Nasir Uddin Khan:

BANGLADESH has around 180 million people living in a small land and ranks number 8 in the world by population. Though the GDP of the country was $2.528 trillion in 2023, the country has neither established any sewage treatment system nor a safe water supply system for the entire nation. Still, waterborne diseases and dengue are the main diseases in the country due to the disposal of untreated sewage all over the country and not having the supply of reliable safe drinking water.

The country is mostly dependent (more than 90 per cent) on groundwater as potable water, which is abstracted through shallow-type tubewells mostly fitted with a hand pump. Usually the Public Health Engineering Department (DPHE) supplies these hand pumps and sanitary latrines in the rural areas. The hand pumps are normally 100-120 ft deep, fitted with a 20-30 ft strainer at the bottom; on the other hand, the sanitary latrines are made by burying 3-4 concrete rings fitted with an Indian type of pan on the top. The joints of the rings and the bottom are not sealed, so the sewage is mixed with the soil and groundwater easily. The situation becomes more hazardous during the monsoon when the surface and groundwater are all mixed with the sewage. These latrines, usually constructed in the proximity of the hand pump, which is common in the rural livelihood, are giving more chance of faecal contamination in the tube well water. On the other hand, the tube well water is used directly without treatment for drinking and other purposes, which is also a great threat to human life. Usually groundwater in Bangladesh has significant amounts of iron, hardness, silica and arsenic (in some areas) and is not safe for drinking without treatment. These contaminations cause different long-term diseases such as diarrhoea, diabetes, nausea, cardiovascular disease, liver and kidney function disorder, etc, to the human body.

The urban and suburban areas are a little different, though they are also not safe from sewage contamination and safe water supply. Dhaka WASA has only a sewage system at a partial capacity in the city, but remaining sewage is collected through a pipe network and disposed of in the nearest rivers without treatment. Other districts and subdistrict cities don’t have sewerage networks or sewage treatment at all; they are using septic tanks for sewage treatment. Honestly, the septic tank system is not a true sewage treatment system at all; it is a kind of primary treatment and retains the sewage for some period, but the discharge water quality remains untreated and pollutes the surface and groundwater of the whole country from generation after generation.

The water supply of the urban and suburban areas is also dependent on the untreated groundwater supply, except in some parts of Dhaka and Chattogram that have a partial surface water treatment system, though the transportation pipeline system is not capable enough to keep the water safe for the city dwellers at their doorstep. The reason why most of the people who are conscious are either boiling or filtering the water before drinking, which creates another health hazard for the people. By boiling or filtering the water, most of the essential minerals in the water become settled down or retained in the filter, and people are drinking almost dead water. Moreover, by boiling the water, people are wasting huge amounts of natural gas every day.

This primary demand of the people was not given priority, and a proper sewage treatment system has not been developed, though the sewage treatment is not a complex issue. Anyone can do this with their limited resources and capabilities. For this, government initiative and awareness are essential. First, we must isolate the sewage from the surrounding soil, which we can do by using a plastic tank instead of rings in this case in rural areas. The plastic tank should be half buried under the ground and the commode/pan should be placed over that tank. This individual plastic tank should be connected to a bigger concrete retention tank (should be in a common place consisting of 30–50 households in the rural community) by pipeline to carry the sewage to that bigger concrete tank. This bigger tank will work like a septic tank. The overflow from the concrete tank should then be taken for biodegradation by using bio-blocks and solar pumps. Treated water from the bio-degradation tank will be safe for disposal or used for irrigation.

The technology of sewage treatment is easy and the equipment is available in the local market. This biodegradation system could also be used in the urban and suburban areas where there are no sewerage systems and people are using septic tanks. This initiative could be implemented as a small community-based project consisting of 30-50, or a maximum of 100, households where the community members will take responsibility to operate and maintain the system on their own.

Similarly, a water treatment plant could also be designed for the targeted people in the community-based project based on groundwater or surface water. This water treatment plant will supply only the drinking water from the project and the residents under the project should collect their daily drinking water from the project. By implementing such initiatives step by step, we can bring the whole nation under the sewage treatment and safe water supply, which also saves huge amounts of money from the health sector by eliminating or reducing the waterborne and other diseases every year. It is evident that sewage treatment and safe water are not a luxury for the citizen, but civil rights irrespective of their race, religion and geographical boundary.

Dr Nasir Uddin Khan is a waste management specialist.