Lime treatment – unplanted drying beds – July 2019

Lime treatment – unplanted drying beds – July 2019

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Lieu de l’étude de cas

Cox's Bazar - Bangladesh

Principaux objectifs de traitement

BOD/COD reduction, Pathogen reduction, Solid/liquid separation

Capex par flux d’entrée de conception

2531 USD/m3/jour

Opex par flux d’entrée réel


Espace requis


Description du processus de traitement

NGO Forum uses an internal expert for any upgrading or decommission of the FSM, following the sector standard and guidelines. In a few cases NGO Forum has hired an external contractor.

Resources temporally needed for upgrade/decommissioning: enough Water, local vehicles for transporting in the hilly area, a necessary community consultation as well as permission from the CIC and SMS.

Mask, Hand Gloves, Gum Boot, Apron and Rake is used as PPE. NGO Forum normally follows the sector standard rules for using PPE. Every dislodging volunteer is responsible for completing the task. Over them, there is the Assistant Engineer and CHP for the monitoring. One of the challenge is that to ensure the quality, our Project Engineer has to supervise directly.

Description du contexte d’urgence

Living area of community: Kutupalong Camp Area in different locations

Local and international WaSH institutions with WaSH active role in the community: NGO Forum and other development organizations such as BRAC, ACF, PCCR, IFRC, Friendship etc.

Main waterborne diseases: Cholera, Diarrhea, Dysentery, Typhoid etc.

Les indicateurs

Le récit

Leçons apprises

If we construct small sewerage boreholes and increase secondary transfer stations and safety tanks then the cost will be reduced.

Constructing small sewerage boreholes or transfer stations, it can reduce contacts between staff and sludge.

Ensuring community engagement and engaging skilled volunteer can guarantee the sustainability of the plant.

The risk of environmental contamination from burial of lime treated sludge is relatively low, since the bacteria and viruses in the sludge are destroyed during the treatment process, leaving only the helminth eggs which are relatively large and are efficiently removed through the physical filtration process in the soil. A burial site which is 6 inch above the water table can therefore be considered safe considering the risk. After burial, sludge should be covered with a 6-inch layer of soil.

Specific challenges:
• the emptying frequency is too high, as a result it is difficult to maintain the retention period
• leakage of convenes pipe
• quality of effluent water
• space in the camps is limited due to the number of people and the topography
• landslides in the rainy season

In this system, there is a possibility of health hazards, by damaging the skin and causing burns for those who are involved in this activity. Gloves were worn when handling lime. Gloves have been issued to workers who are handling sludge or chemicals (lime or chlorine) and Eye protection also have been issued to workers who are handling chemicals (lime or chlorine). Forum has mitigated this risk through proper use of PPE. Besides these, there is a provision of water containing vinegar for washing. If dry lime is spilled on the skin, then it has to be brushed away as much of the lime as possible before it causes burns.



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