Investigation of the Critical Parameters in the Production of - - PowerPoint PPT Presentation

A research executed by:

Isabelle Gensburger October 2011

Investigation of the Critical Parameters in the Production of Ceramic Water Filters

Contents

• 1. Introduction

– Review and Problem Description – Research Objectives – Project Scope

• 2. Summary of Methods

— Filter making process — Filter testing

• 3. Experimental Results & Discussion

– Rice Husk Quantity Variations – Maximum Firing Temperature Variations – Rice Husk Particle Size Variation – Two-month Clogging Test – Strength Test

• 4. Conclusions & Recommendations

Project Objectives

1.To better understand the production components and variables and move towards an international certification programme 2.To investigate ways to increase the flow rate without compromising the water quality and strength of the filter

Research Scope

Set up and test the research production line Test reproducibility of RDI filters by mimicking RDI processes from mixing to firing Experiment with variations

• 1. Rice husk quantity (9.7, 11, 12, 13 and 14 kg)
• 2. Maximum firing temperature (685, 800, 885 and 950 deg. C.)
• 3. Rice husk particle size (<1 and 0.5<mm<1)

Research Production Line

• Water supply
• Electricity supply
• Raw materials
• Equipment
• Machinery:
• Mixer
• Hydraulic press

Research Scope

Set up and test the research production line Test reproducibility of RDI filters by mimicking RDI processes from mixing to firing Experiment with variations

• 1. Rice husk quantity (9.7, 11, 12, 13 and 14 kg)
• 2. Maximum firing temperature (685, 800, 885 and 950 deg. C.)
• 3. Rice husk particle size (<1 and 0.5<mm<1)

Research Kiln

Research Scope

Set up and test the research production line Test reproducibility of RDI filters by mimicking RDI processes from mixing to firing Experiment with variations

• 1. Rice husk quantity (9.7, 11, 12, 13 and 14 kg)
• 2. Maximum firing temperature (685, 800, 885 and 950 deg. C.)
• 3. Rice husk particle size (<1 and 0.5<mm<1)

Methods: Filter Making Process

• 1. Preparation of raw materials

(sieving < 1 mm)

• 2. Mixing of clay components

(10 mins dry and 15 mins wet)

• 3. Forming of clay cubes for

pressing

• 4. Pressing of clay cubes into

ceramic filter form

• 5. Surface finishing and labeling
• f pressed filters
• 6. Drying of pressed filter elements

(dry versus wet season)

• 7. Firing and cooling in kiln

Methods: Filter Making Process

• 1. Preparation of raw materials

(sieving < 1 mm)

• 2. Mixing of clay components

(10 mins dry and 15 mins wet)

• 3. Forming of clay cubes for

pressing

• 4. Pressing of clay cubes into

ceramic filter form

• 5. Surface finishing and labeling
• f pressed filters
• 6. Drying of pressed filter elements

(dry versus wet season)

• 7. Firing and cooling in kiln

Methods: Filter Making Process

• 1. Preparation of raw materials

(sieving < 1 mm)

• 2. Mixing of clay components

(10 mins dry and 15 mins wet)

• 3. Forming of clay cubes for

pressing

• 4. Pressing of clay cubes into

ceramic filter form

• 5. Surface finishing and labeling
• f pressed filters
• 6. Drying of pressed filter elements

(dry versus wet season)

• 7. Firing and cooling in kiln

Methods: Filter Making Process

• 1. Preparation of raw materials

(sieving < 1 mm)

• 2. Mixing of clay components

(10 mins dry and 15 mins wet)

• 3. Forming of clay cubes for

pressing

• 4. Pressing of clay cubes into

ceramic filter form

• 5. Surface finishing and labeling
• f pressed filters
• 6. Drying of pressed filter elements

(dry versus wet season)

• 7. Firing and cooling in kiln

Methods: Filter Making Process

• 1. Preparation of raw materials

(sieving < 1 mm)

• 2. Mixing of clay components

(10 mins dry and 15 mins wet)

• 3. Forming of clay cubes for

pressing

• 4. Pressing of clay cubes into

ceramic filter form

• 5. Surface finishing and labeling
• f pressed filters
• 6. Drying of pressed filter elements

(dry versus wet season)

• 7. Firing and cooling in kiln

Methods: Filter Making Process

• 1. Preparation of raw materials

(sieving < 1 mm)

• 2. Mixing of clay components

(10 mins dry and 15 mins wet)

• 3. Forming of clay cubes for

pressing

• 4. Pressing of clay cubes into

ceramic filter form

• 5. Surface finishing and labeling
• f pressed filters
• 6. Drying of pressed filter elements

(dry versus wet season)

• 7. Firing and cooling in kiln

Methods: Filter Making Process

• 1. Preparation of raw materials

(sieving < 1 mm)

• 2. Mixing of clay components

(10 mins dry and 15 mins wet)

• 3. Forming of clay cubes for

pressing

• 4. Pressing of clay cubes into

ceramic filter form

• 5. Surface finishing and labeling
• f pressed filters
• 6. Drying of pressed filter elements

(dry versus wet season)

• 7. Firing and cooling in kiln

• Flow rate

– constant head method – long-term testing

• E. coli

– indicator of bacteria – membrane filtration method – spiked influent water:

• 103 CFU/ml without silver
• 106 CFU/ml with silver
• Strength

– discs cut from the bottom of the filters – modulus of rupture (MOR)

• Pore size (to be done at TU Delft)

– mercury intrusion porosimetry

Methods: Filter Testing

Variable: Rice Husk Quantity Comparison: Flow Rate and Rice Husk Quantity

5 10 15 20 25 9 10 11 12 13 14 15 Flow Rate (LPH) Quantity of Rice Husk per Batch of 6 Pots (kg) r = 0.867 strong correlation n = 12 n = 12 n = 12 n = 12 n = 12

Variable: Rice Husk Quantity Comparison: LRV and Rice Husk Quantity

1 2 3 4 5 6 9,7 11 12 13 14 LRV (E. Coli) Quantity of Rice Husk per Batch of 6 Pots (kg) Min Outlier Max Outlier WITHOUT SILVER: Average LRV = 2.9 r = 0.056 no correlation n = 10 n = 11 n = 8 n = 13 n = 9

1 2 3 4 5 6 7 8 9,7 11 12 13 14 LRV (E. Coli) Quantity of Rice Husk per Batch of 6 Pots (kg) Min Outlier Max Outlier n = 3 n = 3 n = 3 n = 3 n = 3 WITH SILVER: Average LRV = 6.8

Variable: Rice Husk Quantity + Silver Nitrate Comparison: LRV and Rice Husk Quantity

1 2 3 4 5 6 7 8 9 10 600 700 800 900 1.000 1.100 Flow Rate (LPH) Maximun Firing Temperature (deg. C) 685 deg. C 800 deg. C 885 deg. C 950 deg. C strong correlation

Variable: Maximum Firing Temperature Comparison: Flow Rate and Max. Firing Temperature

Variable: Maximum Firing Temperature Comparison: LRV and Max. Firing Temp.

2 4 6 8 10 12 800 885 950 LRV (E. Coli) Maximum Firing Temperature (degrees C.) Min Outlier Max Outlier r = -0.454 n = 9 n = 6 n = 11 weak correlation

Variable: Rice Husk Particle Size Comparison: LRV and Rice Husk Size

0,5 1 1,5 2 2,5 3 3,5 4 [0 - 1] [0.5 - 1] LRV (E. Coli) Rice Husk Particle Size (mm) n = 16 n = 7 strong correlation

RESULTS Strength Test

0,5 1 1,5 2 2,5 3 3,5 4 9,7 11 12 13 14 MOR (MPa) Quantity of rice husk per batch of 6 pots (kg) Min Outlier Max Outlier

Variable: Rice Husk Quantity Comparison: MOR and Rice Husk Quantity

r(kg rice husk, MOR) = 0.951 strong correlation

n=16 n=10 n=12 n=17 n=4

Variable: Maximum Firing Temperature Comparison: MOR and Max. Firing Temp.

0,5 1 1,5 2 2,5 3 3,5 4 685 800 885 950 MOR (MPa) Maximum Firing Temperature (degrees C.) r = 0.999 strong correlation n=6 n=3 n=16 n=7

Variable: Rice Husk Particle Size Comparison: MOR and Rice Husk Size

0,5 1 1,5 2 2,5 3 3,5 4 < 1 mm [0.5 - 1] mm MOR (MPa) Rice Husk Particle Size Min Outlier Max Outlier

n=16 n=7

RESULTS Long-Term Flow Rate Test

Long-Term Flow Rate Test

using turbid pond water (12.9<NTU<199)

50 100 150 200 250 300 9,7 11 12 13 14 Throughput (L) Quantity of Rice Husk per Batch of 6 Pots (kg) 1st scrub 2nd scrub 3rd scrub 4th scrub 5th scrub 6th scrub Scrubbing Flow Rate < 1 LPH When using less turbid well water (2.7<NTU<27.1):

• Pots (9.7 – 11 kg) already < 2 LPH
• Pots (12 – 13 kg) maintained flow rates > 2 LPH and only had to be scrubbed 2

times in the month

• Pots (14 kg) always maintained flow rates > 2 LPH throughout the whole month

Conclusions & Recommendations

The flow rate can be increased by:

• 1. increasing the porosity of the filter, by increasing the

quantity of burn-out material in the clay mix; and

• 2. increasing the pore size, either by

– changing the particle size distribution of the burnout material, or by – changing the maximum firing temperature.

The bacteria removal effectiveness is only compromised when increasing the pore size

Thanks

Everybody at RDIC My EWB colleagues The Dutch Research Group

Questions?