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R. Majumdar
loaded in the parallelepiped tanks made of stainless steel. Each tank has a carrying
capacity of about 250 kg; however, the sludge per tank is limited to about 220 kg.
The tanks are placed on a conveyer belt which facilitates only linear translation
of the loaded tanks. The sludge-loaded tanks on the conveyer belt move through a
U-shaped path so that both the vertical faces of the tank that represent the largest
area of exposure are exposed to the Co-60 radiation. The calculated optimized dose
for killing all the pathogens is 10 kGy and for each of the tanks to receive this
optimal radiation dose, the required exposure time is about 54 min. The radiation
facility abides by the radiation safety protocol as per the regulations of BARC. The
irradiation unit is controlled using an automated routine in a Programmable Logic
Control (PLC) software platform developed by SYMEC Engineers (India) Private
Ltd. A source loading scheme is already available with BARC for the industrial-scale
irradiation units, and after every source loading, dosimetry is performed. The final
product following the hygienisation is supposed to contain less than 1000 coliforms
or 3 Salmonella sp./4 g < 1 pfu/4 g of enteric viruses <1 helminth ova/4 g [Note:
PFU means Plaque-Forming Unit and it indicates the number of virus particles that
are capable of lysing host cells and forming a plaque]. The hygienised sludge is rich
in organic carbon (~20–40% by weight). However, in order to further enhance the
nutrition value of the irradiated sludge, a solution comprising of consortium of Plant
Growth Promoting Bacteria (PGPB) named BioNPK is employed. Bio-NPK helps
in nitrogen fixation, phosphate solubilization, potassium mobilization and in the biocontrol of plant pathogens. The beneficial bacteria consortium helps in converting
the nitrogen and phosphorus to usable form for the cash crops, leading to higher
yield. The PGPB is cultured in an in-house laboratory facility, which was set-up in
collaboration with Anand Agricultural University, in Gujarat. Gujarat Agro Industries
Corporations (GAIC) is supposed to commercialize the hygienised sludge under the
brand name ‘Bio-Gold’ [73]. The irradiated sludge has demonstrated initial success
in enhancing the soil productivity, and about 12% increase in the crop yield has been
observed for every 1% increase of organic matter in the soil. However, as 90% (by
weight) of the fecal sludge consists of human manure, and human manure is not still
approved as a fertilizer, therefore, for wider acceptance of the irradiated municipal
sludge, necessary approval from Fertilizer Control Order (FCO) is required. In this
context, it can be mentioned that GOI provides a subsidy of Rs. 1.5 per kg for city
compost. Any such incentive for the irradiated sludge will pave a pathway towards
using it as a nature-based solution (NbS) in the agricultural field.
11.4 Scope for Irradiation-Based Advanced Treatment
Facilities in Urban Centres: A Case Study
for Bengaluru City
In order to mitigate the ever-growing problem of Bangalore city’s sewerage, as well
as, for rejuvenating the minor irrigation system in parched rural areas that are facing
R. Majumdar
loaded in the parallelepiped tanks made of stainless steel. Each tank has a carrying
capacity of about 250 kg; however, the sludge per tank is limited to about 220 kg.
The tanks are placed on a conveyer belt which facilitates only linear translation
of the loaded tanks. The sludge-loaded tanks on the conveyer belt move through a
U-shaped path so that both the vertical faces of the tank that represent the largest
area of exposure are exposed to the Co-60 radiation. The calculated optimized dose
for killing all the pathogens is 10 kGy and for each of the tanks to receive this
optimal radiation dose, the required exposure time is about 54 min. The radiation
facility abides by the radiation safety protocol as per the regulations of BARC. The
irradiation unit is controlled using an automated routine in a Programmable Logic
Control (PLC) software platform developed by SYMEC Engineers (India) Private
Ltd. A source loading scheme is already available with BARC for the industrial-scale
irradiation units, and after every source loading, dosimetry is performed. The final
product following the hygienisation is supposed to contain less than 1000 coliforms
or 3 Salmonella sp./4 g < 1 pfu/4 g of enteric viruses <1 helminth ova/4 g [Note:
PFU means Plaque-Forming Unit and it indicates the number of virus particles that
are capable of lysing host cells and forming a plaque]. The hygienised sludge is rich
in organic carbon (~20–40% by weight). However, in order to further enhance the
nutrition value of the irradiated sludge, a solution comprising of consortium of Plant
Growth Promoting Bacteria (PGPB) named BioNPK is employed. Bio-NPK helps
in nitrogen fixation, phosphate solubilization, potassium mobilization and in the biocontrol of plant pathogens. The beneficial bacteria consortium helps in converting
the nitrogen and phosphorus to usable form for the cash crops, leading to higher
yield. The PGPB is cultured in an in-house laboratory facility, which was set-up in
collaboration with Anand Agricultural University, in Gujarat. Gujarat Agro Industries
Corporations (GAIC) is supposed to commercialize the hygienised sludge under the
brand name ‘Bio-Gold’ [73]. The irradiated sludge has demonstrated initial success
in enhancing the soil productivity, and about 12% increase in the crop yield has been
observed for every 1% increase of organic matter in the soil. However, as 90% (by
weight) of the fecal sludge consists of human manure, and human manure is not still
approved as a fertilizer, therefore, for wider acceptance of the irradiated municipal
sludge, necessary approval from Fertilizer Control Order (FCO) is required. In this
context, it can be mentioned that GOI provides a subsidy of Rs. 1.5 per kg for city
compost. Any such incentive for the irradiated sludge will pave a pathway towards
using it as a nature-based solution (NbS) in the agricultural field.
11.4 Scope for Irradiation-Based Advanced Treatment
Facilities in Urban Centres: A Case Study
for Bengaluru City
In order to mitigate the ever-growing problem of Bangalore city’s sewerage, as well
as, for rejuvenating the minor irrigation system in parched rural areas that are facing