Urban wastewater treatment using Scenedesmussp.

Transcription

1 Urban wastewater treatment using Scenedesmussp. Carlo Pozza Urban Water and Waste Management Universitätsstr Essen

2 2 Presentation summary Microalgae and wastewater Experiments Conclusions

3 3 Potential benefits of microalgae Microalgae grow naturally in wastewater Microalgae remove N and P during their grow (proteins are 45-55% of microalgae dry weight) Assimilation of CO 2 for photosynthesis (about 2 t CO 2 for 1 t of microalgae; high tolerance to high CO 2 concentration) Synergic effects (O 2 production (bacteria); rising of the ph for metals and phosphorus precipitation, ammonia volatilization) Biomass production (Biogas production, biofuel, fertilizer, animal feed, high value biomolecules production)

4 4 Project presentation Wastewater nutrient removal with microalgae Study the alternative uses of the microalgae after the harvesting (AD, biofuel) Photobioreactor with internal illumination Conduct large-scale test using this kind of illumination

5 5 Internal illumination With the internal illumination, the light is spread into the reactor allowing a better distribution. There s the possibility to use different kind of light sources in the photobioreactor (sunlight, LED, ) Lower surface requirements compared to high rate ponds. Photobioreactor with fibre optics as a source of light Microalgae illuminated with a round bar made of Plexiglas and red and blue LED.

6 6 Progress Experiments Scenedesmus sp. + artificial wastewater Scenedesmus sp. + real urban wastewater Anaerobic digestion of Scenedesmus sp.

7 7 Experiments artificial wastewater Batch test in 1-Liter reactor with different starting ammonia concentrations (50, 150, 400, 1000 mgn-nh 4 /L) Fluorescent lamps with solar spectrum, µmol/m 2 /s 20:4 light-dark cycle Temperature: 23 C ph control: 6-7,5

8 8 Experiments artificial wastewater Higher removal efficiency and higher growth rate at lower N-NH 4 concentration. The N-NH 4 removal rate is higher, high is the starting concentration. Starting concentration (mgn-nh 4 /L) Removal efficiency N-NH 4 removed (mgn-nh 4 /L) Removal rate (mgn-nh 4 /L/d) % 111 8, % 92 6, % 50 3, % 38 1,8

9 9 Experiments real wastewater A: Urban wastewater + Scenedesmus sp. grown in normal media B:Urban wastewater+ Scenedesmussp. grownwithhigh concentrationof N-NH 4 (1200 mgn-nh 4 /L) C: Control reactor, urban wastewater Fluorescent light with solar spectrum PFD: µmol/m 2 /s, 20:4 light-dark cycle Average temperature: 24 C ph control bubbling pure CO 2

10 10 Experiments real wastewater FISH test The sample is stained with DAPI and is excited with ultraviolet light: all the cells with DNA are bluecolour. The sample is excited with green light and the algae, in these condition, emit naturally the red.

11 11 Experiments real wastewater A: Urban wastewater + Scenedesmus sp. grown in normal media

12 12 Experiments real wastewater B: Urban wastewater+ Scenedesmussp. grownwithhigh concentrationof N-NH 4 (1200 mgn-nh 4 /L)

13 13 Experiments real wastewater Summary Reactor A Scenedesmussp. grown in normal media B Scenedesmussp. grown in high ammonia media COD removal percentage 67% 74% TN removal percentage 94% 97% Time (d) C Control reactor 4% 20% 32

14 14 Biogas production Biogas production (GB21) L/kg ots Scenedesmus sp. Scenedesmus sp. with ultrasound pretreatment Vegetable waste Scenedesmus sp. + vegetable waste Scenedesmus sp. with ultrasound pretreatment + vegetable waste

15 15 Possible applications Nutrient removal Treatment of urban wastewater as secondary or tertiary treatment. Treatment of high polluted wastewater (industrial wastewater, centratefrom sludge thickening from urban wastewater treatment plant, effluent from anaerobic digestion plant, leachate). CO 2 and CH 4 Use of flue gas for enhancing the algal growth (anaerobic digestion plant or power plant). Use of the harvested microalgae for anaerobic co-digestion.

16 16 Thank you for your attention Carlo Pozza Urban Water and Waste Management Universitätsstr Essen