5. Challenges associated with manure handling

Animal manure can be a challenge when produced in excess of requirements. Unsustainable manure management practices, which consist of various disposal approaches, are still prevalent in some places (Table 7). This is particularly the situation in some intensive animal operations. For example, costs associated with manure storage and disposal can contribute to unsustainable practices in handling manure. This is possible especially when the alternatives to sustainable management are considered much cheaper, in terms of financial requirement. However, the public health and economic costs in form of disease outbreaks, rejects of products, products recalls and regulatory fines and so on that could be associated with improper disposal of animal manure or manure contaminated foods and food products may far exceed whatever cost-savings are being targeted by the producers who adopt unsustainable manure


Table 7. Prevalence of unsustainable manure management practices.

4. Some principles associated with manure management

126 Agricultural Waste and Residues

wastes should be managed close to where they are produced.

such a way that will not negatively affect the environment.

problems to the subsequent generations.

5. Challenges associated with manure handling

There are several principles which are associated with waste management [11] and by extension, manure management. It is important to take these principles into account when formulating manure management strategies and interventions. Some of the principles are as follows: • Proximity principle: The principle of proximity indicates that as practicable as possible,

• Self-sufficiency principle: The principle of self-sufficiency indicates that each country, and potentially each state, region and city, should manage its own wastes wherever possible. If applied to animal production facilities, this means farms should manage the wastes that they generate. However, this principle does not foreclose regional cooperation, which may

• The polluter-pays principle: This principle indicates that those who cause or generate pollution should bear its cost. In this context, those who generate manure should bear the cost of managing it to prevent the potential risks to human health and the environment. • Precautionary principle: This principle is applied according to the capabilities of the affected states. According to the principle of precaution, the absence of scientific certainty shall not be used as the reason for postponing cost-effective measures to prevent environment degradation, particularly where substantial threats of serious or irreversible damage exist [11].

• Sustainable development: The principle indicates that development activities geared towards meeting the needs of the present must not compromise the ability of the future generations to meet their own needs. Thus, manure should be handled and managed in

• Principle of intergenerational equity: The principle of intergenerational equity indicates that waste should not be managed in such a way that will leave the responsibility for the

Animal manure can be a challenge when produced in excess of requirements. Unsustainable manure management practices, which consist of various disposal approaches, are still prevalent in some places (Table 7). This is particularly the situation in some intensive animal operations. For example, costs associated with manure storage and disposal can contribute to unsustainable practices in handling manure. This is possible especially when the alternatives to sustainable management are considered much cheaper, in terms of financial requirement. However, the public health and economic costs in form of disease outbreaks, rejects of products, products recalls and regulatory fines and so on that could be associated with improper disposal of animal manure or manure contaminated foods and food products may far exceed whatever cost-savings are being targeted by the producers who adopt unsustainable manure

be the most efficient and environmentally sound way of waste management.

management practices. Manure disposal is the most unsustainable and by far the least desirable strategy in the hierarchy of management. Animal manure could be a valuable resource or a waste depending on how it is handled and managed.

Animal manure contains significant amounts of micro-organisms which make it a source of major risk to the public (Table 8). Risks of nutrients, organic material and pathogens contaminating water bodies and food products are common with increased manure spread [19]. Nutrient run-off into groundwater can occur from uncovered livestock facilities, from manure



Manure management policies could be a stand-alone policy or a part of another. National Agricultural Policy, Environmental Policy, Climate Change Policy, Energy Policy, Renewable Energy Policy, Livestock Development Policy, Poultry Development Policy, Food Safety Policy, Water Policy, Integrated Waste Management Policy and so on do address some aspects of manure management. A challenge with the policies earlier mentioned in relation to manure issues is that they may not be comprehensive as desirable or adequately cover every important aspect of manure management. This is the situation in several countries. Dedicated manure management policies and legislations may address the gaps associated with the other policies in relation to manure issues. The Integrated Livestock Manure Management Policy of Bangladesh is an example of a stand-alone manure policy [20]. Manure management hierarchy can guide the formulation of manure management policy objectives. To make the manure management policies effective, goals and targets can be set over various time scales. It is essential to involve the stakeholders in the processes of formulating the policies and strategies. The stakeholders should also be adequately sensitized as per their roles and responsibilities relating to

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Policy incoherence and weak enforcement due to the lack of coordination among relevant ministries are other major challenges associated with manure policies in several countries [22]. It suffices to note that policy implementation is challenging without accompanying it with enforcement and compliance. Legislations can also contribute to increased litigation associated with manure management. Ref. [23] noted adding incentives in the form of subsidies to mandatory requirements could help to fast-track and enlarge the adoption of sustain-

Dutch manure policy has been reported to have the following impacts: a decreased fraction of phosphate and nitrogen from the synthetic fertilizer and reduced nutrient dispersion in the environment. The success of the policy implementation has been attributed to strict application of standards for agricultural production, more efficient production per animal, low emission

Feeding strategies can also be used to reduce livestock manure yield and potential emissions from manure management. Ref. [24] reported that chickens fed low protein diets had lower manure output and reduced nitrogen output intensity compared to those on higher protein regimes. The studies also found that amino acid supplementation, enzyme supplementation and manure treatments with various types of alum resulted in additional reduction in nitrogen excretion in chickens [24–27]. The implication of the finding is that lower manure and nutrient

Manure treatment can be physical, biological or chemical. The objectives of manure treatment include reduction of manure volume, improvement of its applicability and/or increase in fertilizer

able manure management practices such as anaerobic digestion of animal manure.

from stored and applied manure, manure processing, transportation and export.

6.2.1. Nutritional strategies for reducing the environmental impact of animal agriculture

sound manure management.

6.2. Manure management practices

6.2.2. Manure treatment

output reduces their potential environmental impacts.

Table 8. Animal manure, potential pathogens and illnesses caused in humans.

applied to land, from pasture feeding and watering areas or from direct discharge into water bodies which causes water pollution.

Major consequences of manure pollution in water bodies include oxygen depletion due to increased biological oxygen demand and the resultant effect on sustainable fisheries, eutrophication and algae bloom, water taints and odor, nitrate poisoning in humans and animals and water acting as a carrier for several disease pathogens [21]. Gaseous emissions from manure facilities contribute to noxious odor, greenhouse effect and other potential health hazards. Apart from the direct discharge of manure or its constituents, water bodies can absorb airborne manure constituents. Substantial amounts of nutrients, particularly nitrogen, are lost during manure collection, storage and removal. Therefore, animal manure can be a contaminant for food, soil and water. Manure is also a cause of offensive odor. Therefore, manure management systems must integrate appropriate measures for odor control. Reducing the frequency, intensity, duration and offensiveness of the odor is the main goal of effective odor control.
