Lack of monitoring and emission of harmful gases like dioxins and furans within poorly designed, substandard toilets are major risks posed by small-scale incinerators
Biomedical waste incinerator plant for complete combustion of sanitary napkins.
The theme of Menstrual Hygiene Day 2023 is to make menstruation a normal fact of life by 2030. The predominant objective is to create a world where no one is held back because they menstruate.
However, menstrual awareness also comes with certain type of “environmental consciousness.” So, when we talk about menstrual heath and products, we should also talk about making menstruation greener and environment friendly so as to have least practicable impact on the environment.
According to the Menstrual Hygiene Alliance of India, India generates nearly 12 billion disposable sanitary napkins every year, the majority of which are non-biodegradable in nature, typically made from polypropylene and superabsorbent polymer powder (sodium polyacrylate).
As a result, the management and safe disposal of sanitary waste consisting of soiled disposable napkins is challenging for all the urban local bodies in India. According to Central Pollution Control Board (CPCB) guidelines, sanitary pads’ disposal can be done by deep burial, pit disposal, and thermal treatment (incineration).
However, the preferred method of disposal is incineration as stipulated by the Union Ministry of Drinking Water and Sanitation. The most convenient and commonly adopted method for commercial establishment is through locally made small-scale incinerator plants.
Small-scale locally made incinerators for disposal of menstrual waste are gaining momentum all across India due to their reference in the CPCB Guidelines on Sanitary Waste 2018 and the MHM Guidelines 2015.
Cities like Pune and Bengaluru and states like Goa have installed small-scale sanitary waste incinerators in schools and colleges. Last year, the Delhi government announced the installation of sanitary napkin incinerators with smoke control units in toilet blocks for girls in 550 Municipal Corporation of Delhi schools.
Sanitary pads waste generation in India
Source: Sanitary Waste Management in India (2021): Challenges and Agenda, Centre for Science and Environment, New Delhi
Sanitary waste disposal practices in India
Source: Menstrual Hygiene Management, WaterAid, 2019. Graphic prepared by CSE
It is important to note that when incineration is carried out in a controlled condition and at an appropriate temperature in centralised plants, waste is converted into gases and incombustible solid waste (e.g., ash). Gaseous emissions from incineration are released into the atmosphere after subjecting it to various air pollution control devices or gas cleaning and control measures.
On the contrary, the application of small-scale locally made incinerator plants comes with a wide range of environmental concerns and health hazards.
According to World Health Organization, modern incinerators operating at 850-1100°C and fitted with special gas-cleaning equipment are able to comply with the international emission standards for dioxins and furans.
The European Waste Incineration Directive recommends incinerators reach a temperature of at least 850°C for at least two seconds to ensure full breakdown of toxic substances.
In most of the locally made incinerator plants, combustion takes place at relatively lower temperature. Dioxin formation happens in a temperature range of 200 to 800°C with a maximum reaction rate reached between 350 to 400°C.
It is imperative to understand that two significant factors make small-scale incinerators less attractive. These are:
Disposable pads have chlorine and plastic in them. This mix of chlorine and plastic, when burned, releases extremely hazardous carcinogenic gases including dioxin furans when burnt at low temperatures.
Dioxin and furans are toxic, persistent (do not readily break down in the environment), and bio-accumulative (able to move up the food chain) in nature.
Dioxin and furan toxicity is reported in humans that are potentially exposed to high concentrations occupationally or in industrial accidents.
Studies have also reported the possibility of chronic low-level exposure hazards in humans. The International Agency for Research on Cancer classifies tetra-chlorinated dioxin as a known human carcinogen based on substantial evidence on animal experiments and enough evidence on human studies.
The acute exposure (short-term exposures) can cause skin lesions and liver ailments. Long-term or chronic exposure is likely to affect the immune, nervous, endocrine, and reproductive systems.
Chronic exposure to harmful gases could be disastrous for the girls and women who use these toilets on a regular basis. Therefore, it is highly recommended that incinerators should not be installed in closed rooms or toilet blocks where the risk of emissions being generated into the room is high.
Also, there should be proper arrangement for the outlet pipe (vent stack) to lead outside the room to an appropriate height and away from people.
The Sold Waste Management Rules (2016) and CPCB guidelines on siting criteria of municipal solid waste incinerators states that the incinerator facility should be installed at least 500 metres away from a residential area.
This contradicts the installation of decentralised small-scale incinerators in schools and colleges. Chronic exposure to toxic emissions such as dioxins and furans can cause health hazards to people in close vicinity.
Indian Institute of Science, Bengaluru, studied the performance evaluation of two locally available sanitary napkin incinerators commonly used in India and reported several limitations, including a high concentration of carbon monoxide and carbon dioxide in the stack gases emitted by the small incinerator’s plants.
Preferably, the centralised bio-medical waste incinerators at CBWTFs (common bio-medical waste treatment facilities) should be adopted as a disposal technology for environmentally sound disposal of sanitary waste and energy recovery.
The waste is burnt at high temperature (900 oC). This ensures complete combustion of the waste and all the flue gas generated in the process. However, there are only 208 CBWTFs in the country.
Number of bio-medical waste incinerators in India
Source: CSE (2021)
Switching to ‘greener menstruation’: It is important to note that disposable napkins are 90 per cent plastics which are typically non-biodegradable in nature and can persist in nature for hundreds of years.
Therefore, there is an urgent need to switch to sustainable menstruation which is all about being aware of the negative environmental impacts of disposable sanitary products which eventually contributes to plastic waste generation and ends up in our oceans and landfills.
This movement focuses on the access to sustainable menstruation products to every woman. Less polluting options such as menstrual cups and reusable clothes should be promoted though extensive behavioural change campaigns.
Adequate monitoring protocol: It is well known that incineration will accept any waste so long as the waste is combustible. Needless to stress that the calorific value of the wastes would greatly influence the thermal efficiencies of the system.
The high calorific value of sanitary pads (4619.98 kcal/kg) makes it techno-economically suitable for incineration. Nevertheless, it is important to note that installing a centralised incineration facility equipped with energy recovery can be regarded as the appropriate solution for sanitary waste treatment.
If small-scale incinerators are involved, there should be a full-proof plan and provision for incinerator plants’ design, standardisation, certification, procurement and instalment in schools and colleges. The government should ensure that incinerators are scrutinised not only by the pollution control authorities but also third-party agencies.
There should be a standard certification process in place for the incinerator plants designed by various companies. There should be a proper mechanism for continuous emission monitoring in the incinerator system, which anyone can access.
The emissions should be tested time-to-time by a government-accredited laboratory and confirmed to be within limits. Most importantly, technical guidelines for the design of incinerators have been provided by the MHM Guidelines.
There has to be appropriate planning, compliance with standards in terms of incinerator design parameters and emissions, technical oversight, and constant supervision of incinerator systems to ensure that it should not cause adverse health hazards to nearby people.
Waste recycling options for sanitary waste recycling: In addition, waste entrepreneurs who are working on different technologies for eco-friendly ways of sanitary waste recycling and disposal should be promoted.
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