«MASTER IN ENVIRONMENTAL SANITATION Academic Year 2013-2014 FROM WASTE TO PRODUCTS: ALTERNATIVES TO TRANSFORM URBAN AND INDUSTRIAL RESIDUES INTO ...»
FACULTY OF BIOSCIENCE ENGINEERING
MASTER IN ENVIRONMENTAL SANITATION
Academic Year 2013-2014
FROM WASTE TO PRODUCTS: ALTERNATIVES TO
TRANSFORM URBAN AND INDUSTRIAL RESIDUES INTO
NAYARET KARINA ACOSTA ORTIZ
Dr. Marta Coma Dr. Janine Padilha Botton Master’s dissertation submitted in partial fulfilment of the requirements for the degree of Master of Environmental Sanitation.
COPYRIGHTThe author and the promoters give the permission to use this dissertation for consultation and to copy parts of it for personal use. Every other use is subject to the copyright laws; more specifically the source must be extensively specified when using results from this dissertation.
De auteur en de promotoren geven de toelating deze scriptie voor consultatie beschikbaar te stellen en delen ervan te kopiëren voor persoonlijk gebruik. Elk ander gebruik valt onder de beperkingen van het auteursrecht, in het bijzonder met betrekking tot de verplichting de bron te vermelden bij het aanhalen van resultaten uit deze scriptie.
Ghent, September, 2014
Promoter: Co-promoter: Author:
Dr. Marta Coma Dr. Janine Padilha Botton Nayaret Acosta O.
ACKNOWLEDGEMENTSThe outcome of this thesis is the result of good collaboration with internal and external partners, whose efforts I greatly appreciate.
I have the deepest gratitude to those who have contributed to the completion of this project:
Dr. Marta Coma, my Promotor, for patiently teaching, supervising, encouraging, and for constantly inspiring, guiding me through the all process.
Dr. Janine Padilha Botton, my co-Promotor, and UNILA for their support and help in research work, especially for the experimental design and problem solving in Brazil.
LabMET, for giving me the opportunity to perform my master dissertation. I have learned more during this time than I could ever imagine. This is priceless.
Companies involved in the project, for their support in the development of projects:
Itaipu Technological Park, the authorities and all the technical and laboratory staff who allowed me to learn from inside, the development of biogas technology from the South American perspective.
João Zank, my Tutor, for guiding me through this project even with the distance. I appreciate all your efforts to supervise the experimental work in Brazil.
My friends in Brazil, Dangela, Rafael, Leidiane, Alberto, Jessica, Caroliny, Andreia, Nassir,Alexis, Jhoni, Mariana, Juliana, Tania and Evandro for being there, for joyful spare time, for interesting discussions, for relaxing atmosphere and for making my life a lot easier.
All my laboratory mates at LabMET, especially Thais, for collaborations, contributions and sharing expertise.
SENESCYT, for supporting Ecuadorian students abroad. We will work for our loved country.
My heartfelt gratitude goes to all my family members, especially my parents, you are the fuel who let me go and reach for my dreams.
ABSTRACTThe topic of the thesis is energy and resource recovery evaluation by anaerobic treatments from waste streams. The study has been carried out between the Itaipu Technological Park (PTI) located in Iguassu Falls, Brazil and Laboratory of Microbial Ecology and Technology (LabMET), Belgium. Firstly, a theoretical evaluation from different urban residues was made in PTI focusing on biogas production. Secondly, urban waste prioritized from the theoretical evaluation and four industrial side streams refineries were evaluated by means BMP tests in mesophilic and thermophilic ranges. The main outcome of the tests showed that food waste (FW), 600 L per kg volatile substrate, and common grass (CG), 300 L/ Kg VS, were the most suitable biomasses for anaerobic digestion. Co-digestion improves the biogas production when CG is used as main substrate. The results of BMP of industrial waste showed that Molasses and Attero had the highest biogas production in mesophilic range. In thermophilic conditions, Molasses and Alco obtained the highest biogas production.
In the Belgian framework, resource recovery has been tested by means of fermentation processes within the carboxylate platform. This approach intends to obtain fatty acids as building blocks instead of degrading all organic matter to methane. Different set-ups were tested with molasses or thin stillage (Alco) from a first generation biorefinery. Both substrates were also evaluated for biogas production by means of continuous reactors. Operational parameters have been tested to maximize carboxylate production and decrease methanogenic activity.
In the molasses CSTR fermenter, the highest OLR was 4.24 g COD/L day on average. It is clear that OLR variations affect directly VFA production. There was a VFA production for acetate, butyrate and valerate with 0.60, 0.49 and 0.24 g/L day respectively. The conversion efficiency from COD to VFA was 56%.
In the Alco CSTR-AD, the methane yield reached up 0.65 L/day on average with a peak of 1.23 L/day on day
136. Propionate production was observed, with 2200 mg Prop/L at day 150 when methane production started to decrease, thus being the cause of methanogenesis inhibition. This fact might be related to high concentrations of C5 sugars present in side-streams of bioethanol production. However, when acclimated as a fermenter, the reactor started to build up acetate (9310 mg Ac/L) and even longer chain carboxylates such as butyrate (1980 mg But/L) and valerate (1580 mg Val/L). Alco CSTR-Ferm was operated for185 days. When the pH and VFA concentration was stable, 5.5 and 16000 mg/L respectively, butyrate and valerate were produced. A minimum concentration of intermediates is necessary (acetate and propionate) in order to produce long chain products. Caproate increased sharply since day 159 reaching a concentration of 4.9 g/L.
This caused a drop in VFA production and pH. At day 180 no gas production was observed which indicates the absence of microbial activity. The conversion efficiency from COD to VFA was 27%.
CHAPTER 1 LITERATURE REVIEW
1.1 Waste generation
1.2 Urban and industrial waste
1.3 Environmental/ Industrial Biotechnology
1.4 Anaerobic digestion
1.4.6 Factors affecting anaerobic digestion
1.4.8 Products of anaerobic digestion
1.5 Carboxylate platform
1.5.2 Methanogenesis inhibition
1.5.3 Products of fermentation
1.6 Reactor’s configuration for anaerobic processes.
1.7 Aim of the dissertation
CHAPTER 2 MATERIALS AND METHODS
2.1 Theoretical substrate evaluation
2.1.1 Specific evaluation of substrates per quantity
2.1.2 Specific evaluation of substrates per quality
2.1.3 Importance of criteria
2.2 Biochemical Methane Potential (BMP) test for urban residues
5/67 2.3 BMP test for industrial residues
2.4 Continuous stirred tank reactor (CSTR) in semi-continuous feed
2.5 Upflow anaerobic sludge biofilm (UASB) reactors
2.6 CSTR reactors in fed-batch mode
2.7 Analytical methods
2.7.1 Total and soluble COD
2.7.2 VFA analysis
2.7.3 Solids (TS and VS)
2.7.4 Suspended solids (TSS and VSS)
2.7.6 Kjeldahl Nitrogen
2.7.7 Ionic compounds
2.7.8 Gas composition
CHAPTER 3 RESULTS
3.1 Anaerobic treatment for urban residues
3.1.1 Theoretical substrates evaluation
3.1.2 BMP assays in urban residues
3.2 Anaerobic treatment for industrial residues
3.2.1 BMP assays in industrial residues
3.2.2 Fermentation of molasses
3.2.3 Methane versus carboxylate production from thin stillage
CHAPTER 4 DISCUSSION
BMP and theoretical substrate evaluation as tools for anaerobic digestion prioritization
Effect of co-digestion
Effect of industrial waste streams stocks
Effect of temperature
Anaerobic treatment: methane versus carboxylates
CHAPTER 5 CONCLUSIONS AND FUTURE OUTLOOK
CODsoluble Soluble Chemical Oxygen Demand CODtotal Total Chemical Oxygen Demand CSTR Continuous stirred tank reactor CSTR-AD Continuous stirred tank reactor- anaerobic digester CSTR-Ferm Continuous stirred tank reactor- fermenter
UASB Upflow anaerobic sludge biofilm UASB-AD Upflow anaerobic sludge biofilm- anaerobic digester UASB-Ferm Upflow anaerobic sludge biofilm- fermenter
CHAPTER 1 LITERATURE REVIEW
1.1 Waste generation Any solid or liquid matter which has no longer any economic value is known as waste (Suryawanshi, et al., 2013). Waste materials are generated as either by-product of man’s activities, materials which don’t have any use, or products which have reached the end of useful life. In the past, waste was treated in natural processes like dispersion, dilution and degradation.
Nowadays, natural processes are not enough due to quantitative (waste generation rate is higher than nature absorption) and qualitative composition of waste produced. Further, materials currently used like plastics and detergents are non-biodegradable. All these facts are the cause of pollution in our environment, therefore, it remains a major challenge to treat and dispose properly the increasing quantities of solid waste and wastewater generated (Bogner, 2007).
At present, world cities produce about 1.3 billion tons of solid waste per year. The volume of waste generation is expected to increase to 2.2 billion tons by 2025 (Hoornweg & Bhada-Tata, 2012). The generation rate will increase more than double in lower income countries in the next twenty years (Bogner, 2007); (Hoornweg & Bhada-Tata, 2012). Nowadays, solid waste generation rates range from
0.1 t/cap/yr in low income countries to 0.8 t/cap/yr in high-income industrialized countries (Bogner, 2007).
Globally, solid waste management costs $205.4 billion per year. This amount is predicted to increase to $375.5 billion in 2025. (Hoornweg & Bhada-Tata, 2012). Waste management can constitute a larger percentage of local government’s income because the cost related to equipment and operational costs (Cointreau-Levine, 1994).
Waste streams are only partially valorized at different value-added levels. Examples of waste valorization are spread on land, animal feed, composting and anaerobic digestion. Still, the main volumes are managed as waste with relevant negative effects on the overall sustainability (Federici, et al., 2009).
Valorization is a relatively new concept in the field of urban and industrial residues management promoting the principle of sustainable development.
1.2 Urban and industrial waste Solid waste components are mainly made up of residues coming from households, commercial activities (e.g., shops, restaurants, hospitals, etc.), industry (e.g, pharmaceutical companies, clothes manufacturers, factories, etc.), agriculture (e.g., slurry), and construction activities. In more detail, solid waste can be classified as urban or industrial waste. Urban waste comprises household’s residues, commercial activities and other sources whose activities are similar to those of households and commercial companies. It is made up to residual waste, bulky waste, secondary materials from separate collection (e.g. paper and glass), household hazardous waste, street sweepings and litter collections. The materials that compose municipal waste are paper, cardboard, metals, textiles, organics (food and garden waste) and construction materials (European Topic Centre on Sustainable Consumption and Production, 2013). Wastewater is a liquid waste from residential, commercial, and industrial processes.
Industrial waste comprises many different waste streams arising from a wide range of industrial processes (Bogner, 2007) (Hoornweg & Bhada-Tata, 2012). Some of the largest waste generated from industrial sectors includes basic metals, food, beverage and tobacco products, wood and wood products and paper and paper products (European Topic Centre on Sustainable Consumption and Production, 2013).
Organic waste (urban or industrial) typically consists of high amounts of proteins, sugars and lipids along with particular aromatic and aliphatic compounds. They are present in particulate or dissolved form. This type of waste could be cheap and abundant sources of fine chemicals and biomaterials as well as energy recovery (Federici, et al., 2009)..
The organic loads in industrial waste are much higher in comparison to urban waste. An example is industrial water pollution in develop countries, where China, heads the list by a wide margin, discharges 6 million kilograms of BOD emissions a day while United States releases 2 million kilograms of BOD per day. (World Bank and IMF, 2006).
In the European level, another type of industry is developing. The idea of bio-refinery was born because of the general concern for energy security and availability of feedstocks for organic chemicals.
Nowadays, there are three types of biorefineries. First generation biorefinery plant has fixed processing capabilities and uses grain as a feedstock to produce ethanol. The second generation biorefinery involves current wet milling technology which uses grain feedstock as input. However, it has the capability to produce various end products like starch, high fructose corn syrup, ethanol, and corn oil.