Environmental Biotechnology Pollution & Control PDF

MIC-644 Dr. Sadiah Muhammad Saleem Ullah Khan ENVIRONMENTAL BIOTECHNOLOGY Pollution and Pollution Control Pollution is one of the most important environmental issues. Not all pollutants are manufactured or synthetic and many substances...

MIC-644 Dr. Sadiah Muhammad Saleem Ullah Khan ENVIRONMENTAL BIOTECHNOLOGY Pollution and Pollution Control Pollution is one of the most important environmental issues. Not all pollutants are manufactured or synthetic and many substances may contribute to pollution. Any biologically active substance has the potential to give rise to a pollution effect. ‘Pollution of the environment’ means release of substances from any process which are capable of causing harm to man or any other living organisms supported by the environment. Introduction to EPA What Is the Environmental Protection Agency (EPA)? The Environmental Protection Agency (EPA) was established in December 1970 by an executive order of United States President Richard Nixon. The EPA is an agency of the United States federal government whose mission is to protect human and environmental health. Headquartered in Washington, D.C., the EPA is responsible for creating standards and laws promoting the health of individuals and the environment. Understanding the Environmental Protection Agency The EPA was established in response to widespread public environmental concerns that gained momentum in the 1950s and 1960s. The EPA seeks to protect and conserve the natural environment and improve the health of humans by researching the effects of and mandating limits on the use of pollutants. The EPA regulates the manufacturing, processing, distribution, and use of chemicals and other pollutants. In addition, the EPA is charged with determining safe tolerance levels for chemicals and other pollutants in food, animal feed, and water. Pollution is the introduction of substances into the environment which, by virtue of their characteristics, persistence or the quantities involved, are likely to be damaging to the health of humans, other animals and plants, or otherwise compromise that environment’s ability to sustain life. Classification of Pollution Chemical or physical nature of the substance. Source. The environmental pathway used. The target organism affected or simply its gross effect. Figure 4.1 shows one possible example of classifying pollution. When examining real-life pollution effects, we need to evaluate its general properties and the local environment. This may include factors such as: Toxicity; Persistence; Mobility; Ease of control; Bioaccumulation; Chemistry. Toxicity Toxicity represents the potential damage to life and can be both short and long term. It is related to the concentration of pollutant and the time of exposure to it. Highly toxic substances can kill in a short time, Less toxic ones require a longer period of exposure to do damage. May affect organism’s behavior or its susceptibility to environmental stress over its lifetime, in the case of low concentration exposure. Availability and biological availability to the individual organism. Age and general state of health. Persistence Duration of effect. Environmental persistence is often linked to mobility and bioaccumulation. Highly toxic chemicals which are environmentally unstable and break down rapidly are less harmful than persistent substances, even though these may be intrinsically less toxic Mobility The tendency of a pollutant to disperse or dilute. Very important factor in its overall effect, since this affects concentration. Some pollutants are not readily mobile and tend to remain in ‘hot-spots’ near to their point of origin. Others spread readily and can cause widespread contamination, though often the distribution is not uniform. Pollution may be continuous or a single event. It may arise from a single point or multiple sources. Ease of control Many factors contribute to ease of control: Mobility of the pollutant. The nature, extent or duration of the pollution event and local site-specific considerations. Control at source is the most effective method. In some cases, containment may be the solution. This can form highly concentrated hot-spots. Dilute and disperse approach may be more appropriate though the persistence of the polluting substances must obviously be taken into account when making this decision Bioaccumulation Some pollutants can be taken up by living organisms and become concentrated in their tissues over time. This tendency of some chemicals to be taken up and then concentrated by living organisms is a major consideration, since even relatively low background levels of contamination may accumulate up the food chain. Chemistry Reaction or breakdown products of a given pollutant can sometimes be more dangerous than the original substance. Interaction with other substances present and the geology of the site may also influence the outcome. Both synergism and antagonism are possible. In synergism, two or more substances occurring together produce a combined pollution outcome which is greater than simply the sum of their individual effects; In antagonism, the combined pollution outcome is smaller than the sum of each acting alone. The Polluted Environment Pollution cannot properly be assessed without a linked examination of the environment in which it occurs. The nature of the soil or water which harbors the pollution can have a major effect on the actual expressed end-result. In the case of soil particularly, many factors may influence contamination effect. The depth of soil, its texture, type, porosity, humus content, moisture, microbial complement and biological activity. This can make accurate prediction difficult. The more stable and robust the environmental system, the less damaged by a given pollution. Fragile ecosystems or sensitive habitats are most at risk. The post-pollution survival of a given environment depends on the maintenance of its natural cycles. Artificial substances which mimic biological molecules can often be major pollutants since they can modify or interrupt these processes and pollution conversion can spread or alter the effect. Pollution Control Strategies  Dilution and dispersal It involves the attenuation of pollutants by permitting them to become physically spread out, thereby reducing their effective point concentration. Dispersal and dilution of a pollutant depends on its nature and the characteristics of the specific pathway used to achieve this. It may take place, with varying degrees of effectiveness, in air, water or soil. Air Good dispersal and dilution of gaseous emissions. Heavier particulates tend to fall out near the source and the mapping of pollution effects on the basis of substance weight/distance travelled is widely appreciated. Water Good dispersal and dilution potential in large bodies of water or rivers. Smaller watercourses have a lower dispersal-dilution capacity. Moving water-bodies disperse pollutants more rapidly than still ones. Soil With soil, water playing a significant part. Typically, aided by the activities of resident flora and fauna Concentration and containment Gathering together the pollutant and prevent its escape into the surrounding environment. Practical Applications to Pollution Control Contaminated land and bioremediation. Air pollution & odor control. Bacteria live normally in aqueous environments which clearly present problem for air remediation. Dissolve the contaminant in water, which is then subjected to bioremediation by bacteria. Future development of bioremediation by utilizing the ability of many species of yeast to produce aerial hyphae which may be able to metabolize material directly from the air. A variety of substances can be treated: VOCs., e.g., alcohols, ketones or aldehydes. Odorous substances., NH4 and(H2S). Mixed microbial cultures degrade xenobiotics., chlorinated hydrocarbons like dichloromethane and chlorobenzene. Biotechnology in Environmental Monitoring and Pollution Abatement In recent years, the demand for the use of sustainable and eco-friendly environmental processes is rapidly growing subjected to economic, public, and legislation pressure. Biotechnology provides a plethora of opportunities for effectively addressing issues pertaining to the monitoring, assessment, modeling, and treatment of contaminated water, air, and solid waste streams. In this context, source tracking of environmental pollutants and process modeling using biological based methods are becoming increasingly important, mainly owing to the accuracy and robustness of such techniques. The different biotechniques available nowadays, thus, represent both well-established and novel (bio) technologies, although several aspects of their performance are still to be tested. For instance, the use of novel biocatalysts and reactor designs, the understanding of microbial community dynamics and mechanisms occurring within a (bio)reactor, and the assessment of the performance of (bio)reactors during long-term operation and its modeling. If these mechanisms are understood and the barriers are overcome, novel biotechniques will potentially change the way users rebuild technologies for the sustainable use of different biological processes for wastewater, air, and solid waste treatment. Environmental Monitoring and Modeling: In developing countries, water, air, and soil pollution has become a persisting environmental problem due to rapid industrialization and urbanization. Using environmental Kuznets curve (EKC) it was observed that, during early stages of economic development in a particular region, the environment paid a high price for economic growth as the human race used technology to exploit all possible valuable resources. Nevertheless, in agricultural areas, N, P, and K compounds are easily transported by farmland drainage and surface water to valuable water resources resulting in the deterioration of water quality that warrants the use of novel biosensors to monitor water quality. Recently, it has been proposed that cellular-based biosensor technologies, that is, the bioelectric recognition assay (BERA), utilize live, functional cells in a gel matrix coupled with a sensor system that is able to measure changes in the cellular electric properties. Cells that are able to specifically interact with a target analyte produce a unique pattern of electrical potential as a result of their interaction with this analyte. Concerning modeling, traditionally, the performance of many bioprocesses has been modeled/predicted using process-based models that are based on mass balance principles, simple reaction kinetics, and a plug flow of water/air stream. An alternate modeling procedure consists of a data driven approach wherein the principles of artificial intelligence (AI) are applied with the help of neural networks [2, 3]. The concept of neural network modeling has widespread applications in the fields of applied biosciences and bioengineering. Pollutant Removal and Toxicity: Environmental pollutants such as heavy metals and pesticides are commonly present in water emanating from acid mine drainage or other industries and from agricultural runoffs. These toxic pollutants can accumulate in living organisms and produce adverse effect such as carcinogenicity and acute toxicity. Complete mineralization and/or removal of these pollutants and their toxic byproducts can be achieved using biological process that uses active bacterial/fungal/mixed microbial cultures. Microbial consortia have been shown to be more suitable for bioremediation of recalcitrant compounds such as pesticide residues, as their biodiversity supports environmental survival and increases the number of catabolic pathways available for contaminant biodegradation. In the case of heavy metal contaminated wastewaters, biosorption has emerged as a promising low-cost methodology wherein biological catalysts are employed to remove and recover heavy metals from aqueous solutions. The metal removal mechanism is a complex process that depends on the chemistry of metal ions, cell wall compositions of microorganisms, physiology of the organism, and physicochemical factors like pH, temperature, time, ionic strength, and metal concentration. Biofuels Production. Biohydrogen production through anaerobic fermentation is a sustainable alternative for managing the recent (dogging) energy crisis and creating a sustainable green environment. Fermentative hydrogen production processes are technically feasible and economically cost-competitive and have large-scale commercialization implications [6, 7]. Besides some of the pure microbial species, that can be used to produce biofuels, as of late, it was shown that microbes present in the sediments of mangroves have the capability to yield biohydrogen. Mangrove sediments are inherently rich in organic content and offer the following advantages: flexible substrate utilization and the simplicity of handling, no major storage problems, minimal preculturing requirements, and sediments being available at low cost. Alternatively, the development of (bio)energy using marine and freshwater microalgae as a 3rd generation biomass feedstock has also been explored recently because microalgae can grow fast with high specific growth rates and have excellent CO2absorption capacity and better regulation of lipid and sugar content under various culture conditions. Microalgae exhibit a high photosynthetic efficiency and a strong capacity to adapt to the environment (e.g., high salinity, heavy metal ion content, presence of toxicants, and high CO2 concentration). Microbial Products for the Environment. With increasing concern for the natural environment, biosynthetic and biodegradable biopolymers such as poly-β-hydroxybutyrate (PHB) have attracted great interest because of their excellent biodegradability and being environmentally benign and sustainable. The high production cost of PHB can be curtailed by strain development, improving fermentation and separation processes, and using inexpensive carbon source. Due to recent advancements in fermentation technology and allied sciences, alternative purification solutions are under investigation, among which microbiological ways of utilization of byproducts are very interesting and promising. Such a solution could result in better overall process productivity and facilitate the downstream processing. Concerning the use of enzymes, owing to its lignolytic enzyme system, the white-rot fungus Phanerochaete chrysosporium has been applied in many bioremediation studies. Its ability to degrade a variety of pollutants is thus related to the production of lignin peroxidase and manganese peroxidase, two lignin-modifying enzymes generally expressed under nitrogen- limited culture conditions, as well as to the intracellular cytochrome P450 system. Another practical aspect worth highlighting in this section is the use of an enhanced biological phosphorus removal (EBPR) for phosphorus removal from wastewaters. In EBPR, alternative anaerobic and aerobic phases are adopted and polyphosphate accumulating organisms (PAOs) with excess phosphorus accumulation ability can be enriched. During the anaerobic phase, PAOs take up organic carbons such as acetate and propionate and store them as intracellular polymers such as PHBs, with polyphosphate as the energy source and glycogen as the reducing power source. The metabolism of PAOs and dynamics of polymers under different organic carbon concentrations deserves in-depth examination in order to elucidate the function of polymers in EBPR. Investigating the dynamics of polymers under endogenous respiration conditions will also provide solutions for controlling and adjusting the EBPR performance under low organic carbon induced shock conditions. Eco-Efficient Bioprocesses for the Environment. Nutrient-rich wastewater streams when discharged into receiving water bodies often lead to undesirable problems such as algal blooms, eutrophication, and oxygen deficit. For such commonly reported situations in many developing countries, advanced treatment technologies cannot be applied to treat wastewater due to the requirement of high energy and skilled labor force, high operating and maintenance costs. Under such conditions, low-cost natural treatment systems can be effectively used not only for waste treatment, but also for conserving biological communities in poor nations of the world. For the (bio)treatment of slaughterhouse wastewater, sequencing batch reactors (SBRs) were recommended as one of the best options because they are capable of removing organic carbon, nutrients, and suspended solids from wastewater in a single tank and also have low capital and operational costs. In order to maintain the long-term performance of bioreactors (e.g., stirred tank bioreactor), various strategies to improve the oxygen transfer in bioreactors have been proposed, for instance, dispersing a nonaqueous, organic, second liquid-phase that is immiscible to the system. The presence of this organic phase modifies the medium in such a way that it could carry more oxygen and this approach was found successful in the past. The organic phase has strong affinity for oxygen so that it can increase the apparent solubility of oxygen in water, which in turn increases the specific activity of microorganisms, yielding high removal of target pollutant in bioreactors.