Composting/ vermiculture toilets

Fig. 1: Banu A. (2022). Composting toilet cross-section.

Composting/vermiculture toilets contribute to sustainable waste management by converting human waste into compost while minimising environmental impacts. These systems are designed to mimic natural decomposition processes, utilising microorganisms to break down organic matter.

Name of NbS

Composting/ vermiculture toilets

Type of NbS

Hybrid living/engineered interventions

Location

Composting/ vermiculture toilets are particularly useful in areas with limited water resources or off-grid locations where traditional sewage systems are unavailable.

For example, national parks and wildlife services, roadside rest areas, mines, defence camps in remote areas, tourist lodges and resorts, camping grounds, permaculture centres, remote communities, alpine regions, environmental education centres and local sporting groups etc. However, they can be used in domestic, commercial, or public facilities.

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Case Study:

Composting toilets for Matapōuri

Whangārei District Council (2023). New composting toilets.

Relationship to Indigenous knowledge:

Indigenous knowledge often emphasises cyclical and sustainable approaches to resource use. For example, in Māori culture, the great importance of Te Taiao (the natural world) and the interconnectedness of all living things is recognised (Afoa and Brockbank, 2019). Vermiculture toilets, by working with earthworms and microorganisms, acknowledge and respect the integral role of these organisms in the ecosystem. Many indigenous cultures have a tradition of viewing waste not as a problem but as a resource. With their sustainable approach to waste management and the creation of nutrient-rich compost, these vermiculture toilets also resonate with the idea of Kaitiakitanga (responsible guardianship) of natural resources (Afoa and Brockbank, 2019). 

Climate change benefits

Indirect health, social, and cultural climate change impacts, Loss of other ecosystem services, Reduced soil quality, Reduced fresh-water availability

Conventional sewage systems require significant water for flushing and subsequent treatment. Vermiculture toilets, by minimising or eliminating the need for water flushing, contribute to water conservation. Unlike centralised sewage treatment systems that require energy for transportation, treatment, and disposal of waste, vermiculture toilets operate at a decentralised level, leading to energy savings and a reduced carbon footprint associated with waste management (Anand and Apul, 2014). The compost produced by vermiculture toilets enhances soil structure, fertility, and water retention (Alonso-Marroquin et al., 2023). Healthy soils act as a carbon sink, promoting carbon sequestration. It helps mitigate health risks associated with inadequate sanitation by also promoting proper waste management (Pierre-Louis et al., 2021). It also minimises environmental pollution by avoiding the discharge of untreated sewage into water bodies, thereby preserving water quality and supporting aquatic ecosystems.

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Societal / socio-cultural benefits

Climate change adaptation, Economic and social development, Human physical health and wellbeing, Pressures of urbanisation (waste management, hygiene, etc), Water security and quality.

In rural or remote areas where establishing traditional sewage infrastructure is challenging, vermiculture toilets contribute to local development by addressing a critical aspect of public health and sanitation (Pierre-Louis et al., 2021). Improved sanitation contributes to better health outcomes, positively impacting the overall well-being of community members and addressing challenges related to waterborne diseases. The implementation of vermiculture toilets could be promoted through educational programs, contributing to improved awareness about proper sanitation practices, waste management, and environmental stewardship. The successful implementation of vermiculture toilets can bring a sense of pride and ownership within the community, as they actively participate in a solution that addresses their unique needs and challenges.

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Ecological and biodiversity benefits

Decomposition, Education and knowledge, Habitat provision, Nutrient cycling, Soil building

Vermiculture toilets contribute to nutrient cycling by converting human waste into compost. The resulting compost returns essential nutrients to the soil, supporting plant growth and ecosystem productivity. Earthworms involved in the vermiculture process play a crucial role in soil biodiversity. They create channels and burrows, improving soil aeration and facilitating the movement of other soil organisms (Alonso-Marroquin et al., 2023). The composting process in vermiculture toilets promotes the growth of diverse microbial communities. The compost produced by vermiculture toilets serves as a natural fertiliser, reducing the dependence on synthetic fertilisers.

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Technical requirements

Vermiculture toilets typically have composting chambers where the waste is processed. Multiple chambers are used to allow for continuous composting while one chamber is in use, and the other is maturing or being emptied (Anand and Apul, 2014). Ventilation systems, such as vent pipes or fans, help control moisture levels, prevent odours, and ensure the presence of oxygen for the aerobic microorganisms (Anand and Apul, 2014). Earthworms (e.g., Eisenia fetida) are introduced into the composting chamber to thrive in decomposing organic matter (Pierre-Louis et al., 2021). The composting process generates heat, and vermiculture toilets often maintain a temperature range favourable to the growth of thermophilic (heat-loving) bacteria and accelerate the decomposition process (Alonso-Marroquin et al., 2023). Over time, the combined action of microorganisms and earthworms transforms the waste into nutrient-rich compost which can be used as a fertiliser. Regular maintenance involves monitoring the moisture content, periodically checking and adjusting the worm population, and ensuring proper aeration.

Issues and Barriers

Implementing vermiculture toilets requires a nuanced understanding of cultural preferences and values, and a lack of cultural sensitivity may hinder acceptance (Anand and Apul, 2014). In some remote or underserved areas, there may be limited infrastructure for the construction and maintenance of nature-based sanitation systems. Lack of awareness and understanding about the benefits and proper use of nature-based sanitation solutions can be challenging in adoption (Pierre-Louis et al., 2021). Economic considerations, including the cost of technology and maintenance, may pose challenges for communities or institutions with limited financial resources. Proper maintenance and monitoring are essential for the effective functioning of this nature-based sanitation system. In remote or underserved areas, the lack of resources and trained personnel may affect regular maintenance and monitoring activities (Anand and Apul, 2014). It is vital to make sure that pathogens must be contained and eliminated in composting toilets, they must fulfil sanitary and public health standards by avoiding contacting disease carriers such as flies and they should not create unpleasant odours (Hill and Baldwin, 2012).

Opportunities

Implementing vermicomposting toilets offers an opportunity for community engagement and ownership. Oceania is vulnerable to climate change impacts such as extreme weather events. These toilets are well-suited for locations facing challenges in effluent disposal, such as low soil infiltration, limited available land, scarce water resources, or areas with ecological sensitivity (Nair et al., 2009). Decentralised sanitation solutions, like vermicomposting toilets, provide resilience by operating independently of centralised infrastructure that may be susceptible to climate-related disruptions (Anand and Apul, 2014). Moreover, utilising environmentally friendly practices aligns with the growing interest in sustainable tourism and community-based development. Implementation and maintenance of vermicomposting toilets can also create local employment opportunities (Nair et al., 2009). It also provides an opportunity for innovation and technology transfer.

Financial case

The cost-benefit analysis of vermicomposting toilets involves considering both the initial investment and the long-term savings and benefits associated with sustainable waste management (Bajsa et al., 2004). The costs can vary depending on factors such as the specific technology used, local labour and material costs, and the scale of implementation. Additionally, the benefits go beyond financial considerations and encompass environmental, social, and health aspects (Bajsa et al., 2004). These toilets significantly reduce or eliminate the need for water in flushing. This results in direct water savings, which can be particularly valuable in regions facing water scarcity. The compost produced by vermiculture toilets serves as a valuable fertiliser, reducing the expenses on synthetic fertilisers. In remote or island communities, transportation and logistical challenges may increase the costs associated with the procurement of materials and the construction of infrastructure. Moreover, adequate funding for training and support is essential for ongoing monitoring systems and capacity-building.

References
  • Afoa, E., & Brockbank, T. (2019). Te Ao Māori & Water Sensitive Urban Design. Landcare Research.
  • Alonso-Marroquin, F., Qadir, G., Nazha, J., Pino, V., & Brambilla, A. (2023). A User-Friendly and Sustainable Toilet Based on Vermicomposting. Sustainability15(16), 12593.
  • Anand, C. K., & Apul, D. S. (2014). Composting toilets as a sustainable alternative to urban sanitation–A review. Waste management34(2), 329-343.
  • Bajsa, O., Nair, J., Mathew, K., & Ho, G. E. (2004). Vermiculture as a tool for domestic wastewater management. Water science and technology48(11-12), 125-132.
  • Hill, G. B., & Baldwin, S. A. (2012). Vermicomposting toilets, an alternative to latrine style microbial composting toilets, prove far superior in mass reduction, pathogen destruction, compost quality, and operational cost. Waste Management32(10), 1811-1820.
  • Nair, J., Anda, M., Mathew, K., & Ho, G. (2009). Design of vermiculture systems for organic waste management. In 2009 International Conference on Sustainable Water Infrastructure for Cities and Villages of the Future (SWIF2009).Pierre-Louis, R. C., Kader, M. A., Desai, N. M., & John, E. H. (2021). Potentiality of vermicomposting in the South Pacific island countries: A review. Agriculture11(9), 876.