Microorganisms role in Waste Management and producing different Biomass fuels ( Biogas) .pptx

Presentation on Microorganisms role in Waste Management

1. Microorganisms in Waste Management By/ Ahmed Mohamed Khedr

2. What Is Waste? Waste is generated from human activity mostly. Rapid and unplanned development and modification of livelihood all over the world put complexity in the generated waste. Overall biosphere is degraded rapidly due to continuous release of hazardous pollutants from different industries throughout the world. Rapid expansion of health-care facilities and modernization of agricultural practices generate large quantity of biomedical and agricultural wastes which brings adverse effect on environmental health. There are three kinds of wastes mainly such as solid waste, liquid waste and gaseous waste.   Classification of Waste Waste can be solid, liquid and gas or waste heat. Waste is classified by its source and by its characteristics. Waste products can be differentiated according to their source and types. Generally, there are four sources from where waste can be generated such as industrial, municipal, biomedical and electronic. Waste can be classified on the basis of different criteria such as based on matter, based on degradation feature, based on environmental impact and based on the source. Each category may be of different types which are shown on Fig. 1.

3. What Is Waste Management? WM is basically the storage, collection and disposal and managing of waste materials. The main aim of WM is to reduce the effects and consequences of wastes on human health and environment. It continues to be a rising challenge with rapid urbanization, industrial revolution and tremendous pressure of population on the NR that put great stress on the global environment. WM has basically four parts – industrial, electronic, municipal and biomedical – and all of these wastes are super- vised by particular policies. The concept of 4R theory (refuse, reduce, reuse and recycle) has been applied to the basic principles of WM. In India strategy for WM depends on waste generation, store, collection, transportation, recycle, treatment and disposal. Some of the commonly used WM methods are landfills, incineration, composting and gasification. Schematic view of WM system is shown on Fig. 2.

4. Composting Composting is an aerobic decomposition process and is facilitated by a diverse population of microorganisms. This process has been widely practised for different types of wastes by means of metabolic activity of microbial consortium. Composting has been used to transform and stabilize organic waste into safer and more stabilized form that can be used in various agricultural practices ( Garcıa -Gomez et al. 2005). It is an economically and environmentally appropriate method for handling waste. The main product of composting is humus and plant nutrients, and carbon dioxide, water and heat are the by-products (Abbasi et al. 2000). Different types of microorganisms such as bacteria, actinomycetes, yeasts and fungi are involved in this process. Composting occurs in three different phases: mesophilic phase, thermophilic phase and cooling and maturation phase. Two factors regulate the duration or length of the composting phases: the types of composting organic matter (OM) and the efficiency or effectiveness of the process ascertain by the degree of aeration and agitation. For agricultural waste, challenges arise due to the abundant of lignocellulose composition. Acid and thermal pretreatments of lignocellulose are required before composting process. Pretreatment methods using thermal or chemical is not favourable due to energy consumption and impact of added chemicals to environmental ( Rouches et al., 2016). Compared to chemical and thermal methods, the use of an enzyme such as cellulase to treat the lignocellulose waste is desirable, the industrial enzyme is costly if applied at large scale. The application of thermophilic cellulolytic microorganisms including fungi and bacteria to expedite the composting process is preferable ( Bohacz , 2017). Fungus such as T. reesei has been reported to produce more than 100 g of cellulase per L of culture broth and their ability to grow in liquid and solid medium make it a suitable candidate for treating agricultural waste (Schuster and Schmoll , 2010). This finding suggested that application of thermophilic cellulolytic microorganisms in agricultural waste could reduce the dependency on the industrial enzyme, chemical and thermal pretreatments.

5. Biodegradation Biodegradation is a biological way of degradation of chemical compounds (Alexander 1994). In this process living microbial organisms are used to degrade organic substances into smaller compounds (Marinescu et al. 2009). Biodegradation is closely associated with WM and environmental remediation (Marinescu et al. 2009). In terms of microbiology, biodegradation is degradation of OC by a huge diversity of microbial population mainly bacteria, yeast and fungi. Different types of microbes involved in biodegradation process are shown on Fig. 3.

6. Biodegradation of Xenobiotic Compounds (XC) What Are XC? Xenobiotic (Greek xenos = strange, foreign, foreigner) compounds are human- made chemical compounds that are foreign to the nature. They are highly thermo- dynamically stable, hence are relatively persisting in the environment. The main sources through which XC are released into the environment are chemical and phar - maceutical industries which generate varieties of xenobiotic and synthetic poly- mers . Modernization of agriculture and mining produces huge quantities of fertilizers and pesticides and releases heavy metals into biogeochemical cycles. Toxic chlorinated compounds released from the pulp and paper industry and acci - dental oil spillage in large quantity make the situation more catastrophic. The gen- eral diagram of probable fate of XC in the environment is provided in Fig. 4.

7. Biodegradation of Plastic Wastes Plastics are chemically synthesized synthetic polymeric material prepared for human use and having very much similarity to natural resins in many ways. In all aspects of every day’s life, it has made its presence due to the versatile nature. Plastics are used for manufacturing different types of products as it is durable, strong, lightweight and cheap ( Laist 1987; Pruter 1987). In spite of its vast utility, it creates major environmental hazards due to some unique characteristics such as its buoyant nature, dispersing over long distances, nondegradable and may be sustained in the environment for years (Ryan 1987; Hansen 1990; Goldberg 1995, 1997 ). Types of Plastics Plastics are not only stable and durable but also have suitable thermal and mechanical properties which made its excessive and widespread application in daily life ( Rivard et al. 1995). Plastics are generated from monomeric HC. Mostly plastics are produced by chemical alternation of natural materials or raw materials which may be organic or inorganic. Plastics are basically of three types such as thermosetting, elastomers and thermoplastics or thermo-softening plastic based on their physical nature and can be differentiated on the basis of molecular structure. Most of the plastics are thermoplastic type which can be softened and hardened by heating and cooling to give structure. Thermosetting plastics cannot be remodified by heating. Elastomers have the elastic properties of rubber. Later extensive research work has been started to find out to make biodegradable plastics that could be prototyped for availability to microbial attack in a suitable environment. Biodegradable plastics come up with new possibilities for rejuvenated means of WM approach, as these plastics are formulated to degrade under certain environmental conditions or in biological way of waste treatment equipment (Augusta et al. 1992; Witt et al. 1997).

8. Bioremediation Bioremediation is a natural process which makes the use of microorganism to remove waste or pollutant from the water and soil. This is an environment-friendly and sustainable method as it involves eco-friendly microbes in treating the solid waste ( Kensa 2011). It is of two types: (1) In Situ Bioremediation : Here removal of water or soil is without excavation and transport of contaminants. Biological treatment on surface of the waste is car- ried out by bacteria. It is the alternative method of treatment of soil and groundwater. Ex Situ Bioremediation: It describes the removal of the contaminated soil or water for remedy process. Heavy Metal Bioremediation   Heavy metals are generally considered as metals having relatively high densities and atomic weight. Few heavy metals like silver (Ag), copper (Cu), cadmium (Cd), lead (Pb), zinc (Zn) and chromium (Cr) are considered as heavy metals because of their toxicity properties. The existence of heavy metals in the environment can con- taminate the soil and groundwater through the process of leaching. Toxic metals may enter feeding relationships among organisms through water engendering inaus- picious consequences on the overall living things. Various microorganisms like bac- teria , algae and fungi act as a bio-absorbent in degradation of the metals. Yeasts have been reported of having a significant role in toxic heavy metal elimination from the environment. Some pioneer research work indicate that yeasts are efficient and superior heavy metal accumulator such as Cu(II), Ni(II), Co(II), Cd(II) and Mg(II) compared to certain bacteria (Wang and Chen 2006). Bahafid et al. (2011, 2012) reported that Pichia anomala is able to eliminate Cr (VI) and cells (live or dead) of three yeasts species: Cyberlindnera , Tropicalis, Cyberlindnera fabianii and Wickerhamomyces anomalus are good bio-absorbers of Cr (VI).

9. Biotransformation Biotransformation is a transformation of toxic compounds into less persistence and less toxic form. Bacteria and fungi are the major groups of microorganisms, and their enzymes are involved in this process. Microorganism cells are crucial for bio- transformation due to some causes such as: • Surface-volume ratio: Surface-volume ratio is high in case of microorganism- mediated biotransformation. • Rate of microbial cell growth: Microbial cells have high growth rate which minimizes biomass transformation duration. • Rate of metabolism: Rate of metabolism in microorganism is very high which is needed for efficient transformation. • Sterile condition: In order to make effective biotransformation, it is necessary to maintain sterile condition of the microorganism ( Hegazy et al. 2015).

10. Biotransformation of Petroleum Petroleum is the principal means of propulsion in industry and livelihood (Mathew 2012). However, HC contamination related to the petrochemical industry has a place in the foremost environmental issues right now (Das and Chandran 2011; Dadhich et al. 2015). Soil and water are polluted due to leaks and accidental release of contaminants. Petroleum is a potent carcinogenic and neurotoxic to all biota (O Peter 2011). In order to remediate the contaminated soil and water, various chemical and mechanical methods are available, but utilization of microorganism in biotransformation process is the most effective method for detoxification of the pollutants as it is environment-friendly and cost-effective, and the most important part is that it leads to complete mineralization. Many aquatic and marine microfloras have been reported in the oil spill biodegradation ( McGenity et al. 2012). Bacteria, yeast and fungi are the principal microorganisms for petroleum biotransformation (Atlas 1981). Sphingomonas sp. has been reported to degrade polyaromatic HC ( Daugulis and McCracken 2003).   Some bacterial genera such as Mycobacterium sp., Arthrobacter sp., Rhodococcus sp. and Pseudomonas sp. have been reported to degrade petroleum HC very effec - tively . Several other microorganisms such as Gordonia sp., Brevibacterium sp., Corynebacterium sp., Flavobacterium sp., Pseudomonas fluorescens, P. aerugi - nosa , Actinocorallia sp., Klebsiella sp., Rhizobium sp., Bacillus sp. and Alcaligenes sp., Aeromicrobium sp., Dietzia sp., Burkholderia sp. and Mycobacterium sp. have been extracted from petroleum-polluted zone and are reported to degrade HC very efficiently ( Chaillan et al. 2004). Cephalosporium sp., Aspergillus sp., Penicillium sp., Neosartorya sp., Talaromyces sp. and Amorphoteca sp. are the fungal microor - ganisms found in petroleum-contaminated sites and have been reported in oil spill bioremediation (Koul and Fulekar 2013).

11. Microorganism and Waste Water Management WW management chemical and biological are the two principal treatment methods to clean up WW impurities. In comparison with chemical treatment, biological treatment has obtained more potentiality due to many reasons such as biological treatment is more cost-effective and environmentally sustainable. Microorganisms are of major importance in different WW treatments like industrial, agricultural and in aquaculture. Microbes efficiently eliminate and degrade different toxic materials such as ammonia, nitrite, hydrogen sulphide , etc. The role of microorganisms particularly bacteria and protozoa in WW treatment system is very significant as these organisms are potent degrader of N and phosphorus. Aerobic Bacteria Aerobic bacteria, thriving in oxygen-rich environments, play a crucial role in the initial stages of wastewater treatment. These microorganisms exhibit an unparalleled knack for consuming organic pollutants, including proteins, carbohydrates, and fats. Through aerobic respiration, they transform these complex substances into simpler compounds, laying the foundation for the overall efficiency of wastewater treatment plants. Expanding on this, certain strains of aerobic bacteria are specifically tailored to target and degrade different types of contaminants. For instance, Pseudomonas and Bacillus species are known for their prowess in breaking down hydrocarbons, making them essential in treating wastewater from industries that deal with oil and petroleum products . Anaerobic Bacteria In the oxygen-depleted environments of the secondary treatment phase, anaerobic bacteria take center stage. These microorganisms specialise in breaking down complex organic compounds through anaerobic digestion. The unique byproduct of this process is methane gas, a valuable resource that can be harnessed as renewable energy. This dual functionality positions anaerobic bacteria as key players in treating high-strength industrial wastewater, offering pollution control and energy generation. Moreover, recent research in India has focused on optimising anaerobic digestion processes in wastewater treatment plants to enhance methane production for local energy needs, contributing to the country’s sustainable development goals.

12. Facultative Bacteria Facultative bacteria exhibit unmatched versatility with their ability to thrive in oxygen-rich and oxygen- depleted conditions. This adaptability makes them indispensable at various stages of wastewater treatment, contributing significantly to the reduction of organic matter and nutrients. Further research is ongoing to identify and harness specific strains of facultative bacteria that can thrive in the diverse and dynamic wastewater conditions observed in Indian treatment plants. Results of Using Microorganisms in Wastewater Treatment The integration of microorganisms in wastewater treatment plants yields multifaceted benefits, significantly enhancing the efficiency and environmental sustainability of the process. Let’s delve deeper into the tangible results of employing these microscopic allies. FOG (Fats, Oil, and Grease) Elimination The battle against FOG in wastewater is a constant challenge, particularly in regions with high culinary activity. Aerobic bacteria, with their voracious appetite for fats, oils, and grease, play a pivotal role in preventing the accumulation of these substances in treatment systems. Innovative approaches, such as bioaugmentation (introducing specific microbial cultures), are being explored in sewage treatment plants to address localized challenges related to FOG and to further optimise this process. BOD (Biochemical Oxygen Demand) Reduction Microorganisms, especially aerobic bacteria, act as biochemical surgeons, targeting and reducing the biochemical oxygen demand in wastewater. This reduction is crucial in preventing oxygen depletion in water bodies and safeguarding aquatic ecosystems. Ongoing research is focused on understanding the microbial diversity in Indian water bodies to tailor treatment processes that effectively address the unique challenges posed by varying BOD levels across different regions.

13. COD (Chemical Oxygen Demand) Reduction Reducing chemical oxygen demand is a critical objective in wastewater treatment, and microorganisms are at the forefront of achieving this. Efforts are underway to optimise the groups of microorganisms used in treatment plants to efficiently break down organic and inorganic contaminants, substantially reducing COD levels. These advancements contribute to environmental conservation and the sustainable management of water resources in water-scarce regions. Roles of microorganisms in industrial wastewater treatment Paper and pulp industry Paper and pulp industries are reported by various researchers to be a highly polluting industry that generates toxic wastewater. Chemical constituents including chlorinated compounds, lignin and its derivatives, adhesives, dyes, fillers, peroxides, ozone, etc. are released in the wastewater. During pulp making, pulp bleaching, washing, deinking in paper making, various recalcitrant, and harmful contaminants are produced. Pulping will amount to highest level of generation of polluting contaminants in the papermaking process. Therefore, treatment of wastewater by biological means that utilizes bacteria, fungi, as well as their enzymes produced are identified to be cost-effective and economical methods for degradation of toxic compounds. In the past years, various microorganisms or enzymes from microbial sources are utilized in different biotreatment methods ( biopulping , biobleaching , biorefining, and biological deinking) in paper industry for the biological degradation of xenobiotic pollutants. Biopulping will remove lignin and hemicellulose by enzymatic action (Gautam, A., 2016) produced by fungi (white rot) such as Corioulus versicolor, Ganoderma colossum , Phanerochates chrysosporium , Phlebiopsis gigantean, Physisporinus riv - ulosus , Trametes versicolor, and Schizophyllum commune (Kumar, A., 2017). In comparison to traditional pulping techniques, biopulping results in decreased energy costs and environment issues.

14. Food and beverage industry They are the largest contributors to growth in terms of turnover, employment, and financial and social significance. The processing of various raw materials leads to huge amount of wastewater containing diverse organic, inorganic substances that will pose serious health hazards on human and animals and ultimately ecosystem (Joshi, N. & Deepali., 2012) Waste is produced before storage, during storage, and during processing of raw materials in food and beverage industry. This waste includes mainly starch and sugars acting as primary carbon source. Beverage industry is broadly divided into three major types including brewing, distilling, and manufacture of wine. These industries generate mainly liquid waste with high levels of BOD and COD. The fermentation units produce higher concen - trations of phenols, tannins, and organic acids in the wastewater. Various fungal cul - tures , such as Mycelia sterilia , C. versicolor, G. candidum , Trametes vercicolor , and P. chrysosporium , are utilized for wastewater treatment containing phenols. Candida sp. resulted in decreasing the phenol content and COD by at least 50%. On immo - bilization of C. versicolor in packed bed reactor, the COD was reduced to 77%. Yoshi et al. (Yoshi, H. et al., 2001) reported 90% reduction in COD and BOD when Geotrichum sp. is used for the treatment of distillery wastewater of an alcoholic drink (Shochu). Fun- gal biomass protein production and COD reduction were analyzed for the treatment of waste from winery industry using three fungal cultures like T. viride WEBL0702, Aspergillus niger WEBL0901, and A. oryzae EBL0401 (Zhang, Z. Y. et al., 2008). T. viride WEBL0702 was selected based on results due to its less nitrogen needs and higher level of productivity.

15. In food industry, washing of potato and other similar tubers will generate effluents rich in sugar, starch, and proteins containing higher BOD levels and huge number of suspended solids in wastewater. Microbes like C. utilis and Saccharomycopsis fibuli - gera , Cellulomonas sp., and Bacillus sp. are utilized in food processing industry efflu - ents effectively. For the treatment of wastewater from potato processing unit, various bacterial cultures including B. acidocaldarus , B. coagulans , B. stearothermophilus, B. brevis, B. licheniformis, and Lactobacillus sp. are used. These strains were found effi - cient in decreasing the total solids, starch content, and BOD level of wastewater via ther - mophilic aerobic digestion process in 96 h of treatment ( Malladi , S. & Ingham, S.C.,1993). Wastewater produced by olive mills is of major environmental concern due to the higher organic fraction mainly containing phenolic compounds that are difficult to degrade. Other compounds include lipid, sugar, tannin, polyphenol, pectin, and polyalcohols . Microbes like Bacillus pumi - lis and Azotobacter vinelandii showed significant reduction in the phenol concentration in wastewater produced by olive mill ( Ethaliotis , C. et al., 1999). Pharmaceutical industry Pharmaceutical industry generates wastewater containing mixture of diverse com- pounds (organic and inorganic), solvents, steroids, hormones, antibiotics, residues of active pharmaceutical ingredients, and other toxic chemicals that poses great chal - lenge in its proper treatment. Wastewater contains numerous pharmaceutical agents, hormones, and antibiotics utilized in human and veterinary medicines including diclofenac, ibuprofen, naproxen, fluoxetine, 4-aminophenol, erythromycin, triclo - carban , trimethoprim, diphenhydramine, estrogen, progesterone, testosterone, and androgens (Suresh, A 2018) . These contaminants are present not only in industrial wastewater but also in domestic, surface wastewater, and ground water sources.

16. Microbes in Biogas Production   Microbes used in the treatment of sewage, particularly the anaerobic bacteria, helps in the production of methane, which is biogas. The production of biogas is important since it can be used as a potential energy source as it is a sustainable and renewable energy resource, as shown in Figure 6.2. Hence, microbes in biogas production play a pivotal role in facilitating the production of environmentally beneficial residue or products. Also, since the treatment of sewage is happened is a two-fold procedure, the residual solid waste from the sewage treatment produces ample amounts of nutritious solid matter, which can be used as natural manure and fertilizers in agriculture. This process of waste sewage substances treatment is performed in a controlled environment and treatment facility known as – an incinerator or landfill site. Biogas as a Sustainable Energy The implementation of biomass as sources of renewable energy technology is considered as sustainable technology in meeting energy needs and as well as to minimize the emission of greenhouse gases. In addition, biomass use presents the advantage of cost–benefit viability and reduce the waste flow into the environment ( Bekchanov , M. et al. 2019). The production of biogas from lignocellulosic substrates through the transformation of volatile organic solids (VS) by anaerobic digestion is proven to be an alternative source of energy. The potential of biogas from waste can substitute current use of natural gas in many regions ( Montañez -Hernández, L.E. et al. 2018). Biogas is produced through a bioprocess involving four steps—i.e., hydrolysis, acidogenesis, acetogenesis, and methanogenesis—using a microbial consortium containing many different types of bacteria and archaea ( Curto , D.; Martín, M. 2019) as shown in Figure 6.1. Composition of biogas slightly varies depending on the type of feedstock used in anaerobic digestion. It is mainly composed by CH4 (40–75%) and CO2 (25–60%), with minor impurities such as H2S, NH3, among others ( Parsaee , M., et al. 2019). Furthermore, CO2, the second major component can be sequestered and used to produce chemicals.

17. Figure 6.1 Steps and microorganisms involved in biogas production. Lignocellulosic biomass as Biogas Feed Stock The largest potential feedstock for bioenergy production is lignocellulosic biomass, which represents the most economical and highly renewable natural source in the world. Lignocellulosic biomass is composed of three main biopolymers: cellulose, hemicellulose and lignin (Jiang, B., et al. 2018) The individual composition of different lignocellulosic substrates on dry basis is presented in Table 11 and the structure is presented in Figure 7.

18. Figure 6.2 Biogas production.   Table 11. Composition of different lignocellulosic substrates; cellulose, hemicellulose, and lignin content (%) on dry basis.

19. Biogas Production in Germany Germany is the leading biogas producer in Europe and the world. After years of tremendous growth, the industry has significantly slowed down and is in a state of transition. This is partly due to change in regulations supporting the biogas industry, such as the Renewable Energy Sources Act amendment to energy auctions, sustainability criteria limiting the use of energy crops, and partly due to saturation of certain segments of the industry. The German biogas industry, which has historically been driven by large energy crop-based digesters, is now opening its doors to small manure-based digesters, upgrading plants and flexible energy generation. There is still targeted potential in the market to grow and mature, even if not at the scale we have seen so far. According to Agency for Renewable Resources, FNR (2019) Bioenergy in Germany: Facts and Figures 2019, Germany has an estimated 9,706 biogas plants operating as of 2018. That is the highest number of biogas plants in any country in Europe and the world, excluding small scale community plants prevalent in China and South East Asia. • There are 9,494 operating combined heat and power biogas plants in Germany with a total installed capacity of 4.8GW. 32,500GWh of electricity and 17,184GWh of heat were generated in 2017 using biogas. The installed capacity of CHPs in Germany has been growing slowly since 2016. This may be attributed to a change in environmental policy, which has been discussed under the section Barriers.

20. Waste-to-Energy for a Sustainable Future in Egypt Faced with a growing population, securing energy supplies has become one of Egypt’s biggest priorities. Because of this, the past few years has seen the country importing large amounts of energy from different sources. Egypt has also been experiencing difficulties dealing with the growing amounts of waste produced by the increasing population. With the government’s plan to become a regional energy trading hub, acknowledging waste as an accessible source of energy is becoming necessary. Hence, Egypt has been reviewing tariffs for energy produced from waste in order to encourage waste-to-energy projects for generating sustainable energy. Waste-to-Energy Egypt produces huge amounts of solid waste that can be reused or recycled. Waste that cannot be recycled is processed to decrease its volume and toxicity, and for energy generation. “Egypt has a golden opportunity to capitalize on creating energy from waste, which would be aligned with the new energy strategy of the Egyptian government in which it targets to diversify its energy mix portfolio by adding energy recovery channels to the existing renewable energy projects,” expert in waste management and alternative fuels, Omar M. El Hassanein , told Egypt Oil & Gas.

21. Egypt establishes 1st factory producing electricity from Biogas According to Egyptindependent.com, The MAWARED INDUSTRIES has signed at April 2023, a contract with the National Company for Animal Production of the National Service Projects Organization to establish Egypt’s first factory to generate electricity from bioenergy (biogas) in Sadat City. The factory will annually process 85,000 tons of cattle dung to produce one megawatt/hour of electricity to be connected to the national electricity grid. It will also produce more than 80,000 tons of high-quality organic fertilizer, proven to be effective in restoring agricultural soil fertility and doubling its productivity. The factory also contributes to reducing greenhouse emissions by about 5,000 tons of carbon dioxide. In January 2022, MAWARED INDUSTRIES installed and operated the first portable Biogas units in Zewail City, with a production capacity of 2,200 cubic meter per year to treat organic waste resulting from student restaurants in Zewail City, to be used in cooking at the university. The organic fertilizer resulting from the unit is used for the gardens within the city’s campus, in addition to being a unit in which students and those interested are practically trained. This in turn contributes to the dissemination of biogas technology among students in an academic and research field.   This comes under Egypt’s aims to achieve its sustainable development 2035 initiative, particularly in order to reach 42 percent of clean electricity as a goal.