Denutritor for rainwater use Pilot test at Unilever Ben&Jerry s ice-cream factory

Transcription

1 Denutritor for rainwater use Pilot test at Unilever Ben&Jerry s ice-cream factory Bas van der Zaan Jan Gerritse Leon ter Braak Rudi van der Arend Karin Thelen Claudia Beimfohr Willy van Tongeren

2 What is Denutritor? Denutritor is a biofilter which removes substrates for microbial growth from water (from few mg to µg range) Microorganisms grow preferentially in the filter and growth downstream Denutritor is prevented Denutritor removes the source of biofouling and water spoiling

3 Denutritor activities in AquaFit4Use WP Lab tests with different water types WP Pilot tests at Perstorp Specialty Chemicals Pilots treatment of wastewater effluent finished up to 90% biofouling potential reduction WP Pilot tests at Unilever Ben & Jerry s ice-cream factory Treatment of rainwater, collected for cleaning

4 How does Denutritor function? Fixed-film upflow column system Biofilms grow on polyurethane foam filler

5 Biofilms on filler degrade growth substrates effluent TOC Microbial biofilms on filling material TOC: Total Organic Carbon AOC: Assimilable Organic Carbon Substrate that microbes use for growth TOC influent AOC

6 Denutritor pilot at Ben & Jerry s Ben & Jerry s wants to use rainwater for: Cleaning (containers, pallets) Sanitation (toilets) Rainwater collected on the roof and stored in a buffer tank Growth of microorganisms in rainwater and biofilms? Potential source of pathogens?

7 Denutritor pilot at Ben & Jerry s Lab and Pilot-scale tests: Can Denutritor improve microbial quality of stored rainwater? Is microbiologically safe water produced by combined Denutritor + UV-treatment?

8 Lab-tests with collected rainwater: conclusions Biofouling 33% reduction Bacteria in rainwater No big changes in total concentrations Reduction of coliforms and E. coli Pathogens reduced but trace levels may stay Filler Fine Medium Course Water flow UV treatment Kills bacteria to acceptable levels for cleaning purposes

9 Rainwater systeem at Ben & Jerry s Roof Ben&Jerry s Factory Denutritor Rainwater buffer tank UV disinfection Cleaning pellets containers

10 Roof at Ben & Jerry s ice-cream factory

11 Rainwater buffer tank May 9th, Bruges

12 Denutritor pilot at Ben & Jerry s

13 Scheme Denutritor pilot BM = Biofouling monitor P = Pressure meter WM = Water meter V = Valve BM BM BM BM V [Effluent] [Influent] W M V P P P V V PC ph Redox O 2 Temp. Data logger

14 What did we test? Rainwater stored in the buffer tank without treatment Rainwater stored in the buffer tank with Denutritor Effect of UV treatment on rainwater used for cleaning

15 What did we analyse? In line monitoring process parameters in & out each column O 2 ph Redox potential Temperature Pressure drop Water flow

16 What did we analyse? Biofouling monitors Exposed to influent and effluent of each filter column Protein increase (quantify biofilms)

17 What did we analyse? Chemical water quality in influent and effluent water samples Anions, Cations Nutrients (N, P, S,..) TOC, AOC, COD, Metals

18 What did we analyse? Microbiological water quality Cultivable bacteria (plate counts) Total cells & viable cells (FISH) Water-born pathogens and indicators (FISH) Enterobacteriaceae, Legionella, Klebsiella pneumoniae, Ps. aeruginosa Pathogens harmful in Food (FISH) Salmonella, Listeria, Enterobacter sakazakii

19 Results Denutritor waterflow Denutritor waterflow Volume (m3) ,8 0,6 0,4 0,2 Waterflow (m3/h) Volume Waterflow Days

20 Results Denutritor Pressure over filters Pressure over filter columns 1,0 Pressure (bar) 0,8 0,6 0,4 0,2 Filter 1 Filter 2 Filter 3 0, Days

21 Results water quality Reference Denutritor treated Concentration (mg/l) chloride nitrate sulphate sodium ammonium calcium Concentration (mg/l) nitrate (mg/l) days days Relatively low concentrations Ion concentrations are stable with Denutritor and in Reference after start. Increase of nitrate NO3 < 10 mg/l (max. in drinking water-: 50 mg/l) PO 4 <0.5 mg/l

22 Results biofouling potential Denutritor Biofouling potential Test run Days (mg/m2/day) , , , , ,92 0,62 ± 0,27 Reference Test run Days (mg/m2/day) , , ,76 2,19 ± 0,83 72% reduction biofilm potential

23 Results biofouling potential -substrate Denutritor Substrate (AOC) Day 155 5,2 < 10 μg Ac-C / L = indicated as minimal biofouling potential (H. Veenendaal, 2009) Reference Day µg Ac-C / L 88 30

24 Results -microbiology cell counts / 100 ml Denutritor treated rainwater total; cells direct viable Enterobacteriaceae Legionella Ps. Aerigunosa K. pneumoniae Absent: Salmonella Listeria E. sakazakii cell counts / 100 ml Reference WHO and Unilever treshold for coliforms <1 cfu/ 100 ml

25 Results UV test cell counts / 100 ml Denutritor treated rainwater Influent 500 J/L 2500 J/L CFU 30 CFU 37 total; cells direct viable Enterobacteriaceae cell counts / 100 ml Reference Administrative issues Influent 500 J/L 2500 J/L CFU 30 CFU 37 total; cells direct viable Enterobacteriaceae

26 Conclusions and Discussion Rainwater treatment with Denutritor is easy Denutritor reduced biofouling potential of rainwater with 72% Amount of bacteria in rainwater not reduced But. amount of pathogens in stored rainwater significantly reduced UV-treatment more efficient on starved cells!

27 Denutritor pilot at Ben & Jerry s Lab and Pilot-scale tests: Can Denutritor improve microbial quality of stored rainwater? YES Is microbiologically safe water produced by combined Denutritor + UV-treatment? YES

28 Broader impact Applicable for other industrial water types (cooling water, waste water re-use, water for sanitation) Save and safe water Reduced energy for uv desinfection Reduce risks with pathogens Reduce use of chemicals (more sustainable) Cleaner water systems

29 Future needs Built up experience and confidence Optimizing Denutritor treatment / UV-reduction From prototype to product!

30 Thank you for your attention!

31 Global costs estimation Investment (keur) Vessel 1 Filler 0.3 Distributor 0.2 Piping 0.5 Engineering 0.5 Total 3 Yearly costs (keur/yr) Depreciation (10%/yr) 0.3 Interest (5%/yr) 0.15 Refill (once in 3 yr) 0.1 Maintenance (5%/yr) 0.15 Personnel EUR/hr) Energy EUR/kWh) Total 2.6