which could also be mixed with stormwater (Aryal et al. 2011). Every day, around
2 million tons of sewage, agricultural, and industrial wastewater are released into the
world’s water, the equivalent of the weight of the entire human population of
6.8 billion people. The UN estimates that the amount of wastewater produced
annually is about 1500 km
3 , approximately six times more water than exists in all
the rivers of the globe (UN WWAP 2003; World Water Quality Facts And Statistics
2013).
Wastewater utilization for irrigational purposes is one of the emerging perspectives particularly in water-scanty places in the world. Zhang and Shen (2017)
reported that wastewater is very advantageous for farming activities because it
provides continuous water supply in the duration of the irrigation period and
decreases the risk of income losses and crop failure. Wastewater use in agriculture
is a reliable supply of water; its supply is irrespective of weather variability and
seasonal drought and reduces the dependability on climate or weather conditions for
rainwater which is frequently seen in many developing countries (Mateo-Sagasta
et al. 2013; Magwaza et al. 2020). In agriculture, crop growth required a mixture of
biodegradable organic material (carbon and nitrogen), as well as most of the mineral
nutrients (e.g., phosphorous, potassium, magnesium, boron, molybdenum, selenium,
and copper); all do present in enough quantity in wastewater (Durán-Álvarez and
Jiménez-Cisneros 2015).
Heavy metal is an inevitable element in the wastewater, and they get accumulated
in the soil and plants, when irrigated by wastewater. Several techniques and technologies emerged to get rid of trace metals. There are mainly three types of treatment
processes: physical, chemical, and biological; these include ion exchange, chemical
precipitation, flocculation, membrane filtration, floatation, co-precipitation, electrochemical treatment, and adsorption (Bolisetty et al. 2019). These techniques are not
techno-efficient or cost-effective methods. But some techniques like physical
adsorption are highly effective and feasible for the elimination of heavy metal
from waste stream; it includes activated carbon use as adsorbent in the water and
wastewater treatment plants (Ahmad et al. 2020a, b). But activated charcoal is not an
economically effective method. After the extensive research, the most cost-effective
alternative has come out, i.e., the use of low-cost agricultural and horticultural
by-products such as sugarcane bagasse, rice husk, sawdust, coconut husk, oil palm
shell, neem bark, etc. for the removal of trace metals from the wastewater, and it has
been investigated successfully (Sharma et al. 2013; Castillo-Monroy et al. 2020;
Tandon et al. 2020). This quality of wastewater promotes the number of researches
and studies globally. The reuse of wastewater in agriculture investigations and their
report states that judicious and rationale use will enhance the properties of soil,
promote plant growth, and appreciate the bacterial activity. But unjustifiable and
irrational use will create plenty of other issues.
With the above context, the present chapter has all the detailed information
regarding the status of wastewater generation and their treatment. The consequent
effect of wastewater irrigation on soil and plant health is also discussed with a short
description on the most cost-effective technique, i.e., the use of agricultural residues
to mitigate the problem of metal toxicity up to a certain extent. It will definitely
178
Monika et al.
2 million tons of sewage, agricultural, and industrial wastewater are released into the
world’s water, the equivalent of the weight of the entire human population of
6.8 billion people. The UN estimates that the amount of wastewater produced
annually is about 1500 km
3 , approximately six times more water than exists in all
the rivers of the globe (UN WWAP 2003; World Water Quality Facts And Statistics
2013).
Wastewater utilization for irrigational purposes is one of the emerging perspectives particularly in water-scanty places in the world. Zhang and Shen (2017)
reported that wastewater is very advantageous for farming activities because it
provides continuous water supply in the duration of the irrigation period and
decreases the risk of income losses and crop failure. Wastewater use in agriculture
is a reliable supply of water; its supply is irrespective of weather variability and
seasonal drought and reduces the dependability on climate or weather conditions for
rainwater which is frequently seen in many developing countries (Mateo-Sagasta
et al. 2013; Magwaza et al. 2020). In agriculture, crop growth required a mixture of
biodegradable organic material (carbon and nitrogen), as well as most of the mineral
nutrients (e.g., phosphorous, potassium, magnesium, boron, molybdenum, selenium,
and copper); all do present in enough quantity in wastewater (Durán-Álvarez and
Jiménez-Cisneros 2015).
Heavy metal is an inevitable element in the wastewater, and they get accumulated
in the soil and plants, when irrigated by wastewater. Several techniques and technologies emerged to get rid of trace metals. There are mainly three types of treatment
processes: physical, chemical, and biological; these include ion exchange, chemical
precipitation, flocculation, membrane filtration, floatation, co-precipitation, electrochemical treatment, and adsorption (Bolisetty et al. 2019). These techniques are not
techno-efficient or cost-effective methods. But some techniques like physical
adsorption are highly effective and feasible for the elimination of heavy metal
from waste stream; it includes activated carbon use as adsorbent in the water and
wastewater treatment plants (Ahmad et al. 2020a, b). But activated charcoal is not an
economically effective method. After the extensive research, the most cost-effective
alternative has come out, i.e., the use of low-cost agricultural and horticultural
by-products such as sugarcane bagasse, rice husk, sawdust, coconut husk, oil palm
shell, neem bark, etc. for the removal of trace metals from the wastewater, and it has
been investigated successfully (Sharma et al. 2013; Castillo-Monroy et al. 2020;
Tandon et al. 2020). This quality of wastewater promotes the number of researches
and studies globally. The reuse of wastewater in agriculture investigations and their
report states that judicious and rationale use will enhance the properties of soil,
promote plant growth, and appreciate the bacterial activity. But unjustifiable and
irrational use will create plenty of other issues.
With the above context, the present chapter has all the detailed information
regarding the status of wastewater generation and their treatment. The consequent
effect of wastewater irrigation on soil and plant health is also discussed with a short
description on the most cost-effective technique, i.e., the use of agricultural residues
to mitigate the problem of metal toxicity up to a certain extent. It will definitely
178
Monika et al.