Low cost Fecal Sludge Management (FSM) system by WaterAid in emergency Rohingya responese, Bangladesh
Bangladesh opened its border officially for forcibly displaced Myanmar nationals from 25 August,2017. Since then about 905,000 people fled to Bangladesh from persecution of Myanmar military in Rakhine state.[1] First they started trespassing to Bangladesh in 1970. From 1970 to before opening border officially about 300000 to 500000 people entered Bangladesh different time. About every family here in refugee camp lost someone nearest; killed or raped in front of their own eye. As a part of planned ethnic cleansing, Myanmar military set fire on thousands house of Rohingya, killed and torturing them in tormenting way, raped their women and child. When Bangladesh government has opened its border officially, they found the hope of light towards life. A new journey began in Rohingya camp.
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It was not too easy to manage a huge influx of Rohingya population, their food, shelter, health, water and sanitation facilities. Specially managing water sanitation and hygiene (WASH) facilities are very tough here. Dense population, hilly and rocky terrain, lack of transport facility available materials and technicians, urgent need of huge number of toilet and most importantly they are not used to using proper sanitation system and they feel free in open defecation. Challenges to provide the WASH facilities for them are not limited to above and mostly all of them are illiterate about sanitation and hygiene practice. Different government, non- government organizations, local host community, rich people, different companies and groups came forward to help Rohingya people. Among them so many are involved with installation of tube wells and toilets. As there were no proper management and coordination different parties are installing tube wells and latrines here and there, and within a short time latrines are being filled up. As there were no desludging and Faecal Sludge Management (FSM) system, decommissioning existing toilets and finding another place for new toilet was the only option. At the beginning there were enough land to find out another place for latrine after buried one but within a few months finding land also became hard due to huge influx of Rohingya population. Burying latrines with untreated faecal sludge also increased the risk of health hazards for people.
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To solve this problem, WaterAid panned to provide faecal sludge management system for refugee camp. We have designed a context specific, low cost, low maintenance and low land required biological FSM plant for refugee camp. About twenty FSM (20) are established in different zone of kutupalong Rohingya camp. Each FSM plant are designed to serve about 150 toilet surrounding of plant and it can accumulate about 10 cubic meter faecal sludge per month.[2] Total land required for biological treatment unit is about 50 to 60 square meter. An intermediate transfer station is required to transfer sludge form toilet to treatment unit. To complete the whole operation two group of ten Rohingya people are trained on communication with Mazhi[3], Stabilization of sludge, desludging it and maintaining the biological treatment plant. When any toilet filled up responsible mazhi contacts with focal of trained team and tells him the location. Desludging group goes there and open up the toilet pan slab. Then use about 250 gm of Alum in faecal sludge and stir it with bamboo and replace the pan slab. This same process is done in second day and third day. Alum is used here as flocculants, so that solid and liquid part can be separated. At a time, desludging team clean about 50% of a toilet to keep more toilet functional with desludging same volume of sludge. With a motor and pipe system the sludge is transferred to transfer station. Transfer station is a 1 cubic meter box which is constructed with brick wall and cement plaster over it. This transfer station is connected with biological treatment unit by PVC pipe. Generally, transfer station situated uphill and biological treatment unit is in downhill so that sludge can automatically have transferred from transfer station to biological treatment unit in gravity flow.
Biological treatment unit is composed of two part. One is constructed wetlands where sludge comes from transfer station in gravity flow and another is filtration chamber where liquid part is treated finally (secondary treatment) for disposal to environment. There is an underground pipe to connect construction wetland part and sand filtration chamber. After primary treatment liquid passes to filtration chamber from constructed wetland part through this pipe. Constructed wetland is made of clay lining, Stone chips and plants for biological treatment. Two perforated pipe is being used to ensure oxygen availability in root zone of plant, which is the basic requirement for aerobic bacteria.2 As the decomposition process is done automatically with root zone aerobic bacteria, no extra care or technical people is required regularly which makes this system easily operate able and maintainable. 30 mm compacted clay layer is used to prevent infiltration of untreated liquid part to the ground. Generally, lily, Cana Indica, P. Australis are used as plant. Plants plays a very important role in this treatment process. Plant evapotranspiration reduce the volume of sludge, its root zone supports aerobic bacteria which involves with different process of sludge and water treatment. In aerobic treatment process nutrients are break down in two or three steps. Involvement of bacteria is very important here. The process may be like:
Organic matter + O2 + nutrients→ CO2 + H2O + C5H7NO2 + other products
Where C5H7NO2 are the newly synthesized cells.
C5H7NO2 + 5O2 → 5CO2 + 2H2O + NH3 + energy
Again in nitrification process nitrosomonas and nitrobacter produced nitrate which become gaseous nitrogen in denitrification bacteria.
Pathogen is removed in different part of constructed wetland system by its process and through predation of root zone bacteria and protozoa. A number of physical and biological process are involved with pathogen removal. Natural die off is also a part of pathogen removal in planted dyeing bed.
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At the very beginning when the influx has started, there were about 250 cubic meter fecal sludge generated. WaterAid constructed 20 FSM unit which has total daily capacity is about 20 to 25 cubic meter. Though the total capacity was low, that was the starting. After a few month successful operation, different organizations have started to replicate this technology in their sites. This is also a great achievement towards providing the WASH facilities. Now it is estimated that one FSM unit can treat about 2400 cubic meter (considering 95% is liquid) of sludge in five years.
Except 27 FSM unit WaterAid established total 190 tube wells, 400 toilets, about 100 bathing place for women and distribute 6500 hygiene kit, 7000 jerry cans and 15,00,000 water purifier tablets. There are also 10000 hygiene session conducted to provide basic idea of hygiene. The interventions may be limited compared to requirement but those are influential and sustainable. We hope one day displaced Myanmar nationals will get back to their homeland.
References[edit]
- ↑ "ISCG". ISCG.
- ↑ S.M., Tariquzzaman (28 April 2018). "The daily Samakal". Saying from kutupalong Rohingya Camp.
- ↑ Community Leader
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