Proper decomposition of excreta a challenge
India’s open defecation free (ODF) status is being lauded by experts, although they add that the challenge now is the disposal of the excreta collected in many pit-style toilets. Safe disposal can go a long way in preventing soil and groundwater contamination, they said.
India was declared ODF on October 2.
The national annual rural sanitation survey (NARSS) of 2018-19 conducted by the ministry of drinking water and sanitation shows that 34% of the toilets have septic tanks with soak pits, 30% have twin leach pit toilets, about 20% have single leach pits, 3.3% have septic tanks without soak pits, and 13% have closed pits.
While the NARSS considers disposal through septic tank with soak pit, single leach pit, double leach pit, closed drain with sewer system and closed pits to be safe, an analysis by Centre for Science and Environment (CSE) shows such a definition can be erroneous.
“The definition is about the containment system (type of pit for holding the excreta) and not disposal of the excreta. It does not examine how often or where the excreta is disposed—which can be a water body, vacant plots or farmland,” said Sushmita Sengupta, programme manager (water) at Centre for Science and Environment (CSE). Everything depends on the quality of construction; if the pits or septic tanks are not built properly as per specifications, the excreta will not decompose and contaminate groundwater.
“The scale of Swachh Bharat Mission is huge. After several attempts in the past, the ODF mission has been accomplished. The question however remains whether excreta is being disposed safely. The beneficiaries receive ₹12,000 for construction of toilet but it should be monitored how septic tanks or the pits are emptied and whether they are discharged in water body or rivers without treatment. The focus of SBM 2.0 should be excreta management,” Sushmita added. SBM stands for Swachh Bharat Mission, the campaign to make India ODF.
The twin pit system is considered the safest. With the single pit system beneficiaries often get very deep pits dug, so that it doesn’t need to be emptied soon, which can contaminate groundwater. The septic tanks are also often constructed without following BIS standards; tanks need to be emptied regularly. The twin pit system works thus—there are two pits, each measuring 3.5 feet deep and one metre in diameter; the distance between them is one metre. When twin pit toilets are used, fecal matter will be allowed to pass and settle in one pit only. When that pit is filled in about four to five years, the channel to the first pit is closed and the second opened for the fecal matter to pass into. After a one year rest period, the content of the first pit becomes manure.
There is no recent study by Central Pollution Control Board (CPCB) assessing the impact of ODF on Ganga water quality. According to Swachch Bharat Mission, the 4507 villages around the river are ODF and 2.091 million toilets have been constructed in them. CPCB released a report on microbial characterization of Ganga last year which is based on samples collected in 2017. The study concluded that from Gangotri to Uttarkashi and in Alaknanda River at Devprayag, the probability of microbial contamination is nil. At many locations from Bijnor to Varanasi Salmonella/ Cryptosporidium and E Coli contamination was found; in some stretches severe contamination was recorded. Use of river water at these locations could cause typhoid fever, paratyphoid fever and diarrhea, the study said. In 2017, about 3812 villages along the Ganga stretch were ODF.
“There is no analysis on how ODF has impacted Ganga water quality. The pollution from open defecation in Ganga is minuscule. The fecal matter from open defecation reaches the river only during monsoon. The highest load is from untreated sewage in big cities such as Kanpur, and waste from tanneries and textile industries. If you look at Delhi, 90% of the pollution load in Yamuna is from sewage while 10% is from industries. I don’t think ODF can make a big difference to Ganga water quality,” said Manoj Mishra, convenor of Yamuna Jiye Abhiyan.