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increase in the frequency and intensity of extreme weather events, such as cyclones, floods, and droughts, which Bangladesh is already prone to. These events can disrupt sanitation infrastructure and lead to public health crises. Higher temperatures and changing precipitation patterns can exacerbate waterborne diseases, while compromised sanitation systems can lead to outbreaks of cholera, diarrhoea, and other infectious diseases. The DPHE in Bangladesh has recognised the need to address GHG emissions from the sanitation value chain. Their strategies include encouraging the adoption of technologies that reduce methane and nitrous oxide emissions. This includes promoting anaerobic digesters with biogas recovery, which can capture methane for use as a renewable energy source. DPHE will also upgrade existing wastewater treatment plants (WWTPs) to more efficient systems that minimise GHG emissions, such as aerobic treatment processes, advanced oxidation processes (AOPs), and constructed wetlands. DPHE will also implement proper faecal sludge management (FSM) practices, including the safe collection, transport, treatment, and disposal or reuse of sludge, to prevent methane emissions from uncontrolled decomposition. It will also increase the energy efficiency of sanitation facilities and incorporating renewable energy sources, such as solar power, to reduce CO2 emissions from energy use. It will strengthen policies and regulations to support the implementation of low-emission sanitation technologies and practices, along with setting targets for GHG emission reductions in the sanitation sector. Finally, it will establish robust systems for monitoring, reporting, and verifying GHG emissions from the sanitation sector to track progress and make data-driven decisions for further interventions. How is WSUP Bangladesh tackling the issue of waste management that contributes to flooding during heavy rains? Uttam: One of the main reasons for the clogging of drains during heavy rains in Bangladesh is improper waste management.
DPHE and WSUP work together to enhance the technical capabilities of local authorities and communities in managing water and sanitation systems. Shramistha Debnath Executive engineer, DPHE
How is water and sewage lines provided and maintained in Dhaka city? What are some technologies employed? Shramistha: The primary body responsible for water supply in Dhaka is Dhaka Water Supply and Sewerage Authority (DWASA). It sources water from both rivers and groundwater. Its key WTPs include Sayedabad, Chandnighat, and Pagla. These plants treat water from rivers like the Buriganga and Shitalakshya. DWASA maintains an extensive network of pipelines to deliver treated water to households and businesses. DWASA also oversees sewage collection through a network of underground pipes and open canals. The key sewage treatment plants (STPs) include the Pagla STP, which is the largest, treating wastewater to reduce environmental contamination. The city uses combined sewer systems where stormwater and sewage share the same infrastructure, leading to challenges during heavy rains. Geographic information systems (GIS) and supervisory control and data acquisition (SCADA) systems are used for mapping and monitoring the water and sewage networks in real time. The automated meter reading (AMR) technology is employed to improve billing accuracy and detect leaks or unauthorised connections. Furthermore, advanced treatment processes such as ultrafiltration (UF), chlorination, and UV treatment are used to ensure water quality.
how that is affecting Bangladesh. How does DPHE plan to tackle this issue? Shramistha: GHG from the sanitation value chain encompass emissions from various stages, including the collection, treatment, and disposal of human waste. These emissions predominantly consist of methane, nitrous oxide, and CO2. The sanitation sector contributes to GHG emissions through several mechanisms, such as wastewater treatment. Conventional wastewater treatment processes can release significant amounts of methane and nitrous oxide. Anaerobic decomposition of organic matter in sewage produces methane, while nitrification and denitrification processes can lead to nitrous oxide emissions. Furthermore, on-site sanitation systems like septic tanks and pit latrines can be sources of methane due to anaerobic conditions. Additionally, sludge management can help improperly managed faecal sludge and solid waste to decompose anaerobically, releasing methane and nitrous oxide. Finally, energy consumption in sanitation facilities, especially those relying on fossil fuels, contributes to CO2 emissions. In Bangladesh, the sanitation value chain’s GHG emissions are contributing to the broader challenge of climate change, which has severe implications for the country. As a low-lying nation with a vast delta region, Bangladesh is vulnerable to sea-level rise. Increased GHG emissions contribute to global warming, causing sea levels to rise. This poses a threat to Bangladesh’s coastal areas, leading to land loss, salinisation of freshwater resources, and displacement of communities. Climate change is linked to an
Tell us about greenhouse gas emission (GHG) from the sanitation value chain and
20 Water & Wastewater Asia | September-October 2024
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