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Dr.-Ing. Eric Valette
Planet Horizons Technologies SA CTO CH-3960 Sierre, Switzerland
Reduction of excess sludge production in a conventional activated - - PowerPoint PPT Presentation
Reduction of excess sludge production in a conventional activated - - PowerPoint PPT Presentation
Reduction of excess sludge production in a conventional activated sludge system by a new electromagnetic treatment Dr.-Ing. Eric Valette Planet Horizons Technologies SA CTO CH-3960 Sierre, Switzerland Summary Introduction First trials
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Introduction
Goal: reduction of excess sludge production Processes:
Physical and chemical treatments Mechanical treatments Biochemical treatments Increase in dissolve oxygen
Alternative way:
Electromagnetic treatment
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Laboratory scale trials
Set-up: Ref line EM line
Décanteur
Réfrigérateur E B E R AC Bio V = 22,5 L Bio V = 22,5 L Q0 = 2 L/h Q0 = 2 L/h QL = 2 L/h QL = 2 L/h (1+R).Q
0 = 6 L/h
(1+R).Q
0 = 6 L/h
V = 6 L V = 6 L R.Q0 = 4 L/h R.Q0 = 4 L/h
Décanteur Electrodes
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Laboratory scale trials
Electromagnetic device: Electronic command:
- 2 frequencies (50 Hz to 20 kHz)
- Tension (< 100 V)
- Electromagnetic induction: few pico to
few nanoTeslas Antenna:
- 2 specific wires around the tank
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Laboratory scale trials
Operating conditions:
Different conditions were studied, the following results are obtained
while maintaining the extraction flow constant.
Flow rate of influent: Q0 (l h-1) COD in influent: (mgO2 l–1) COD in effluent: (mgO2 l–1) TS in aeration tank: (gTS L-1) TS in excess sludge: (gTS L-1) REF- line 2 548 ± 11 162 ± 32 4.97 ± 0.9 7.1 ± 1.4 EM-line 2 146 ± 29 4.35 ± 0.8 6.7 ± 1.3
Removal efficiencies of organic substrate: 70% REF-line and 73% EM-line
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Laboratory scale trials
Excess sludge production: reduction of 34%
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Laboratory scale trials
Important to underline:
This trial was the better one obtained All trials conducted in different operating conditions shown an
improvement in the reduction of excess sludge production with EM treatment from 0 to 34% It can be explained:
Difficulty to work in a 20L scale pilot (to maintain some parameters
constant, development of filamentous bacteria, etc.)
Duration of trials (30 to 60 days) Modification in EM parameters (frequencies, intensity, nature of
signal, kind and shape of antenna, etc.)
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Full-scale installation
Wastewater treatment plant of Penthaz (near Lausanne), Switzerland
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Full-scale installation
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Full-scale installation
Electromagnetic device: Electronic command:
- 2 frequencies (50 Hz to 20 kHz)
- Tension (< 100 V)
- Electromagnetic induction: few pico to
few nanoTeslas
- P < 6,5 kJ.m-3 treated
Antenna:
- 5 rectangular shape antennas (1m x 2,3
m)
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Full-scale installation
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Full-scale results
Operating conditions:
The total solids in the aeration tanks and the hydraulic and organic
loading rates were maintained at identical levels in the two lines by extracting excess sludge.
Flow rate of influent: Q0 (m3 d-1) COD in influent: tCOD0 (mgO2 l–1) COD in effluent: tCODL (mgO2 l–1) TS in aeration tank: X (gTS L-1) TS in excess sludge: XE (gTS L-1) REF- line 680 370 17.9 ± 3.6 1.6 ± 0.4 3.0 ± 0.7 EM-line 660 19.7 ± 4.2 1.3 ± 0.3 2.8 ± 0.7
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Full-scale results
Operating conditions:
Volumetric loading rate (kgCOD m-3 d-1) Specific loading rate (kgCOD kg-1TS d-1) Excess sludge production (kgTS d-1) Apparent sludge retention time (d) REF-line 1.05 0.66 106 3.5 EM-line 0.81 48 6.4
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Full-scale results
Removal efficiencies of organic substrate: about 94-95%
20 40 60 80 100 100 200 300 400 7 14 21 28 35 42 49 56 COD effluent (mg/l) COD influent (mg/L) Time (day) REF EM
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Full-scale results
Excess sludge production: reduction of 55%
200 400 600 800 1000 1200 5 10 15 20 25 30 35 Cumulative slude production (kg TS) Time (day)
REF-line EM-line
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Full-scale results
Switching off the treatment:
2000 4000 6000 8000 5 10 15 20 25 30 35 40 45 50 55 60 65 Cumulative excess sludge production (kg TS) Time (day)
REF EM
August September
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Full-scale results
Switching off the treatment:
50 100 150 200 250 5 10 15 20 25 30 35 40 45 50 55 60 Dayly excess sludge production (kg TS/d) Time (day)
REF EM
x3
August September
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Full-scale results
Biological sludge activity: A biomass stress index (BSI) was
defined (ratio ATP extra-cellular over total ATP). This index was similar in the two lines and lower than 0.5 not showing any negative effects on biomass due to electromagnetic treatment.
N and P balance
Ntotal N-NH4
+
N-NO2
- N-NO3
- Ptotal
P-PO4
3-
Sample mg · L-1 mg · L-1 mg · L-1 mg · L-1 mg · L-1 mg · L-1 Influent 36 54 0.9 24 3.0 2.6 Effluent REF-line 46 62 0.3 23 1.9 1.4 Effluent EM-line 28 45 0.1 13 1.0 0.6 Excess sludge REF-line 41 53 0.3 12 1.1 0.6 Excess sludge EM-line 33 43 0.2 13 1.0 1.0
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Perspectives
PhD study with University of Savoie - LOCIE (FR) and University of
Grenoble – G2Elab (FR)
- Influence on the proteinic synthesis
- Cellular stress and physiological stress
- Influence on the transfers of electrons
- Measurement and modelling of EMF
New trials in the wastewater treatment plant of Penthaz
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Perspectives
New trials in the wastewater treatment plant of Penthaz
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