measurements of water quality at different
locations differ without any possible
explanation (e.g., case 7 in Mexico City).
(iv) Only a few studies report soil data (e.g.
case 1 very broadly in terms of “sands and
gravel”, case 6 in terms of various
“clayey” textures, case 7 in Mexico City
as soil classifications: Leptosols, Phaeozems and Vertisols and case 9 in Colombia as Inceptisols with vertic properties.
But the link between Taxonomic soil
classes and their hydraulic and purifying
behaviour remains obscure which not only
limits the interpretation of local processes
but also the possibility to extrapolate
results to other areas with comparable
soils.
(v) Major problems are encountered when
judging rules and legislation related to
applying wastewater to soils. Aside from
malfunctioning WWTPs, which appears to
be common, top-down rules and regulations clearly don’t work (see descriptions
in cases 2 (Lima), 3 (Egypt), 5 (Brasilia),
11 (South Africa), 12 (Bolivia), 13
(Nepal), 14 (Argentina) and 15 (Iran)).
Carlos Antonio Pailles Bouchez of the
“Council for certification of irrigation with
treated water” in Mexico, presents a crucial remark: “the culture of water in our
countries does not include the importance
of the treatment of wastewater”. Only
education and demonstration of successful
examples of wastewater application to
soils, that consider the complete flow
system, can turn this around. This not only
applies to stakeholders but to the policy
arena as well. In fact, the policy arena can
best be approached by presenting specific
case studies demonstrating that well guided waste applications to soil represent
significant contributions towards reaching
SDGs. Such case studies should go
beyond anecdotal data, applying modern
measurement, monitoring and modeling
techniques for soil and water. This was
lacking in the case studies presented by
Hettiarachchi and Ardakanian (2016b) but
can show the way for effective future
research. Usually, politicians are more
than willing to share the success stories,
rather than failures. Top-down rules and
regulations based on theoretical and conceptual considerations can hardly be
effective as they bypass stakeholder opinions and experiences in the real world.
Clearly, data on liquid waste application to
soil is strongly restricted to the first part of the
chain: waste generation and treatment, chemical
characteristics of the waste in different phases of
the particular treatment being followed and, less
so, to application to the soil by flooding or drip
irrigation. Also, groundwater quality is being
measured, but not everywhere. Quality of crops
and vegetables that are grown receive much
emphasis. How water infiltrates into the soil and
the travel path to the groundwater, which determines the purification process that is quite variable in different soils, does not receive any
attention at all. If infiltration rates are too low,
surface runoff into surface water may occur as
well as erosion both leading to significant pollution of surface waters. Nor is there any attention for the water regime in a more regional
context: where does the irrigation water move
once it has reached the groundwater aquifer or
surface waters? The conclusion can only be that
the water-soil-waste nexus is as yet quite
incomplete and fragmented.
3 How to Complete the Water-SoilWaste NEXUS Chain?
The cases reported by Hettiarachchi and
Ardakanian (2016b) are most valuable as they
allow a realistic appraisal of the state-of-the-art
dealing with the application of wastewater to
soils. A similar publication on applying solid
waste derived compost to soils would be very
welcome because of the similar problems likely
to be found here. Compost may increase the
organic matter content of soils, increasing its
How to Integrate and Balance Water, Soil and Waste …
19
locations differ without any possible
explanation (e.g., case 7 in Mexico City).
(iv) Only a few studies report soil data (e.g.
case 1 very broadly in terms of “sands and
gravel”, case 6 in terms of various
“clayey” textures, case 7 in Mexico City
as soil classifications: Leptosols, Phaeozems and Vertisols and case 9 in Colombia as Inceptisols with vertic properties.
But the link between Taxonomic soil
classes and their hydraulic and purifying
behaviour remains obscure which not only
limits the interpretation of local processes
but also the possibility to extrapolate
results to other areas with comparable
soils.
(v) Major problems are encountered when
judging rules and legislation related to
applying wastewater to soils. Aside from
malfunctioning WWTPs, which appears to
be common, top-down rules and regulations clearly don’t work (see descriptions
in cases 2 (Lima), 3 (Egypt), 5 (Brasilia),
11 (South Africa), 12 (Bolivia), 13
(Nepal), 14 (Argentina) and 15 (Iran)).
Carlos Antonio Pailles Bouchez of the
“Council for certification of irrigation with
treated water” in Mexico, presents a crucial remark: “the culture of water in our
countries does not include the importance
of the treatment of wastewater”. Only
education and demonstration of successful
examples of wastewater application to
soils, that consider the complete flow
system, can turn this around. This not only
applies to stakeholders but to the policy
arena as well. In fact, the policy arena can
best be approached by presenting specific
case studies demonstrating that well guided waste applications to soil represent
significant contributions towards reaching
SDGs. Such case studies should go
beyond anecdotal data, applying modern
measurement, monitoring and modeling
techniques for soil and water. This was
lacking in the case studies presented by
Hettiarachchi and Ardakanian (2016b) but
can show the way for effective future
research. Usually, politicians are more
than willing to share the success stories,
rather than failures. Top-down rules and
regulations based on theoretical and conceptual considerations can hardly be
effective as they bypass stakeholder opinions and experiences in the real world.
Clearly, data on liquid waste application to
soil is strongly restricted to the first part of the
chain: waste generation and treatment, chemical
characteristics of the waste in different phases of
the particular treatment being followed and, less
so, to application to the soil by flooding or drip
irrigation. Also, groundwater quality is being
measured, but not everywhere. Quality of crops
and vegetables that are grown receive much
emphasis. How water infiltrates into the soil and
the travel path to the groundwater, which determines the purification process that is quite variable in different soils, does not receive any
attention at all. If infiltration rates are too low,
surface runoff into surface water may occur as
well as erosion both leading to significant pollution of surface waters. Nor is there any attention for the water regime in a more regional
context: where does the irrigation water move
once it has reached the groundwater aquifer or
surface waters? The conclusion can only be that
the water-soil-waste nexus is as yet quite
incomplete and fragmented.
3 How to Complete the Water-SoilWaste NEXUS Chain?
The cases reported by Hettiarachchi and
Ardakanian (2016b) are most valuable as they
allow a realistic appraisal of the state-of-the-art
dealing with the application of wastewater to
soils. A similar publication on applying solid
waste derived compost to soils would be very
welcome because of the similar problems likely
to be found here. Compost may increase the
organic matter content of soils, increasing its
How to Integrate and Balance Water, Soil and Waste …
19