agro-rural development

agro-rural development

RECYCLING OF HUMAN WASTES : NEED OF THE HOUR

Shrikant M.Navrekar
Introduction

Every human being on this earth creates filth, if not anything else. He starts taking his diet a few hours after his birth, which continues until his death. Similarly, the acts of defecation & urination also continue throughout his life. In addition to the wastes like feces & urine, which are given out of a human body, two more inevitable wastes are produced in our daily routine viz; waste water (sullage) & garbage (solid waste).
Feces, urine, wastewater & garbage are all, directly or indirectly, harmful to human health.
If we peep into the history of human civilization, we find that in the earliest era, man was a nomadic creature, his population was limited & he used to live in the vicinity of forests. Therefore, there wasn’t any accountable danger from his wastes. (In that era, wastewater & garbage never existed). The problem of waste disposal started arising since man started colonization, & the real hazards of human wastes came into light only after the industrial revolution when very huge crowds of people started settling around industries in an indiscriminate manner.
It is true that all the human wastes cause health hazards & hence deserve destruction. The estimates show that about 80 % of the world’s diseases are linked with inadequate sanitation & 10 to 25 million people die of these diseases every year. Thus, sanitation is of prime importance from the point of view of health. However, this is only one side of the coin. The other side, which was hitherto neglected, has started coming into light & environmentalists world over are realizing its importance. It is the ‘Reuse potential of human wastes’. Thus in addition to the health aspect, sanitation is also important from the economic point of view.

‘ Waste management ’ not ‘ waste disposal ’

In the modern era, especially in the western countries the health aspect was over-emphasized resulting in the development of methods, which aimed at mere destruction, or disposal of human wastes. However, a time has now come when we must change our attitude from ‘ mere destroying the wastes ’ to ‘managing the wastes’. It is an established fact that most of the human wastes can best be converted into high quality organic manures & energy. This has a direct bearing on our agriculture, our village economy & ultimately on our national economy too! In fact, for a developing country like India, with its limited resources & unlimited challenges to meet, this recycling capability of wastes is a boon indeed!

The Nature’s Cycle

In nature, like all other systems, which maintain the ecological balance, there exists a system to deal with various waste products. For example, dead leaves of a tree in the forest fall down and accumulate beneath it an d due to rains and moist conditions, get decayed adding to the fertility of the soil. The droppings of animals get dried, decomposed and mixed with the soil as manure.













So far as the dietary pattern of man and the cropping pattern adopted for the same are concerned, there exists an implicit cycle which must be maintained for a balanced ecosystem. Out of the crops grown, the grain part is consumed by man and the straw by his animals. Hence, the dung of the animals as well as the human excreta must be returned to the soil in an appropriate manner. In fact, we owe it to the soil.
“If the night soil of a person (feces and urine) is properly converted into manure, it provides sufficient plant nutrients to produce enough crops to fulfill his dietary needs.”
Today, with the craze of modernity and with a greed for higher yields, we have broken the above cycle and our agriculture has thus become totally dependent on synthetic fertilizers, disadvantages and other consequences of which are well known.

Reusability of human wastes

If the human wastes like feces, urine and garbage are scientifically recycled, large quantities of organic manure can be obtained which is evident from the following table.

Table 1- India : Plant nutrients obtainable from human wastes

Plant Nutrient

Average quantity obtainable
Qty. obtainable only from rural population
From feces & urine
gm /day/ head
(a)*
From garbage
gm /day/ head
(b)*
Total
gm/day /head

(c=a+b)
Total
Kg /Year /Head
(million tons/year)
Nitrogen
12.90
3.00
15.90

4.06
Phosphorus
4.15
2.10
6.25

1.60
Potassium
3.04
3.90
6.94

1.80
* Note : (a) Ref.: Feachem et.al. – Appropriate Technology for water & sanitation
(b) Ref.: H.B.Gotaas – Composting
If we take into consideration the manure obtainable from the livestock, we get the following statistics.

Table 2 – India: Plant nutrients obtainable from livestock waste

Total livestock in India
240 million
Dung production per day (@ 10 kg / cattle)
2.4 mill. tons
Dung utilized for manure (assuming 30 % use)
0.72 mill. tons
Qty. of manure obtainable per day (50% of the fresh dung wt)
0.36 mill.tons
Qty. of manure obtainable per year
131.4 mill. tons


Nutrient
Qty. obtainable per year
Nitrogen
1.7 mill.tons
Phosphorus
1.5 mill.tons
Potassium
1.3 mill.tons
Ref.: Handbook of Agriculture ICAR
Note : Plant nutrients from animal urine not considered.

Now let us compare the availability of plant nutrients from table 1& 2 with the total requirement of plant nutrients of India.









Table 3 – India : Comparison between the availability & requirement
of plant nutrients



Plant Nutrient
Qty. removed by all crops per year
(million tons)

Qty. obtainable from human wastes
(million tons)
a
Qty. obtainable from livestock wastes
(million tons)
b
Total
(million tons)

a+b
Nitrogen
4.27
4.06
1.7
5.76
Phosphorus
2.13
1.6
1.5
3.10
Potassium
7.42
1.8
1.3
3.10

From the above table it can be concluded that almost all the manurial needs of a nation can be compensated by recycling the wastes. The techniques to achieve this are also very simple & low cost. It is the need of the hour to explore the possibilities of propagating these technologies along with the principles & thought behind it.

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