Prospects for Increased Energy Recovery from Horse Manure—A Case Study of Management Practices, Environmental Impact and Costs

Abstract

A transition to renewable energy sources and a circular economy has increased interest in renewable resources not usually considered as energy sources or plant nutrient resources. Horse manure exemplifies this, as it is sometimes recycled but not often used for energy purposes. The purpose of this study was to explore horse manure management in a Swedish municipality and prospects for energy recovery. The case study includes a survey of horse manure practices, environmental assessment of horse manure treatment in a biogas plant, including associated transport, compared to on-site unmanaged composting, and finally a simplified economic analysis. It was found that horse manure management was characterized by indoor collection of manure most of the year and storage on concrete slabs or in containers, followed by direct application on arable land. Softwood was predominantly used as bedding, and bedding accounted for a relatively small proportion (13%) of the total mix. Anaerobic digestion was indicated to reduce potential environmental impact in comparison to unmanaged composting, mainly due to biogas substituting use of fossil fuels. The relative environmental impact from transport of manure from horse facilities to anaerobic digestion plant was small. Results also indicate a relatively high cost for horse keepers to change from composting on site to anaerobic digestion in a centralized plant.

How Can Biodigesters Help Drive the Circular Economy? An Analysis Based on the SWOT Matrix and Case Studies

“…[36,53] Renewable energy Biogas allows the generation of clean energy from waste. [33,40,43,54,55] Closing the product loop Closing product cycles, extending the useful life of each resource [27,36,38,46,56] As shown in Table 1, one of the advantages most addressed by studies when looking at the use of biodigesters and CE is the reuse of waste. This occurs due to the possibility of closing the cycles, in which the transformation of a waste into raw material occurs, with the treatment of organic waste, generating clean energy (biogas), recycling the nutrients of the waste streams, and reducing the emission of greenhouse gases (GHG) [40].…”

“…High transportation costs when the biodigester is far away from the point of waste collection or from the land where the biofertilizer is to be used [35,36,54,58,62] Lack of knowledge about the energy potential of the sector Lack of awareness of the energy potential that can be obtained with the use of biogas [40] Population awareness Lack of knowledge of the population about the advantages of biodigesters and the need for proper separation of waste [40,58] Contamination of soil, air, water, etc.…”

“…The construction of the biodigester and a system for collecting and using the biogas requires a high investment cost [27,30,40,51,54] Bad smell If not stored correctly, a bad smell can occur around the waste storage [58]…”

Global Warming and Acidification Potential Assessment of a Collective Manure Management System for Bioenergy Production and Nitrogen Removal in Northern Italy

“…It is important not to underestimate that centralised biogas plants fed with livestock manure, must keep transport cost under control due to distances to collect manure, to stay competitive [8]. Moreover, the transfer of effluents from farms to the treatment plant and back to farms for utilization must be carefully evaluated to take into account the associated pollutant emissions, although, in some condition the emissions due to transport to a centralised facility might have a limited influence on the overall impact [9].…”

Energy Recovery Potential of Livestock Waste with Thermal and Biological Technologies: Analysis on Cattle, Sheep, Goat and Chicken Manure

“…The basic principle of these concepts is to apply clean technologies to avoid waste generation, if possible or waste reduction and reuse and recycle in cases where waste generation is inevitable. Especially in industries with high amount of organic waste the energy recovery from waste becomes vital instead of disposal of the waste (Akyurek, 2019a;Hasan et al, 2021;Hadin et al, 2017).…”