Taste of life: Poona’s tryst with handling waste all about manure for growth
The disposal of night-soil to the best advantage had been a very important issue since the middle of the 19th century India. When Poona started its journey towards becoming a city, excreta and offal began to be a nuisance and the question of disposal of these substances became important.
Since pre-municipal days, sweepers belonging to particular castes collected night-soil from houses every day. They then sold the manure to cultivators.
These sweepers and manual scavengers were considered “untouchables”. They were required to collect the excreta, carry it in cane or metal containers on their heads, and empty the contents at a designated site a few miles away from the city. Because the residents did not want the “sweepers” to “pollute” their houses with their touches, or mere presence, toilets were constructed at the entrances of the residential buildings, so that the sweepers would collect the excreta and left without entering their dwellings.
The local population of Poona had gotten used to the stench which would greet them upon entering their houses and while walking down the lanes. The Poona City Municipality deliberated over the issue of toilets and foul smells and decided to put the night-soil to better use.
Mixing night-soil with earth, ashes, or town sweepings and the application of the mass to the land was one of the simplest methods to utilise the waste. Called “sonkhat” in Marathi, the use of night-soil as manure was not altogether unknown in the Bombay Presidency. Its use in many places was obstructed due to prejudice, and the caste dynamics it brought into play.
To overcome these issues, the Agriculture Department at the then College of Science, Poona, (now College of Engineering, Pune), at the request of the Municipality, undertook a series of experiments with the help of the Sanitation Department after 1890. HK Kelkar, an Associate Professor of Agriculture, was put in charge.
The Municipality had then already adopted the “Poona method” of making poudrette of manure. In this system, fresh excreta was carted to a depot and covered with ashes and town sweepings in shallow beds. This mixture was exposed to the sun to dry; when properly dried it was heaped away and sold to farmers as manure.
Ashes were used primarily to remove the foul odour. They also made the poudrette richer in potash. In the rainy season, the drying had to be done under cover and consequently, the process took about a fortnight, whereas in the winters it took about a week. During summer, the process needed five days to complete.
In the Poona Cantonment, a slightly different system was used. Pits were dug about five feet deep and of convenient length and breadth. Into these pits, night-soil and earth were put in alternate layers and in equal proportions. This system was more sanitary than the one adopted by Poona City Municipality, but the poudrette manufactured by this method could not be handled for several months.
Several systems of purifying sewage were tried by the Agricultural Department in co-operation with the Poona Municipality and Sanitation Department from 1894 to 1905 on the Poona and Manjari farms in connection with the Poona drainage system.
In the first set of experiments carried out in 1894, fresh night-soil was directly applied to the land by the shallow bed system. One month from the date of application, the land was ploughed, harrowed, and sown with Sundhia (a cultivar of Sorghum from Gujarat) for fodder. The yield obtained was 1,133 bundles of fodder per acre, which was “significantly more” than the yield of crop obtained without the use of night-soil as manure.
Next year, experiments were conducted on the Manjari Farm owned by the Agriculture Department with poudrette manufactured by the Poona method. The yield of sugarcane per acre was measured and compared with different manures such as cattle dung from “ordinary fed animals”, Safflower cake, Castor cake, Karanji cake, cottonseed cake, and Bassia cake. It was found that the yield obtained with poudrette was “slightly better” than with the other manures.
In 1898, a small septic tank was constructed in Mangalwar peth and the effluent from this tank was carted to the Kirkee farm daily and applied to the crops, viz. sugarcane, Guinea-grass, Lucerne, Sundhia, and maize. The effluent was compared with farmyard manure and poudrette at the rate of 20 and 25 tonnes per acre respectively. The outturn of produce per acre was “almost double” for effluent.
The next year, the effect of effluent on various garden crops was tested. They were mostly vegetables like onions, potatoes, “knoll-khols”, sweet potatoes, turmeric, and yams.
Encouraged by the results obtained at the Kirkee farm, JC Pottinger, sanitary engineer, planned in consultation with the Agricultural Department, a trial of three distinct systems of sewage purification at Manjari.
A septic tank, Dib-Dins filter, and a macerating tank were constructed and sewage purification under these three systems was carried out for six years, from 1899.
The effluent of these different systems was compared with poudrette, farmyard manure, castor-cake, niger-cake, and safflower-cake respectively. The results were encouraging as before.
The success of these experiments was so marked that the government, on the advice of the Sanitary Department, undertook to demonstrate conclusively the agricultural value of the sewage and to furnish a basis for calculation in carrying out the drainage scheme of Poona.
A purification plant was set up at the Manjari farm which consisted of a mixing tank, a septic tank, bacteria beds, and sand filters. In the septic tank, the organisms, which thrived well in the absence of air, dissolved the whole of the solid matters of the sewage and simplified the organic compounds. The nitrogenous substances were largely converted into nitrates. Fish lived well in the effluent liquid and it could be passed into the river without causing any kind of nuisance. Various kinds of crops like sugarcane, onions, groundnut, turmeric, yams, and ginger were grown by its aid at Manjari.
In 1906, the Poona Municipality discontinued the regular manufacture of poudrette as it did not cover the expenses. The carting of night-soil, urine, and sweepings, etc. from the city was put to auction every year. The contractor manufactured poudrette and sold the same to farmers.
The municipality later started encouraging homeowners to construct toilets with septic tanks behind their houses to facilitate proper disposal of the waste. The efforts continued for many decades.
The social stigma reinforced by caste-designated occupation of manual scavenging and widespread discrimination perpetuated by untouchability have sadly not yet been eliminated.