for a period of 7 to 14 days.Results The consortium of microorganisms (bacteria and yeasts) was identified as: Pseudomonas aeruginosa strain Kasamber 11, Pseudomonas aeruginosa strain 1816, Klebsiella sp. strain DE004, Enterobacter sp. DKU NT 01, Pseudomonas sp. KC31, Bacillus sp. MG06, Candida thaimueangensis NWP2-1, Klebsiella sp. SI-AL-1B, Bacillus pumilus strain LX11, Bacillus sp. B9 (2015b), Bacillus pumilus strain Y7, Planomicrobium sp. strain MSSA-10 16S, Candida thaimueangensis strain S04-2.2 and one microorganism without identification. A reduction of approximately 40-80% of specific parameters and contamination indicators such as biological oxygen demand (BOD5), chemical oxygen demand (COD) and electrical conductivity was achieved.Conclusion The microbial consortium achieved the reduction of the original contamination of the effluent from "mechanized olives" by biostimulation, transforming it into a less contaminated liquid that could be used for other uses or destinations.

Purpose Sawdust, an organic residue abounds in many parts of Nigeria; they often block drainage channels, sometimes burnt to further aggravate the greenhouse gases in the atmosphere. However, it can be harnessed as soil amendment.Method A field experiment was carried out at the Teaching and Research Farm, University of Ilorin, Nigeria during the 2018 and 2019 wet seasons to evaluate the performance of four sesame varieties using sawdust biochar. The experiment was laid out in a split-plot design, replicated four times. The main plots consisted of four varieties of Sesame (E-8, Ex-Sudan, NCRI-Ben001M, and NCRI-Ben002M), the subplots were sawdust biochar (0, 5, 10, 15, and 20 Mgha-1). Data were collected on water holding capacity, plant height, and number of leaves, leaf area index, and yield per hectare. Data were subjected to analysis of variance (ANOVA) and means were separated using new Duncan Multiple Range test at 5% level of probability.Results Results showed significant (Ƿ ˂0.05) effects of variety, and sawdust biochar rates on plant height, number of leaves, leaf area index, crop growth rate and yield per hectare. Variety NCRI-Ben001M gave a yield of 670 kgha-1 at the application rate of 15 tha-1 sawdust biochar (676 kgha-1) compared to the average yield of sesame in Nigeria.Conclusion Farmers are therefore encouraged to cultivate NCRI-Ben001M variety and use saw dust biochar at the rate of 15 Mg ha-1 for optimum yield.

Purpose Soil is an important accelerator for biodegradable processes. Soil resource circulation concept by using the compost from the previous crop as cover materials for the recent composting mass was evaluated as it contained soil and amorphous Fe as an energy source. Therefore, this research was focused on the possibility and the changes in the electron acceptors in the organic waste composting process.Method The 2 experiments using different covering materials: paddy soil as a control (T1) and compost (T2) in a completely randomized design. An amount (670 g) of organic wastes was altered with 210 g of materials covered in 3 layers with 60 mL of water added every 7 days during a period of 30 days. The physico-chemical parameters, redox potential (Eh), and electrical conductivity (EC) were studied beside the basic soil parameters including electron acceptors such as NO-3, MnO2, Fe2O3, and SO4-2.Results The changes in physical and chemical properties during the degradation process were not different. The Eh reacted intensely and continuously in the same direction. The T2 compost product contained the highest SO4-2 level compared to T1 but there were no significant differences in the organic carbon and C/N ratio, though the quality of T1 was better.Conclusion Covering the organic waste with compost improved the nutrient content in the compost products. Therefore, compost can be used as a cover material instead of soil in the composting process. However, to increase the number of electron acceptors, cover materials should be mixture of soil with compost for greater efficiency.

Purpose Olive mill wastewater (OMW) is annually generated in large amounts in Jordan without any treatment creating major environmental and public health issues. The objective of this study is to determine changes in OMW characteristics under three climatic zones in the North of Jordan during two harvest seasons.Method OMW samples were obtained from 10 olive mills, representing three climatic zones (arid, semi-arid, and semi-arid to sub-humid) during November 2017 and November 2018. Physicochemical characterization and multivariate analysis were performed.Results OMW is characterized by acidic conditions (pH< 5.0), high electrical conductivity (EC) (>7 dS/m), and high total phenols (2700 mg/L) and organic loads (chemical oxygen demand [COD] 41340 mg/L). OMW in the sub-humid climate contained higher total phenols, COD, EC, Ca, and K than other climates. Principal component analysis (PCA) showed that total phenols had high loadings in favour with Ca, and TSS in arid, total nitrogen in the semi-arid, and COD in the sub-humid climates.Conclusion OMW properties were markedly affected by the climate. PCA showed that climate mainly affected the organic loading of extracted components. Overall, treatment of OMW is highly recommended before any use.

Purpose Nitrogen-fixing bacteria (NFB) are essential for biologically fixing nitrogen in natural and soybean crop systems. The use of organomineral fertilizers is a promising crop management tool made from the mixing of an organic source and mineral fertilizers. This study evaluated the efficacy of an organomineral fertilizer (sewage sludge-based) as a carrier for the Azospirillum brasilense inoculation and the influence of A. brasilense plus Bradyrhizobium japonicum on the soybean antioxidant metabolism.Method The experiment was performed under greenhouse conditions. The soybean cultivar (AS 3680 IPRO) was evaluated in a 4×2(+1) factorial scheme, corresponding to four doses of A. brasilense [0, 100, 200, 300 mL ha-1 (2x108 viable cells mL-1) per 50 kg-1 of soybean seeds], with or without B. japonicum [100 mL ha-1 (5x109 viable cells mL-1) per 50 kg-1 of soybean seeds], and a control treatment (without inoculants or fertilizers). Soybean antioxidant metabolism (enzymes, oxidative processes, proline amino acid) was evaluated in different plant stages.Results The seed inoculation with A. brasilense via organomineral fertilizer enhanced the soybean plant protection factors. Plant protection to stresses happened mainly by reductions in the superoxide dismutase activity, lipid peroxidation, and hydrogen peroxide concentration. The co-inoculation of A. brasilense with B. japonicum enhanced the proline activity at the V3 and R5 soybean phenological stage compared to A. brasilense inoculated alone.Conclusion The studied organomineral fertilizer is an efficient inoculant carrier for A. brasilense in soybean plants via seed treatment. The protective results observed for A. brasilense were improved when co-inoculated with B. japonicum.

Purpose Olive mill waste sludge (OMWS) is a solid by-product resulting from olive oil extraction, OMWS is usually left decanting in landfills causing environmental pollution and a significant loss of recyclable organic resources. This study aims to evaluate the feasibility of producing an organic amendment through treating OMWS with solar drying (SDy), which is a low-cost method, highly adapted to semi-arid and low-income countries.Method We investigated the effect of 90 days SDy on OMWS physico-chemical properties, then the agronomic efficiency of the resulting product was assessed under greenhouse conditions, using Zea mays as a crop model.Results The SDy treatment significantly reduced OMWS initial moisture and the C/N ratio, while the nutrient content of the final product was improved. Pot trial under greenhouse conditions revealed that the application of SDy-OMWS improved the soil physico-chemical properties. The initial application decreased soil pH from 8.19 to 7.06, and soil phosphorus (P), potassium (K), iron (Fe) and zinc (Zn) increased by 209%, 162.4%, 290% and 270% respectively compared to the unamended control. SDy-OMWS application initially induced a delayed seed germination and plant growth at early stages, which was followed by a significant improvement of plant above and below ground traits, including photosynthetic activity, stomatal conductance, and root parameters (RL, RSA and RV).Conclusion Overall, SDy significantly reduced the C/N ratio, moisture, and improved the nutrient content of OMWS. Despite improving soil fertility, SDy-OMWS application negatively affected the plant development at early stages. However, such effect was completely alleviated at the end of the experiment.

Purpose This paper focuses on monitoring the behavior of five different types of waste and humus during composting to see the impact of the nature of the substrate on the process and the quality of mature compost.Method Green waste, coffee waste, household waste (Fraction of the household waste which having dimensions smaller than 8 mm) and humus were collected separately from different areas of Oran city, western Algeria, composted in windrows of 2 m long, 1 m wide, and 0.5 m high each for 150 days during the winter and spring period (2019-2020). The physicochemical parameters and characteristics were determined on the one hand, and on the other hand, the evolution of the microflora was monitored.Results The results show a correlation between the parameters of each substrate. Furthermore, it was found that green waste, coffee waste, and household waste can give the best quality of compost if the process conditions are respected (maintenance of C/N ratio and moisture level). However, small waste and very small waste can also be used to amend green areas and public gardens. The results also showed that the concentration of pathogenic microorganisms such as Salmonella and Shigella did not exceed the NFU44-051 standard.Conclusion The findings support the industrialization of waste valorization by composting as an effective technique for waste reduction given the current situation and encourage investors and promote the industrialization of waste recovery by composting in Algeria.

Purpose This study aimed to investigate the effects of compost and vermicompost of municipal solid waste application on the growth of Dracaena marginata tricolor. Then, the results of foliar application of compost tea and vermicompost tea on the plants were examined.Method Experimental treatments included compost and vermicompost of municipal solid waste in proportions of 50 and 70% combined with the perlite. Then we sprayed compost tea and vermicompost tea on the plants at a concentration of 10 ml. At the end of the study, the physical and chemical properties of the substrates, the amounts of macronutrients in the substrates and the plants, growth indices, as well as anthocyanin content, were evaluated.Results The results showed that conversion municipal solid waste compost to vermicompost improved the physical and chemical properties of this material and the absorption of nutrients.  Also, the vegetative indices and anthocyanin content of this plant were positively affected. Foliar application of compost tea and vermicompost tea caused higher nutrient absorption and improved plant growth indices, except for dry root weight. In general, combining 50% of the organic components of substrates with perlite achieved better results.Conclusion Based on the findings, compost, and vermicompost of municipal solid waste are cheap and available alternatives to peat moss in the cultivation of Dracaena marginata tricolor. Also by spraying compost tea and vermicompost tea, it significantly improved the amounts of nutrients, vegetative indicators, and its appearance.