Farmers were of the opinion that whilst
wastewater is available, they will practice farming; when there is no water source, they will sell
off the land. Despite the risks associated with
unsafe usage of wastewater, the FGD revealed
that the benefits gained through wastewater irrigation are low cost of cultivation (as less fertilizer is required than under freshwater irrigation)
and higher productivity since wastewater is rich
in nutrients. However, the amount of weedicide
applied is higher on account of prolific weed
growth. The weeds increased because of the
fertile nature of the sewage and the increased
availability of water in the areas that were traditionally rain-fed. The increase in the number of
weeds also had implications in terms of labour
required, which adds to either the direct costs of
hired labour or opportunity costs of household
members. All these need to be further studied to
better understand the cost-effectiveness of
wastewater agriculture.
3.5 Risk Mitigation Measures
The fundamental global challenges of human
development and environmental protection with
respect to sanitation and agriculture can be
tackled only if they are viewed as a nexus
(Hettiarachchi and Ardakanian 2018). The nexus
perspective is a driver of sustainable development goal (SDG) #3 (good health and wellbeing), #6 (clean water and sanitation), and #11
(sustainable cities and communities). To make
the safe use of treated human waste socially,
epidemiologically, environmentally, and economically feasible and acceptable, it is essential
to ensure safety to public health and the
environment.
3.5.1 Best Farmers’ Practices
There are some minimal and cost-effective on-farm
treatment methods that will reduce pathogen load
and minimize health risks. There is a wide range of
treatment options available to treat wastewater.
Some of the best farmer practices for treating
wastewater through locally available solutions are
settling tanks and filtration or screening.
Settling tanks
Settling tanks or wastewater storage tanks are
constructed by some farmers on their fields to
store wastewater for one to two days before use
on fields (Fig. 7). This will help to remove the
settle-able suspended solids. This cost-effective
partial treatment through sedimentation and
retention improves wastewater quality by
retaining most of the nutrients.
A sedimentation/settling tank allows suspended particles to settle out of water
or wastewater as it flows slowly through the
tank, thereby providing some degree of purification. A layer of accumulated solids (sludge),
forms at the bottom of the tank and is periodically removed. This settling tank method is
common in Maradgi village, which is very near
to Govankoppa.
Filtration or screening
About 25% of total respondents were found to be
using a simple screen or filter prior to applying
the wastewater to the field. This filtration serves
two purposes: it prevents debris entering the
pump thereby reducing wear and tear, and it
prevents the degradation of soil with solid waste
(basically plastic, medical waste, and textiles)
present in the sewage.
3.5.2 Recommended Safe Use Practices
A multiple-barrier approach is recommended to
mitigate the risks of wastewater farming. This refers
to the sequential combination of control measures
to guide improvements for agricultural use. In
combination, all controls should ideally achieve or
exceed the target log reductions (WHO 2016).
The key concepts behind the WHO guidelines
(WHO nd) are as follows:
• All exposure groups (farmers, crop handlers,
and consumers) should be adequately protected
• It may not initially be feasible to meet target
log reductions for farmers and consumers in
all circumstances. Improvement plans should
aim to incrementally improve the situation.
Sustainable and Safe Use of Wastewater …
51
wastewater is available, they will practice farming; when there is no water source, they will sell
off the land. Despite the risks associated with
unsafe usage of wastewater, the FGD revealed
that the benefits gained through wastewater irrigation are low cost of cultivation (as less fertilizer is required than under freshwater irrigation)
and higher productivity since wastewater is rich
in nutrients. However, the amount of weedicide
applied is higher on account of prolific weed
growth. The weeds increased because of the
fertile nature of the sewage and the increased
availability of water in the areas that were traditionally rain-fed. The increase in the number of
weeds also had implications in terms of labour
required, which adds to either the direct costs of
hired labour or opportunity costs of household
members. All these need to be further studied to
better understand the cost-effectiveness of
wastewater agriculture.
3.5 Risk Mitigation Measures
The fundamental global challenges of human
development and environmental protection with
respect to sanitation and agriculture can be
tackled only if they are viewed as a nexus
(Hettiarachchi and Ardakanian 2018). The nexus
perspective is a driver of sustainable development goal (SDG) #3 (good health and wellbeing), #6 (clean water and sanitation), and #11
(sustainable cities and communities). To make
the safe use of treated human waste socially,
epidemiologically, environmentally, and economically feasible and acceptable, it is essential
to ensure safety to public health and the
environment.
3.5.1 Best Farmers’ Practices
There are some minimal and cost-effective on-farm
treatment methods that will reduce pathogen load
and minimize health risks. There is a wide range of
treatment options available to treat wastewater.
Some of the best farmer practices for treating
wastewater through locally available solutions are
settling tanks and filtration or screening.
Settling tanks
Settling tanks or wastewater storage tanks are
constructed by some farmers on their fields to
store wastewater for one to two days before use
on fields (Fig. 7). This will help to remove the
settle-able suspended solids. This cost-effective
partial treatment through sedimentation and
retention improves wastewater quality by
retaining most of the nutrients.
A sedimentation/settling tank allows suspended particles to settle out of water
or wastewater as it flows slowly through the
tank, thereby providing some degree of purification. A layer of accumulated solids (sludge),
forms at the bottom of the tank and is periodically removed. This settling tank method is
common in Maradgi village, which is very near
to Govankoppa.
Filtration or screening
About 25% of total respondents were found to be
using a simple screen or filter prior to applying
the wastewater to the field. This filtration serves
two purposes: it prevents debris entering the
pump thereby reducing wear and tear, and it
prevents the degradation of soil with solid waste
(basically plastic, medical waste, and textiles)
present in the sewage.
3.5.2 Recommended Safe Use Practices
A multiple-barrier approach is recommended to
mitigate the risks of wastewater farming. This refers
to the sequential combination of control measures
to guide improvements for agricultural use. In
combination, all controls should ideally achieve or
exceed the target log reductions (WHO 2016).
The key concepts behind the WHO guidelines
(WHO nd) are as follows:
• All exposure groups (farmers, crop handlers,
and consumers) should be adequately protected
• It may not initially be feasible to meet target
log reductions for farmers and consumers in
all circumstances. Improvement plans should
aim to incrementally improve the situation.
Sustainable and Safe Use of Wastewater …
51