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Treatment of Faecal Sludge in Emergencies

Katie Anderson

The Project Team

Happiness Nobela

Eliette Gonzalez

Dennis Malambo

Urea

Quick Lime

Lactic Acid

Jan Spit

Lobke de Pooter

Katie Anderson

Urea

Hydrated Lime

Project Leader

Presentation Overview

Desludging Technologies

Faecal Sludge Treatment

1. Introduction: Emergency Sanitation

2. Key Criteria for Faecal Sludge Treatment

3. Objectives of Fieldwork in Malawi and Experimental Set up

4. Characteristics of Faecal Sludge

5. Faecal Sludge Treatments: Lactic Acid, Urea, Lime

a. Theory

b. Treatment Process

c. Field Results

Raised Latrine

Hurricanes

Earthquakes

War

Malawi

Emergency Situations

Acute Phase of Emergency

Faecal-Oral diseases : 40% deaths

Phases of Emergency Response

Phase 3:

Recovery

Phase 1

Immediate

Emergency

Months - Years

1-2 Weeks

Resolution

Emergency

Phase 4:

Settlement

Phase 2:

Stabilisation

Years

2 weeks to 2 months

Phase 1 & 2

Faecal Sludge Treatment :

Contain and treat Excreta --> Mitigate outbreak of communicable diseases

Order of Importance

Fieldwork in MALAWI

Objective

To investigate and evaluate the suitability of Urea, Lime and Lactic Acid Treatment processes as a means of treating faecal sludge and the applicability to emergency situations

1. Safety

2. Sanitation : Meet WHO guidelines E-coli <10^3 CFU/100ml

3. Robustness : Treat Liquid and Solid Sludge

4. Treatment Time

5. Process conditions : Optimum dosage, Physical conditions

6. Required Resources:( Chemical Dosage/ Energy Input)

7. Upscalability

8. Applicability of treatment to Phase 1-2 Emergency

Bangwe Market

Pit Latrines

50-100 users per day

Sludge Age: 2 weeks- 1 month

Emptying Pit

High Pressure Fluidizer

Vacuum Pump

Faecal Sludge Characterisation

Rubish: Stones, Corncobs, menstral rags, plastic botles

pH: 6-7.6

TS: 4-15%

VS: 45-75%

E-coli: 10^6 CFU/100ml

COD: 50-150 g/L

Ammonia 1.2-1.5 g NH3-N/L

Influenced by:

1. Storage duration

2. Temperature

3. Intrusion of groundwater

4. Pit emptying technology and pattern

5. Admixture to FS ( solid waste/grease/kitchen waste)

Zingwangwa WWTP

Experiment site

Faecal Sludge Emptied into 50L Plastic Drums

Faecal Sludge Treatment Experiments

Lactic Acid

Urea

Lime

Experimental Set up

Future Work

Faecal Sludge Treatment

Thank you for your attention

Summary and Conclusions

Questions?

Treatment Method Comparison

Based on the Small-scale 50L Batch Experiments:

All three treatment methods : Lime, Lactic Acid, Urea

proved to be suitable to sanitize Faecal sludge

All three treatments were able to be conducted safely

Safety:

Sanitisation:

Robustness:

All three treatments were able to meet the WHO guidelines <10^3 CFU/100ml

All three treatments were able to treat sludge with varying %TS

Bangwe Market Toilet Trial

Lactic Acid

Objectives

Method A

To determine if sanitized sludge can be produced by adding lime periodically into the toilet whilst the public latrine is in use

Method B

To determine if adding lime through the fluidization process during desludging is sufficient to produce a homogeneously sanitised sludge

Pre culture

Innoculum Material

Methodology

Lactic Acid

- reduce intracellular pH

Lactic Acid Formation

Lactic Acid Bacteria

Carbohydrates

Lactic Acid

Lactobacillus casei Shirota

65ml Yakult

6.5 'billion

Gram positive species

Preferential nonaerobe

Aerotolerant

Acid tolerant

Strictly Fermentative

Theory

Resultsss

Method A: Daily Addition

Method B: Bulk Lime Addition

Pathogen deactivation not observed for lower sludge layers

0.2% w/w Yakult : Milk Innoculum

Methodology

Fluidizer was inadequate to produce homogeneous mixing

Desired pH not achieved and pathogen destruction not observed

Sugar Source

48h at room temperature

10% w/w Inocculum to sludge

Results

pH

Lactic Acid Bacteria Process Results

Lactic Acid Concentration

E-Coli Suppression

20-30g/L Lactic Acid Concentration for E-coli suppression

Lactic Acid Test Result Summary

E-coli deactivation achieved in 7 days :

Conditions:

pH <4,

Lactic Acid concentration 20-30g/L

Temperatures of experiments >20 degrees

Batch Testing : Initial intense mixing

Chemical Dosage:

Initial Pre-culture: 10%w/w sludge (0.2%w/w Yakult to Milk)

- This can be replaced by treated faecal sludge as inoculum for successive treatments

Sugar Addition : 10% w/w sludge

Treatment Time

Urea

10%w/w sugar source to sludge

Lime

Urea-->Ammonia

Sanitising mechanism

Ammonia

Soluble in water and lipids

Diffusive transportation

Ammonia over cell membrane

Ammonia Inside Cell:

1. Increase pH

2. Destruction of membrane potential

3. Denaturalisation of bacterial membrane

and cell protein

Ultimate Effects

Cell decay

Overall Pathogen destruction

Locally sourced Urea

Theory

Purity 40%

3 min Mixing

Sampling

d 1,2,4,7,9

Methodology

Hydrated Lime

Increases Hydroxide ion concentration - raising pH

Highly alkaline environment

Cell growth suppression

Pathogen deactivation

Ammonia Summary

Adequate Log Removal ( 3 Log removal) for E-coli observed between 4-8 days after addition of urea

2% Urea observed to be the most effective

pH 9 – 9.5

Reactors must be sealed to ensure no ammonia gas escapes

Next Phase – upscale to Bladder Experiments – to be conducted in 2 weeks

High temperature can enhance treatment therefore effective use of sunlight will aid treatment

Urea Treatment Results

Results

Control

Theory

Methodology

Results

1%w/w Urea

3%w/w Urea

Lime Treatment Results

Summary of Lime Treatment

-Buffering capacity varied for each sludge

-pH of the reactor maintained over first 2 hours

-Above pH 10.5 reduction in E.coli and Total Coliforms to <10^3 CFU/100ml within 2 hours

-No distinct reduction in COD

- No distinct reduction in TS or VS (TS around 15%, VS around 50%)

0.85g Urea

33kg Sludge

2.51kg Urea

33kg Sludge

10min intense mixing

Stirred Manually for 3 minutes

sampling : 0h,1h,2h, 5h

Sampled over 8 days

pH, NH3-N and E-coli Concentration

Measured

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