Recommended
Recommended
More Related Content
What's hot
What's hot (20)
Similar to Thesis_11 11 2016
Similar to Thesis_11 11 2016 (20)
Thesis_11 11 2016
- 1. Pranoti Kikale MS Thesis Candidate Environmental Engineering MS Thesis Defense University of Colorado, Boulder November 11, 2016 Maximizing Resource Recovery: Life cycle comparison of water quality impacts on non-potable water reuse and energy recovery
- 2. Acknowledgement 2 A quick thank you!!!!!!! Assistant Professor Sherri Cook Cook Research Group Committee Members Family Colleagues and Friends
- 5. Because water is scarce, we need to have a consistent supply of water that is sustainable. Motivation: 1. Water reuse By 2030, U.S. NIC predicted 40% increase in water demand. 2. Recovery of Energy and Minerals/Nutrients – Water and wastewater – $7.5 billion/year in 2010 4. Life cycle and systems thinking approach 5 3. Anaerobic technology - Reduction in net energy required for wastewater treatment
- 6. Globally, 70% of the freshwater withdrawals is for irrigation 6 http://www.unwater.org/statistics/en/?page=11&ipp=10&tx_dynalist_pi1%5Bpar%5D=YTox OntzOjE6IkwiO3M6MDoiIjt9
- 7. Non-potable water reuse standards 8 Unrestricted use Restricted use Agricultural: food crops Agricultural: non-food crops Target standards BOD (mg/l) ≤ 10 ≤ 30 ≤ 10 ≤ 10 10 TSS (mg/l) 30 ≤ 30 5 30 5 TN (mg/l) < 10 < 10 10 10 10 Turbidity (NTU) ≤ 2 - 2 10 2 Cl residual (mg/l) >1 >1 >1 >1 1 UV Disinfection (mJ/cm2) - - 100 - 100 Bacterial Indicators (mL) 23/100 ≤ 200/100 23/100 ≤ 200/100 23/100
- 9. Functional unit: Production of non-potable reuse water from 20 MGD medium strength wastewater over 40 years. 10 EnergyChemicals Water Quality
- 10. Life cycle assessment (LCA) is a standardized methodology to evaluate the environmental consequences of a product or activity. 11 goal definition & scoping inputs raw materials energy outputs atmospheric emissions water emissions solid wastes classify and characterize respiratory effects global warming smog ozone depletion acidification carcinogenics non-carcinogenics ecotoxicity Eutrophication Fossil fuel depletion Inventory Impact inventory impact interpretation classification characterization valuation
- 12. A novel treatment train employing mainstream anaerobic processes was designed for water reuse. 13 Design model for AnMBR Energy production CH4 in biogas Dissolved CH4 Energy consumption Membrane scouring Pumping Heating of influent Mixing of bioreactor Degasifier Membranes Chemicals Lime for alkalinity Membrane cleaningAlum as coagulant for removal of TOC Deep-bed anthracite filter for removal of turbidity Disinfection in form of chlorination and UV Solids handling system
- 13. 14 Parameters Influent ANA effluent Filtration pre- treatment effluent Granular media filtration effluent pH 7.5 7.5 7.5 7.5 COD (mg/l) 430 35 17 17 BOD (mg/l) 190 7 < 5 < 5 TOC (mg/l) 140 20 10 10 TSS (mg/l) 210 11 7 7 TN (mg/l) 40 41 41 41 TP (mg/l) 7 7 7 7 Turbidity (NTU) - 5 3 0.1
- 14. 15 Parameters Influent Primary sedimentation effluent AER effluent Filtration pre- treatment effluent Granular media filtration effluent pH 7.5 7.5 7.5 7.5 7.5 COD (mg/l) 430 250 75 37 37 BOD (mg/l) 190 125 15 7.5 7.5 TOC (mg/l) 140 125 42 20 20 TSS (mg/l) 210 85 10 7 7 TN (mg/l) 40 40 32 32 32 TP (mg/l) 7 7 7 7 7 Turbidity (NTU) - - 5 3.2 0.1
- 15. Variation of water quality for each bioreactor effluent 16 0 10 20 30 40 50 60 70 80 COD, mg/l BOD, mg/l TOC, mg/l TSS, mg/l TN, mg/l TP, mg/l Turbidity, NTU Bioreactoreffluentparameters(mg/l) ANA effluent AER-HRAS effluent AER-NO3 effluent
- 17. Process flow diagrams of ANA and AER treatment trains 18
- 18. 0.00 0.20 0.40 0.60 0.80 1.00 1.20 RelativeenvironmentalimpactnormalizedtoANA+UV ANA + UV Ten impact categories were used to comprehensively evaluate the treatment alternatives. 19
- 19. Environmental impacts in each category were normalized to ANA+UV. 20 0.00 0.20 0.40 0.60 0.80 1.00 1.20 Carcinogenics Ecotoxicity Ozone depletion Global warming Fossil fuel depletion Non carcinogenics Respiratory effects Smog Acidification Eutrophication RelativeenvironmentalimpactnormalizedtoANA+UV ANA + UV WORSE BETTER ANA+UV
- 20. The ANA and AER scenarios using chlorine disinfection had the largest environmental impacts due to ammonia. 21 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 Carcinogenics Ecotoxicity Ozone depletion Global warming Fossil fuel depletion Non carcinogenics Respiratory effects Smog Acidification Eutrophication RelativeenvironmentalimpactnormalizedtoANA+UV ANA + UV ANA + Cl AER + UV AER + Cl NH3
- 21. 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 Carcinogenics Ecotoxicity Ozone depletion Global warming Fossil fuel depletion Non carcinogenics Respiratory effects Smog Acidification Eutrophication RelativeenvironmentalimpactnormalizedtoANA+UV ANA + UV ANA + Cl AER + UV AER + Cl 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 Since high effluent ammonia concentrations were desired for irrigation, UV disinfection was preferred. 22 RelativeenvironmentalimpactnormalizedtoANA+UV
- 22. The ANA and AER baseline scenarios used UV disinfection for medium strength wastewater. 23 Baseline scenario
- 23. 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 Carcinogenics Ecotoxicity Ozone depletion Global warming Fossil fuel depletion Non carcinogenics Respiratory effects Smog Acidification Eutrophication RelativeenvironmentalimpactnormalizedtobaselineANA ANA AER AER is best in 6 out of 10 impact categories as compared to ANA scenario. 24 AER BEST AER WORSE
- 24. -0.20 0.00 0.20 0.40 0.60 0.80 1.00 1.20 ANA AER Percentprocesscontributionforcarcinogenicnormalizedto baselineANAscenario Others Disinfection Coagulation Aeration ANA Operational Energy - Others ANA Operational Energy - Membrane Scouring Biogas Carcinogenics: Coagulation had the maximum impact for ANA, and aeration dominated the impact for AER. 25
- 25. 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 Carcinogenics Ecotoxicity Ozone depletion Global warming Fossil fuel depletion Non carcinogenics Respiratory effects Smog Acidification Eutrophication Relativeenvironmentalimpactnormalizedtobaselinescenario ANA AER ANA had minimum impact in eutrophication as compared to AER due to biogas offset. 26
- 26. -1.00 -0.50 0.00 0.50 1.00 1.50 2.00 2.50 ANA AER Percentprocesscontributionforeutrophicationnormalized tobaselinescenario Others Disinfection Coagulation Aeration ANA Operational Energy - Others ANA Operational Energy - Membrane Scouring Fertilizer offset Biogas Eutrophication: ANA membrane scouring had the highest contribution, and biogas production makes ANA best. 27
- 27. 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 Carcinogenics Ecotoxicity Ozone depletion Global warming Fossil fuel depletion Non carcinogenics Respiratory effects Smog Acidification Eutrophication Relativeenvironmentalimpactnormalizedtobaselinescenario ANA AER AER-NO3 AER with nitrification had largest negative impact in all 10 categories due to high required oxygen (aeration energy). 28
- 28. -1.00 -0.50 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 ANA AER AER-NO3 PercentcontributionforGWPnormalizedtobaseline ANA Dissolved Methane Emissions Others Disinfection Coagulation Aeration ANA Operational Energy - Others ANA Operational Energy - Membrane Scouring Biogas Global Warming: AER’s aeration energy and ANA’s dissolved methane had the largest contributions to each. 29
- 30. -0.60 -0.40 -0.20 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 ANA Baseline ANA Max CH4 recovery AER PercentprocesscontributionforGWPnormalizedto baselinescenario Dissolved Methane Emissions Others Disinfection Coagulation Aeration ANA Operational Energy - Others ANA Operational Energy - Membrane Scouring Biogas Increasing dissolved methane recovery greatly improved the ANA scenario’s environmental performance. 31
- 32. ANA “best case” is better in all 10 categories due to maximum energy production and minimum energy consumption and sludge yield. 33 0 0.2 0.4 0.6 0.8 1 1.2 Eutrophication Global warming potential Smog Acidification Respiratory effects Non- carcinogenic Fossil fuel depletion Ozone depletion Ecotoxcity Carcinogenic Relativeenvironmentalimpactnormalizedtobaselinescenario ANA - best case ANA
- 33. Mainstream ANA can be better than conventional AER with appropriate design considerations and operation. 34 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Eutrophication Global warming potential Smog Acidification Respiratory effects Non- carcinogenic Fossil fuel depletion Ozone depletion Ecotoxcity Carcinogenic RelativeenvironmentalimpactnormalizedtoAER ANA - best case ANA - baseline ANA - worst case AER
- 34. 35 Baseline scenario High strength WW Medium strength High Strength BOD (mg/) 190 350 TSS (mg/l) 210 400 TN (mg/l) 40 70 TP (mg/l) 7 12 Alkalinity (mg CaCO3/) 200 400
- 35. ANA is worse in all 10 impact categories compared to AER. 36 0.00 0.20 0.40 0.60 0.80 1.00 1.20 Carcinogenic Ecotoxcity Non- carcinogenic Ozone depletion Respiratory effects Fossil fuel depletion Acidification Smog Eutrophication Global warming potential RelativeenvironmentalimpactnormalizedtoANA ANA AER
- 36. ANA is worse in all 10 categories due to high alum doses required for coagulation and higher effluent TOC. 37 0.00 0.20 0.40 0.60 0.80 1.00 1.20 Carcinogenic Ecotoxcity Non- carcinogenic Ozone depletion Respiratory effects Fossil fuel depletion Acidification Smog Eutrophication Global warming potential RelativeenvironmentalimpactnormalizedtoANA
- 37. 0.00 0.20 0.40 0.60 0.80 1.00 1.20 50 100 150 200 250 300 350 400 450 500 GWPimpactnormalizedtoANA Aum dose (mg/l) GWP for ANA for different alum dose Comparable impacts for ANA and AER can be achieved by optimizing the alum dose. 38 ANA 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 20 40 60 80 100 120 140 160 Carcinogenicimpactnormalizedto ANA Alum dose (mg/l) Carcinogenic impact for ANA for different alum dose ANA AER at 85 mg/l alum dose AER at 85 mg/l alum dose
- 38. An alum dose of 120 mg/l improved the environmental performance of the ANA scenario for high strength wastewater. 39 0.00 0.20 0.40 0.60 0.80 1.00 1.20 Carcinogenics Ecotoxicity Ozone depletion Global warming Fossil fuel depletion Non carcinogenics Respiratory effects Smog Acidification Eutrophication RelativeenvironmentalimpactnormalizedtoAER ANA+UV AER+UV
- 39. 40 Baseline scenario Maximum CH4 recovery Best case - ANA High strength WW Maximum dissolved CH4 recovery reduces the GWP impact by 50% Best Case ANA has the potential to be environmentally sustainable Expanded experimentation is needed to realize the potential of ANA processes
- 40. Future work can further support the sustainable design of water reuse systems. 41 AnMBR experimental data - Coagulation, TOC, alkalinity - Operational analysis - Temperature effect on energy model Agronomics Potable reuse water system Disinfection vs. irrigation (NH3)
- 41. 42 Baseline scenario Maximum CH4 recovery Best case - ANA High strength WW Maximum dissolved CH4 recovery reduces the GWP impact by 50% Best Case ANA has the potential to be environmentally sustainable Expanded experimentation is needed to realize the potential of ANA processes
- 42. 43
- 43. Comparison of AER-NO3 with scenario 1 and 2 44 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 Carcinogenics Ecotoxicity Ozone depletion Global warming Fossil fuel depletion Non carcinogenics Respiratory effects Smog Acidification Eutrophication RelativeenvironmentalimpactnormalizedtobaselineANA+UV ANA + UV AER + UV AER-NO3 + Cl AER-NO3 + UV
- 44. Nitrification causes maximum negative impact due to aeration. 45 -0.50 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 AER-HRAS + UV AER-HRAS + Cl AER-NO3 + UV AER-NO3 + Cl PercentunitprocesscontributionforGWPnormalizedtoAER-HRAS+UV scenario Others Disinfection Coagulation Aeration Biogas
- 45. Comparison of all aerobic scenarios 46 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 Carcinogenics Ecotoxicity Ozone depletion Global warming Fossil fuel depletion Non carcinogenics Respiratory effects Smog Acidification Eutrophication RelativeenvironmentalimpactforAERscenariosnormalizedto AER-HRAS+UV AER-HRAS + UV AER-HRAS + Cl AER-NO3 + UV AER-NO3 + Cl
Editor's Notes
- Because water is scarce, we need to have a consistent supply of water that is sustainable. DPR and NPR (“fit for purpose”) Motivation for: Water reuse Definition Why we need reuse “Fit for purpose“ Energy recovery How much energy is used for WWT and DWT in the U.S. (energy negative) Embodied energy in WW (recover and don’t waste it) (energy neutral or positive is possible!) Life cycle and systems thinking approach
- http://energy.gov/downloads/water-energy-nexus-challenges-and-opportunities http://energy.gov/sites/prod/files/2015/09/f26/Energy%20Water%20Flow%20Diagram.png
- Analyzed water quality for ANA scenarios, for each unit process
- Similarly for AER, water quality was analyzed for unit process effluent
- Just to highlight the fact, this bar graph shows the water quality specific to each bioreactor effluent. Due to varied effluent concentration the design for wastewater and downstream water reuse system will vary on water quality
- Now we will evaluate different scenarios based on disinfection (Chlorine or UV)
- Impact after applying TRACI Carcinogenic – causing cancer Ecotoxicity – ecosystem disruption Ozone depletion – CFC production depleting ozone layer in stratosphere GWP – increase in CO2, increase in global temperature Fossil fuel depletion – depletion of renewable energy resources Non-carcinogenics – toxic but not causing cancer Respiratory effects – damage to human respiratory system Smog – O3 formation at tropospheric level Acidification – Presence of sulfur and nitrogen oxides in atmosphere, cause for acid rain Eutrophication – high levels of N and P in water.
- TRACI applied to all 4 scenarios to understand the environmental impact for each All impacts normalized to ANA+UV Above 1, worse than ANA+UV Below 1, better than ANA+UV
- Comparison of ANA+UV & ANA+Cl, AER+UV & AER+Cl Similar trend observed for scenarios with UV as disinfection < than Cl as disinfection Main reason for Cl to have huge impact is due to presence of ammonia in effluent stream (ANA process and AER (without nitrification))
- Cl disinfection has a huge impact in all impact categories, due to high Cl demand associated with presence of ammonia in effluent. Also, ammonia is desired nutrient in water for irrigation purpose, UV disinfection would be preferred in place chlorine
- After removing chlorination for disinfection, the two scenarios were compared – ANA+UV, AER+UV These 2 scenarios will be called as baseline scenarios
- AER is best, has fewer impacts than ANA The system boundary for ANA includes, huge amount of alum coagulation and energy associated with AnMBR operation Now, we will look at detailed breakdown of carcinogenics impact, were AER is best out of 6
- Unit process breakdown for carcinogenics impact Black box is the net environmental impact as seen in previous slide for carcinogenics impact (both env impact + benefits due to biogas production) Coagulation impact – 83% for ANA system Aeration – 42% for AER
- Now we will look at eutrophication – ANA was best than AER Process breakdown for eutrophication
- Membrane scouring – 68% for ANA Aeration – for AER Largest biogas offset – 77% Maximum fertilizer offset achieved for AER, due to high amount of solids production in AER system than ANA And eutrophication deals with amount of N eq, hence large amount of fertilizer offset can be seen for AER in eutrophication rather than any other impact
- Now we will look at AER with nitrification To evaluate env impacts for AER and AER-NO3 AER-NO3 requires large amount of aeration energy (mainly due to nitrification) As aeration dominates the environmental impacts for AER system, AER-NO3 shows max env impct
- Aeration required for nitrification in AER-NO3 approximately twice as much as compared to AER SRT values for AER-NO3 (>3 days to account for nitrification) > AER (1-2 days)
- As found in experimental lit for recovery of diss methane, around 80% methane recovery was achieved for high strength WW Recovery of dissolved methane from 35% to 80%, decreases the impact by 50% for GWP The overall impact also reduces as more energy will be produced due to max methane recovery, and hence larger offset due to biogas production
- Now we looked at best case for ANA Best case – max energy production – increasing energy from green box, min energy requirement – decreasing energy from red box for AnMBR system
- With best case scenario, ANA has potential to be environmental sustainable As compared to baseline ANA, best case has less environmental impact in all 10 categories Now we will compare with AER, to see how the impacts compare with AER
- As we are comparing with the baseline AER scenario, the red line is at 1.00, all scenarios normalized to 1.00 Again, a quick reminder, any impact above this red line, worse than AER and any impact below this red line will be better than AER For best case ANA, we can observe the ANA to be better than AER in almost 8 out of 10 categories. The base case as we had compared earlier is better than AER in only 4 out of 10 categories. Worst case – max energy consumption, min energy production by AnMBR Worst case – worse than all in all 10 categories If ANA is not operated properly, without producing and recovery max methane – it will not be comparable to conventional AER process
- Due to high amount of organic matter in the ANA effluent, alum dose is expected to be much high Depending on the effluent for AER and ANA, we increased the alum dose relative to the increase in TOC
- We tried to find the alum dose with could have similar impacts for ANA as comparable to AER system for high strength WW For carcinogenic, alum dose was around 120 mg/l for ANA For GWP, 400 mg/l of alum was sufficient to have similar impact
- With minimum alum dose as found from the tradeoff analysis, ANA would be better in all 10 categories by AER But the efficient removal of TOC must be taken in to consideration for low alum dose
- Baseline scenario – AER is best in 6 out of 10 impact categories Max CH4 recovery – GWP impact reduced by almost 50%, and more environmental benefit was achieved due to high amount of biogas produced ANA has potential to be environmental sustainable than AER with best case scenario For high strength WW – proper model development is required to accommodate the change in influent wastewater composition.
- AnMBR experimental data -Coagulation, TOC, Altalinighta -Oper
- Baseline scenario – AER is best in 6 out of 10 impact categories Max CH4 recovery – GWP impact reduced by almost 50%, and more environmental benefit was achieved due to high amount of biogas produced ANA has potential to be environmental sustainable than AER with best case scenario For high strength WW – proper model development is required to accommodate the change in influent wastewater composition.