Cox’s Bazaar Bangladesh

ABR – constructed wetland – ponds – drying beds – December 2019

Jules Gouron
July 31, 2020
No Comments
Crises : Rakhine

Anaerobic Baffled Reactor – maturation ponds – December 2019

Olivier Denis
April 1, 2020
No Comments
Crises : Rakhine

Aerobic treatment – August 2019

Octopus
December 19, 2019
No Comments
Crises : Cox's Bazaar Bangladesh

Upflow filter – Constructed wetland – July 2019

Octopus
January 15, 2020
2 Comments
Crises : Cox's Bazaar Bangladesh

Lime treatment – unplanted drying beds – July 2019

Octopus
December 17, 2019
No Comments
Crises : Cox's Bazaar Bangladesh

Constructed Wetland – June 2019

Octopus
December 19, 2019
No Comments
Crises : Cox's Bazaar Bangladesh

Anaerobic Baffled Reactor – June 2019

Octopus
December 19, 2019
No Comments
Crises : Cox's Bazaar Bangladesh

Lime Stabilization – Unplanted drying beds – March 2019

Octopus
December 19, 2019
One Comment
Crises : Cox's Bazaar Bangladesh

Geotube – Filtration – October 2018

Octopus
January 27, 2020
One Comment
Crises : Cox's Bazaar Bangladesh

Local constraints

Definition of the indicator

This indicator defines the constraints faced in the area where the treatment plant is located.

Unit/value

High water table
Rocky ground
Flood prone area
Earthquakes
Mountainous topography
Only locally available material
Other

How to measure or calculate it

High water table: check, at the end of rainy season, the groundwater table at the faecal sludge site by digging a pit and/or checking dug wells nearby (in the early morning before water is taken and water level drops). If it’s not possible to do it at the end of the rainy season, ask for information from the local population about the water level in the wells during the year. If there is less than 1m between the water table and the ground level, consider that it is a high water table.
Rocky ground: check if the ground is rocky where the plant is located, thanks to local knowledge of the population, reference documents or by digging a hole next to the treatment plant.
Flood prone area: verify with litterature and local knowledge if a flood occurred in the area next to the faecal sludge treatment site, in the last period equivalent to the design life (see indicator).Take in consideration only the faecal sludge treatment site and not the access to it or the latrines.
Earthquakes: verify with litterature and local knowledge if an earthquake occurred in the area next to the faecal sludge treatment site, in the last period equivalent to the design life (see indicator). Take into consideration only the faecal sludge treatment site and not the access to it or the latrines.
Mountainous topography: the area where the plant is implemented is not flat, there are hills or mountains.
Only locally available material: analyse the purchase documents for the faecal sludge treatment site and identify if only locally available material and equipment were used. Don’t tick the box if material and equipment from abroad were used.
Other: indicate any other constraints faced locally.

Why is it important to measure it

All these constraints will influence the chosen technologies for the treatment plant: construction in areas with a high ground water table requires more complex structures as faecal sludge is composed of contaminants that spread easily and quickly in water; rocky ground will make digging work more complex and expensive; plants in flood prone areas will need extra work to be protected against flooding, as flooding may stop operations for several weeks and/or spread faecal contamination out of the faecal sludge treatment site; plants in earthquake-prone areas will need extra work and consolidation in order to be resistant to earthquakes; a mountainous topography may determine the type of treatment facilities to be built and may influence the transportation and pumping costs; plants contructed and operated only with locally available material reduce costs and are easier to replicate in the same area.

Real input flow

Definition of the indicator

This indicator is required to know how much sludge is currently treated at the faecal sludge treatment site. It can differ from the design flow and be lower.

Unit/value: m3/day

How to measure or calculate it

Calculate the real input flow by measuring the sludge volume in transport tanks arriving to the faecal sludge treatment site or by measuring the pump flow rates and their time of use (duration of usage) during desludging. Consider an average value including also the days the faecal sludge treatment activities are not running.
If it’s not possible to measure in the field, the input flow is estimated as follows:
For emergency simple pit latrines emptied at regular intervals and with poor pit infiltration: it is estimated to 2.2 lcd (litres per capita per day) (1 for anal cleansing and toilet cleaning + 1.2 for faeces)
For emergency simple pits where effluent can infiltrate and latrines are emptied at regular intervals consider the following sludge accumulation rates:
– Wastes retained in water where water is used as anal cleansing material: 25 litres per capita per year (lcy);
– Wastes retained in water where degradable anal cleansing materials are used: 40lcy;
– Wastes retained in water where non-degradable anal cleansing materials are used: 60lcy;
– Wastes retained in dry conditions where degradable anal cleansing materials are used: 60lcy;
– Wastes retained in dry conditions where non-degradable anal cleansing materials are used: 90lcy.
For pour-flush facilities where water cannot infiltrate and be emptied at regular intervals: it is estimated at 4.2 lcd (2 for additional flush water),
For small networks (small bore sewerage, solids free sewerage) where domestic drinking water network is available: it is estimated that 80% of the drinking water supply ends up in the sanitation system.

References, tips, examples

Examples:
Simple pit latrines emptied at regular intervals and with poor pit infiltration: only water used for anal cleansing and cleaning the toilet enters the receptacle together with the volume of urine and faeces. Typical volume for anal cleansing is 1 litre per person per day (lcd or litres per capita per day). Typical volume of fresh urine and faeces is 1.2 lcd. Hence, for 1.000 people: 1.000 * (1+1.2) = 2,200 litres or 2.2 m3/day;
Pour-flush facility where water cannot infiltrate, emptied at regular intervals: water used for anal cleansing and for manually flushing the toilet enters the receptacle. A typical volume for pour-flush is 2-3 lcd. Hence, for 1,000 people: 1,000 * (3+1.2) = 4,200 litres or 4.2 m3/day;
Small network (small bore sewerage, solids free sewerage) where domestic drinking water network is available: when wastewater is collected, conveyed and treated, usually 80% of the drinking water supply ends up in the system. Hence, if for example drinking water is 25lcd, wastewater is 25 * 0.8 = 20lcd. Hence, for 1,000 people: 1,000 * 20 = 20,000 litres or 20 m3/day.

Why is it important to measure it

The real input flow can be compared with the design flow and upgrades or flow increases can be planned accordingly.

Cox’s Bazaar Bangladesh

ABR – constructed wetland – ponds – drying beds – December 2019

Anaerobic Baffled Reactor – maturation ponds – December 2019

Aerobic treatment – August 2019

Upflow filter – Constructed wetland – July 2019

Lime treatment – unplanted drying beds – July 2019

Constructed Wetland – June 2019

Anaerobic Baffled Reactor – June 2019

Lime Stabilization – Unplanted drying beds – March 2019

Geotube – Filtration – October 2018

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Skills level

Local constraints

Location

COD reduction

Organization

Technologies employed

Capex per design input flow

Design population

Design input flow

Faecal coliforms reduction

Design life

Time construction and commisionning

Opex per real input flow

Main treatment objectives

Real input flow

Required space

Resources needed for operation

Source of sludge

TS reduction

Types of output

Indicators notice