Adsorbent-Based Algal Cultivation System to Facilitate Integration with Wastewater Treatment

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1 Adsorbent-Based Algal Cultivation System to Facilitate Integration with Wastewater Treatment Dr. Lance Schideman, PE Chih-Ting Kuo Dr. Yuanhui Zhang Illinois Sustainable Technology Center Department of Agricultural & Biological Engineering 1

2 Algal Wastewater Treatment Motivation & Limitations Inevitably, wastewater treatment and recycling must be incorporated with algae biofuel production. DOE National Algal Biofuels Tech. Roadmap (21) Free nutrients and water Dual use infrastructure Limitations for integrated algal biofuel/wastewater treatment systems Effluent water quality is more variable than conventional activated sludge Algae can be more sensitive to physico-chemical environment changes Harvesting algal biomass can be more difficult than activated sludge Incorporating adsorbents can help resolve many of these issues Captures fugitive organics and nutrients for future biomass growth Algae can bio-regenerate adsorbents minimizes adsorbent costs Sequesters toxic and inhibitory compounds in water Enhances biofilm formation easier to harvest biomass

3 Swine Manure Lagoon Process Flow Diagram Lagoon Decant Water AlgaeWheel with or without Adsorbents Treated Water Post Hydrothermal WasteWater (PHWW) with high C, N, P Filter Bag Dewatering Dewatered Biomass HTL Crude Oil 3

4 Experiment Site Swine Research 4

5 Dynamic response & recovery of adsorbent-based algal WW treatment system from shock loading AlgaeWheel w/adsorbents EAC+Zeolite 5g+5g EAC+Zeolite 5g+5g EAC 1g EAC 1g Zeolite 1g Zeolite 1g AlgaeWheel w/o Adsorbents Add.5 to 4L of post-htl WW (PHWW) into first chamber (.5%-4% PHWW) Monitor nutrient change at chamber 2,4,6 in both tanks to track the nutrient removal within systems 5

6 AWT w/ adsorbent 3 4% 2 2% 1.5% 1% 1/3 1/13 1/23 11/2 11/12 11/22 12/2 1 Spike Test Response NH3-N (mg/l) EAC+Zeolite 5g+5g EAC+Zeolite 5g+5g AWT w/o adsorbent 3 4% 2 1 2% 1%.5% 1/3 1/13 1/23 11/2 11/12 11/22 12/2 1 5 EAC 1g /3 1/13 1/23 11/2 11/12 11/22 12/2 1 EAC 1g Zeolite 1g /3 1/13 1/23 11/2 11/12 11/22 12/2 1 5 Zeolite 1g /3 1 1/13 1/23 11/2 11/12 11/22 12/2 5 1/3 1/13 1/23 11/2 11/12 11/22 12/2 System w/ adsorbents had less variation when shock loaded System with adsorbents recovered to steady-state faster 1/3 1 1/13 1/23 11/2 11/12 11/22 12/ /3 1/13 1/23 11/2 11/12 11/22 12/2

7 15 1 2% 4% 5.5% 1% 25 1/3 1/23 11/12 12/ AWT + adsorbents 251/3 1/23 11/12 12/ /3 1/13 1/23 11/2 11/12 11/22 12/ /3 1/13 1/23 11/2 11/12 11/22 12/2 Spike Test Response COD (mg/l) EAC+Zeolite 5g+5g EAC+Zeolite 5g+5g EAC 1g Zeolite 1g Zeolite 1g EAC 1g System w/ adsorbents had less variation when shock loaded System with adsorbents recovered to steady-state faster 15 1 AWT w/o ad. 4% 2% 5 1%.5% 1/3 1/23 11/12 12/ /3 1/23 11/12 12/ /3 1/23 11/12 12/ /3 1/23 11/12 12/2

8 NH3-N(mg/L) Continuous PHWW Addition Test- NH3 Performance Swine wastewater 1% PHWW 1.5% PHWW 2 % PHWW Influent Algaewheel Algaewheel+ adsorbent /1 1/31 3/1 3/31 4/3 5/3 6/29 7/29 Effluent NH3-N Algaewheel w/ Adsorbent Algaewheel w/o Adsorbent (mg/l) Day Night Day Night % PHWW.35 ±.8.47 ±.1.55 ± ±.22 1% PHWW.74 ± ± ± ± % PHWW.71 ±.12.7 ±.19.8 ± ±.15 2% PHWW 1.12 ± ± ± ± 5.77 Adsorbent based system performed was able to treat 2% PHWW Adsorbent based system had less diurnal variation in effluent NH3 8

9 COD(mg/L) Continuous PHWW Addition Test- COD Performance Swine wastewater 1% PHWW 1.5% PHWW 2 % PHWW Influent Algaewheel Algaewheel+Adsorbent /1 1/31 3/1 3/31 4/3 5/3 6/29 7/29 Algaewheel w/ Adsorbent Algaewheel w/o Adsorbent Day Night Day Night % PHWW 4.1 ± ± ± ±7.3 1% PHWW 252. ± ± ± ± % PHWW ± ± ± ± % PHWW ± ± ± ± 77. Adsorbent AWT removed more biodegradeable COD Effluent COD didn t have significant diurnal variations 9

10 Biomass Productivity (g/m2-d) Continuous PHWW Addition Test Biomass Productivity % PHWW 1% PHWW 1.5% PHWW 2% PHWW Algaewheel w/ Adsorbent Algaewheel w/o Adsorbent Continuous feed of PHWW > 1% reduced biomass productivity w/o adsorbents Adsorbent based system maintained biomass productivity 1

11 Biomass Properties & Hydrothermal Bio-oil Yield Adsorbent based system had higher ash, but still had a higher energy yield 11

12 q (mg/g) Effects of Service Time on Zeolite 3.5 Zeolite Isotherm C (mg/l) Vingin 4 month 1 month The capacity of 1 month old zeolite was reduced by up to 2% 12

13 q (mg/g) Effects of Service Time on Activated Carbon 3 EAC Isotherm 25 Virgin 4 Month 1 Month C (mg/l) After 1 months, the capacity of EAC was reduced by 45% 13

14 Scenario 1. Baseline Condition (Municipal WW HRP Transesterification AD) CO 2 Treated Water 1 o Clarifier High Rate Pond 2 o Clarifier Dewater/Drying Extraction Transesterification Biodiesel CO 2 /Nutrients CHP Anaerobic Digestion Scenario 2. AHTL-CHG (Municipal WW Algaewheel HTL CHG) Treated Water 1 o Clarifier Algaewheel 2 o Clarifier Dewater HTL Hydro-treating Gasoline CO 2 /Nutrients CHP CHG Scenario 3. AdsAW HTL (Municipal WW Algaewheel + Adsorbent HTL ) Treated Water 1 o Clarifier Algaewheel +Adsorbent 2 o Clarifier Dewater HTL Hydro-treating Gasoline CO 2 /Nutrients

15 Key Inputs Scenario Productivity (AFDW g/m2-d) Cultivation Area HRT (day) Treated WW (MLD) By-Products Baseline 22 1 ha 4 62 AHTL-CHG 3 1 ha 1 5 AdsAW-HTL 35 1 ha 1 5 WW credits Electricity WW credits Electricity WW credits 15

16 Fuel Production Costs & Areal Productivity Feedstock is the major cost for the fuel production 16

17 Minimum Fuel Selling Price Low-cost cultivation system is essential to improve the algal biofuel economics Wastewater treatment credit can make bio-crude oil very economically favorable

18 Summary Integration of adsorbents into algal wastewater systems can improve water quality, resiliency and biomass production Integrating adsorbents allowed the system accommodate recycling 2% PHWW without pretreatment Adsorbents could increase the ash content of biomass, which reduces crude oil yield Wastewater treatment credits can facilitate algal biofuels that are economically competitive with petro-fuels 18

19 Questions? Inevitably, wastewater treatment and recycling must be incorporated with algae biofuel production. - National Algal Biofuels Technology Roadmap (DOE, 21)