Waste valorization-opportunities & Challenges

solid waste management

1. 11-Mar-22 waste valorization 1 Waste Valorization Presented by Dr. Arvind Kumar, Assistant Professor Department of Chemical Engineering NIT Rourkela-769008

2. The waste-to-wealth concept aims to promote a future sustainable lifestyle where waste valorization is seen not only for its intrinsic benefits to the environment but also to develop new technologies, livelihoods and jobs.  11-Mar-22 2 waste valorization

3. Waste valorization is  the process of converting waste materials into more useful products including chemicals, materials, and fuels . 11-Mar-22 3 waste valorization

4. Valorization of dairy waste and by-products Dairy waste is a great source of biodegradable feedstock for sustainable production. Microbes can valorize whey waste from dairy into bio-plastics and bio-surfactants . Dairy waste is a beneficial substrate to culture microbes for bio-fuel production. Integrated strategies for dairy waste valorization can drive sustainable growth. 11-Mar-22 4 waste valorization

5. Treatment of dairy waste The general routes for treatment of dairy waste include physicochemical and biological methods, cost-effective and environment-friendly - biological methods Due to rich organic nature of dairy waste makes it a valuable feedstock for production of value-added products 11-Mar-22 5 waste valorization

6. anaerobic and aerobic treatment techniques Activated Sludge Process, Sequential Batch Reactors (SBR), Moving Bed Biological Reactor (MBBR ), Completely Stirred Tank Reactor (CSTR), Up-flow Sludge Anaerobic Blanket (USAB ), Fluidized Bed Reactor (FBR), wetlands , and co-composting 11-Mar-22 6 waste valorization

7. Many factors determine the efficacy of the biobased techniques , substrate type and characterization, operational parameters and the performance of the microbes themselves. anaerobic conversion of dairy waste is significantly impacted by the syntrophic activity of the microbes active in different phases of anaerobic digestion ( Pagliano et al., 2019). Pagliano , G., Ventorino , V., Panico , A., Romano, I., Pirozzi , F., Pepe , O., 2019. Anaerobic process for bioenergy recovery from dairy waste: meta-analysis and enumeration of microbial community related to intermediates production. Frontiers in microbiology 9, 3229. 11-Mar-22 7 waste valorization

8. Dairy effluent has been demonstrated to be a beneficial substrate for enzymatic hydrolysis using Saccharomyces cerevisiae to produce ethanol ( Parashar et al., 2016). Parashar , A., Jin, Y., Mason, B., Chae , M., Bressler , D.C., 2016. Incorporation of whey permeate, a dairy effluent, in ethanol fermentation to provide a zero waste solution for the dairy industry. J. Dairy Sci. 99 (3), 1859–1867. The enzymes produced by filamentous fungi can hydrolyse complex carbohydrates present in dairy waste into simple sugars aiding in production of high-quality biomass suitable as animal/fish or even human consumption ( Mahboubi et al., 2017). Mahboubi , A., Ferreira, J.A., Taherzadeh , M.J., Lennartsson , P.R., 2017. Value-added products from dairy waste using edible fungi. Waste management (New York, NY) 59, 518. 11-Mar-22 8 waste valorization

9. hydrolysis of lipids during the anaerobic digestion of fat/oil rich dairy waste inhibits the overall process, which can be overcome by addition of enzymes ( Meng et al., 2017). Meng , Y., Luan, F., Yuan, H., Chen, X., Li, X., 2017. Enhancing anaerobic digestion performance of crude lipid in food waste by enzymatic pretreatment. Bioresource Technology 224, 48–55. 11-Mar-22 9 waste valorization

10. the formation of sludge in anaerobic treatments can be a potential inhibitor to its large-scale implementation as the remediation cost becomes higher along with its ability to absorb toxic and organic material from the feedstock itself ( Dabrowski et al., 2017). Dabrowski , W., ˙ Zyłka , R., Malinowski, P., 2017. Evaluation of energy consumption during aerobic sewage sludge treatment in dairy wastewater treatment plant. Environmental Research 153, 135–139. Most of the dairy effluent treatments are aerobic in nature, although they are not the most efficient processes due to high acidification and growth of filamentous fungi (Ahmad et al., 2019). Ahmad, T., Aadil , R.M., Ahmed, H., Rahman , U.U., Soares , B.C.V., Souza, S.L.Q., 2019. Treatment and utilization of dairy industrial waste: a review. Trends Food Sci. Techn . 88, 361–372. 11-Mar-22 10 waste valorization

11. Value-added products from dairy waste Bioresource Technology 346 (2022) 126444 11-Mar-22 11 waste valorization

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13. Biohydrogen integrating the production of methane with hydrogen from the biodegradation of organic waste such as dairy waste, food waste and other organic industrial waste has been touted as the next stage in developing green energy from waste (Aziz, 2016). Aziz, M., 2016. Integrated hydrogen production and power generation from microalgae. International Journal of Hydrogen Energy 41 (1), 104–112. The development of the two-stage approach integrating reduction of dairy wastewater pollution with bioenergy generation (methane and hydrogen) via two-phase process has been shown to be a cost-effective and highly productive process in energy recovery ( Zhong et al., 2015). Zhong , J., Stevens, D.K., Hansen, C.L., 2015. Optimization of anaerobic hydrogen and methane production from dairy processing waste using a two-stage digestion in induced bed reactors (IBR). International Journal of Hydrogen Energy 40 (45), 15470–15476. 11-Mar-22 13 waste valorization

14. Despite these obvious advantages, few downstream and upstream parameters such as the choice of bacterial culture for the dairy waste treatment and their biohydrogen production efficiency still need to be studied in depth to test the large-scale feasibility and setup of these integrated techniques. microbial populations including bacteria, fungi, algae are known to produce biohydrogen using dairy waste biomass as their carbon source in anaerobic conditions. Biohydrogen photo fermentation (PF) and dark fermentation (DF )- by product- volatile fatty acids 11-Mar-22 14 waste valorization

15. Biofuels Biodiesel for instance is a clean fuel that contains no sulphur or other toxic compounds, and its combustion causes much lower emission of particulate matter, hydrocarbons, and carbon monoxide (Bhatia et al., 2018). Bhatia, S.K., Joob , H., Yanga , Y., 2018. Biowaste -to- bioenergy using biological methods – a mini-review. Energy Conversion and Management 177, 640–660. Bioresource Technology 346 (2022) 126444 11-Mar-22 15 waste valorization

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17. Biosurfactants Various microbes such as bacteria, fungi and yeast are capable of producing bio-surfactants also known as surface-active agents which can be used in place of other organic surfactants. The global market for biosurfactants has been estimated to stand at USD 30.64 billion (Singh et al., 2019). Singh, P., Patil , Y., Rale , V., 2019. Biosurfactant production: emerging trends and promising strategies. Journal of applied microbiology 126 (1), 2–13. Biosurfactants such as Sophorolipids , Rhamnolipids , Trehalose lipids, and Ornithine lipids have all been demonstrated to be produced by various microbial cultures using organic waste as substrates ( Varjani et al., 2020). Varjani , S., Rakholiya , P., Ng, H.Y., Taherzadeh , M.J., Ngo, H.H., Chang, J.S., Wong, J. W., You, S., Teixeira, J.A. and Bui, X.T., 2020. Bio-based rhamnolipids production and recovery from waste streams: Status and perspectives. Bioresource technology, p.124213. 11-Mar-22 17 waste valorization

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19. its industrial production from dairy waste is posed with challenges such as low yield, high cost, feedstock availability, and downstream purification and processing Bioplastics extract a high amount of polyhydroxyalkanoate (PHA ) bioplastic (60 g/kg) Poly-3-hydroxybutyrate (PHB) Other bioproducts galacto -oligosaccharides (GOS), microbial pigments and industrial enzymes from dairy waste. microbes such as Streptococcus thermophiles , Aspergillus oryzae , Bifidobacterium bifidum , Bacillus circulans , and Kluyveromyces lactis have been used to produce β- galactosidase biocatalyst ( Contesini et al., 2019 ;). Contesini , F.J., de Lima, E.A., Mandelli , F., Borin , G.P., Alves , R.F. and Terrasan , C.R.F., 2019. Carbohydrate active enzymes applied in the production of functional oligosaccharides. 11-Mar-22 19 waste valorization

20. bioactive peptides from dairy whey using methods such as proteolytic activity of microorganisms and starter cultures and, enzymatic hydrolysis by digestive enzymes (Mohan et al., 2015). Mohan, A., Udechukwu , M.C., Rajendran , S.R., Udenigwe , C.C., 2015. Modification of peptide functionality during enzymatic hydrolysis of whey proteins. RSC advances 5 (118), 97400–97407. the microbial fermentation can form biopeptides with opioid characteristics ( Garg et al., 2018) anticancer ( Hern´andez - Ledesma et al., 2017) and antioxidant (Rocha et al., 2017) Garg , G., Singh, S., Singh, A.K., Rizvi , S.I., 2018. Whey protein concentrate supplementation protects rat brain against aging-induced oxidative stress and neurodegeneration . Applied Physiology, Nutrition, and Metabolism 43 (5), 437–444. Hern´andez-Ledesma , B., Hsieh, C.C. and Martínez-Villaluenga , C., 2017. Food bioactive compounds against diseases of the 21st century 2016. Rocha, G.F., Kise , F., Rosso , A.M., Parisi , M.G., 2017. Potential antioxidant peptides produced from whey hydrolysis with an immobilized aspartic protease from Salpichroa origanifolia fruits. Food chemistry 237, 350–355. Carotenoids have also been produced from dairy waste such as β- carotene, γ- carotene, and lycopene 11-Mar-22 20 waste valorization

21. filamentous fungal species such as Penicillium chrysogenum and Penicillium purpurogenum have been reported to produce pigments by using cheese whey as the sole carbon source. Basto , B., Silva, N.R.D., Silv´erio , S.I.C. and Teixeira, J.A., 2019. Low-cost alternative culture media for fungal pigments production . bioprocesses require further exploration to identify the metabolic pathways involved in the production of useful biomolecules and there are several challenges that need to be overcome for in vitro and in vivo production of these molecules. For instance, development of new bioprocessing techniques using omics approaches such as nutrigenomic , proteomics, and peptidomics , are being progressed for bioactive peptides production 11-Mar-22 21 waste valorization

22. gaps and future research directions the efficiency and yield of bio-energy is very dependent on the process parameters such as temperature, pH, co-substrates, mode of operation, and reactor configuration. multi-channel approach would not only reduce the burden of waste disposal at an industry level, but also provide additional source of income for the plant. the production of organic acids from dairy waste, there is a lot of variability in the process and a large dependency on process parameters to successfully produce acids . the identification of an appropriate microbial strain in bio-plastic production that produces higher yields and also high-quality product remains a challenge. microbes with higher carbon consumption efficiency and the capability to produce a single product i.e., bio-plastic . This would further help in reducing the cost of downstream processing and improve quality. 11-Mar-22 22 waste valorization

23. microbial treatment techniques developed in the recent past are progressing the conversion of dairy waste into useful products . Anaerobic treatment can directly convert the waste into valuable energy resource, whereas other biotechnological methods can use it as a substrate for production of other value-added products such as bio-surfactants , bio-plastics and bio-molecules . These strategies are promoting circular economy and reducing the impact of waste disposal on the environment. Conclusion 11-Mar-22 23 waste valorization

24. 11-Mar-22 waste valorization 24 Silva et. Al., Cleaner Engineering and Technology 7 (2022) 100453 the feasibility of replacing feldspathic flux by ceramic sludge waste (CS) in the sanitary ware production.

25. Food waste valorization  - SCG valorization Food waste valorization is a goal of sustainable development, gaining high interest in resolving environmental and resources challenges. Coffee use generates massive quantities of spent coffee grounds (SCG), a resource rich in fatty acids, amino acids, polyphenols , minerals, and polysaccharides.  11-Mar-22 25 waste valorization

26. Food waste valorization-perspectives of spent coffee grounds biorefinery 11-Mar-22 waste valorization 26 Journal of Cleaner Production Volume 211, 20 February 2019, Pages 1553-1566

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28. 28 Water pollution from fly ash MoEF&CC (3/11/2009): “Fly ash "means and includes all the coal or lignite ash generated at thermal power plant, such as ESP ash, dry fly ash, bottom ash, pond ash and mound ash for the purpose of utilization”. Fly-Ash NTPC Kaniha

29. 29 Present situation of Fly ash generation and utilization in India MoEF & CC Amendments on fly ash utilization: i ) 27th August, 2003 ii) 3rd November, 2009 iii) 25th January, 2016 Target for 100% fly ash utilization by 31st December, 2017 Mode of Fly-Ash Utilization 2016-17 Source: CEA, MOP

30. Fly Ash- A potential source of making Zeolite Zeolite-a versatile green material 30 Formula ( wt %) Raw coal fly ash Na 2 O 9.091 MgO 3.923 Al 2 O 3 22.933 SiO 2 55.186 K 2 O 0.581 CaO 0.529 TiO 2 2.219 Fe 2 O 3 5.530 BaO 0.004 SiO 2 / Al 2 O 3 2.40 Surface area (m 2 /g) 5.93

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34. 11-Mar-22 waste valorization 35 Waste Tyre Pyrolysis Rubber 38% Fillers (Carbon black, silica, carbon chalk) 30% Reinforcing material (steel, rayon, nylon) 16% Plasticizers (oils and resins) 10% Vulcanisation agents ( Sulphur , zinc oxide, various chemicals) 4% Antioxidants to counter ozone effect and material fatigue 1% Miscellaneous 1% Elementary Composition Carbon 86.40% Hydrogen 8.00% Nitrogen 0.50% Sulphur 1.70% Oxygen 2.40% Proximate Analysis Volatiles 62.10% Fixed carbon 29.40% Ash 7.10% Moisture 1.30% Composition of Whole Tyres Composition of Whole Tyres

35. 11-Mar-22 waste valorization 36 Pyrolysis process pathway Gasification process pathway

36. 11-Mar-22 waste valorization 37 Pyrolysis Gasification Liquefaction H 2 S H2 H2 CO CO CO CO 2 CO2 CO2 CH 4 CH4 Alkanes Alkanes Ethane Alkenes alkenes Ethylene H 2 S (trace) Acetylene PGL Gas Constituents

37. 11-Mar-22 waste valorization 38 Pyrolysis Gasification Reaction Temp °C Tyre gas wt% Tyre gas wt% Reaction Temp °C Tyre gas wt% 450 4.5 6.8 850 34.7 500 5.5 8.0 925 64.5 600 8.9 8.1 1000 85.9 Pyrolysis and Gasification Gas Yield Pyrolysis Gasification Liquefaction Reaction Temp, °C Tyre Oil, wt% Tyre Oil, wt% Reaction Temp, °C Tyre Oil, wt% Reaction Temp, °C Tyre Oil, wt% 450 58.1 28.3 850 27.0 320 67.4 500 56.2 41.1 925 21.8 370 90.2 600 53.1 39.4 1000 5.3 380 83.7 PGL Fractional Oil Yield PGL FRACTIONAL CHAR YIELD Pyrolysis Gasification Liquefaction Reaction Temp, °C Tyre Oil, wt% Tyre Oil, wt% Reaction Temp, °C Tyre Oil, wt% Reaction Temp, °C Tyre Oil, wt% 450 37.4 53.4 850 43.4 320 24.1 500 38.3 44.1 925 38.5 370 4.7 600 38.0 44.5 1000 33.3 380 2.3

38. 11-Mar-22 waste valorization 39 Process Liquefaction Gasification Pyrolysis Process definition Liquefaction is the thermochemical conversion of an organic solid into liquids. Gasification is a sub-stoichiometric oxidation of organic material to maximize waste conversion to high temperature flue gases, mainly CO 2 and H 2 . The thermal degradation of carbonaceous material in an oxygen deprived atmosphere to maximize thermal decomposition of solid into gases and condensed liquid and residual char. Operating conditions: Reaction environment Oxidizing (oxidant amount larger than that required by stoichiometric combustion) Reducing (oxidant amount lower than that required by stoichiometric combustion) Total absence of any oxidant Reactant gas none Air, pure oxygen, oxygen enriched air, steam None Temperature Between 300 o C and 450 o C [ 19 ] Between 550 – 900 o C [ 20 ] (in air) Between 400 and 800 o C [ 3 ] Pressure Atmospheric Atmospheric Slightly above atmospheric pressure Process output: Produced gases H 2 , CO, CO 2 , Alkanes Alkenes, H 2 S (trace) CO, H 2 , CO 2 , H 2 O, CH 4 CO, H 2 , CH 4 and other hydrocarbons Produced liquids Petroleum like liquid, heavy molecular compounds with properties similar to those of petroleum based fuels. Condensable fraction of tar and soot which is minimal. Oil is similar to diesel and can be used as a fuel. High aromatic content, thus can serve as a feed stock in the chemical industry Produced solids After the combustion process. Bottom ash is often produced as vitreous slag that can be utilized as backfilling material for road construction. The pyrolysis char residue has a considerable amount of carbon content and can either be utilized as tyre derived fuel for the process or be sold as a carbon-rich material for the manufacture of activated carbon or for other similar industrial purposes Pollutants SOx, NO x , CO, H 2 S, HCl, CO, NH 3 , HCN, tar, alkali, particulate. H 2 S, HCl , NH 3 , HCN, tar, particulate.

39. 40 Paradigm Shift in the Waste management strategy UNEP 2011 Application of Waste Management Hierarchy helps in preventing emissions of greenhouse gases reduces pollutants save energy conserves resources stimulate the development of green technologies

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