Where do Landfills Fit In The Changing Paradigm of Circular Economy- Resource Recovery and Social Aspects By Aditi Podder 1 , Debra Reinhart 2 and Ramesh Goel 3 1,3 Department of Civil & Environmental Engineering, University of Utah 2 Department of Civil, Environment, Construction Engineering, University of Central Florida
Liquid Waste-streams in Urban Environment • All the waste-streams are contaminated • Contaminants of concerns are mainly Carbon, Nitrogen and Phosphorus • Industrial Wastewater and liquid generated from solid waste also contains metals and toxic chemicals HOW CAN WE ACHIEVE ENVIRONMENTAL SUSTAINABILITY?? Solid Waste Leachate Ref: SPUHLER (2010) Landfill Wastewater Treatment Plant
Two Urban Waste streams rich in resources Leachate Landfill Solid Waste DUMPED INTO WWTP High Ammonia Content Low BOD/COD ratio High recalcitrant matters Low Phosphorus Content High dissolved methane High Toxicity COMPLEX WASTESTREAM Sludge Anaerobic Filtrate/Centrate/Reject water Dewater Digester Characteristics of Typical Filtrate Parameter Composition URBAN COD (mg/L) 100~400 WASTESTREAM + -N (mg/L) NH 4 400~1000 High Ammonia Content TN (mg/L) vairable Sent back to Biological Treatment Train TP (mg/L) 200~400 Increases Ammonia Load inside Bioreactor
Liquid waste Treatment (Carbon management) Different Aerobic Reactors Performance (Renou et al., 2008 ) (a) (d) (b) (c) Figure: (a) Activated Sludge Process, SUEZ's degremont, water handbook; (b)SBR, Beun et al.,1988; (c)MBBR, Colloide Engineering,ENVIROPRO; (d)Trickling Filter
Liquid Waste Treatment (Carbon management) Different Anaerobic Reactors Performance (Renou et al., 2008, Fernandez et al., 2000 ) Figure: Anaerobic Digester Source: A Primer on Anaerobic Filters, Fundamentals & Applications
The need to integrate “recover” with “removal” Current paradigm • Landfill leachate is rich in N and C, and handled separately. • The current management schemes focus on removal which is also threatened by the presence of recalcitrant and toxic chemicals in landfill leachate • Wastage of C, N and P • Dumped into WWTP Circular Metabolism • Recognizes the fact that waste streams contain valuable resources • Most important ones are nitrogen and phosphorus • Provides a much reduced burden to stakeholders and the environment
Overcome P limitations by mixing two concentrated streams Characteristics of Filtrate Characteristics of Leachate BOD 5 (mg/L) 58_5 + BOD 5 (mg/L) 79_5 + + COD (mg/L) 1435_10 + COD (mg/L) 450_25 + Ammonia (mg/L) as N 457_5 + Ammonia (mg/L) 485_15 Phosphorus (mg/L) 7.6_2 + Phosphorus (mg/L) 400±25 Nitrate as N (mg/L) <0.01 Nitrate as N (mg/L) 1.2 _ 0.2 + Nitrite as N (mg/L) <0.01 Nitrite as N (mg/L) 0 TOC (mg/L) 280_5 + TOC (mg/L) 128_12 + Characteristics of Mixture (20%Leachate+80% Filtrate) + BOD 5 76_5 Final concentration + COD(mg/L) 547_10 depends upon the ration Ammonia (mg/L) 435_10 + two waste streams are Phosphorus (mg/L) 250±35 mixed Nitrate as N(mg/L) <0.01 Nitrite as N (mg/L) <001
Implementation of Circular Metabolism Economical Issues Environmental Issues Societal Issues Recovering useful nutrients make the Recovered nutrients will need to • If prior to dumping the nutrients into • • nutrients available for further use which be processed for downstream uses water bodies, they can be recovered, the boosts economy which might increase job risk of algal bloom can be reduced opportunity Instead of dumping the organics and • Generated methane gas can be used in • nutrients, if they are treated and electricity generation in wastewater When the concept of scarcity and recovered, additional source of • treatment plants limited availability of resources chemicals in treatment of water can be will be widespread, more public reduced Composts generated from landfills and participation is accepted, which • A green environment can be expected if • from biosolids can be sold in market for will also provide job opportunity the treated water (rich in nutrients) can agricultural purpose be used for agricultural purpose Water reuse will ensure the balance in • Reused/ reclaimed water can also • fresh water resources for future contribute in economy generation Environmental Sustainability can be achieved with a proportional balance of these THREE issues Recovering Nutrients Provide Environmental Sustainability
Challenges-Leachate Characteristics SLVSWMF Leachate Huan ‐ jung et al. Raghab et al. Robinson et al. Zazouli et al. Sampling, American (2006) (2013) (2017) (2012) West Analytical Laboratories (2016) BOD 5 (mg/L) 58 20-57000 3400 7.6 48 COD (mg/L) 1590 140-15200 8250 1900 3960 + (mg/L) as N NH 4 168 50-2200 3745 1200 532 Phosphorus (mg/L) 1.9 0.1-23 1308 7.83 21 Nitrate as N (mg/L) <0.01 nd 3.95 1800 nd Nitrite as N (mg/L) <0.01 nd nd 1.05 nd TOC (mg/L) 280 30-29000 nd 776 nd Low Biodegradable Organics present High in ammonia nitrogen but low in phosphorus Due to low P, strategies like struvite precipitation not feasible
Challenges and solutions • Variable characteristics of leachate make it difficult to develop a single management option. • High ammonia and low phosphorus leaves plenty of ammonia nitrogen P in the liquid waste even after nutrient recovery • Hence, integrated approaches are needed to manage leachate.
Proposed Integrated approach Approach REUSE RECOVER TREAT WATER NUTRIENTS WATER
Microbial Protein Production-for excess ammonia Promising alternative in promoting Circular Economy • Low value recovered resources High quality feed + -N + CO 2 • NH 4 High quality edible microbial H 2 oxidizing protein Electrochemical Ammonia Recovery from Source Bacteria Separated Urine for Microbial Protein Production (Christiaens et al., 2017) From Green From Biogas From Energy Sources produced Effluent of such as Wind & during Wastewater Solar Energy Anaerobic Treatment powered Water Digestion RESOURCE RECOVERY UNDER Plant Electrolysis CIRCULAR ECONOMY • Supports a shift from resource dissipation to resource recovery Crude protein content on CDW basis of the microbial biomass • Can be used as a suitable substitute for conventional produced under CR configuration by the Sulfuricurvum spp. feed sources such as fishmeal or soybean meal dominated culture compared with other microbial protein (bacterial meal), animal protein (fishmeal) and vegetable protein (soybean meal) (Matassa et al., 2016)
Struvite Precipitation in Recovery of Phosphorus + NH 4 Mg 2 + pH = 9 3- PO 4 3- + PO 4 NH 4 Mg 2+ P:Mg = 1:1.2 MAXIMIZES PRECIPITATION Optimization of pH and Mg: P ratio during struvite precipitation
Knocking down Carbon in Granular Reactor Granular Sludge Technology is a • Novel Approach in simultaneous removal of Organics, Nitrogen and Phase I Phase III Phosphorus Phase II (b) (a) (a) Conditions inside granules (b) Microorganisms abundance in flocs (Winkler et al., 2012) COD removal percentages in granular reactor FEEDING WITH REAL LEACHATE CHANGES THE MORPHOLOGY OF GRANULES 08. 22. 2017 12. 15. 2017 02. 27. 2018
Treatment of Ammonia- Nitrogen in Granular Reactor Microbial High Settle- Diversity ability Phase I Phase II Phase III Effective for AEROBIC Low Energy v high strength GRANULES Cost WW <60% of BNR Low Carbon Simultaneous Footprint P and N <40% of BNR Removal Ammonia nitrogen removal percentages in granular reactor
Treatment of Ammonia- Nitrogen in Single Stage PN/A ANaerobic AMMonium Oxidation (Anammox) Stoichiometry: Phase II 1.32NO 2 0.066HCO 3 0.13H 0.066CH 2 O 0.5 N 0.15 1.02N 2 0.26NO 3 2.03H 2 O NH 4 Phase III Phase I 1.146NO 2 0.07HCO 3 0.057H 0.071CH 1.74 O 0.31 N 0.20 0.986N 2 0.161NO 3 2.002H 2 O NH 4 Partial Anammox N 2 PN/A= nitritation NH + NO 4 - 2 • Benefits of PN/A (a) Nitrification- Nitritation- Proces s es PN/A denitrification denitritation O 2 demand 4.57 3.43 1.95 + -N) (kg O 2 /kg NH 4 Alkalinity demand 7.07 N/A 4.6 + -N) (mg CaCO 3 /mg NH 4 (b) BOD demand Ammonia nitrogen removal percentages in PN/A reactor ~ 3.5 ~ 2.1 0 + -N) (kg BOD/kg NH 4 Biomas s yield ~ 0.8 ~ 0.5 ~ 0.1 (a) Suspended Growth Granular Anammox (Jian-Tang et al.,2013) + -N) (kg DS/kg NH 4 TM mox, Veolia Water Technologies (b) ANITA
Integrated Approach in Treatment of Landfill Leachate + Org-NH 4 + Org-NH 4 + + Org-NH 4 Org-NH 4 3- -P PO 4 3- -P PO 4 3- -P 3- -P PO 4 PO 4 rbCOD STRUVITE GRANULAR PARTIAL rbCOD rbCOD rbCOD PRECI- ACTIVATED NITRITATION PITATION SLUDGE /ANAMMOX INFLUENT EFFLUENT PROCESS REUSE WATER RECOVER NUTRIENTS TEAM GREEN FERTILIZER
Conclusions • There is a need to think beyond the conventional treatment paradigm and incorporate recovery and innovative processes. • Single management approach may not be suitable due to constantly changing leachate characteristics. • Leachate cannot be considered as a separate “one” liquid waste stream. It should be considered under the broader spectrum of urban circular metabolism. • Our integrated approach incorporating struvite recovery, granular activiated sludge process and single stage anaerobic ammonia oxidation showed good promise.
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