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R. Majumdar
which have the potential to be transmitted via the flow of DWW and cause pandemic
[15, 17].
Agriculture, which accounts for 70% of water consumption worldwide, plays a
major role in polluting the natural flows of water and the agricultural run-off is termed
as a non-point or diffuse source of pollution. Agricultural wastewater (AWW) typically comprises of organic matter, nutrients (N, P and K), inorganic matter (dissolved
minerals), toxic chemicals coming from fertilizers, herbicides, and pesticides and also
pathogens [18]. The quest for the growth of crop production to ensure upliftment in
the rural livelihood has led to extensive use of chemical fertilizers and pesticides in the
agricultural lands [18]. In a number of growing economies, AWW has already overtaken the contamination due to the domestic and industrial activities, and has become
a leading factor in the degradation (e.g. eutrophication) of inland freshwater, as well
as, the coastal waters [9]. As per the World Water Development Report (WWDR)
2014 of the United Nations, the nitrate ion from the agricultural run-offs has emerged
as the most common chemical contaminant worldwide in the groundwater aquifers
[19]. Furthermore, compounds present in the pesticides and the herbicides, such as
the triazine group (e.g. Atrazine), the phenyl urea group (e.g. chlorotoluron, diuron
and isoproturon), the phenoxy acid group (e.g. Mecoprop and 2, 4-D) can also be
found in the AWW [12]. Organic matter present in AWW is largely attributed to
the excreta of the farm-grown livestock, unconsumed animal feed, mismanaged crop
residues and leftover from the animal-processing industries. The untreated organic
wastes discharged from the fisheries and aquaculture also contribute to the organic
load in the AWW [18]. Over the past three decades, there has been a conscious effort
towards reusing treated municipal wastewater for agricultural purposes [20–23]. The
conventional primary and secondary wastewater treatment facilities tend to recover
most of the organic matter, dissolved solid, as well as, the suspended solid particulates in the form of sludge [23]. However, the microbial load remains unfazed by
the conventional wastewater treatment processes and the pathogenic microorganisms
continue to survive both in the treated wastewater and the concentrated sludge. The
sludge recovered from the municipal sewage water is rich in nutrients (e.g. nitrate
and phosphate) and hence, upon drying the sludge often it is used in the agricultural
land for improving productivity [24]. Therefore, the pathogenic microorganisms may
enter the agricultural field via the treated municipal wastewater, as well as, the dried
municipal sludge. Subsequently, the pathogenic load of AWW will be very similar to
that observed in case of DWW samples. Additionally, pathogens from the vegetable
waste, viz. bacteria (e.g. Pseudomonas lacrimans, Xanthomonas campestris etc.) and
viruses (e.g. Potato virus X, Potato virus Y, beetroot and onionmosaic viruses etc.)
[25], can also enter the AWW streams. In the agricultural lands, the plants may take
up the pathogenic bacteria and subsequently, it may enter the food chain. Therefore,
the nutrient-rich bio-solids recovered from the sewage sludge need to be hygienised
before being used for fertilizing soil [26]. For the municipal water to be reused in
food crop production, EPA Guidelines for Water Reuse recommend a minimum of
secondary treatment accompanied by disinfection [27]. However, for the municipal
sludge no such guideline is available, and therefore, there is a need for regulatory
framework for proper sludge hygienisation and management.
R. Majumdar
which have the potential to be transmitted via the flow of DWW and cause pandemic
[15, 17].
Agriculture, which accounts for 70% of water consumption worldwide, plays a
major role in polluting the natural flows of water and the agricultural run-off is termed
as a non-point or diffuse source of pollution. Agricultural wastewater (AWW) typically comprises of organic matter, nutrients (N, P and K), inorganic matter (dissolved
minerals), toxic chemicals coming from fertilizers, herbicides, and pesticides and also
pathogens [18]. The quest for the growth of crop production to ensure upliftment in
the rural livelihood has led to extensive use of chemical fertilizers and pesticides in the
agricultural lands [18]. In a number of growing economies, AWW has already overtaken the contamination due to the domestic and industrial activities, and has become
a leading factor in the degradation (e.g. eutrophication) of inland freshwater, as well
as, the coastal waters [9]. As per the World Water Development Report (WWDR)
2014 of the United Nations, the nitrate ion from the agricultural run-offs has emerged
as the most common chemical contaminant worldwide in the groundwater aquifers
[19]. Furthermore, compounds present in the pesticides and the herbicides, such as
the triazine group (e.g. Atrazine), the phenyl urea group (e.g. chlorotoluron, diuron
and isoproturon), the phenoxy acid group (e.g. Mecoprop and 2, 4-D) can also be
found in the AWW [12]. Organic matter present in AWW is largely attributed to
the excreta of the farm-grown livestock, unconsumed animal feed, mismanaged crop
residues and leftover from the animal-processing industries. The untreated organic
wastes discharged from the fisheries and aquaculture also contribute to the organic
load in the AWW [18]. Over the past three decades, there has been a conscious effort
towards reusing treated municipal wastewater for agricultural purposes [20–23]. The
conventional primary and secondary wastewater treatment facilities tend to recover
most of the organic matter, dissolved solid, as well as, the suspended solid particulates in the form of sludge [23]. However, the microbial load remains unfazed by
the conventional wastewater treatment processes and the pathogenic microorganisms
continue to survive both in the treated wastewater and the concentrated sludge. The
sludge recovered from the municipal sewage water is rich in nutrients (e.g. nitrate
and phosphate) and hence, upon drying the sludge often it is used in the agricultural
land for improving productivity [24]. Therefore, the pathogenic microorganisms may
enter the agricultural field via the treated municipal wastewater, as well as, the dried
municipal sludge. Subsequently, the pathogenic load of AWW will be very similar to
that observed in case of DWW samples. Additionally, pathogens from the vegetable
waste, viz. bacteria (e.g. Pseudomonas lacrimans, Xanthomonas campestris etc.) and
viruses (e.g. Potato virus X, Potato virus Y, beetroot and onionmosaic viruses etc.)
[25], can also enter the AWW streams. In the agricultural lands, the plants may take
up the pathogenic bacteria and subsequently, it may enter the food chain. Therefore,
the nutrient-rich bio-solids recovered from the sewage sludge need to be hygienised
before being used for fertilizing soil [26]. For the municipal water to be reused in
food crop production, EPA Guidelines for Water Reuse recommend a minimum of
secondary treatment accompanied by disinfection [27]. However, for the municipal
sludge no such guideline is available, and therefore, there is a need for regulatory
framework for proper sludge hygienisation and management.