Recycling Of Organic Wastes Research Articles

Comparative effectiveness of different composting methods on the stabilization, maturation and sanitization of municipal organic solid wastes and dried faecal sludge mixtures

BackgroundComposting is one of the integrated waste management strategies used for the recycling of organic wastes into a useful product. Composting methods vary in duration of decomposition and potency of stability, maturity and sanitation. This study was aimed to investigate the comparative effectiveness of four different methods of composting viz. windrow composting (WC), Vermicomposting (VC), pit composting (PC) and combined windrow and vermicomposting (WVC) on the stabilization, maturation and sanitization of mixtures of municipal solid organic waste and dried faecal sludge.MethodsThe composting treatments were arranged in a completely randomized block design with three replications. The changes in physico-chemical and biological characteristics of the compost were examined at 20 days interval for 100 days using standard laboratory procedures. The analysis of variance was performed using SAS software and the significant differences were determined using Fisher’s LSD test at P ≤ 0.05 level.ResultsThe evolution of composting temperature, pH, EC, {text{NH}}_{ 4}^{ + }, {text{NO}}_{ 3}^{ - }, {text{NH}}_{ 4}^{ + }:{text{NO}}_{ 3}^{ - } ratio, OC, C:N ratio and total volatile solids varied significantly among the composting methods and with composting time. The evolution of total nitrogen and germination index also varied significantly (P ≤ 0.001) with time, but their variation among the composting methods was not significant (P > 0.05). Except for PC, all other methods of composting satisfied all the indices for stability/maturity of compost at the 60th day of sampling; whereas PC achieved the critical limit values for most of the indices at the 80th day. A highly significant differences (P ≤ 0.001) were noted among the composting methods with regard to their effectiveness in eliminating pathogens (faecal coliforms and helminth eggs). The WVC method was most efficient in eliminating the pathogens complying with WHO’s standard.ConclusionTurned windrow composting and composting involving earthworms hastened the biodegradation process of organic wastes and result in the production of stable compost earlier than the traditional pit method of composting. The WVC method is most efficient in keeping the pathogens below the threshold level. Thus, elimination of pathogens from composts being a critical consideration, this study would recommend this method for composting organic wastes involving human excreta.

Influence of vermicompost application on soil consistency limits and soil compactibility

Soil organic matter (SOM) is a composite indicator of soil quality. Recycling of organic wastes is one of the environmentally compatible and economically viable options to increase and/or maintain SOM content. Our study was conducted to evaluate the effects of vermicompost (0%, 0.5%, 1%, 2%, and 4% w/w) on the consistency limits and the Proctor compaction test parameters of three texturally different soils (sandy loam, loam, and clay) from similar climatic conditions and cropping management practices. Results showed that vermicompost increased the optimum moisture content (OMC) with an associated decrease in maximum dry soil bulk density (MBD). The increase in OMC at 4% vermicompost was 64.2%, 42.4%, and 33.9% for sandy loam, loam, and clay, respectively, when compared to the control. Similarly, the rate of decrease in MBD at 4% vermicompost was 8.9%, 10.9%, and 10.4% for sandy loam, loam, and clay, respectively, than that of the control. Vermicompost increased the moisture contents of both liquid (LL) and plastic (PL) limits at OMC, in which the MBD occurred. While the OMC at control was 53% of LL and 75% of PL, these values were found as 55%, 56%, 56%, and 57% of LL and as 75%, 80%, 80%, and 76% of PL for 0.5%, 1%, 2%, and 4% vermicompost rates, respectively. Our results indicate that vermicompost could be applied to minimize physical degradation and compaction caused by the adverse effects of frequent tillage at higher soil moisture contents. The electrical conductivity of vermicompost used in this study was high and it requires careful and controlled use in terms of soil salinity when applied in high doses.

Organic Waste Recycling: Technology, Management and Sustainability - 4th Edition

Organic Waste Recycling: <i>Technology, Management and Sustainability</i> - 4th Edition

Recycling of Organic Wastes for Sustainable Soil Health and Crop Growth

Enormous amount of organic wastes are generated from plant, animals and industrial activities in day to day life. A considerable part of which remains unutilized and are either burnt or dumped nearby sites that create pollution, harbours pathogen for diseases and causes severe problem of disposal. Instead of disposing, it can be used as source of organic wastes and effectively recycled for the production of compost to meet the nutritional requirement of crops. Considering growing deficiency of plant nutrients in crop field, higher cost of synthetic fertilizers and poor efficiency of chemical fertilizers, the organic wastes recycling for plant nutrient supply is becoming more essential for replenishment of plant nutrients, sustaining soil health, reducing the pollution problem and creating employment opportunities. The study was aimed to explore the possibility of bioconversion of different organic wastes to utilize the embedded nutrients for supplying enriched organic manure for better soil health and crop growth, which will not only improve the yield and quality of the produce but also conserve energy, minimize pollution, save foreign exchange and improve the fertilizer use efficiency subsequently that will helps to revitalize and restore the soil fertility and will revive the microbial activities for sustainable crop production.

유기성 폐기물의 자원화 방법에 대한 경제성 평가

유기성 폐기물의 자원화 방법에 대한 경제성 평가

The plant stimulant humic acid extracted from organic waste recycled by composting combined with liming and fertilization

The disposal of organic waste can be an environmental problem; on the other hand, this waste can be the raw material for the production of biostimulants, among other recycling processes. The objective of this study was to recycle waste bovine manure and poultry litter through composting and isolate its humic acids in order to test their use, in the presence and absence of liming and fertilization, on corn plants as indicators. The experiment was conducted in a randomized block design with four replications. The experimental unit was a vase of 1 dm3 filled with soil that received treatments generated by the combination of the factors under study: humic acids via seed, liming, and fertilization. After thirty days of the experiment, growth characteristics were measured to estimate the initial performance of the indicator corn plants in response to the treatments. The results showed that the combination of chemical fertilization with humic acids extracted from organic compounds increased the plants development. In conclusion, the use of biostimulants based on humic substances is positive and complementary to fertilizers used in agriculture, forming a superior combination. Such use is also recommended because it allows for the recycling of organic waste via composting, as well as the preparation of biostimulants for added technical, and potentially economic, value.

Guiding phosphorus stewardship for multiple ecosystem services

The essential role of phosphorus (P) for agriculture and its impact on water quality has received decades of research attention. However, the benefits of sustainable P use and management for society due to its downstream impacts on multiple ecosystem services are rarely acknowledged. We propose a conceptual framework—the “phosphorus‐ecosystem services cascade” ()—to integrate the key ecosystem processes and functions that moderate the relationship between P released to the environment from human actions and ecosystem services at distinct spatial and temporal scales. Indirect pathways in the cascade via soil and aquatic processes link anthropogenic P to biodiversity and multiple services, including recreation, drinking water provision, and fisheries. As anthropogenic P cascades through catchments, it often shifts from a subsidy to a stressor of ecosystem services. Phosphorus stewardship can have emergent ecosystem service co‐benefits due to synergies with other societal or management goals (e.g., recycling of livestock manures and organic wastes could impact soil carbon storage). Applying the framework, we identify key research priorities to align P stewardship with the management of multiple ecosystem services, such as incorporating additional services into agri‐environmental P indices, assessing how widespread recycling of organic P sources could differentially impact agricultural yields and water quality, and accounting for shifting baselines in P stewardship due to climate change. Ultimately, P impacts depend on site‐specific agricultural and biogeophysical contexts, so greater precision in targeting stewardship strategies to specific locations would help to optimize for ecosystem services and to more effectively internalize the downstream costs of farm nutrient management.

Nitrogen amendment of green waste impacts microbial community, enzyme secretion and potential for lignocellulose decomposition

Microorganisms involved in biomass deconstruction are an important resource for organic waste recycling and enzymes for lignocellulose bioconversion. The goals of this study were to examine the impact of nitrogen amendment on microbial community restructuring, secretion of xylanases and endoglucanases, and potential for biomass deconstruction. Communities were cultivated aerobically at 55 °C on green waste (GW) amended with varying levels of NH4Cl. Bacterial and fungal communities were determined using 16S rRNA and ITS region gene sequencing and PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) was applied to predict relative abundance of genes involved in lignocellulose hydrolysis. Nitrogen amendment significantly increased secretion of xylanases and endoglucanases, and microbial activity; enzyme activities and cumulative respiration were greatest when nitrogen level in GW was between 4.13–4.56 wt% (g/g), but decreased with higher nitrogen levels. The microbial community shifted to one with increasing potential to decompose complex polymers as nitrogen increased with peak potential occurring between 3.79–4.45 wt% (g/g) nitrogen amendment. The results will aid in informing the management of nitrogen level to foster microbial communities capable of secreting enzymes that hydrolyze recalcitrant polymers in lignocellulose and yield rapid decomposition of green waste.

Recycling of organic wastes in Brazil: composting, substrate and fertilizer manufacture

Recycling of organic wastes in Brazil: composting, substrate and fertilizer manufacture

Past, present and future of composting research

Concerns have been raised by some researchers that there is no future in compost research. This paper attempts to take an overview of composting and to set it in a historic context. Composting represents one of the most widely utilised technologies for organic waste recycling in agriculture, which has been used by mankind for many thousands of years: accounts go back to Chinese records from over 5000 years ago. Largely unchanged until early in the 20th century, it is only in the last 50 years or so that effective research has been carried out, on both the composting process and use of the compost product. Much of this research has been driven by the increasing need to find an alternative to landfill for biodegradable wastes, the importance of compost quality and the implementation of compost quality standards. Looking through past research, it is apparent that some researchers have been better at disseminating the results of their work than others. The importance of dissemination is considered, together with the available routes through publications, conferences, networking and outreach. The future of composting is closely linked to the interests of researchers, governments and other funding agencies. Despite the great deal of research over the past 50 years, certain areas are identified where it is considered that work is needed. These include: pathogen identification and control, modelling feedstock and process variations, assessing health impacts of compost and the use of modern tools such as DNA extraction for pathogen enumeration. Composting will continue to be an important process both on its own, particularly in developing countries, and as a complementary process for systems such as anaerobic digestion in industrialised countries. In terms of the compost product, researchers are looking at ways of enhancing its value and performance, for example with the use of biochar. In addition, there are certain components of the compost, such as phosphate, for which supply options are diminishing, and it is important that we recognise the opportunity for compost to supply these needs.

From agricultural use of sewage sludge to nutrient extraction: A soil science outlook

The composition of municipal wastewater and sewage sludge reflects the use and proliferation of elements and contaminants within society. In Sweden, official statistics show that concentrations of toxic metals in municipal sewage sludge have steadily decreased, by up to 90 %, since the 1970s, due to environmental programmes and statutory limits on metals in sludge and soil. Results from long-term field experiments show that reduced metal pollution during repeated sewage sludge application has reversed negative trends in soil biology. Despite this Swedish success story, organic waste recycling from Swedish towns and cities to arable land is still limited to only about 20 % of the total amount produced. Resistance among industries and consumers to products grown on land treated with sewage sludge may not always be scientifically grounded; however, there are rational obstacles to application of sewage sludge to land based on its inherent properties rather than its content of pollutants. We argue that application of urban organic wastes to soil is an efficient form of recycling for small municipalities, but that organic waste treatment from large cities requires other solutions. The large volumes of sewage sludge collected in towns and cities are not equitably distributed back to arable land because of the following: (i) The high water and low nutrient content in sewage sludge make long-distance transportation too expensive; and (ii) the low plant availability of nutrients in sewage sludge results in small yield increases even after many years of repeated sludge addition. Therefore, nutrient extraction from urban wastes instead of direct organic waste recycling is a possible way forward. The trend for increased combustion of urban wastes will make ash a key waste type in future. Combustion not only concentrates the nutrients in the ash but also leads to metal enrichment; hence, direct application of the ash to land is most often not possible. However, inorganic fertiliser (e.g. mono-ammonium phosphate fertiliser, MAP) can be produced from metal-contaminated sewage sludge ash in a process whereby the metals are removed. We argue that the view on organic waste recycling needs to be diversified in order to improve the urban–rural nutrient cycle, since only recycling urban organic wastes directly is not a viable option to close the urban–rural nutrient cycle. Recovery and recycling of nutrients from organic wastes are a possible solution. When organic waste recycling is complemented by nutrient extraction, some nutrient loops within society can be closed, enabling more sustainable agricultural production in future.

Theoretical and experimental investigations of thermal conditions of household biogas plant

Abstract The construction of domestic continuous bioreactor is proposed. The modeling of thermal modes of household biogas plant using graph theory was done. The correction factor taking into account with the influence of variables on its value was determined. The system of balance equations for the desired thermal conditions in the bioreactor was presented. The graphical and analytical capabilities were represented that can be applied in the design of domestic biogas plants of organic waste recycling.

China’s agricultural nitrogen flows in 2011: Environmental assessment and management scenarios

Nitrogen (N) cycling has been increasingly disturbed by agricultural activities throughout the world and in China as well. By applying a previously developed model, i.e. Eubolism (Elementary Unit based nutrient Balance mOdeLing in agro-ecoSysteM), this study quantified China’s agricultural N flows in 2011 and provided a systematic comparison of the environmental performance of the N flows between China and other countries in terms of N balance, productivity, efficiency, recycling, and emissions. The potential of different N management options, including reducing synthetic fertilizer and substituting synthetic fertilizer with organic N resources, to enhance the environmental performance of N flows were also evaluated with the model. China’s agricultural N flows are characterized by high input, high output, high surplus, and high dependency on synthetic fertilizer, yet with an internal imbalance between cropland and grassland. The “four highs” characteristics have supported the high productivity of China’s agriculture while also caused its low efficiency in N utilization and high N emissions to the environment. Reducing the application of synthetic fertilizer by 30% in China would significantly decrease its soil N surplus and total N emissions without threatening its food security. However, reducing the application of synthetic fertilizer alone has limitations on its effectiveness, and increasing the recycling of organic wastes to substitute synthetic fertilizer has the potential to augment its effectiveness, including more decrease in total N emissions and less loss in N productivity. China is now on the right track to implement integrated N management policies, whereas more ambitious targets and better coordinated actions among government ministries are needed.

Recycling of Organic Solid Wastes of Cities to Biofertilizer Using Natural Raw Materials

A pilot composting system was conducted at the factory of recycling of organic solid wastes in Al-Usifia near Baghdad city, to investigate the possibility of the conversion organic fraction of Municipal organic solid waste (OFMSW) to biofertilizer. Results of MSW analysis showed the presence of 64% of biodegradable organic matter and 36% non-biodegradable. The initial composition of OFMSW had a high C/N ratio 37.02, and low availability N content. The additives used in OFMSW composting such as Buffalo, chicken and sewage sludge to the compost pile to treat N deletion and to obtain a desirable C/N ratio in treating piles. Various parameters were determined during the composting process of OFMSW and mixtures, to evaluate their suitability as indicators for the composting process. Results showed that after 6-10 weeks of incubation, the OFMSW turned to black-like substances with earthy smelling compost material. The pH of the mature compost ranged from 7.8 to 7.89; EC in all piles ranged from 3.11 to 5.41 dS/m. The N% increased with time in all piles reaching at the end of maturation to 1.04 to 1.84, the total phosphorous was high in all piles and varied from 1.11 to 1.6% in all piles. However, the results also revealed a higher potassium concentration varied from 1.18 to 3%, compared to initial concentration ranged from 0.6 to 1.6 in all piles. The water holding capacity of compost samples in all piles increased during composting and varied from 69 to 90% compared to initial ratio ranged from 14 to 45%. The windrow system was more effective for heavy metal marinating. The temperature in piles 2, 3 and 4 increased rapidly above 50°C for 4 weeks and reached to the peak recorded value of more than 60°C indicating higher degradation rate, while the temperature in pile 1 and 5 increased slowly relative to the other piles. The biodegradation of organic wastes, as indicated obviously by the reduction of C/N ratio, was rapid and decreased from 27.4 – 37.02 to 9.47 – 15.26 after 6 weeks of composting. Total viable count in all piles showed a marked increase in initial composting process when the temperature increased and a marked decrease at the end of maturation. The total number of bacteria in Piles 2, 3 and 4 was higher than in Piles 1 and 5. Coliform bacteria were found till 6 weeks in piles 2, 3 and 4, while recording up to 10 weeks in piles 1 and 5. Salmonella and Shigella did not appear throughout the study after 6 weeks of incubation, with exception in piles 1 and 5; these organisms were detected till weeks 10 to 14. Total fungi count decreased in piles 2, 3 and 4 when the temperature increased from 52°C to 60°C, while continued to increase till the end of maturation when the temperature fell to 30°C. Total fungi count recorded at the end of maturation was higher than the initial stage. Physiochemical and microbial characteristics of the final compost product could be recommended that the OFMSW is suitable for composting using the turning windrows system.

댐 주변지역 통합슬러지의 자원화 가능성 평가

This study was carried out to recommend the recycling technology from the organic wastes generated in the neighborhood of a dam in Kroea. The order of production of the organic wastes without the suspended materials and energy corps are Chungju-dam(649.9 ton/day), Daechung-dam(525.1ton/day), Hapcheon-dam(485ton/day), Namgang-dam(478ton/day), and Soyang-dam(246.4ton/day). Because livestock excretions and nightsoil were composed of 72 to 93% of the total organic wastes, they should be proferly reflected in the plan of recycling. It was investigated that the biodegradability was 40~80%, biogas production, 0.22~1.70m3/kg VS, methan production, 0.15~1.07m3/kg VS, and methan contents, 63~79%, respectively, in case of the livestock excretions, which constituted over than 50% of organic wastes. Therefore, the appropriate technology for the recycling of organic wastes can be considered anaerobic co-digestion; this technology can create high added value because of using the fuel for new regeneration enery. SCFMR(Semi-Continuously Fed and Mixed Reactor) for an anaerobic digestion reactor was suited for the treatment of organic wastes because the retention time was relatively constant, compared to CSTR(Continuous Stirred Tank Reactor), power consumption was small, and operation and management of reactor was easy and economical.

Low‐grade heat recycling for system synergies between waste heat and food production, a case study at the European Spallation Source

AbstractAt present food production depends almost exclusively on direct use of stored energy sources, may perhaps they be nuclear‐, petroleum‐, or biobased. Arable land, artificial fertilizers, and fresh water resources are the base for our present food systems, but are limited. At the same time, energy resources in the form of waste heat are available in ample quantities. The European Spallation Source (ESS) will require approximately 270 GWh of power per year to operate, power that ultimately is converted to heat. This multidisciplinary case study details an alternative food production cooling chain, using low‐grade surplus heat, and involving fermentation, aquaculture, nutrient recapture, and greenhouse horticulture including both use of low‐grade surplus heat and recycling of society's organic waste that is converted to animal feed and fertilizer. The study indicates that by combining the use of surplus energy with harvest of society's organic side flows, for example, food waste and aquatic‐based cash crops, sustainable food systems are possible at a level of significance also for global food security. The effects of the proposed heat reuse model are discussed in a system perspective and in the context of the UNSCD indicator framework. The potential sustainability benefits of such an effort are shown to be substantial and multifaceted.

A multi-level analysis of China's phosphorus flows to identify options for improved management in agriculture

Phosphorus (P) is a finite natural resource and is essential for food production. The amount of P involved in food production in China relative to the increase of food production has increased dramatically over the past decades, which has led to serious environmental pollution. Because of China's enormous share in global P fertilizer production (30%) and consumption (37.5%), it evidently plays a crucial role in developing a more sustainable use of this essential resource for agriculture. We performed an integrated analysis of the P flows, P stocks, P utilization efficiencies (PUE) and environmental implications at the national level in China for the year 2010, complemented with an analysis at regional, county and farm levels. The static Material Flow Analysis approach based on the law of mass balance was used. We found that P accumulation in the arable land and P losses in the livestock raising industry are the major contributors to environmental pollution. Improving the PUE in arable land and the livestock raising industry, on the basis of the actual demands combined with efforts to promote the use of residual soil P on arable land and the recycling of organic manure and wastes, will significantly reduce the consumption and losses of P from the food chain, and will slow down the depletion of this finite natural resource.

Chemical study of vermicomposted agroindustrial wastes

The disposal of solid waste is a serious environmental problem for humanity. Vermicomposting is used as one of the methods for recycling of organic waste, resulting in a humified material of great agronomic potential which promotes carbon sequestration when applied to the soil. The aim of this study was to evaluate the chemical characteristics of vermicomposts from cattle manure (CM), orange peel (OP) and filter cake (FC). Three compost piles were set up, 2:1 OP + CM, 3:1 FC + CM and CM. The piles were initially composted for 60 days. Thereafter, earthworms were added to the piles to initiate the vermicomposting process. The pH and the organic carbon contents were above the minimum recommended values for organic fertilizers. The N content was below the minimum value but the C/N ratio was in the required range. The C/N values where lower in OP + CM and FC + CM than in CM. Further, the N contents of treatments were different with OP + CM having the highest value. The C/N ratios of the piles were 9.52, 9.62 and 11.03 for OP + CM, FC + CM and CM, respectively, and were lower than the maximum recommended value by the Ministry of Agriculture, Livestock and Food (Ministry of Agriculture 2009). Thus, co-vermicomposting of filter cake and orange peel with cattle manure has the potential for application sustainable agriculture.

Conversion of injected waste plastics in blast furnace

Operation of several blast furnaces proved that waste plastic (WP) injection makes recycling of industrial and municipal organic wastes and coke saving possible. However, the extent and reaction kinetics of plastic conversion are hardly explored yet. Therefore, a comprehensive study on WP characteristics and conversion behaviour under simulated raceway, bird's nest and shaft conditions, as well as on its interaction with coke, has been undertaken. Numerous analytical, laboratory and pilot facilities have been used. It has shown that despite favourable chemistry, it is hardly possible to reach a high conversion degree of plastics under the raceway conditions. Consumption of unburned residues in coke bed and in shaft is possible. The effect of this phenomenon on coke reactivity has to be considered as well.

Effect of agro-industry by-product on soil fertility, tree performances and fruit quality in pear (&lt;em&gt;Pyrus communis &lt;/em&gt;L.)

Organic materials from agro-industry processes can be used in agriculture as a way to recycle materials that still maintain a high fertilizing value. The aim of the experiment was to evaluate the value of soil applied apple juice by-product as fertilizer for pear trees. A 3-year experiment was carried out in a mature pear orchard (cv Abbe Fetel grafted onto quince MC) in the Po valley (Italy), where the following treatments were compared: 1) unfertilized control; 2) mineral N fertilization (60 kg N ha −1 year −1 split in two spring applications); 3) apple juice by-product (1.3 t ha −1 year −1 , equal to 60 kg N ha −1 ), fully supplied at petal drop; 4) apple juice by-product, at twice the rate of the previous treatment. Apple juice by-product soil decomposition accounted for 12% in the first 6 months. At the end of the 24-month-assay, the decomposition accounted for 24% on total dry weight that makes 28% of initial C and 36% of initial N. Soil nitrate-N concentration was increased by the mineral N fertilizer, while the application of apple juice by-product increased microbial carbon. Tree growth, yield and fruit quality were not affected by treatments, while mineral N fertilization raised leaf and fruit N concentration. In conclusion, in our conditions the use of apple juice by-product did not show negative effects on tree performances and fruit quality, with some advantages related to the recycling of organic wastes in agriculture.