Your search found 11 records
(Location: IWMI HQ Call no: e-copy only Record No: H046105)
(0.43 MB)
Today wastewater treatment plants are evaluated not only in terms of their treatment efficiency but also concerning their energy efficiency. Increasing energy efficiency can be realized either through operational optimisation or by realising an already existing potential for energy generation on-site. The main source of energy at a municipal wastewater treatment plant is the biogas produced in the anaerobic sludge digester. Studies indicate excess digester capacities of about 20% in Germany available for co-fermentation of organic substrates other than sewage sludge. This paper presents an example of a municipal wastewater treatment plant going towards an energy self-sufficient operation and even a surplus energy production as the result of an increasing co-fermentation of sludge from grease skimming tanks. In 2005 on average 113% of the electricity consumed for plant operation was generated on-site in gas engines. Co-fermentation of about 30% (related to the total dry residue input) of grease interceptor sludge in the presented case does not only effect a 4-times increased gas yield, but also an intensified 20% higher anaerobic degradation of the organic matter of the sewage sludge and thus having a positive influence not only on the energy and financial balance but also on the anaerobic sludge stabilisation with respect to the degradation degree of the organic fraction.
(Location: IWMI HQ Call no: e-copy only Record No: H047435)
(1.66 MB)
Deforestation due to farmland expansion, fragile soils, undulating terrain, and heavy seasonal rains makes the highlands of Ethiopia vulnerable to soil erosion. The diverse terrain of the rural highlands requires spatially explicit investments in land management structures. This paper utilizes recent hydrological and meteorological data collected from the Mizewa watershed in the Blue Nile Basin of Ethiopia, as well as household survey data on farmer preferences and investments, in order to better understand the physical impact of sustainable land management activities. The effectiveness of the simulated conservation practices (terraces, bunds, and residue management) is evaluated using the Soil and Water Assessment Tool taking into account investment decisions on different terrain types. Simulations include terracing on steep and mid-range hillsides; a mix of terracing and bunds on varying slope gradients; and a mix of terraces and residue management on varying terrain. Simulated conservation practices are evaluated at the outlet of the Mizewa watershed by comparing model simulations that take into account the limited investments that currently exist (status quo) with simulations of increased terracing and residue management activities within the watershed. Results suggest that a mixed strategy of terracing on steep slopes and residue management on flat and middle slopes dramatically decrease surface runoff and erosion. A landscape-wide investment of terraces and bunds throughout the watershed landscape provides the greatest reduction in surface flow and erosion. However, the type and amount of investment in sustainable land management activities have different implications with respect to labor input and may be cost-prohibitive in the medium term.
(Location: IWMI HQ Call no: IWMI Record No: H047671)
(1 MB)
Recovering energy from waste offers dual benefits – a) improved waste management, and b) provision of reliable energy to households, institutions and commercial entities. In this report, we present a socioeconomic assessment of three energy business models (briquette manufacturing, on-site (public toilet) energy generation, and agro-waste electricity generation) based on feasibility studies carried out in the city of Kampala, Uganda. We assess the potential economic, environmental and social impacts of waste-to-energy business models taking into consideration a life cycle of emissions to provide decision makers with the overall costs and benefits of the models to society versus a business-as-usual scenario.
(Location: IWMI HQ Call no: e-copy SF Record No: H047924)
(Location: IWMI HQ Call no: e-copy only Record No: H047945)
(1.05 MB)
Background: Faecal matter biochar offers an interesting value proposition where the pyrolysis process guaranties a 100% pathogen elimination, as well as significant reduction in transport and storage weight and volume. Therefore, to evaluate the effect of (1) biochar produced from dried faecal matter from household based septic tanks, and (2) N fertilizer, as well as their interaction on yield and nutrient status of lettuce (Lactuca sativa), lettuce was grown over two growing cycles under glasshouse on two contrasting soils amended once at the start with factorial combination of faecal matter biochar at four rates (0, 10, 20 and 30 t ha-1) with 0, 25 and 50 kg N ha-1 in randomized complete block design. Results: For both soils, maximum fresh yields were recorded with biochar and combined application of biochar with N treatments. However, the greatest biochar addition effects (with or without N) with regard to relative yield were seen in less fertile sandy loam soil. We have also observed that faecal matter biochar application resulted in noticeable positive residual effects on lettuce yield and tissue nutrient concentrations in the 2nd growing cycle. For both soils, most nutrients analyzed (N, P, K, Mg, Cu and Zn) were within or marginally above optimum ranges for lettuce under biochar amendment. Conclusions: The application of faecal matter biochar enhances yield and tissue nutrient concentrations of lettuce in two contrasting soils, suggesting that faecal matter biochar could be used as an effective fertilizer for lettuce production at least for two growing cycles. Moreover, the conversion of the faecal matter feedstock into charred product may offer additional waste management benefit as it offers an additional (microbiologically safe) product compared to the more common co-composting.
(Location: IWMI HQ Call no: IWMI Record No: H047991)
(2 MB)
Where modern heating and cooking fuels for domestic, institutional, commercial and industrial use are not readily available, briquettes made from biomass residues could contribute to the sustainable supply of energy. This study reviews the briquette making process, looking at the entire value chain starting from the type and characteristics of feedstock used for briquette making to the potential market for briquettes in developing countries. It also analyzes the role that gender plays in briquette production. Depending on the raw materials used and technologies applied during production, fuel briquettes come in different qualities and dimensions, and thus require appropriate targeting of different market segments. Key drivers of success in briquette production and marketing include ensuring consistent supply of raw materials with good energy qualities, appropriate technologies, and consistency in the quality and supply of the briquettes. Creating strong partnerships with key stakeholders, such as the municipality, financiers and other actors within the briquette value chain, and enabling policy are important drivers for the success of briquette businesses.
7 Gebrezgabher, Solomie; Musisi, A. 2018. Briquettes from agro-waste (Kampala Jellitone Suppliers, Uganda) - Case Study. In Otoo, Miriam; Drechsel, Pay (Eds.). Resource recovery from waste: business models for energy, nutrient and water reuse in low- and middle-income countries. Oxon, UK: Routledge - Earthscan. pp.41-51.
(Location: IWMI HQ Call no: IWMI Record No: H048626)
(1.37 MB)
(Location: IWMI HQ Call no: e-copy only Record No: H049124)
(3.06 MB)
Increasing water scarcity and Asia’s rapid economic and social development, specifically the growing demand for animal products and biofuels, is forcing farmers to transform their traditional lowland double-rice cropping systems [R-R] to mixed lowland-upland systems where upland crops such as aerobic rice [R-A] or maize [R-M] are grown instead of paddy rice during the dry period. Such changes have implications on the C and N cycling in the soil-plant system, including major shifts in soil greenhouse gas (GHG) emissions from CH4 to N2O once paddies are used for upland cropping. Moreover, soil organic carbon stocks are decreasing, thereby jeopardizing soil fertility. In this study, we investigated if straw residue incorporation and/or catch crop cultivation impairs the greenhouse gas footprint of diversifying rice cropping systems and thus, presents an alternative to open-field straw burning and intensive mineral N fertilization. For this, we calculate annual global warming potentials (GWP) and yield-scaled GWPs of three different rice systems (R-R: rice-rice, R-A: rice- aerobic rice, R-M: rice maize) without (control) or with additions of straw (+6 Mg ha-1 [S]) or + straw + mungbean as catch crop ([M + S]) on the basis of high-temporal-resolution GHG emissions (CH4 and N2O), and measurements of yield parameters. The field trial was carried out at the International Rice Research Institute (IRRI), Philippines, covering two full years. Although dry season N2O emissions increased twice- to threefold in the diversified systems (R-A, R-M), the strong reduction of CH4 emissions during this period resulted in significantly lower annual yield-scaled GWP as compared to the traditional R-R system. The same pattern was observed after application and incorporation of organic material (straw and mungbean), but led to higher substrate availability for methanogens during the following season. Therefore, the GWP was 9–39% higher in treatments including straw incorporation as compared to a control treatment without organic substrate amendments. Additional incorporation of mungbeans further increased GWPs, whereby the increment was highest in R-R rotation (88%) and lowest in R-M rotation (55%), with annual GHG emissions of 11.8 and 5.6 Mg CO2-eq ha-1, respectively. Our study shows that the yield-scaled GWP, as well as irrigation water demand, is lowest for rice-maize (R-M) cropping systems, followed by R-A and R-R systems. This ranking persists even with the incorporation of crop residues, a requirement for farmers as the ban of open-field burning is increasingly enforced. Our work also calls for a refinement of IPCC emission factors for lowland-upland rotations and the inclusion of the land-preparation period within the GHG balance of rice cropping systems.
9 Joly, Gabrielle; Nikiema, Josiane. 2019. Global experiences on waste processing with black soldier fly (Hermetia illucens): from technology to business. Colombo, Sri Lanka: International Water Management Institute (IWMI). CGIAR Research Program on Water, Land and Ecosystems (WLE). 62p. (Resource Recovery and Reuse Series 16) [doi: https://doi.org/10.5337/2019.214]
(Location: IWMI HQ Call no: IWMI Record No: H049395)
(1.68 MB)
Black soldier fly colonies can produce about 100 times more protein per year than chicken or soybeans, not to mention cattle, on the same area of land. The flies can directly feed on different types of organic wastes, leapfrogging closed loop processes within a circular food economy. Also, where no protein is needed, for example, to feed fish or pigs, the larvae can be processed into high-quality biodiesel. However, can this be done at scale? The answer is ‘Yes’. The report showcases some of the leading global businesses in Black Soldier Fly production.
(Location: IWMI HQ Call no: e-copy only Record No: H051639)
(553 KB)
Burkina Faso has a huge opportunity and natural resources to develop circular bioeconomy (CBE) sector. The agricultural sector employs 63% of the employed workforce and contributes to 16% of the Gross Domestic Product. Large production of cereals results in large quantities of agricultural residues. In a country where the industrial sector is still in its infancy, CBE solutions offer significant opportunities for reconfiguring economies, labor and resource use. However, implementing CBE solutions remains at small scale and scaling up faces numerous challenges. This report reviews the enabling environment - drivers, barriers, and opportunities for promoting CBE initiatives in the country and presents conclusions and recommendations.
11 Patra, K.; Parihar, C. M.; Nayak, H. S.; Rana, B.; Sena, Dipaka R.; Anand, A.; Reddy, K. S.; Chowdhury, M.; Pandey, R.; Kumar, A.; Singh, L. K.; Ghatala, M. K.; Sidhu, H. S.; Jat, M. L. 2023. Appraisal of complementarity of subsurface drip fertigation and conservation agriculture for physiological performance and water economy of maize. Agricultural Water Management, 283:108308. [doi: https://doi.org/10.1016/j.agwat.2023.108308]
(Location: IWMI HQ Call no: e-copy only Record No: H051898)
(3.00 MB) (3.00 MB)
The Indo-Gangetic Plains (IGP) in north-west (NW) India are facing a severe decline in ground water due to prevalent rice-based cropping systems. To combat this issue, conservation agriculture (CA) with an alternative crop/s, such as maize, is being promoted. Recently, surface drip fertigation has also been evaluated as a viable option to address low-nutrient use efficiency and water scarcity problems for cereals. While the individual benefits of CA and sub-surface drip (SSD) irrigation on water economy are well-established, information regarding their combined effect in cereal-based systems is lacking. Therefore, we conducted a two-year field experiment in maize, under an ongoing CA-based maize-wheat system, to evaluate the complementarity of CA with SSD irrigation through two technological interventions–– CA+ (residue retained CA + SSD), PCA+ (partial CA without residue + SSD) – at different N rates (0, 120 and 150 kg N ha-1) in comparison to traditional furrow irrigated (FI) CA and conventional tillage (CT) at 120 kg N ha-1. Our results showed that CA+ had the highest grain yield (8.2 t ha-1), followed by PCA+ (8.1 t ha-1). The grain yield under CA+ at 150 kg N ha-1 was 27% and 30% higher than CA and CT, respectively. Even at the same N level (120 kg N ha-1), CA+ outperformed CA and CT by 16% and 18%, respectively. The physiological performance of maize also revealed that CA+ based plots with 120 kg N ha-1 had 12% and 3% higher photosynthesis rate at knee-high and silking, respectively compared to FI-CA and CT. Overall, compared to the FI-CA and CT, SSD-based CA+ and PCA+ saved 54% irrigation water and increased water productivity (WP) by more than twice. Similarly, a greater number of split N application through fertigation in PCA+ and CA+ increased agronomic nitrogen use efficiency (NUE) and recover efficiency by 8–19% and 14–25%, respectively. Net returns from PCA+ and CA+ at 150 kg N ha-1 were significantly higher by US$ 491 and 456, respectively than the FI-CA and CT treatments. Therefore, CA coupled with SSD provided tangible benefits in terms of yield, irrigation water saving, WP, NUE and profitability. Efforts should be directed towards increasing farmers’ awareness of the benefits of such promising technology for the cultivating food grains and commercial crops such as maize. Concurrently, government support and strict policies are required to enhance the system adaptability.
Powered by DB/Text
WebPublisher, from