Nutrient Recovery and Microalgae Biomass Production from Human Urine in Membrane Photobioreactor Van-Thuan Nguyen *, Thanh-Tin Nguyen, Thi-Thanh-Thuy Ngo, Nguyen-Tra-My Phan & Xuan-Thanh Bui Ho Chi Minh City University of Technology Email: nguyenvanthuan071@gmail.com Application of Microalgae Biofuels production Wastewater treatment Reducing CO2 Bioproducts Why Urine? Liquid fertilizer (Watering) Urine Contains the major part of the daily excretion of N, P, K contributing 88%, 67% and 73% (Karak & Bhattacharyya, 2011) Struvite crystals formation - Urine contains a high amount of N & P  eutrophication - To rescue a huge amount of nutrient, urine can be used as liquid fertilizer, watering directly or transform into struvite products Characteristics of Human Urine Parameters Value (Krak & Bhattacharyya, 2011) pH 8.90-8.96 TN 1,795–2,610 mg/L NH4+-N 1,117–1,726 mg/L NH3-N 574–773 mg/L NO3 N 45 µg/L NO2 N 10–20 µg/L Urea TP 85% TN 200–210 mg/L A nutrient source of N & P  good for microalgae cultivation Microalgae: Chlorella Vulgaris Microalgae strain: Chlorella Vulgaris Domain Regnum Eukaryota  Able to survive in wastewater (Das, 2011)  Suitable to grow in the climate of Vietnam (Pulz, 2001)  Grow in a wide range of salinity Vegatation Division Chlorophyta Class Trebouxiophyoeae Ordo Chlorellales Familia Chlorellaceae Reasons for  selecting  Chlorella Vulgaris  Genus Chlorella High commercial values Able to grow in high concentration of CO2 (40%) (Das, 2011) High yield of oil contents (28-32%) (Chisti, 2007) Why Sponge MBR technology Why Membrane Photobioreactor (MPBR)? Photobioreactor Permeate Feed (screened) Effluent Withdraw biomass PBR • • • • Membrane module MPBR Prevent washout problem of algae; Operate at high flow rate & complete retention of biomass; Enhance light accessibility, sufficient mixing, easily accessible carbon source  decreasing the costs for construction & operation; Independent HRT & MRT  higher biomass productivity, enhance nutrient removal & less footprint requirement Research Objectives Research Objectives Nutrient recovery & biomass production from human urine in microalgae membrane photobioreactor Methodology Research Contents Evaluation of biomass growth and nutrient recovery in MPBR using urine as substrate MPBR Flux = LMH HRT = days MRT = 10, 7, days • Microalgae biomass productivity; • Nutrient recovery from urine Parameter Analysis  Cell density  Analytical methods Parameters Methods pH 4500 – H+ B Electrometric Method 4500 – Norg B Macro – Kjeldahl TKN Method TP 4500-P D Standard Method NO3 N Measuring with sunfanilic NO2 -N 4500 - NO2- B MLSS 2540 D Standard Method Daily recorded by a digital pressure TMP gauge, PG30, Japan Fuchs-Rosenthal & Burker method: Cell density (cell/mL)= α x 0.25 x 106 α: cell number of one large square which accounted for an average value from large squares in the chamber One large square contains 16 small squares with the area of 0.0025 mm2 & chamber depth of 0.1 mm Cell counting! Results & Discussion Biomass Growth 3500 Biomass concent rat ion (mg L-1) MRT = days MRT = 10 d ays Start-up MRT = d ays Bioma ss centration 3000 1575 2500 2000 1500 1000 2145 2025 500 0 10 20 30 40 50 60 70 Cult ivat ion (days) 80 90 100 110 120 130 - Fast growing in first 10 days  adapt well with human urine feed; - Average biomass conc = 2025, 2145 & 1575 mg/L (MRT = 10, & d)  Effectiveness of membrane avoiding biomass wash-out - Biomass conc reached 2120 mg/L after 10 days (higher results of Honda et al., 2012; Gao et al., 2014) Biomass Productivity Biomass product ivit y (mg L-1 day1 ) 350 Biomass productivit y 300 315 306 250 203 200 150 100 50 MRT (days) 10 - Biomass conc & productivity were greater than Marbelia et al (2014) (Biomass conc = 590 mg/L, biomass productivity = 60 mg/L.d)  Productivity from urine was much higher than other wastewaters (raw municipal, treated sewage, aquaculture, etc.) ; - Shorter MRT with a frequent larger amount of mixed biomass (algae/bacteria/protozoa) withdrawn  less competition of bacteria to microalgae growth  Promoted strong growth of microalgae - Highest productivity at MRT = d Microscopic Observation Appearance of protozoa Amoeba proteus Amoeba proteus • • Most MRTs, protozoa and bacteria was detected Less protozoa observed at shorter MRT Algae Flocs & Morphology Cell flocculation Algae cells and flocs observed (x10 magnification) Algae cells and flocs observed (x40 magnification) Flocs morphology at MRT = 10 days Flocs morphology at MRT = days Microscopic Observation Appearance of protozoa and flocs formation Rotifer Paramecium Flocs formation • Flocs formation appeared in MPBR after 10 days of cultivation, • Less protozoa observed at shorter MRT Microscopic Observation Rotifer observed under microscope with x40 magnification Nitrogen Removal Influent TN 200 Effluent TN The average TN removal rate 73.1 T N removal rat e (mg N L- day- 1) Tot al nit rogen (mg L1 ) 250 38.4 70 35.5 150 100 60 50 40 30 20 MRT (days) 50 80 10 0 10 - Urea was hydrolyzed into ammonia  easily used as a nutrient source - Short MRT facilitated higher nitrogen uptake due to higher productivity - TN removal efficiency was also higher than previous studies - Chlorella vulgaris could adapt well in medium with high nitrite and nitrate Phosphorus Removal Influent TP Effluent TP The average TP removal rate T P removal rat e (mg P L- day- 1) 16 Tot al Phosphorus (mg L- 1) 14 12 2.43 2.67 2.7 2.6 2.28 10 2.8 2.5 2.4 2.3 2.2 2.1 10 MRT (days) - Average N/P ratio = 20:1 in human urine was higher than Redfield ratio (16:1) so phosphorus could be considered as a limited nutrient - N/P of 15:1 was optimal to Chlorella vulgaris growth (Tin et al., 2013) Comparison Membrane photobioreactor Nutrients conc in influent References Nutrients loading Nutrients removal rate Biomass growth Wastewater/me mbrane SVR (m-1) TN (mg/L) TP (mg P /L.d) TN (mg N/L.d) TP (mg P/L.d) TN (mg N/ L d) TP (mg P/ L d) SS (mg/L) Microalgae productivity (mg/L d) This study Urine (HF) 47.1 218.67 13.55 109.34 6.78 73.05 2.67 1575 315.0 Marbelia et al (2014) Synthetic, MBR permeate (FS) 20 7.4822.1 1.69-2.17 3.7411.05 0.8451.085 3.494.55 0.5450.755 590 60 Gao et al (2014) Gao et al (2016b) Gao et al (2016a) Treated sewage (HF) Aquaculture (HF) 32.3 19.12 1.24 8.39 0.56 4.13 0.43 57.5 13.31 0.72 6.66 0.36 5.8 0.255 1724 50.72 56.2 6.81 0.42 6.81 0.42 5.86 0.35 1100 42.6 Aquaculture 39.93 Notes: All of above study, Chlorella vulgaris cultivation in previous study Abbreviations: SVR: surface area to volume ratio; TN: total nitrogen; TP: total phosphorus, SS: suspended solid Biomass productivity & nutrient removal using urine as substrate was observed to be greater compared to other fed wastewaters Conclusions Concluding Remarks - Shorter MRT in MPBR using human urine reduced the inhibition of bacterial competition  thus maintain the better growth of microalgae; - Short MRT achieved higher biomass conc., biomass productivity, nutrient recovery & algae bioflocculation; - Biomass production and nutrient removal in MPBR using urine was much higher than those using other wastewaters in previous studies Acknowledgements Research was funded by Heineken – Vietnam: Thanks for supports from BIOSEP members: HCMUT, Vietnam: Thi-Thanh-Thuy Ngo, Trung-Tin Vo, Thi-Thanh-Huyen Nguyen, Thi-Hang Nguyen ENSIL, France: Hugo Dadu, EPFL, Switzerland: Alexander Marcos 25 T MP ( kPa ) MRT = 10 days MRT = days 20 15 TMP column TMP column 10 68 69 70 71 72 75 76 77 78 79 82 83 84 85 86 89Days 90 91 92 93 96 97 98 99 100 4.18 The chang e of TMP by the Fig time During operation time, the value of TMP ranged from 8.3 – 12 in satge with MRT=10days In a new retention time, the value of TMP increased significantly with the MRT =7days (range 12.8 – 19.4) When flux in higher leads to speed of dirty membrane is faster The selection of a suitable flux is an important matter A study by Rawiwan Boonchai and Gyutae Seo (2015) have compared based on the value of flux 42; 58.5; 70.5 and 103.5 L/m2/h with concentration Chlorella sp 1000 mg/l using MF membrane systems found the rate of increase corresponding TMP 0.12; 0.19; 0.41 and 1.03 Increased TMP speed can be defined as the speed and results dirty film speed slightly soiled membrane flux value below 58.5 L / m2 / h ...Application of Microalgae Biofuels production Wastewater treatment Reducing CO2 Bioproducts Why Urine? Liquid fertilizer (Watering) Urine Contains the major part... biomass productivity, enhance nutrient removal & less footprint requirement Research Objectives Research Objectives Nutrient recovery & biomass production from human urine in microalgae membrane. .. floater Membrane module Valve be used to take11sample Wood box Materials Photobioreactor Membrane (Mitsubishi, Japan)  Chlorella vulgaris Supplied by The Research Institute for Aquaculture No.2, Vietnam