Filter case studies

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

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Skills level

Definition of the indicator

This indicates if the knowledge and experience level of an FSM specialist is required to be able to design, contruct, operate and maintain the faecal sludge treatment site successfully.
Communitarian operation means the faecal sludge treatment system is operated exclusively by the beneficiary community without constant external support.

Unit/value:

FSM specialist for design
FSM specialist for construction
FSM specialist for operation and maintenance
Communitarian operation

How to measure or calculate it

For design: the indicator is determined by assessing the design process and understanding if specialists were involved or not.
For construction: the indicator is determined by assessing the construction process (including selection of contractors or construction staff) and understanding if specific contractors and specialists for special supervision, know-how, equipment use were involved or not.
For operation and maintenance: analyse the CV of the manager of the O&M of the faecal sludge treatment site and identify if he/she has completed higher education related to FSM and if this education is strictly necessary for his/her role.
For community operation: analyse responsibilities and tasks of the faecal sludge treatment site management. Identify if they are covered by the beneficiary community. If there is occasional external support, still consider that the site is completely operated by the community.

References, tips, examples

Example of different design skills in the same context: the design of Oxfam’s large scale faecal sludge treatment site in Cox’s Bazaar was implemented in collaboration with Borda (sanitation experts); Oxfam’s small lime stabilization faecal treatment site was implemented by WASH officers (not FSM specialists).

Why is it important to measure it

This indicator is important to know what kind of skills are needed to have a properly functioning treatment plant, to be able to hire the right people for the task and to select the technologies according to the local skills available.

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.

COD reduction

Definition of the indicator

Chemical oxygen demand (COD) is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution. It is commonly expressed in mass of oxygen consumed over volume of solution (mg/L) and is composed principally of proteins, carbohydrates and fats.
The reduction is related to the COD concentration of the effluent exiting the faecal sludge treatment site in comparison to the COD concentration of the influent entering the faecal sludge treatment site.

Unit/value: %

How to measure or calculate it

The reduction is calculated as a relative percentage of the average COD value of the effluent exiting the faecal sludge treatment site over the average COD value of the influent entering the faecal sludge treatment site in the same period.
% = (1-Ce/Ci) x 100
with Ce = effluent COD concentration (mg/l)
Ci = influent COD concentration (mg/l)

The laboratory test protocol can be found at:
The STeP Global Testing Protocols & Parameters – A best practices guide for testing sanitation technologies in the field
http://stepsforsanitation.org/?smd_process_download=1&download_id=4171

References, tips, examples

If the influent COD concentration of the treatment plant is 3000 mg/l and the effluent COD concentration is 1000 mg/l:
(1-1000/3000) x 100 = 66% of COD reduction.
Influent values example from Zambia: 50,000-100,000mg/l for pit latrines and 10,000-20,000mg/l for septic tanks

Why is it important to measure it

Faecal sludge characteristics vary widely between cities, types of on-site sanitation systems and types of emptying system used. Samples taken from the same pit latrine can have significant variations in standard physio-chemical testing, which impacts how sludge must be treated.
The COD parameter monitors the available oxygen which has a direct impact on aquatic life. If biodegradable organics are discharged untreated to the environment, their biological stabilisation can lead to the depletion of natural oxygen resources and to the development of septic conditions.

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.

TS reduction

Definition of the indicator

Total solids is the measurement of the concentration of particulate solids that can dissolve or suspend in wastewater. It is commonly expressed as mass of solids in comparison to volume of solution (% weight-volume).
The reduction is related to the total solids concentration of the effluent exiting the faecal sludge treatment site in comparison to the total solids concentration of the influent entering the faecal sludge treatment site.

Unit/value: %

How to measure or calculate it

The reduction is calculated as a relative percentage of the average total solids value of the effluent exiting the faecal sludge treatment site over the average total solids value of the influent entering the faecal sludge treatment site in the same period.
% = (1-Ce/Ci) x 100
with Ce = effluent TS concentration (mg/l)
Ci = influent TS concentration (mg/l)

References, tips, examples

Septage (contents of a septic tank) usually has a low percentage of solids (typically 1-2 %) and faecal sludge from pit latrines usually has a high percentage of solids (typically 10-15%). Example values from Zambia: 7-15% for pit latrines and 1-2% for septic tanks.
For example if the influent TS concentration of the treatment plant is 1000 mg/l and the effluent TS concentration is 400 mg/l:
(1-400/1000) x 100 = 60% of TS reduction.

Why is it important to measure it

Faecal sludge characteristics vary widely between cities, types of on-site sanitation systems and types of emptying system used. Samples taken from the same pit latrine can have significant variations in standard physio-chemical testing, which impacts how sludge must be treated.
Suspended solid can lead to the development of sludge deposits and anaerobic conditions when untreated wastewater is discharged in the aquatic environment.
Moreover, as an example, solids content is an important parameter to estimate the volume of dried sludge to be removed from the drying beds of sludge treatment plants.

Indicators notice

Objective

Definition of indicator

The objective, in this case, is the desired treatment or modification of the input sludge before disposal or reuser.

How to measure or calculate it ?

If possible, revise design document and ask to the design team or consultants: the objective should have been considered to design and dimension the faecal sludge treatment site. Usually, the objective is related to the quality of input sludge and the environmental conditions of disposal sites or the desired reusing methodology.

Why it is important to measure it

This is very important to design the faecal sludge treatment site and to evaluate the efficacy of the treatment.

Life expectancy and reliability

Definition of Indicator

This indicator defines at the moment of design how long the faecal sludge treatment site should be operational..

How to measure or calculate it ?

Identify immediate and long term needs. Analyse population growth and movements trends (see design beneficiary indicator), donors and implementing actors commitments.

References, tips, examples

The size of the population today might be 1,000 persons (often referred to as ‘capita’), but in 1 year this may double and in 5 years this might increase ten-fold; moreover it is important to know how long the facility will need to last to determine the building materials to use.

Why it is important to measure it ?

It is important to know the design period as this will help to calculate the designed beneficiary population (see indicator) of the faecal sludge treatment site. Moreover, it is important to know how long the facility will need to last to determine the building materials to use.

Skill level required for design (low skilled: general WASH officer /skilled: FSM specialist)

Definition of indicator

This indicates the level of knowledge and experience required to be able to design faecal sludge treatment site successfully.

How to measure or calculate it ?

The indicator is determined by assessing the design process and understanding if specialists were involved or not.

References, tips and/or examples

Example of different design skills in the same context: Design of large scale faecal sludge treatment site of Oxfam in Cox Bazar was implemented in collaboration with Borda (sanitation experts). The small lime stabilization faecal treatment site of Oxfam was implemented by the ‘regular’ WASH officers.

However it’s always preferable to check designs with FSM specialists as in practice the law of Murphy rules: anything that can go wrong, will go wrong.
So for example also during the design of a simple facility such as a septic tank the following mistakes are common:
– inlet and outlet are mixed up;
– plans and cross-sections are mixed up;
– capacity of the facility is far too large;
– absence of ventilation pipes;
– absence of infiltration facilities;
– leaking tanks;
Etc., etc. etc.

Why it is important to measure it ?

Faecal sludge is a potentially dangerous material: a simple mistake impacts the lives of many people
This indicator is important for actors interested in implementing faecal sludge treatment for planning reasons.

Technology suitable for context with high water table

Definition of indicator

The indicator defines if the technology also works well if ground-water is less than 1 metre from ground levelat least for a part of the year

How to measure or calculate it ?

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 rainy season, ask for information from the local population about water level in the wells during the year.

References, tips, examples

In areas with high water tables, it might be a challenge to dig pits/ tanks as pumps for keeping the pit dry might be absent. Even if pumps are available, care must be taken to avoid floating of empty tanks. Floating can be avoided by adding enough weight (stones, concrete) to the tank to prevent floating. Hence, above ground / raised facilities are advised such as raised Oxfam tanks.

Why it is important to measure it ?

Faecal sludge is potentially dangerous material and when in contact with water, contaminants will spread easily and quickly. Moreover, construction in areas with high ground water table requires extra measures and more complex structures (expensive).

Source of sludge

Definition of indicator

It defines the type of sanitation infrastructures from which the sludge comes from

How to measure or calculate it ?

If existing, analyse the documents of desludging which report this information, otherwise observe the desludging activities and the sanitation infrastructures from which the sludge comes from. Talk with people in charge of desludging.

References, tips, examples

Hospitainer has developed specific solutions for hazardous hospital waste in the framework of S(p) eedkits : https://hospitainer.com/add-ons/sanitation/ . Both IBBK and A-aqua have developed sludge pasteurizers: http://www.a-aqua.no/Products-Services/Humanitarian-Aid/Hygieniser100-Sludge-Pasteurising-Unit ;

Why it is important to measure it ?

It is important to know the source to estimate the characteristics of the sludge and likeliness of contamination with pathogens (of course, any faecal sludge needs to be treated as hazardous material but waste from hospitals is likely to be more hazardous and needs special attention.)

Design beneficiary population

Definition of indicator

Number of people who can benefit from the faecal sludge treatment service.

How to measure or calculate it ?

Analyse current population, its growth and movement trends. In a stable growing population, population to be served can be calculated as follows:
Pn = P0 * (1+i)^n
Pn = Population in year ‘n’ (refer to life expectancy indicator)
n = design period
P0 = Population in year 0
i = annual growth of the population
However in humanitarian context, this will usually depend on the security context (forecast of the population affected by the natural /manmade disaster).

References, tips, examples

Example:
n = design period (say 5 years)
P0 = Population in year 0 (say 1,000)
i = annual growth of the population (say 10% influx per year)]
P5 = 1,000 * (1+0.1)^5 = 1,610 persons, say 1,600

Why it is important to measure it ?

When the population is known, there is a solid basis for sizing the facility: sizing of the tanks AND sizing of any pumps, drying beds, etc.

Required space

Definition of indicator

This is the space occupied by the faecal sludge treatment site in relationship with the design beneficiary population (see indicator).

How to measure or calculate it ?

Measure in the field, or in the project designs, the total area of the faecal sludge treatment site and divide it by the design beneficiary population (see indicator).

Why it is important to measure it ?

In humanitarian contexts, the population is often obliged to settle in crowed areas with unfavourable environmental conditions. This has a consequence also on the availability of space for faecal sludge treatment sites and sanitation facilities in general.

Topography

Definition of indicator

This indicator, in this case, defines the general slope of the area of the sludge treatment site.

How to measure or calculate it ?

If some types of topography are equally present, please provide multiple answers.

Why it is important to measure it ?

The topography may determine the type of treatment facilities to be built and may influence the transport and pumping costs.

Design input flow

Definition of indicator

This indicator defines for which sludge flow the facility has been designed.

How to measure or calculate it ?

If possible, revise design calculation document and ask the design team or consultants. The design input flow should have been considered for dimensioning. Usually, 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 2.2 lcd (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, emptied at regular intervals: it is estimated 4.2 lcd (2 for additional flush water),
For small network (small bore sewerage, solids free sewerage) where domestic drinking water network is available: it is estimated 80% of the drinking water supply ends up in the sanitation system.
For some environmental conditions and infrastructures, groundwater infiltration inside the sanitation facilities should have been considered.

References, tips, examples

Example:
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 volumes of fresh urine and faeces 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 manually flushing the toilet enters the receptacle. 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 and conveyed and treated, usually taken as 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 it is important to measure it ?

When the design flow is known, there is a solid basis for sizing the facility: sizing of the tanks AND sizing of any pumps, drying beds, etc. Sludge can easily be much more than the volume of urine and faeces and has a big impact on the sizing. If this is neglected, the facilities are too small and retention / treatment times are shortened, resulting in poor results.

Type of outputs

Definition of indicator

The indicator defines if the main outputs of the faecal sludge treatment site are composed only of sludge, effluent or both

How to measure or calculate it ?

Observe if two different outputs originating from solid/liquid separation mechanisms can be distinguished on the basis of their density and solids content.

References, tips, examples

For example, the ratio between the two in the simplest treatment system (sludge drying beds) has been assessed as following:
septage (contents of a septic tank) % of solids (typically 1-2 %)
faecal sludge from pit latrines with a high % of solids (typically 10-15%).
Solids content is an important parameter to estimate the volume of dried sludge to be removed from the drying beds of sludge treatment plants. After 2 weeks drying period the typical solids content is 40% dry solids. Hence, 1 m3 (1,000 litres) of septage containing 1% of dry solids has been decreased to 1,000 *1%/(40%) = 25 kg of biosolids. The remainder (typically 1,000-25 = 975 litres has partially evaporated, partially drained away. The drainage water, say max 975 litres, needs to be treated in a filter / pond system. Also, 1 m3 (1,000 litres) of faecal sludge containing 15% of dry solids has been decreased to 1,000 *15%/(40%) = 375 kg of biosolids. The remainder (typically 1,000-375 = 625 litres has partially evaporated, partially drained away. The drainage water, say max 625 litres, needs to be treated in a filter / pond system

Why it is important to measure it ?

Knowing if there are different outputs enables the creation of specific different treatment chains and disposal mechanisms.

Using locally available material

Definition of indicator

Locally available material is material that doesn’t need to be imported.

How to measure or calculate it ?

Analyse the purchase documents for the faecal sludge treatment site and equipment and identify material imported from abroad.

References, tips, examples

Typical imported materials are the raised latrines discussed above, Oxfam tanks for sludge treatment (e.g. lime treatment) and a ‘plug-and-play’ wastewater treatment plant for a hospital.

Why it is important to measure it ?

During the first few days of an emergency, it might be difficult to source local material. Hence, these need to be flown in. However, locally available material should as much as possible be sourced to reduce construction costs.

Fencing

Definition of indicator

Barrier which doesn’t allow entrance to the faecal sludge treatment site for people, animals, vehicles who are not involved in the treatment operations.

How to measure or calculate it ?

Observe if a fencing is in place all along the perimeter of the faecal sludge treatment site. Identify if there are any weak points which allow people, animals, or vehicles who are not involved in the treatment operations to enter the site.

Why it is important to measure it ?

Adequate fencing is a must under all circumstances in conjunction with 24/7 guards: septage, wastewater and faecal sludge are hazardous material and can easily be used to contaminate the entire community. Think of vandalism by punching a hole in a bladder full of sludge.

Drainage implemented

Definition of indicator

Drainage are all the systems that avoid water logging and the entrance of run-off water to the faecal sludge treatment site.

How to measure or calculate it ?

Observe if there are specific infrastructures for drainage in the faecal sludge treatment site. Identify if there is any major waterlogging or water run-off which causes surface water contamination or makes the treatment operations difficult.

Why it is important to measure it ?

Adequate drainage is a must under all circumstances to prevent flooding and lead storm water away from the site without major contamination.

Flood risk

Definition of indicator

The indicator defines if the area of the faecal sludge treatment site is affected by flood.

How to measure or calculate it ?

Verify with literature and local knowledge when last flood occurred in the faecal sludge treatment site. The indicator defines if the area of the faecal sludge treatment site has been affected in the last period equivalent to the life expectancy (see indicator) and nothing has been done to avoid flood in the area during construction. The indicator takes in consideration only the faecal sludge treatment site and not the access to it or to latrines.

Why it is important to measure it ?

Faecal sludge is a potentially dangerous material: flooding may stop operations for several weeks and/or spread faecal contamination out of the faecal sludge treatment site.

Capex per current flux (including costs of land)

Definition of indicator

This indicator defines the total of:

– Preliminary and general items (Office and transport contractor and supervisors, security, insurance, electricity supply connection, etc.)
– Purchase of land
– Civil works
– Electromechanical works: pumps, GenSet,
– Design (typically 5% of Civil & Electromechanical costs)
– Supervision of implementation (typically 5-15% of Civil and Electromechanical costs)

divided by current flow.

How to measure or calculate it ?

All the expenditure for the construction and put in place of sludge faecal treatment system have to be considered and divided by the real input flow (see indicator). It includes also a quota of human resources involved in the conception and construction, that can have been involved also in other tasks.

References, tips, examples

A treatment plant in inaccessible areas where cement bags need to flown is easily 10 times more expensive than the same plant in areas where cement can be purchased ‘of the shelf’.

Why it is important to measure it ?

Capital expenditure per real input flow on any faecal sludge treatment site differ from place to place and depends mostly on transport costs.

Capex per current flow (excluding costs of land)

Definition of indicator

This indicator defines the total of:

– Preliminary and general items (Office and transport contractor and supervisors, security, insurance, electricity supply connection, etc.)
– Civil works
– Electromechanical works: pumps, GenSet,
– Design (typically 5% of Civil & Electromechanical costs)
– Supervision of implementation (typically 5-15% of Civil and Electromechanical costs)

divided by current flow.

How to measure or calculate it ?

All the expenditure for the construction and installation of the faecal sludge treatment system (EXLUDING PURCHASE OF LAND) has to be considered and divided by the real input flow (see indicator). It includes also a quota of human resources involved in the conception and construction, that can also have been involved in other tasks.

References, tips, examples

A treatment plant in inaccessible areas where cement bags need to be flown in is easily 10 times more expensive than the same plant in areas where cement can be purchased ‘off the shelf’.

Why it is important to measure it ?

Capital expenditure per real input flow on any faecal sludge treatment site differs from place to place and depends mostly on transport costs.

Skill level required for construction

Definition of indicator

This indicator defines the level of knowledge and experience required to be able to build a faecal sludge treatment site successfully.

How to measure or calculate it ?

The indicator is determined by assessing the construction process (including selection of contractors or construction staff) and understanding if specific contractors and specialists for special supervision, know-how, equipment were involved or not.

References, tips, examples

Skill level for construction can be reduced by standardization, use of kits and clear and univocal instruction materials.

Why it is important to measure it ?

Faecal sludge is a potentially dangerous material: a simple mistake in infrastructures construction may stop operations for several weeks and affect the sustainability of faecal sludge treatment.

Total Opex per current flow

Definition of indicator

Operation expenditure includes the daily average of:

– Staff costs
– Energy costs (especially high when electricity needs to be generated separately)
– Chemical costs
– Transport costs
– Administration costs
– Water for cleaning / operating costs
– Personal Protection Equipment costs
– Etc.

divided by real input flow.
It doesn’t include desludging costs.

How to measure or calculate it ?

All the expenditure for operations has to be considered and divided by the real input flow (see indicator). Also expenditures for extraordinary operations as a daily average should be considered. It also includes a quota of human resources involved in the operations, that can also be involved in other tasks.

References, tips, examples

Typical O&M costs for faecal sludge treatment around the world are USD 6-10 /m3.

Why it is important to measure it ?

It represents the economical efficiency of the faecal sludge treatment systems by comparing daily operational costs with real input flow.

Skill level for O&M

Definition of indicator

This indicator defines the skill level of the manager of the O&M tasks of the faecal sludge treatment site.

How to measure or calculate it ?

Analyse the CV of the manager of the O&M of the faecal sludge treatment site and identify if he/she has an education higher than the compulsory one (high school, university) and if this education is strictly necessary for his/her role.

Why it is important to measure it ?

This indicator provides information on the staff to be hired for the management of the faecal sludge treatment site.

Real input flow

Definition of indicator

This indicator is required to know how much sludge is currently really treated at the faecal sludge treatment site.

How to measure or calculate it ?

Calculate the real input flow by measuring the sludge volume in transport tanks to the faecal sludge treatment site or by measuring the pumps flow rates and their time of use during desludging. Consider an average value including also the days the faecal sludge treatment activities don’t run.

Why it is important to measure it ?

When the real input flow is known, it’s possible to compare it with design input flow and with the output sludge production and give important indications about possible upgrading.

Output sludge production in comparison to sludge input flow

Definition of indicator

This indicator defines how much sludge is produced daily by the faecal sludge treatment site in comparison to real input flow for an average operational period

How to measure or calculate it ?

Measure weight of the sludge produced daily before disposal or reuse out of the sludge treatment site. Divide it by real input flow (see indicator). Consider an average value including also the days faecal sludge treatment activities don’t run.

References, tips, examples

Output sludge production in comparison to sludge input flow can vary a lot according to treatment processes:
Chemical treatment like lime where the volume of sludge does not change (volume sludge in = volume sludge out);
Physical and biological treatment (separation of solids from fluids, aerobic or anaerobic digestion of sludge). Here the volume of sludge decreases drastically to 5-15% of the original volume (see examples).

Why it is important to measure it ?

The volume of sludge is an important parameter in sizing the transportation and disposal system of processed sludge from the faecal sludge treatment site.

BOD reduction

Definition of indicator

Biochemical Oxygen Demand (BOD, also called Biological Oxygen Demand) is the amount of dissolved oxygen needed (i.e. demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period. The BOD value is most commonly expressed in milligrams of oxygen consumed per litre of sample during 5 days of incubation at 20 °C (mg/L).
The reduction is related to the BOD of effluent exiting the faecal sludge treatment site in comparison to the BOD of influent entering the faecal sludge treatment site.

How to measure or calculate it ?

The reduction is calculated as COMPLEMENTARY PERCENTAGE of the average BOD of effluent exiting the faecal sludge treatment site over the average BOD of influent entering the faecal sludge treatment site in the same period.

References, tips, examples

The laboratory test protocol can be seen at:
The STeP Global Testing Protocols & Parameters – A best practices guide for testing sanitation technologies in the field
http://stepsforsanitation.org/?smd_process_download=1&download_id=4171
Influent example from Zambia: 25,000-40,000mg/l for pit latrines and 1,000-2,000mg/l for septic tanks
maximum concentration example of liquid effluent as per the ZEMA standard 50mg/l.

Why it is important to measure it ?

Faecal sludge characteristics vary widely between cities, types of on site sanitation systems and type of emptying system used. Even samples taken from the same pit latrine.

COD reduction

Definition of indicator

Chemical oxygen demand (COD) is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution. It is commonly expressed in mass of oxygen consumed over volume of solution (mg/L).
The reduction is related to the COD of effluent exiting the faecal sludge treatment site in comparison to the COD of influent entering the faecal sludge treatment site.

How to measure or calculate it ?

The reduction is calculated as COMPLEMENTARY PERCENTAGE of the average COD of effluent exiting the faecal sludge treatment site over the average COD of influent entering the faecal sludge treatment site in the same period.

References, tips, examples

The laboratory test protocol can be seen at:
The STeP Global Testing Protocols & Parameters – A best practices guide for testing sanitation technologies in the field
http://stepsforsanitation.org/?smd_process_download=1&download_id=4171
Influent example from Zambia: 50,000-100,000mg/l for pit latrines and 10,000-20,000mg/l for septic tanks
maximum concentration example of liquid effluent as per the ZEMA standard 50mg/l.

Why it is important to measure it ?

Faecal sludge characteristics vary widely between cities, types of on site sanitation systems and type of emptying system used. Even samples taken from the same pit latrine have been shown to have significant variation in standard physio-chemical testing. Such characteristics impact how sludge can be processed following removal. Stabilised sludge is very poor in terms of gas release in an anaerobic digester.

Faecal coliforms reduction

Definition of indicator

Faecal coliforms are facultatively anaerobic, rod-shaped, gram-negative, non-sporulating bacterium. Coliform bacteria generally originate in the intestines of warm-blooded animals. Faecal coliforms are capable of growth in the presence of bile salts or similar surface agents, are oxidase negative, and produce acid and gas from lactose within 48 hours at 44 ± 0.5°C.The term “thermotolerant coliform” is more correct and is gaining acceptance over “faecal coliform”.
Coliform bacteria include genera that originate in feces (e.g. Escherichia) as well as genera not of faecal origin (e.g. Enterobacter, Klebsiella, Citrobacter). The assay is intended to be an indicator of faecal contamination; more specifically of E. coli which is an indicator microorganism for other pathogens that may be present in feces. They are commonly expressed in colony forming units over 100mL volume of solution (CFU/100mL).
The reduction is related to the faecal coliforms of effluent exiting the faecal sludge treatment site in comparison to the faecal coliforms of influent entering the faecal sludge treatment site.

How to measure or calculate it ?

The reduction is calculated as COMPLEMENTARY PERCENTAGE of the average faecal coliforms of effluent exiting the faecal sludge treatment site over the average faecal coliforms of influent entering the faecal sludge treatment site in the same period.

References, tips, examples

The laboratory test protocol can be seen at:
The STeP Global Testing Protocols & Parameters – A best practices guide for testing sanitation technologies in the field
http://stepsforsanitation.org/?smd_process_download=1&download_id=4171
Influent example from Zambia: 2*107 CFU/100ml for pit latrines and 1*105 CFU/100ml for septic tanks
maximum concentration example of liquid effluent as per the ZEMA standard 2500CFU/100ml.

Why it is important to measure it ?

Faecal sludge characteristics varies widely between cities, types of on site sanitation systems and type of emptying system used. Even samples taken from the same pit latrine have been shown to have significant variation in standard physio-chemical testing. Such characteristics impact how sludge can be processed following removal. Stabilised sludge is very poor in terms of gas release in an anaerobic digester.

TS reduction

Definition of indicator

Total solids are the total dissolved solids (TDS) + total suspended solids (TSS). They are commonly expressed as mass of solids in comparison to volume of solution (% weight-volume).
The reduction is related to the total solids of effluent exiting the faecal sludge treatment site in comparison to the total solids of influent entering the faecal sludge treatment site.

How to measure or calculate it ?

The reduction is calculated as COMPLEMENTARY PERCENTAGE of the average total solids of effluent exiting the faecal sludge treatment site over the average total solids of influent entering the faecal sludge treatment site in the same period.

References, tips, examples

The laboratory test protocol can be seen at:
The STeP Global Testing Protocols & Parameters – A best practices guide for testing sanitation technologies in the field
http://stepsforsanitation.org/?smd_process_download=1&download_id=4171
Septage (contents of a septic tank) is much easier to pump and treat due to the low % of solids (typically 1-2 %) than faecal sludge from pit latrines with a high % of solids (typically 10-15%). Solids content is an important parameter to estimate the volume of dried sludge to be removed from the drying beds of sludge treatment plants. After 2 weeks drying period the typical solids content is 40% dry solids. Hence, 1 m3 (1,000 litres) of septage containing 1% of dry solids has been decreased to 1,000 *1%/(40%) = 25 kg of biosolids. The remainder (typically 1,000-25 = 975 litres has partially evaporated, partially drained away. The drainage water, say max 975 litres, needs to be treated in a filter / pond system. Also, 1 m3 (1,000 litres) of faecal sludge containing 15% of dry solids has been decreased to 1,000 *15%/(40%) = 375 kg of biosolids. The remainder (typically 1,000-375 = 625 litres has partially evaporated, partially drained away. The drainage water, say max 625 litres, needs to be treated in a filter / pond system;
Influent example from Zambia: 7-15% for pit latrines and 1-2% for septic tanks.

Why it is important to measure it ?

pH variation

Definition of indicator

pH is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. It is approximately the negative of the base 10 logarithm of the molar concentration, measured in units of moles per litre, of hydrogen ions. Indeed it doesn’t have unit measure.
The variation is related to the pH of effluent exiting the faecal sludge treatment site in comparison to the pH of influent entering the faecal sludge treatment site.

How to measure or calculate it ?

The variation is calculated as positive (when effluent pH is higher than influent pH) or negative (when effluent pH is lower than influent pH) difference of the average pH of effluent exiting the faecal sludge treatment site in comparison to the average pH of influent entering the faecal sludge treatment site in the same period.

References, tips, examples

The laboratory test protocol can be seen at:
The STeP Global Testing Protocols & Parameters – A best practices guide for testing sanitation technologies in the field
http://stepsforsanitation.org/?smd_process_download=1&download_id=4171
Influent example from Zambia: 7.5-7.8 for pit latrines and 7.0-7.5 for septic tanks
Example range of liquid effluent as per the ZEMA standard 6-9.

Why it is important to measure it ?

Helminths eggs reduction

Definition of indicator

Parasitic worms, also known as helminths, are large macroparasites, which as adults can generally be seen with the naked eye. Many are intestinal worms that are soil-transmitted and infect the gastrointestinal tract. It is an umbrella term that includes many species of worm from different genera. Helminth eggs of concern in wastewater used for irrigation have a size between 20 and 90 μm. They are commonly expressed in number of eggs per gram of solution (n/g).
The reduction is related to the Helminth eggs in the effluent exiting the faecal sludge treatment site in comparison to the Helminth eggs in the influent entering the faecal sludge treatment site.

How to measure or calculate it ?

The reduction is calculated as COMPLEMENTARY PERCENTAGE of the average Helminths eggs in the effluent exiting the faecal sludge treatment site over the average Helminth eggs in the influent entering the faecal sludge treatment site in the same period.

References, tips, examples

The laboratory test protocol can be seen at:
The STeP Global Testing Protocols & Parameters – A best practices guide for testing sanitation technologies in the field
http://stepsforsanitation.org/?smd_process_download=1&download_id=4171
It is very difficult to inactivate helminth eggs, unless temperature is increased above 40 °C or moisture is reduced to less than 5%.

Why it is important to measure it ?

Helminth eggs (or ova) are a good indicator organism to assess the safety of sanitation reuse systems for resource recovery because they are the most environmentally resistant faecal pathogens and they can in extreme cases survive for several years in soil.

Exclusively communitarian operation

Definition of indicator

The indicator defines if the faecal sludge treatment system is operated exclusively by the beneficiary community without any constant external support.

How to measure or calculate it ?

Analyse responsibilities and tasks of the faecal sludge treatment site management. Identify if they are all cover by the beneficiary community or part of it. If there is occasional external support, still consider that the site is completely operated by the community.

Why it is important to measure it ?

It is important to know the complexity of operations in relation to the skills of the community in order to plan the faecal treatment site management and forecast long-term sustainability.

Safety and hygiene: washing capacity availability

Definition of indicator

The indicator defines if washing capacities are available for the faecal sludge treatment workers.

How to measure or calculate it ?

Analyse if washing capacity (with adequate privacy and supplied with enough water and soap/chlore) are available and accessible at the key moments (before eating or drinking and before leaving the faecal sludge treatment site).

Why it is important to measure it ?

Washing capacity is key to protect the health of faecal sludge treatment workers and their family.

Safety and hygiene: PPEs availability

Definition of indicator

The indicator defines if Personal Protection Equipment (PPEs) are available for the faecal sludge treatment workers and potential visitors.

How to measure or calculate it ?

Analyse if Personal Protection Equipment (PPE) are available, accessible and frequently washed or replaced.

Why it is important to measure it ?

PPEs are key to protect the health of faecal sludge treatment workers and their family.

Skill level required for up)grading/decommissioning

Definition of indicator

This indicator defines the level of knowledge and experience required to be able to upgrade or decommission the faecal sludge treatment site successfully.

How to measure or calculate it ?

The indicator is determined by forecasting an eventual upgrading or decommissioning phase taking lessons learnt from the construction process (including selection of contractors or construction staff). Should specific contractors and specialists be involved for special supervision, know-how, equipment?

Why it is important to measure it ?

Faecal sludge is a potential dangerous material: a simple mistake in infrastructures construction may stop operations for several weeks and affect the sustainability of faecal sludge treatment. For the same reason, decommissioning and disposal of faecal sludge treatment infrastructures and equipment can contaminate the environment and affect population living around the disposal site or dismissed faecal sludge treatment site.

Filter case studies

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