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Special
Reports/Water Crisis |
Use of wastewater: opportunities and
threats
By Abedullah & Shahzad Kouser
FOR
the last many decades, there has been growing concern that
the world is moving towards water crisis. Growing water
scarcity threatens economic development, sustainable human
livelihoods and environment quality. Urban population
growth, particularly in developing countries, places immense
pressure on water and land resources.
Due to increasing pressure on water demand, planners are
continually searching for new sources of water, which can be
used economically, and effectively to promote development
process. The use of urban wastewater in agriculture is a
centuries-old practice that is receiving renewed attention
with the increasing scarcity of freshwater resources in many
arid and semi -arid regions.
Wastewater is water that has been adversely affected in
quality by any anthropogenic influence. It includes liquid
waste discharged from domestic houses, industrial,
agricultural or commercial processes. Driven by rapid
urbanisation and growing wastewater volumes, wastewater is
widely used as a low-cost alternative to conventional
irrigation water. It supports livelihoods and generates
considerable value in urban and peri-urban agriculture
despite the health and environmental risks associated with
this practice.
It is estimated that up to one-tenth of the world’s
population eats food produced from wastewater. As
populations continue to grow and more freshwater is diverted
to cities for domestic use — 70 per cent of which later
returns as wastewater — the use of wastewater is certain to
increase, both in terms of the areas irrigated, and in the
volumes applied.
Nothing is wrong to use treated wastewater, but there are
serious concerns to apply untreated wastewater in vegetable
production. Untreated wastewater is not only affecting
productivity of agricultural labourer by increasing
probability of getting sick but it also affects the soil
productivity of land in the long run and further it is
affecting the quality of ground water. The story is not
ending here yet rather it also affects the health of those
consumers using vegetables grown with untreated wastewater.
Different literature indicates that annual risk of
contracting infectious diseases including typhoid fever,
rotavirus infection, cholera and hepatitis
The damages of untreated wastewater have not been estimated
in Pakistan but we have attempted to estimate the value of
forgone labour earnings and soil productivity loss from
untreated wastewater use. Since, a very poor segment of the
society is involved in small farming activities and their
livelihood is totally depending on their net income. The
foregone labour earning due to high probability of sickness
and therefore, more expenditure on medical treatment will
worsen the poverty level of this poorest segment of the
society.
The supply of untreated wastewater to vegetable production
is adversely affecting the quality of ground water that is
multiplying the expenditure on the medical treatment for the
poor of the poor. In order to shift this group above the
poverty line the government not only has to take measures to
increase their agricultural productivity but also have to
reduce non-productive expenditure (medical) by improving
physical infrastructure.
Our study based on the data set collected from the vicinity
of Faisalabad, the total area under wastewater irrigation is
2,139 ha (5283.2 acreage) located in different sites of
Faisalbad. The results indicate that in wastewater area land
preparation cost is higher compared to freshwater irrigated
area because land has become more compact and hard due to
untreated wastewater use since long time.
The land requires relatively more cultivations and planking
in wastewater area. This indicates that wastewater is
affecting soil quality and its structure as it can be
observed in Pic 1.
The average cost of pesticides is almost double in
wastewater compared with irrigated farms because wastewater
create conducive environment for insects to grow (Pic 2).
Higher amount of pesticide use together with wastewater is
affecting the quality of environment adversely and farmers
are paying for environment in terms of higher medical cost
in wastewater area. However, the situation is reversed in
case of fertiliser cost. Freshwater farmers spent four times
more on fertilisers compared to wastewater farmers.
Cost and benefit of production in both wastewater and
freshwater areas are estimated with and without
externalities (negative impact). The per acre per crop net
benefits are respectively, Rs23,692 and Rs24,486 for
freshwater and wastewater users. It is observed that both
total cost and gross revenue are higher for freshwater users
but net benefits of wastewater users are higher in vegetable
production. The net benefits are almost four per cent higher
in wastewater area compared to freshwater area. The rate of
return on cash investment is slightly higher (1.9 per cent)
in wastewater area compared to freshwater fields (1.3 per
cent) mainly because of lower cash cost incurred in
wastewater area. Benefit or value of wastewater use is Rs794
per acreage.
Untreated wastewater irrigation is not only deteriorating
the soil productive capacity but also negatively affecting
the farmers’ health especially those who get exposure to it
during different agronomic practices. The major contribution
of the present study is to estimate the economic values of
negative externalities to evaluate the wastewater use in
crop production especially in vegetable in peri-urban areas
of Faisalabad. The annual opportunity cost of land,
associated with wastewater induced land degradation is Rs4.5
million.
Farmers who are irrigating their land with wastewater are
found to have significantly higher prevalence of hepatitis,
vomiting, stomach ach, skin allergy, cholera, diarrhoea,
typhoid and dysentery than those who are irrigating their
land with canal or tube-well water because untreated
wastewater contained high concentration of helminth eggs and
faecal coli form bacteria.
Net economic value of labour productivity loss due to
different sicknesses (hepatitis, vomiting, stomach pain,
allergy, cholera, diarrhoea, typhoid and fever) is estimated
at Rs52 million in wastewater area. In addition to value
loss due to forgone earning (Rs52 million), the loss of
money in terms of medical expenditures is Rs63 million due
to untreated wastewater irrigation.
Total cost of externalities (damages) due to wastewater use
only in Faisalbad is Rs1.2 billion per annum. After
including the cost of externality, the cost of production in
wastewater area has significantly increased, indicating that
crop production with wastewater is economically not feasible
when the cost of externalities are included.
It is not sufficient to say that crop production is not
economically feasible rather annual net return from crop
production become negative and the value of negative profit
is Rs1 billion per annum and Rs29 million per crop for the
whole wastewater area in Faisalabad. In order to make the
vegetable production economically feasible from wastewater
use, the price of cauliflower should be higher than market
price due to cost of externality.
Policy Suggestions: The analysis clearly depicts that after
internalising all the cost of production externalities, the
benefit loss of untreated wastewater irrigation is Rs1.2
billion per annum only in Faisalabad city (Consumption
externality “i.e. externality by consuming vegetable grown
with wastewater”, is not included yet) and it shows that
wastewater irrigation does not remain economically feasible.
On the based of empirical findings the present study
suggests the following options;• Government has to stop the
untreated wastewater supply in order to save the enormous
losses in terms of public health damages and soil
deterioration or it has to properly dispose off the
untreated wastewater because it is the prime responsibility
of the government to provide clean living environment to its
inhabitants.
• Other option is that the government can install the
treatment plant and the cost of treatment plant can be
recovered within couple of years by saving the cost of
negative externalities that both consumers and producers are
suffering from.
• The third option is that the government should pay the
subsidy equal to labour loss (forgone labour earnings) and
medical expenditures to inhabitants of that area.
• The last and most practical option is, the cost of damages
should be recovered from industrialists by imposing taxes
equal to the cost of externalities or the govt. should force
them to install the treatment plant before throwing water in
the main stream.
The treated wastewater is not dangerous at all rather it is
a gift of God to the farmers. Most of the European nations
are extracting a big share of their water consumption from
recycled wastewater.
Courtesy :
The DAWN
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Pakissan.com;
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