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\title{Reuse of sewage sludge as organic agricultural products: An efficient
technology-based initiative}



\author[1]{DR. SRIMOYEE BANERJEE}%
\author[1]{Acharya Balkrishna}%
\author[1]{Vedpriya Arya }%
\author[1]{Sourav Ghosh}%
\author[1]{Sumit Kumar Singh}%
\affil[1]{Affiliation not available}%


\vspace{-1em}



  
  \date{May 18, 2024}


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Acharya Balkrishna\textsuperscript{1,2}, Srimoyee
Banerjee\textsuperscript{2*}, Sourav Ghosh\textsuperscript{1}, Sumit
Kumar Singh\textsuperscript{1}, Vedpriya Arya\textsuperscript{1,2}

\textsuperscript{1} Patanjali Herbal Research Division, Patanjali
Research Institute, Haridwar, Uttarakhand 249404

\textsuperscript{2} Department of Applied and Allied Sciences,
University of Patanjali, Haridwar, Uttarakhand.

*Corresponding Author

Patanjali Herbal Research Division, Patanjali Research Institute,
Haridwar, Uttarakhand 249404; srimoyee.banerjee@prft.in

\textbf{Abstract}

Rapid urbanization has led to a dramatic increase in sewage generation
and sludge production in turn. There are very limited methods of
disposal and usage of sludge which are associated with drawbacks of
energy intensiveness and economic expenses. In the current study, sludge
from the Jagjeetpur sewage treatment plant (STP) has been collected,
composted, and characterized. A comparison of STP sludge compost and
compost made from farmyard manure showed the pH to be 6.67 which is
within the prescribed limit. The phosphate content was 1.013\% which is
almost double the desired concentration. Few other parameters were weak
in comparison but drastic changes were seen upon analyzing the fortified
products. For the first product, Jaivik Poshak, the metal concentrations
were highly reduced after a dilution effect due to fortification. The
concentration of nine nutrients was higher in modified Jaivik Poshak.
For Jaivik Khad, the second product, almost all physicochemical
parameters were matched with the routine product and the Nitrogen and
Phosphorous content was higher than the prescribed limits making it more
suitable for fertilizer use. Phosphate was highly enriched in Jaivik
Prom due to the fortification. The Zinc, Boron, Manganese, and Sodium
were found to be higher in the amended product. Thus, it can be said
that sludge can be converted into valuable agricultural products with
minimal energy expenses and monetary benefits in addition. This can be a
viable option for the management of bulk quantities of sludge in an
eco-friendly manner to generate valuable returns for farmers and sustain
the environment too.

\textbf{Keywords:} Sludge management, Organic farming, Agriculture

\textbf{Introduction}

The semi-solid slurry generated from various industrial processes, from
wastewater treatment and on-site sanitation systems is known as sludge.
It may be generated as a settled suspension from drinking water
treatment, as sewage sludge from wastewater treatment, or as fecal
sludge from septic tanks. After treatment of wastewater in the treatment
plant, 99\% of the water is recovered which is discharged as rejuvenated
water. The remaining 1\% which comprises solids is the sludge.

Treatment of wastewater includes several stages. During preliminary
treatment which involves the removal of large particles like sticks,
stones, plastic, etc, the screened material is typically landfilled and
does not become a part of the sludge. Primary treatment comprises
gravity sedimentation and floatation during which half of the solids
that enter this stage are removed and become the primary sludge. It
comprises both organic and inorganic components. Secondary treatment is
a carefully controlled and biologically governed process where the
microbes degrade the organic components in the wastewater. The microbial
biomass generated as a result of this is organic in nature and becomes
the next component in the sludge. Tertiary treatment is done to reduce
the nitrogen and phosphorus component, suspended solids, and biological
oxygen demand. Precipitated components during the tertiary stage of
treatment add to the total sludge quantity. The final step includes
disinfection to kill the pathogenic microbes and discharge of the
rejuvenated water (Penn state extention, 2010). On average, dry sludge
contains 50-70\% organic matter, 30-50\% mineral content, 3.4-4\%
Nitrogen, 0.5-2.5\% Phosphorous, and several other nutrients depending
on the types of wastes treated and the stabilization processes involved
(Kacprzak et al., 2017).

Owing to the rapid urbanization and industrialization, the quantity of
sludge produced has become huge, and hence special attention is required
for its management. One aspect of sludge management is its use in
agriculture. Application of large and uncontrolled amounts of untreated
sludge results in the seepage of heavy metals, phenolic compounds,
polycyclic aromatic compounds into the soil, groundwater, and
surrounding water bodies which may bring about drastic changes in soil
fertility and damage to flora and fauna (Balkrishna et al., 2022.;
Houillon \& Jolliet, 2005). It is important to pre-treat the sludge,
make it suitable to meet legal regulations, and then use it for a
particular purpose. However, pretreatment technologies are complicated,
expensive, and pose the question of the disposal of concentrated
pollutants separated from the sludge. Thermal incineration is another
alternative that significantly reduces the volume of sludge. The ash
thereby generated as a result of incineration needs other methods for
cyclization. The products of incineration may be used in cementing
industry or for vitrification (Cie\selectlanguage{polish}ś\selectlanguage{english}lik, 2015). Other methods exist for
the recovery of valuable substances from the sludge. Pyrolysis of sewage
sludge under anaerobic conditions can be done to generate adsorbents
after the addition of various reactants. Other by-products include
pyrolysis oil which can be used as fuel. In this way, partial recovery
of sludge is possible (Cie\selectlanguage{polish}ś\selectlanguage{english}lik, 2015; Samolada \& Zabaniotou, 2014).
Phosphorus recovery is another technology implemented by most treatment
plants.

The presence of heavy metals poses a problem for almost all sludge
management systems (Mailler, 2015). Recovery of such metals is done in
furnaces in oxidative or reducing conditions. Metals recovered in this
process are used in industries as catalysts or additions in special
products. This process is mainly done in developed countries owing to
the high-end instrumentation requirements, cost, and energy inputs
involved (Cie\selectlanguage{polish}ś\selectlanguage{english}lik, 2015).

Underdeveloped nations primarily dispose of the sludge at the source
which thereby creates environmental problems and risks for humans and
aquatic life (Balkrishna et al., 2022). The wastewater treatment
processes concentrate heavy metals, organic pollutants, and pathogens.
Sludge disposal can therefore bring about the release of toxic
components into the environment which can thereby enter the food chain
(Chen et al., 2012; Wei \& Liu, 2005; Pathak, 2009). Though landfilling
is an economical and low energy consuming process, it becomes a
significant source of CH\textsubscript{4} and N\textsubscript{2}O which
are greenhouse gases (Peters \& Rowley, 2009). Landfilling is also
incapable of utilizing any of the nutrients that are present in the
sludge. Landfill leachates containing P and heavy metals can also
significantly affect groundwater and surface waters. Land application of
sludge also has many benefits as it improves soil qualities and is
inexpensive. However, land application is also limited owing to its
heavy metal, micropollutant, and pathogenic microbe content (Wang et
al., 2008).

The current manuscript deals with how sludge may be converted into a
valuable agriculture input in an eco-friendly way. Three organic
fertilizers routinely made with farmyard manure compost have been
modified by using sewage treatment plant (STP) sludge compost. In our
study, expensive and energy-intensive procedures have been completely
avoided yet the product developed meets regulatory parameters. The
optimum fortification of sludge with suitable additives led to the
production of organic fertilizer with reduced heavy metal concentration
yet increased capacity for plant growth promotion. This procedure could
solve the problems of managing drastic amounts of sludge while creating
valuable agricultural inputs. It is proposed as a sustainable option for
converting waste into a valuable product for use in agriculture.

\textbf{Materials and methods:}

\textbf{2.1 Site of sludge collection} :

The sludge sample was collected from a sewage treatment plant at
Jagjeetpur in Haridwar, Uttarakhand, India. The location coordinates are
29.9015435, 78.1376691. This treatment plant has been commissioned since
November 2019 under the Namami Gange Program as a part of its
interventions to prevent the flow of untreated wastewater into the river
Ganga. The plant came under working conditions in June 2020. The total
treatment capacity of the plant is 68 million liters per day (MLD) and
uses sequential batch reactors for the treatment process. An average
sludge production reported for April 2021 was 399 MT (National Mission
for Clean Ganga, 2021). During our inspection to the site on 08.02.2022
and 15.02.2022, we found no tertiary treatment to be taking place in
this plant. As told by the head engineer of the site, the average sludge
production per day was approximately 19.68 MT. Also, the sludge
generated from the plant was deposited within the plant premises near
the Ganga River bank. It was found that the untreated sludge was
supplied to farmers on their demand for usage as agriculture input. The
head engineer of the site handed over the data regarding the inlet and
outlet wastewater parameters for January and till mid-February which
were collected by the auto analyzer as well as manually rechecked. With
regard to sewage, the data of solid particles (in \%) in the outlets of
seven centrifuges for the period of January, 2022 was given. The extent
of dewatering of the sewage can be understood from that. The data for
MLSS in the six basins of the sequential batch reactor was also given
for January, 2022 which indicated the extent of suspended solids in the
sequential process and the extent of purification taking place after the
waste water crossed each basin.

\textbf{Sample collection and characterization} :

The sludge sample was collected in bulk in sealed packets and brought to
the laboratory. For the characterization of the sample, moisture
content, total organic carbon, pH, C/N ratio, Total Nitrogen content,
Total Phosphate content, Total Potassium content (as
K\textsubscript{2}O) and Total NPK were measured. The metal content was
analyzed using Atomic Absorption Spectroscopy (AAS). All the procedures
for the measurement of different parameters as well as metals were
followed from Fertilizer Control Order (FCO), 1985 (Government of India,
1985). A comparative assessment was done between the metal and macro and
micronutrient parameters of routinely prepared compost and compost from
the STP sludge to understand the nutrient status as well as heavy metals
status in both the compost.

\textbf{2.3 Product preparation}

There are few tested products by Patanjali Organic Research Institute
(PORI) which are used as organic fertilizer inputs in agriculture. They
are prepared by mixing the individual components in a fixed ratio which
has been deciphered by experimentation and trials. The products contain
compost as one of the components which is prepared at the institute from
farmyard manure. The products are developed with the purpose of
increasing agricultural productivity and are under huge demand by
farmers in Uttarakhand and India. In order to take a step forward in the
management of the huge quantities of sludge produced at wastewater
treatment plants while conforming to environmental parameters and
increasing agricultural productivity, PORI has attempted to make organic
fertilizer from STP sludge. Three different products have been prepared
by using STP sludge from Jagjeetpur instead of in-house compost.

Patanjali Jaivik Poshak is a mycorrhiza-based patented (Patent number
201811028449) granular biofertilizer that contains a small but powerful
nutrient nano compound mixture. A modified version of the existing
product was prepared by mixing the ingredients by replacing the
routinely used in-house compost with compost prepared from STP sludge.
The mixture was made for a total of 10 Kg.

The next product is Patanjali Jaivik Khad which is a 100\% organic
manure made from the leftovers of medicinal plants, flowers, vegetables,
and cattle dung composting procedures and is fortified
with\emph{Trichoderma} , \emph{Pseudomonas} , and \emph{Aspergillus} .
Humic acid, amino acids, seaweed, and natural nutrients are all balanced
in this product. It enables plants to defend themselves against
illnesses and insects. This formulation strengthens crops' immune
systems and helps them resist disease. It can be used for paddy, wheat,
sugarcane, potato, soybean, groundnuts, peas, onion, and a variety of
vegetables, pulses, and fruits, among other crops. This was also made
for a total quantity of 10Kg.

The third product is Jaivik Prom (Patent number 201811028448). It is a
phosphorous-rich organic farming input that contains 10.42 to up to 12\%
phosphorous. Bio residues, rock phosphate, Khalil, amino acid, plant
development factors, and helpful micro bacteria makes up this patented
product. Paddy, maize, wheat, sugarcane, potato, soya, groundnut,
peanut, onion, and numerous vegetables, legumes, fruit, flowers, and
medicinal plants can all benefit from the application of this product.
This particular product has also been prepared by substituting the
in-house compost with STP sludge compost. The final 10kg product thereby
prepared was compared with the original product.

All three products are routinely produced using in-house compost made
from farmyard manure. They are all patented. The compost component was
replaced by the STP sludge. After mixing in the desired proportions the
parameters were analyzed for the routinely made products and the
modified products. A comparative analysis was done to understand the
effect brought about with the substituted compost.

In order to characterize the product quality made with the STP sludge, a
comparative analysis was done to understand the effect of the
fortification process. The metal and nutrient status of the standard
product and the modified products was compared.

\textbf{Results and discussions}

\textbf{3.1 Sampling site}

The 68 MLD Sewage treatment plant was found to be a well-functioning and
maintained plant in Jagjeetpur, Uttarakhand, India. It was effectively
cleaning wastewater generated from the city and its surroundings and
thereby preventing Ganga River from pollution due to numerous
contaminants. Two representative images of the STP plant are shown below
in figure 1.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

Figure 1: Representative images of Jagjeetpur STP

The sludge generated regularly was dumped within the plant premises and
hence alternative solutions for its usage need to be found.

The data of soild partciles (\%) in each centrifuge outlet which is an
indicatorof the extent of dewatering, for the month of January 2022 was
obtained from the head engineer and has been given as given as table 1
in the supplementary material.

The geometric mean of solid particles generated from the seven
centrifuge outlets was plotted as a time series which is shown in Figure
2 below.

\par\null\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Figure-2/Figure-2}
\caption{{This is a caption
{\label{970225}}%
}}
\end{center}
\end{figure}

Figure 2: Time series plot of geometric mean of the solid particles in
different centrifuge outlets

From the time series plot it is evident that there are certain ups and
downs as the geometric mean of seven outlets has been taken but the
overall efficiency of dewatering is within a range of 22.24 to 28.09\%
which is a very small range. The standard deviation is also very less
with a maximum value of 4.78. It can be deciphered that the working
efficiency of the plant is very high and all the centrifuges are working
at comparable efficiencies. Data over a month in this range also states
that the sludge generation capacity is also optimum.

Data for MLSS (mg/L) in the six basins of the SBR in January, 2022 has
been given as Table 2 in supplementary material

The mean of each basin along with the standard deviation was plotted and
is shown in Figure 3 below.

\par\null\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/Figure-3/Figure-3}
\caption{{This is a caption
{\label{720344}}%
}}
\end{center}
\end{figure}

Figure 3: Average MLSS values in January, 2022 in the six basins of the
SBR

From the figure, it can be seen that there is a sequential increase in
the MLSS values in the six basins except for a slight fall in basin 3.
Again after that, the MLSS values have continuously increased and basin
6 has the highest MLSS value which is the normal case for an SBR. As the
wastewater purification proceeds in a stepwise manner, the water content
is sequentially removed, increasing amounts of solids accumulate and
hence the first basin shows minimum MLSS concentration while the last
shows the maximum value. The standard deviation values also are within
limits which shows that the performance of the plant over the month was
highly stable and efficient.

\textbf{3.2 Sample characterization}

The routinely prepared in-house compost, as well as the compost prepared
from STP sludge, were characterized simultaneously to compare their
characteristics. The STP sludge had certain undesirable components like
grass which were could create problems in the final product. The STP
sludge was ground well before analysis in order to prevent lump
formation due to its sticky nature. The comparative analysis of the
in-house compost and STP sludge compost along with the prescribed
specifications as per FCO, 1985 is given below in Table 1.

Table 1: Comparative analysis of in-house sludge and STP sewage sludge
compost\selectlanguage{english}
\begin{longtable}[]{@{}lllll@{}}
\toprule
Serial number & Parameter & Specification & Concentration in in-house
compost & Concentration in STP compost\tabularnewline
\midrule
\endhead
1 & Moisture content (\%) & Not more than 25\% & 30.551 &
52.109\tabularnewline
2 & Total Organic Carbon (\%) & Minimum 14\% & 15.243 &
15.017\tabularnewline
3 & pH & 6.5-7.5 & 7.56 & 6.78\tabularnewline
4 & C:N ratio & Less than 20 & 15.911 & 25.45\tabularnewline
5 & Total Nitrogen (N) & Minimum 0.5\% & 0.958 & 0.59\tabularnewline
6 & Total phosphate as P\textsubscript{2}O\textsubscript{5} (P) &
Minimum 0.5\% & 0.766 & 1.013\tabularnewline
7 & Total Potassium as K\textsubscript{2}O (K) & Minimum 0.5\% & 0.37 &
0.164\tabularnewline
8 & Total NPK nutrient & Not less than 3\% & 2.094 &
1.767\tabularnewline
\bottomrule
\end{longtable}

From the above comparative analysis, it is evident that there are few
parameters where the STP compost is not as good as in-house compost and
vice versa. The moisture content is way higher for the STP compost than
the prescribed limits. The major reason for this is that the sludge was
collected on a rainy day and as it is lying open in the plant premises
it is quite usual for it to get wet. However, this can be easily managed
with regular drying technologies. The organic carbon content is above
15\% for both in-house and STP sludge compost against the specification
of 14\%. Interestingly, the pH of the sludge compost is within the
prescribed specifications as compared to the pH of in-house compost.
This is beneficial as it would not require external additions to bring
the pH within the limit thereby saving cost and preserving the chemical
nature of the compost. The C/N ratio for the sludge compost is much
higher than the specifications which is due to the low N content. It can
be seen that the N content is just marginally higher than the prescribed
specification in the case of the sewage sludge but the in-house compost
is of better quality in this respect. The phosphate content is almost
double the specifications in the case of sludge compost. The phosphate
content is approximately 0.8\% for in-house compost as compared to a
specification of 0.5\%. The Potassium content of STP sludge compost is
way lower than the recommended specification. The in-house compost also
does not contain the desired concentration. The total NPK content is
also lower than the specifications for both in-house and sludge compost.
Overall, we find that the STP sludge contains a number of valuable
nutrients. Most of them are in concentrations greater than the desired
specifications. The presence of plant macronutrients also makes it an
important constituent that may be used in addition to other inputs so as
to utilize those for plant growth. Fortification of the sludge compost
with correct additives will enhance its properties and make it a
fruitful addition for agriculture.

We have tried to analyze the metal concentrations present in the sludge
as well as in-house compost using Atomic Absorption Spectroscopy. The
macro and micronutrient status were also measured and analyzed. The
table 2 below shows the results of heavy metals in STP and in-house
sludge in comparison to the desired concentration as specified by
government regulations (Government of India, 1985).

Table 2: Concentration of metals in the sludge\selectlanguage{english}
\begin{longtable}[]{@{}llllll@{}}
\toprule
Serial Number & Metal contaminant & Units & Specified concentration for
use as agricultural fertilizer & Measured concentration in in-house
compost & Measured concentration in STP sludge compost\tabularnewline
\midrule
\endhead
1 & Arsenic & mg/Kg & 10 & 3.77 & 3.00\tabularnewline
2 & Cadmium & mg/Kg & 5 & 0.65 & 0.84\tabularnewline
3 & Mercury & mg/Kg & 0.15 & 0.67 & 1.39\tabularnewline
4 & Lead & mg/Kg & 100 & 13.18 & 18.01\tabularnewline
5 & Chromium & mg/Kg & 50 & 10.61 & 14.15\tabularnewline
\bottomrule
\end{longtable}

The metal concentrations in the sludge are well below the permissible
limit except for Mercury. The concentration of Mercury is 0.67 in STP
sludge which is higher than the prescribed specification but lower than
the previously used compost values of 1.39. Appropriate fortification of
the dried sludge not only helps in reducing the metal content by
dilution procedure but also helps in significantly improving its quality
for usage in agriculture. The comparison of the macro and micronutrients
is shown in the table 3 below.

Table 3: Comparative analysis of nutrients in STP sludge compost and
farmyard compost\selectlanguage{english}
\begin{longtable}[]{@{}lll@{}}
\toprule
& Concentration in STP sludge & Concentration in farmyard compost
Sludge\tabularnewline
\midrule
\endhead
K & 2858.95 & 5171.93\tabularnewline
Na & 1162.75 & 1764.79\tabularnewline
Ca & 1655.58 & 1999.02\tabularnewline
B & 28.92 & 13.23\tabularnewline
Mn & 115.18 & 137.33\tabularnewline
Fe & 6169.52 & 7836.75\tabularnewline
Co & 2.12 & 2.36\tabularnewline
Ni & 12.42 & 7.77\tabularnewline
Cu & 40.29 & 32.09\tabularnewline
Zn & 230.3 & 156.97\tabularnewline
\bottomrule
\end{longtable}

The macro and micronutrient status of both the compost show that there
are sufficient amounts of plant macronutrients present in the STP sludge
with great potential for utilization in agriculture. The concentration
of Boron, Zinc, Copper and Nickel are higher than the STP sludge while
the concentrations of rest of the nutrients are lower in comparison to
the routinely used in-house compost. The status of these ingredients and
the product quality would change further after the fortification
process.

\textbf{3.3. Product characterization}

The three products prepared with the STP sludge were analyzed along with
the products prepared routinely with in-house compost. The comparative
analyses of each product are discussed subsequently below. The following
table 4 describes the comparative analysis of Jaivik Poshak.

Table 4: Comparative analysis of Physico-chemical parameters of Jaivik
Poshak\selectlanguage{english}
\begin{longtable}[]{@{}lllll@{}}
\toprule
\textbf{Serial Number} & \textbf{Parameter} & \textbf{Jaivik Poshak
recommendations} & \textbf{Jaivik Poshak analysis results} &
\textbf{Comparison of modified Jaivik Poshak}\tabularnewline
\midrule
\endhead
1 & Physical state & Granular & Compliant & Compliant\tabularnewline
2 & Solubility in water & Partially Soluble & Compliant &
Compliant\tabularnewline
3 & pH & 6.5-7.5 & 8.90 & 7.10\tabularnewline
4 & Moisture content & 8-12\% & 11.19 & 8.68\tabularnewline
5 & Average spore count per gm & 60 minimum & 86 & 22\tabularnewline
6 & Bulk density & Less than 1 & 0.79 & 0.73\tabularnewline
\bottomrule
\end{longtable}

For the modified Jaivik Poshak, the physical parameters and solubility
were compliant with the standard specifications. The moisture content
was well within the limits. The pH was found to improve as compared to
routinely prepared Jaivik Poshak and stay within specifications. The
spore count was found be 22/gm which is lesser than the desirable value.
This may be amended in future to enrich the spore numbers.

The table 5 below describes the comparative analysis of Jaivik Khad.

Table 5: Comparative analysis of Physico-chemical parameters of Jaivik
Khad\selectlanguage{english}
\begin{longtable}[]{@{}lllll@{}}
\toprule
\textbf{Serial Number} & \textbf{Parameter} & \textbf{Jaivik Khad
recommendations} & \textbf{Jaivik Khad analysis results} &
\textbf{Comparison of modified Jaivik Khad}\tabularnewline
\midrule
\endhead
1 & Color & Blackish Grey Powder & Compliant & Compliant\tabularnewline
2 & Physical state & 90\% material pass through 4mm sieve & Compliant &
Compliant\tabularnewline
3 & Moisture content & Not more than 25\% & 30.50 & 30.32\tabularnewline
4 & Bulk Density & Less than 1 & 0.61 & 0.58\tabularnewline
5 & Total organic carbon\% & Minimum 14\% & 14.93\% &
16.057\tabularnewline
6 & pH & 6.5-7.5 & 7.217 & 6.833\tabularnewline
7 & C:N ratio & Less than 20 & 17.30 & 13.73\tabularnewline
8 & Total Nitrogen (N) & Minimum 0.5\% & 0.863 & 1.169\tabularnewline
9 & Total Phosphorous as P2O5 (P) & Minimum 0.5\% & 2.58 &
1.781\tabularnewline
10 & Total Potassium as K2O (K) & Minimum 0.5\% & 0.716 &
0.32\tabularnewline
11 & Total NPK nutrient & Not less than 3\% & 4.159 &
3.27\tabularnewline
\bottomrule
\end{longtable}

For modified Jaivik Khad, the colour and physical state are compliant as
per the original product. The moisture content was higher which can be
managed during the production process. The pH is within the specified
limit. The total nitrogen appears to be in greater quantities in the
modified product as compared to the original one.

For the third product, Jaivik Prom the comparative results are shown
below in Table 6

Table 6: Comparative analysis of Physico-chemical parameters of Jaivik
Prom\selectlanguage{english}
\begin{longtable}[]{@{}lllll@{}}
\toprule
\textbf{Serial Number} & \textbf{Parameter} & \textbf{Jaivik Khad
recommendations} & \textbf{Jaivik Khad analysis results} &
\textbf{Comparison of modified Jaivik Khad}\tabularnewline
\midrule
\endhead
1 & Color & Blackish Grey Powder & Compliant & Compliant\tabularnewline
2 & Physical state & 90\% material pass through 4mm sieve & Compliant &
Compliant\tabularnewline
3 & Moisture content & Not more than 25\% & 8.64 & 14.44\tabularnewline
4 & Bulk Density & Less than 1.6 & 0.95 & 0.94\tabularnewline
5 & Total organic carbon\% & Minimum 7.9\% & 8.16 &
13.261\tabularnewline
6 & pH & Maximum 6.7 & 8.17 & 7.07\tabularnewline
7 & C:N ratio & Less than 20 & 11.36 & 10.12\tabularnewline
8 & Total Nitrogen (N) & Minimum 0.4\% & 0.718 & 1.31\tabularnewline
9 & Total Phosphorous as P2O5 (P) & Minimum 10.4\% & 12.19 &
9.353\tabularnewline
10 & Total Potassium as K2O (K) & Minimum 0.5\% & 1.3 &
0.62\tabularnewline
11 & Total NPK nutrient & Not less than 3\% & 14.208 &
11.283\tabularnewline
\bottomrule
\end{longtable}

It can be seen from the comparative analysis that the moisture content
for the modified product is within the limit. The total organic carbon
is much higher in the modified product than in the routinely prepared
product. The pH was found to be slightly higher in the modified product
which can be amended by neutralization as done routinely for other
similar products. The total nitrogen content which is the major plant
macronutrient is much higher in concentration in the modified product
and is more than the specification as well as the routine product. The
Potassium content and the total NPK content are all meeting with the
specifications.

The data for the comparative analysis is shown below for the three
modified products. The analyses for Jaivik Poshak is shown in Figure 4.
owing to the different data ranges for the macronutrients and some
micronutrients the metals have been grouped according to their values.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image2/image2}

\end{center}
\end{figure}

Figure 4: Comparison of metal and nutrient status of amended and
routinely made Jaivik Poshak

It was seen that the metal concentration was within limits for all
metals except for Cadmium in the product made from in-house compost. The
Cadmium concentration was approximately 10 times lower in the modified
product and hence can be stated to be safe for agricultural application.
In terms of nutrient status, the modified Jaivik Poshak was lower in
Boron, Sodium and Cobalt content only with respect to the product
prepared normally with in-house compost. The concentration for nine
other nutrients was higher in the modified product. The percentage
increase in the nutrient concentration was seen to range from a minimum
of 6.5\% for copper to up to 863\% for Phosphorous as can be visualized
from Figure 4.

The comparison of results for Jaivik Khad is shown in Figure 5 below.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image3/image3}

\end{center}
\end{figure}

Figure 5: Comparison of metal and nutrient status of amended and
routinely made Jaivik Khad

From the analyses we found the mercury concentration to be marginally
higher in the amended product with respect to the permissible limit. For
Cadmium too, the measured concentration is higher than the limit
although for the amended product it is marginally higher or almost at
par with the recommendation. From the viewpoint of Cadmium, the amemded
product is safer than the routinely made Jaivik Khad. With respect to
the nutrient concentrations, Nickel and Copper are higher in the amended
product as compared to the routine product although the concentrations
present are good for plant growth.

Figure 6 below shows the comparative analyses for Jaivik Prom.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image4/image4}

\end{center}
\end{figure}

Figure 6: Comparison of metal and nutrient status of amended and
routinely made Jaivik Prom

For Jaivik Prom, the heavy metal concentrations for the amended product
are well within permissible limits for the amended product except for
the Cadmium concentrations. The nutrient concentration is higher for
Zinc, Boron, Manganese, and Sodium in the amended product. The other
nutrients are lesser as compared to routine products but the inherent
levels in the modified product are good enough to be used for plant
growth promotion.

\textbf{Conclusion}

With increasing volumes of sludge, there is a dire need for sludge
management. While direct land disposal takes place in underdeveloped
countries, it is not a viable option as it leads to accumulation of
toxins like aromatic hydrocarbons, heavy metals in the soil contaminates
groundwater as well as nearby surface water due to seepage problems.
Landfilling has also been found to be a potential source of greenhouse
gases and leads to global warming. The other technologies like
incineration, pyrolysis, metal and phosphorous extraction, use for fuel
also exist associated with their costs and energy expenses. In this
study we have proposed a unique solution for the sludge for Jagjeetpur
STP in haridwar whereby it can be usefully converted to agrcicultural
inputs after treatment. Analysis of the data obtained directly from the
plant, commissioned under Namami Gange Program showed the stability in
its performance from the timeline of solid particles produced in the
centrifuge outlets and MLSS data. Three products were made from the STP
sludge compost instead of using the routinely made compost from farmyard
manure. Detailed analysis of STP sludge compost showed the presence of
plant nutrients which can be used for the purpose of growth promotion.
Upon fortification of the sludge with other ingredients to make products
for specific purposes it was seen that the concentration of heavy metals
in the modified product was well within limits for the a barring few
exceptions. the physicochemical parameters were also within the
prescribed specification of tye FCO, 1985. The nutrient concentrations
were also in the desirable range and hence can be used as a good organic
fertilizer. The mixing of different ingredients for the three products
respectively and appropriate fortification resulted in bringing the
undesirable parameters within specified limits with an increase in the
desirable nutrient concentrations. Further amendments with more
experimental data will further improve the quality of the products for
obtaining better results. This can be a sustainable solution for sludge
management with minimal input of energy. Moreover, sale of these reputed
products can bring revenue for the company and gains for the farmers.
Thus, it is a true situation of conversion of waste to value added
products.

\textbf{Acknowledgement}

The authors express their deep sense of gratitude to Honourable Swami
Ramdev ji for his guidance and support. The swift administrative support
from Mr. Lalit Mohan is also highly acknowledged.

\textbf{Conflict of interest}

None

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