Waste Treatment Lagoons

Primary reference(s)

Spellman, F.R. and R.M. Bieber, 2012. Environmental Health and Science Desk Reference. Government Institutes, 807.

Annotations

Key relevant UN convention / multilateral treaty

The UN-Water Policy Brief on the United Nations global water conventions: Fostering sustainable development and peace. (UN-Water, 2022)

Drivers

Effluents from livestock industrial production are commonly discharged into the environment or stored in ‘lagoons’, from which waste may spill or leak into nearby streams and groundwater supplies. Noxious gases escape into the atmosphere, subjecting downwind neighbours to sickening odours and contributing to atmospheric aerosol formation, build-up of greenhouse gases and acid rain (FAO, 2007).

Impacts

The environmental and public health risks of industrial feedlots and effluent lagoons can be limited by ensuring that they are not located too close to each other, to streams and aquifers and to densely populated communities. Environmental damage can be reduced further by encouraging and enforcing standards for the design and construction of buildings and lagoons to conform with approved manure management system (FAO, 2007). Meat processing plants produce large amounts of slaughter- house wastewater, treatment and final disposal (Bustillo-Lecompte and Mehrvar, 2017). Livestock waste lagoons and manure storage basins may spill or leak into nearby streams and groundwater supplies. Further- more, cracks, improper construction, increased rainfall, storm or stronger than normal winds can cause lagoon overflow. Ponds or lagoons used to store effluents should be lined to reduce leaching and be big enough to allow for manure storage at times when application on crops is not suitable, such as during the rainy season (FAO, 2007). Overflow can spread harmful bacteria, pesticides, animal antibiotics, additional oestrogens, heavy metals, and protozoa into the groundwater supply and contaminate surrounding areas and these could be identified as socio-economically generated sediments (Sharma and Singh, 2015). 

Pollution associated with animal waste management in intensive livestock production include (FAO, 2007): 

• Leaching of nitrates into groundwater, threatening drinking water supplies.
• Eutrophication of surface water, as nitrogen, phosphorus and other nutrients are discharged or run off into streams, damaging wetlands and fragile coastal ecosystems, and fuelling algae ‘blooms’ that use up oxygen in the water, killing fish and other aquatic life.
• Build-ups of excess nutrients and heavy metals in the soil, damaging soil fertility and shrinking arable land resources.
• Contamination of soil and water resources with pathogens, heavy metals or drug residues.
• Release of ammonia, hydrogen sulphide, methane, carbon dioxide and other gases into the air, some of which can negatively impact health hazards, damage crops and ecosystems.

Multi-hazard context

The figure below summarises common interactions between waste treatment lagoons and other hazards. This information should be used with caution and not be solely relied upon in Disaster Risk Management, particularly as some interactions may not have been included. Note that hazardous events occurring together or locally in space or time may not necessarily cause, amplify or be otherwise related to each other. Specific examples of multi-hazard context can be found in the ‘Hazard drivers’ and ‘Impacts’ sections above.

Multi-hazard diagram

Risk Management

Effective policies and legislation to regulate intensive livestock operations and support environmentally and economically sustainable approaches, the use of adequate practices and technologies are of high importance for addressing these challenges and mitigating production of the pollutants. Livestock waste is a major source of nutrients and energy which contributes to improving the circular bioeconomy. Proper management and use of livestock waste as a fertiliser or for conversion into biogas, compost and vermicompost is a useful means to increase crop yield, sustainability, and income (Sorathiya et al., 2014).

Monitoring

FAO provides guidance on wastewater reclamation and reuse systems that should contain both design and operational requirements necessary to ensure reliability of treatment (FAO, no date). Reliability features such as alarm systems, standby power supplies, treatment process, emergency storage or disposal of inadequately treated wastewater, monitoring devices, and automatic controllers are important. From a public health standpoint, provisions for adequate and reliable disinfection are the most essential features of the advanced wastewater treatment process with a monitoring programme that should always be incorporated into the design of overland flow projects both for wastewater and effluent quality and for application rates (FAO, no date).