4 Storyline of the Book
As a starting point, Bouma (2021) explains in the
chapter “How to Integrate and Balance Water,
Soil and Waste Expertise When Realizing the
Corresponding Nexus Approach” that achieving
the balance between the environmental resources, such as water, soil and waste, but also the
respective expertise is critical for the water-soilwaste nexus approach. Reviewing recent nexus
case studies he argues that the water-soil-waste
nexus, currently exemplified mainly by applications of wastewater to soils, needs to be complemented by a stronger focus on solid (organic)
waste, thus compost. In line with this conclusion,
Hettiarachchi et al. (2020b) elaborate on this
issue from various perspectives. Addressing the
water-soil-waste nexus requires interdisciplinarity and Bouma particularly emphasizes the much
needed, but limited interaction between soil sciences and hydrology. Both disciplines produce
enormous amounts of data, making it challenging
to transform them into information and knowledge. Common platforms, which could be termed
nexus observatories (Kurian et al. 2016) are
considered as useful, but require careful
selection/development/adaptation of tools for
data analysis—which may require another (sub-)
platform for model selection (Mannschatz et al.
2016). Bouma argues that a focus on SDGs may
be helpful to shape a nexus-oriented data analysis. However, interdisciplinarity is not enough:
transdisciplinary research approaches, engaging
stakeholders from the outset are required—an
issue taken up in several of the contributions to
this book. Eventually, they may result in case
studies that should be most effective to inform
and inspire governance of the nexus approach, a
major aim of this book.
The chapter “Nutrient Recovery for Use in
Agriculture: Economic assessment of Decentralized
Compost Business Model in Nairobi” by Gebrezgabher et al. (2021) provides a successful example
of implementing a water-soil-waste nexus, focusing
on solid waste as promoted in the previous chapter.
The study describes the development of a business
model for composting urban solid waste, which can
be a viable resource for urban dwellers and farmers.
The composting mechanism is developed in view of
the water-soil-waste nexus approach for resource
recovery and reuse while taking care of socioeconomic feasibility—similarly emphasized by
Hettiarachchi et al. (2020a). Considering the waste
streams as environmental resources, resource
recovery and the reuse business model of Nairobi
may provide a solution to the mismanagement of the
city’s waste, soil nutrient depletion, and environmental pollution.
While making use of organic solid waste for
composting is required for a comprehensive watersoil-waste nexus approach, the more common
approach of wastewater reuse has to be considered, too. In the chapter “Sustainable and Safe
Reuse of Wastewater for Food Production in Periurban Areas of Karnataka, India”, Ramakrishna
and Hanisch (2021) discuss safe options for
wastewater reuse for food production in the state
of Karnataka in India using cost-effective on-farm
treatment technologies. Nutrient availability in the
wastewater motivated smallholder farmers to
apply untreated or partially treated wastewater for
irrigation, which, however, led to health risks for
farmers and crop handlers, but also may cause soil
and groundwater salinization and contamination
(Jampani et al. 2018). Capacity development on
safe wastewater reuse practices is needed to
farmers and local peri-urban dwellers, and appropriate primary on-farm treatment technologies
should be introduced to capture nutrients, mitigate
health risks and increase crop productivity. The
study also shows that the implementation and
further development of nexus-oriented resources
management is facilitated by a participatory
approach.
Where wastewater is not available, but water is
a limiting factor for agriculture, water harvesting
techniques can be an option for sustainable food
and biomass production. In the chapter
“Usefulness of Surface Water Retention
Reservoirs Inspired by ‘Permaculture Design’: A
Case Study in Southern Spain Using Bucket
Modelling”, Fiebrig and van de Wiel (2021)
developed a simple hydrological model to assess
the efficacy of permaculture inspired surface water
6
S. Hülsmann and M. Jampani
As a starting point, Bouma (2021) explains in the
chapter “How to Integrate and Balance Water,
Soil and Waste Expertise When Realizing the
Corresponding Nexus Approach” that achieving
the balance between the environmental resources, such as water, soil and waste, but also the
respective expertise is critical for the water-soilwaste nexus approach. Reviewing recent nexus
case studies he argues that the water-soil-waste
nexus, currently exemplified mainly by applications of wastewater to soils, needs to be complemented by a stronger focus on solid (organic)
waste, thus compost. In line with this conclusion,
Hettiarachchi et al. (2020b) elaborate on this
issue from various perspectives. Addressing the
water-soil-waste nexus requires interdisciplinarity and Bouma particularly emphasizes the much
needed, but limited interaction between soil sciences and hydrology. Both disciplines produce
enormous amounts of data, making it challenging
to transform them into information and knowledge. Common platforms, which could be termed
nexus observatories (Kurian et al. 2016) are
considered as useful, but require careful
selection/development/adaptation of tools for
data analysis—which may require another (sub-)
platform for model selection (Mannschatz et al.
2016). Bouma argues that a focus on SDGs may
be helpful to shape a nexus-oriented data analysis. However, interdisciplinarity is not enough:
transdisciplinary research approaches, engaging
stakeholders from the outset are required—an
issue taken up in several of the contributions to
this book. Eventually, they may result in case
studies that should be most effective to inform
and inspire governance of the nexus approach, a
major aim of this book.
The chapter “Nutrient Recovery for Use in
Agriculture: Economic assessment of Decentralized
Compost Business Model in Nairobi” by Gebrezgabher et al. (2021) provides a successful example
of implementing a water-soil-waste nexus, focusing
on solid waste as promoted in the previous chapter.
The study describes the development of a business
model for composting urban solid waste, which can
be a viable resource for urban dwellers and farmers.
The composting mechanism is developed in view of
the water-soil-waste nexus approach for resource
recovery and reuse while taking care of socioeconomic feasibility—similarly emphasized by
Hettiarachchi et al. (2020a). Considering the waste
streams as environmental resources, resource
recovery and the reuse business model of Nairobi
may provide a solution to the mismanagement of the
city’s waste, soil nutrient depletion, and environmental pollution.
While making use of organic solid waste for
composting is required for a comprehensive watersoil-waste nexus approach, the more common
approach of wastewater reuse has to be considered, too. In the chapter “Sustainable and Safe
Reuse of Wastewater for Food Production in Periurban Areas of Karnataka, India”, Ramakrishna
and Hanisch (2021) discuss safe options for
wastewater reuse for food production in the state
of Karnataka in India using cost-effective on-farm
treatment technologies. Nutrient availability in the
wastewater motivated smallholder farmers to
apply untreated or partially treated wastewater for
irrigation, which, however, led to health risks for
farmers and crop handlers, but also may cause soil
and groundwater salinization and contamination
(Jampani et al. 2018). Capacity development on
safe wastewater reuse practices is needed to
farmers and local peri-urban dwellers, and appropriate primary on-farm treatment technologies
should be introduced to capture nutrients, mitigate
health risks and increase crop productivity. The
study also shows that the implementation and
further development of nexus-oriented resources
management is facilitated by a participatory
approach.
Where wastewater is not available, but water is
a limiting factor for agriculture, water harvesting
techniques can be an option for sustainable food
and biomass production. In the chapter
“Usefulness of Surface Water Retention
Reservoirs Inspired by ‘Permaculture Design’: A
Case Study in Southern Spain Using Bucket
Modelling”, Fiebrig and van de Wiel (2021)
developed a simple hydrological model to assess
the efficacy of permaculture inspired surface water
6
S. Hülsmann and M. Jampani