Decentralized waste water treatment- need of our times for growing urban centres in south Asia, focusing on Chittagong, Bangladesh
Student name: Ms Sahrin Jahan
Guide: Ms Ranjana Ray Chaudhuri
Year of completion: 2017
Host Organisation: TERI University
Abstract: Wastewater treatment is one of the major problems in sanitation sector both in Bangladesh and
India. Though Bangladesh has significantly reduced the percentage of open defecation, wastewater
management remains a challenge for the country due to several unfavorable conditions. Bangladesh
has very few sewage treatment plants while the wastewater produced now is large due to growing
urban centres. In urban areas the wastewater issues are worsened because of high population density
and unplanned city development. In the cities of Bangladesh rapid urbanization along with economic
adversity is making it difficult to implement the underlying solutions of wastewater treatment. This
situation is aggravated by political complicacy and lack of collaboration among concerned
organizations. The condition remains same in most of the cities of India along with a considerable
percentage of open defecation. To get an idea of urban sanitation status and their wastewater
management, a focused group discussion and a questionnaire survey was designed and conducted in
Pura Colony, Chittagong, Bangladesh and HarijanBasti and Krishangarh Village in Delhi, India.
The discussion provided information about the challenges, faced by the dwellers of Pura Colony,
Chittagong and informal settlements of Delhi. Decentralized wastewater treatment can bring a
positive change in the current situation by improving the sanitation status of the cities, as centralized
treatment system is expensive, needs more land and takes time to construct. Delhi has already
considered several public and private decentralized treatment projects to treat domestic wastewater.
Among many others the performance of three small decentralized wastewater treatment sites was
monitored for the study by collecting samples and conducting lab experiment. According to the
result, two of the systems are performing well along with rejuvenating its surrounding ecosystem
whereas the third one is required to adopt more technology and innovative ideas to improve the
performance.
This situation is more serious in Chittagong, the second largest city of Bangladesh as it does not have
any wastewater treatment plant. A pilot design has been developed based on decentralized solution
by using bamboo plant for Pura Colony area in Chittagong. For the design, running bamboo has
been found efficient in that certain region. A replicate experiment was conducted by planting bamboo
(Phyllostachys aurea) in layers of soil and sand in pots and running two different wastewaters
through the pots. The lab experiment of the filtered water through the vegetation system is showing a
significant improvement of the water quality by reducing the BOD and COD level to 69% and 41%
respectively. Detail vegetation and soil analysis is being conducted to understand the filtration and
treatment pattern.
Finally, to implement the project a careful monitoring and maintenance is very essential. The
research is being conducted in order to validate the use of decentralized waste water systems in large
cities, so that clear policy guidelines on this matter can be included in Bangladesh and India.
Key Words-
Sanitation, Decentralized Wastewater Treatment, Bamboo plant, Chittagong, Sanitation Policy
