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The dairy industry has seen notable changes in the last couple of decades, including increased size of farms and regional concentrations of dairies. This has resulted in substantial manure production in small geographical areas, raising environmental concerns. Vermifiltration, an emerging low cost and eco-friendly technology for treating wastewater, was evaluated to assess the influence of earthworm population density on the performance of a laboratory-scale vermifilter treating liquid dairy manure. We monitored the reduction efficiencies of various components, including total nitrogen (TN), ammonium-nitrogen (NH 4 + -N), nitrate-nitrogen (NO 3 - -N), total phosphorus (TP), orthophosphate (ortho-P), chemical oxygen demand (COD), total solids (TS), and total suspended solids (TSS), in treated dairy wastewater. This evaluation was conducted at 0; 5000; 10,000; and 15,000 earthworm densities per cubic meter (m -3 ) of bedding. Reduction efficiencies of 41%-89% (TN), 46%-86% (NH 4 + -N), 34%-74% (NO 3 - -N), 3%-17% (TP), 18%-38% (ortho-P), 35%-66% (COD), 24%-54% (TS), and 50%-87% (TSS) were observed with higher earthworm densities exhibiting greater reduction efficiencies. Notably, the densities of Eisenia fetida at 10,000 and 15,000 earthworms m -3 showed no significant difference in vermifilter performance. This suggests that increasing the Eisenia fetida density beyond 10,000 earthworms m -3 may not further improve the vermifilter's performance in treating dairy wastewater. This study's findings indicate that using vermifiltration with an earthworm population density of 10,000 earthworms m -3 could effectively mitigate the negative environmental impact of liquid dairy wastewater at a low cost and sustainably., (© 2024 The Author(s). Journal of Environmental Quality published by Wiley Periodicals LLC on behalf of American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.)

Dairy effluent is a potential source of gaseous pollutants associated with global warming and soil acidification. Mitigating such emissions during handling and storage requires substantial financial and labor input. This study evaluated a low-cost technology for mitigating gaseous emissions from dairy wastewater. For 9 mo, a pilot-scale vermifilter system installed on a commercial dairy farm was studied. Bimonthly samples of the dairy wastewater influent and effluent from the vermifilter system were collected. These samples' potential gas emissions (ammonia [NH 3 ], methane [CH 4 ], carbon dioxide [CO 2 ], and nitrous oxide [N 2 O]) were measured using a closed-loop dynamic flux chamber method. Results indicated the following reductions in emissions of these gases by the vermifilter system: 84-100% for NH 3 , 58-82% for CO 2 , and 95-100% for CH 4 . Nitrous oxide emissions were mainly below our instrument detection limits and were thus not reported. The vermifilter showed the potential of reducing the global warming potential from the dairy wastewater by up to 100%. This study further indicated that higher ambient temperatures led to higher emissions of CH 4 (R 2  = .56) and NH 3 (R 2  = .53) from untreated dairy wastewater. Overall, the vermifilter system has potential to mitigate gaseous emissions from dairy wastewater., (© 2022 The Authors. Journal of Environmental Quality published by Wiley Periodicals LLC on behalf of American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.)

Agricultural biomass is widely recognized as a clean and renewable energy source, with increasing potential to replace conventional fossil fuels in the energy market. Uganda, like other developing countries, has a high dependency (91%) on wood fuel, leading to environmental degradation. With a coffee production of 233 Metric Tonnes per annum, relating to 46.6 Mega Tonnes of coffee husks from processing, transforming these husks into syngas through gasification can contribute to resolving the existing energy challenges. The objective of this article is to briefly review the energy potential of coffee husks through gasification, and how the gasification process could increase energy recoveries for coffee farmers. Previous  findings indicate that the 46.6 Mega Tonnes per year of coffee husks generated in Uganda, with a heating value of 18.34 MJ/kg, is capable of generating 24 GWh of energy. This will address a 0.7% portion of the energy situation in Uganda, while protecting the environment., Competing Interests: Competing interests: No competing interests were disclosed.

Urban animal farming is becoming increasingly important in feeding the growing population of many sub-Saharan African cities. However, management of the animal manure generated is proving to be challenging due to space restrictions. Vermicomposting is one of the methods proposed to address this challenge. This study investigated the environmental performance of the vermicompost system by measuring the gaseous emissions generated from the system. In addition, the vermicompost system was compared with other manure management systems currently in use, using life cycle assessment (LCA) methodology. The emissions factors for the vermicompost system were found to be 10.8, 62.3 and 12.8 g/Megagram biowaste for methane, nitrous oxide and ammonia, respectively. LCA showed satisfactory performance of vermicomposting in terms of global warming and eutrophication potential, although if the vermicompost generated is dumped, this could lead to increased eutrophication. However, this is still much lower than the eutrophication caused by open dumping of untreated manure., (Copyright © 2016 Elsevier Ltd. All rights reserved.)