1. Department of Hydraulic and Environmental Engineering
Development of an ”at-line” sensor for monitoring bio-fouling potential in membrane filtration systems for drinking water treatment using ezyme activity measurements. Blanca Magdalena Gonzalez Silva Advisors: Cheng Sun, post doc; Stein W. Østerhus professor.

2. Aim
Development of an non-destructive early warning monitoring at-line of enzyme activity, as an indicator of biofouling potential in membrane filtration process.

3. Introduction:
Demand for on- line,non-destructive real-time information about biofilms in technical systems:
Examples: Physical or physico-chemical on- line methods:
a) Detect ↑or↓ of material accumulating on a surface (not ≠ biomass and other components of a deposit).
Most have not successful proof of operation at laboratory
None are specially designed for membrane biofouling monitoring
b) Provide biological information and distinguish between biotic and abiotic material.
c) Provide detailed chemical information.

4. Introduction For in-situ or at-line monitoring of membrane biofouling:
Exo-enzymes Exo-hydrolases: hydrolyse organic compounds.
Heterotrophic bacteria excellent producers of hydrolytic enzymes.
The activity of such exo-enzymes can therefore be used as a measure of total active biomass.

5. How was done the enzymatic activity in previous experiments ?
Ultrasonic treatment  biofoulant removal
Enzyme activity assays

6. Strategy for carried out the development of an ”at- line” sensor:
Mixed time = 1 min
2.- Substrate injection (MUH)
Substrate concentration= ≥ 0.02 mg MUH/mL
Monitoring: Trans membrane pressure (TMP); Temperature
1.- Biofouling development
Raw water
permeate
Monitoring: Trans membrane pressure (TMP); Temperature
1.- Biofouling development
Raw water
permeate
3.- Enzyme measurement
Fluorimeter
Flow=1 mL/min

7. 3.- Enzyme measurement MUH: 4-methylumbelliferyl heptanoate
MU: fluorescent 4-methylumbelliferone
Fluorimeter
Flow=1 mL/min
Sofware : Clarity lite

8. Expected results
Fluorescence
Time (min)
Day 1
Day 5
Day 10
Enzymatic activity = Amount of 4methylbumbelliferone (MU) per minute per litre.
Activity per cm2 membrane surface = μmol of MU realised per minute, per cm2.

9. Expected results Understanding biofouling behaviour and responses:
Enzyme activity
Biomass/Biofouling
Understanding biofouling behaviour and responses:
to choose optimal operating conditions for biofouling mitigation and
control.
It is assumed that cleaning can be more efficient when biofouling is in a early stage of colonisation

10. Initial determinations and preparations
Parameters:
Volumen =440mL,Total membrane area (outside) = 0.015m2; Flux =20 L/m2*h; Flow valule= 5.0mL/min;
Initial preparations
Familiarization with the fluorescence detector.
Determination of fluorescence signal with MU stock solution.
Familiarization with the software : Clarity chromatography station
Tests to find out how the software works

11. Tasks / activities: Test and calibrate unit for enzyme measurement
Perform experimental plan with small-scale test modules.
Analysis and reporting of experimental results.
Test at-line enzyme measurement with pilot scale membrane filtration systems.

12. Thank you for your attention!!