system, etc., are used for anaerobic degradation of contaminants in wastewater.
Generally, these integrated approaches have been applied for removing higher
level of organic matters from the wastewater. In the present time, awareness about
these integrated approaches rapidly improved due to number of advantages, e.g., low
chemicals requirement, less sludge production, higher resource recovery potential,
less equipment requirement, and easy handling. Some disadvantages are also found
related to this integrated approach such as membrane fouling, equipment
malfunctions, and need of higher proficiency for its operation, but overall performance of these integrated approach is impressive (Goli et al. 2019).
Fazal et al. (2019) investigated the simultaneous removal of COD, nitrate, and
sulfate from the wastewater using aerobic and anaerobic biodegradation approach.
Medium properties, i.e., pH was the main determining factor for biodegradation of
COD, nitrate, and sulfate. In aerobic treatment process, COD was degraded
completely in CO 2 and H 2 O, nitrate removal efficiency ranged from 83% to 90%
in cellular metabolism. However, anaerobic process removes from 68% to 80%
COD via methanogenesis process, nitrate removal efficiency ranged between 93%
and 98%, sulfate changed into elemental sulfur from 85% to 97%. In anaerobic
process, COD conversion rate was also found lower than those of the aerobic
process. More studies are still required for integrated approach to enhance its
contaminants removal efficiency, energy production as well as for reducing its
operational cost and negative environmental impacts.
6.5.3 Molecular Approach
Conventional microbial techniques for wastewater treatment are mainly based on
pure culture isolation. The morphological, physiological, and biochemical assay of
microbes extensively provided information of microbial biodiversity in natural and
engineered systems. However, improving the efficiency of conventional wastewater
treatment techniques using molecular approaches is very important. Molecular
docking is important bioinformatics modelings in which contaminants bind with
other substances and stabilized it (Liu et al. 2018). Molecular techniques such as
cloning and gene library generation, fluorescent in-situ hybridization with DNA
probes (FISH), and denaturant gradient gel electrophoresis (DGGE), etc., are also
used in wastewater treatment. Although cloning and gene library generation are
time-consuming processes they provide very significant taxonomical information.
For identification of microbes at any desired taxonomic level, FISH techniques are
used depending on the used probe specificity. DGGE is a simple and quick method
for characterizing band patterns of different samples and sample profiling rapidly but
genetic analysis is analyzed by particular band sequencing (Sanz and Köchling
2007).
Zahedi et al. (2019) assessed the eukaryotic waterborne pathogens in wastewater
treatment plants (WWTPs) responsible for public health threat. In this study, they
identified fecal pathogenic eukaryotes including Cryptosporidium sp., at different
6 Wastewater Reuse in Peri-Urban Agriculture Ecosystem: Current Scenario,. . .
139
Generally, these integrated approaches have been applied for removing higher
level of organic matters from the wastewater. In the present time, awareness about
these integrated approaches rapidly improved due to number of advantages, e.g., low
chemicals requirement, less sludge production, higher resource recovery potential,
less equipment requirement, and easy handling. Some disadvantages are also found
related to this integrated approach such as membrane fouling, equipment
malfunctions, and need of higher proficiency for its operation, but overall performance of these integrated approach is impressive (Goli et al. 2019).
Fazal et al. (2019) investigated the simultaneous removal of COD, nitrate, and
sulfate from the wastewater using aerobic and anaerobic biodegradation approach.
Medium properties, i.e., pH was the main determining factor for biodegradation of
COD, nitrate, and sulfate. In aerobic treatment process, COD was degraded
completely in CO 2 and H 2 O, nitrate removal efficiency ranged from 83% to 90%
in cellular metabolism. However, anaerobic process removes from 68% to 80%
COD via methanogenesis process, nitrate removal efficiency ranged between 93%
and 98%, sulfate changed into elemental sulfur from 85% to 97%. In anaerobic
process, COD conversion rate was also found lower than those of the aerobic
process. More studies are still required for integrated approach to enhance its
contaminants removal efficiency, energy production as well as for reducing its
operational cost and negative environmental impacts.
6.5.3 Molecular Approach
Conventional microbial techniques for wastewater treatment are mainly based on
pure culture isolation. The morphological, physiological, and biochemical assay of
microbes extensively provided information of microbial biodiversity in natural and
engineered systems. However, improving the efficiency of conventional wastewater
treatment techniques using molecular approaches is very important. Molecular
docking is important bioinformatics modelings in which contaminants bind with
other substances and stabilized it (Liu et al. 2018). Molecular techniques such as
cloning and gene library generation, fluorescent in-situ hybridization with DNA
probes (FISH), and denaturant gradient gel electrophoresis (DGGE), etc., are also
used in wastewater treatment. Although cloning and gene library generation are
time-consuming processes they provide very significant taxonomical information.
For identification of microbes at any desired taxonomic level, FISH techniques are
used depending on the used probe specificity. DGGE is a simple and quick method
for characterizing band patterns of different samples and sample profiling rapidly but
genetic analysis is analyzed by particular band sequencing (Sanz and Köchling
2007).
Zahedi et al. (2019) assessed the eukaryotic waterborne pathogens in wastewater
treatment plants (WWTPs) responsible for public health threat. In this study, they
identified fecal pathogenic eukaryotes including Cryptosporidium sp., at different
6 Wastewater Reuse in Peri-Urban Agriculture Ecosystem: Current Scenario,. . .
139