Bioremediation Techniques

Bioremediation Techniques Bioremediation is a remediation technique that aims to reduce or eliminate pollutants, both organic and inorganic, by using biological agents such as algae, fungi, bacteria, and plants. One of the advantages of bioremediation is that it is environmentally friendly and more economical compared to physical and chemical methods. In the bioremediation process, the waste or pollutants are converted or completely degraded into inorganic compounds such as carbon dioxide, water, and methane. Bioremediation uses biological mechanisms to reduce the concentration of pollutants or pollutants to safe levels through degradation, detoxification, mineralization, or transformation processes (Melati 2020). A. Types of Bioremediation ● Ex situ Processing is carried out in other places so it needs to be moved. The ex situ bioremediation technique involves removing pollutants from the contaminated location and then moving them to another place for remediation processes. The selection of ex situ bioremediation techniques is usually influenced by several factors, such as the cost of treatment, the severity of the contamination, the type of pollutant, the level of pollution, the geographical location, and the geology of the polluted site (Melati 2020). ● In situ Processing is carried out at the place of contamination without removal. In situ bioremediation techniques involve the treatment of pollutants directly at the contaminated site. Environmental factors such as electron acceptor status, humidity, nutrient availability, pH, and temperature also affect the effectiveness of in situ bioremediation techniques (Melati 2020). B. Ex-situ Bioremediation (1) Composting Composting is a bioremediation method that involves using a combination of contaminated soil with the addition of harmless organic waste compost, such as litter, straw, agricultural waste, and wood. This technique aims to decompose and remove pollutants in the soil naturally through the process of decomposition by microorganisms. By adding these organic matter, the microbial composition in the soil can be improved, thereby accelerating the biodegradation process and reducing the level of contamination. This allows the contaminated soil to be cleaner and more fertile. (Zafira 2021). One of the problems that can be overcome by using composting techniques is waste generated from workshop activities. Workshop activities often produce waste oil that is often dumped directly into the environment, causing soil and water pollution. Therefore, workshop activity is an indicator and has the potential to cause the risk of soil pollution. By applying the composting technique, the waste oil can be processed into compost that is safe and useful for improving soil quality. This helps reduce the risk of environmental pollution caused by workshop waste (Dewi et al. 2023). Soil pollution due to the disposal of used oil from workshops is due to the absence of a used oil waste management installation system. Used oil is categorized as hazardous and toxic waste (B3) because it is recalcitant, mutagenic, and carcinogenic in humans, has heavy metals, such as lead, iron, zinc, arsenic, cadmium, copper, benzene, toluene, ethylbenzene, xylenes known as BTEX, and Polycyclic Aromatic Hydrocarbon (PAH) compounds. This method uses several ratios and substrates (polluted soil, compost soil, and liquid fertilizer) to be used and tested for TPH parameters. The results of the study reported that soil media samples polluted by waste oil had a Total Petroleum Hydrocarbon (TPH) concentration of 0.218%. As the final stage of the composting process, TPH concentrations were analyzed on days 7, 14, 21, and 28 to monitor the changes that occurred. The results of bioremediation of waste oil for 28 days showed a significant decrease in TPH condensation. After the bioremediation process is completed, varying results are obtained. Classic hydrocarbon microbes, which are a type of microorganism that uses hydrocarbon compounds as a source of carbon, play a role in this process. Figure 1. Illustration of a reactor design scheme for bioremediation tests. (2) Bioreactor A bioreactor is a container or tank in which entire cells or cell-free enzymes convert raw materials into unwanted biochemical products and/or by-products. The objective is to study the effect of TPH (Total Petroleum Hydrocarbon) concentration and Bacillus cereus bacteria concentration on bioremediation of petroleum-contaminated land and calculate the kinetic parameters of Bacillus cereus bacteria bioremediation of petroleum-contaminated land (Tahuloula and Juliastuti, 2020). The technique used for this bioremediation is the ex situ bioremediation technique. Because ex situ bioremediation is a bioremediation process that is carried out by moving contaminants to a place to provide several treatments. Bioreactors support a biodegradation process that allows microorganisms to remove contaminants from waste with aerobic or anaerobic options. There are several types of bioretractors, namely batch, fed-batch, batch sequencing, continuous and multi-level (Tahuloula and Juliastuti 2020). The functions of the Biorector are arranged: 1. Providing alternative waste treatment technology with a bioreactor system that utilizes microbes as a reducer of harmful substances in petroleum so that it can overcome environmental pollution due to petroleum spills 2. Providing the benefits of applying bioremediation techniques in the field of environmental management and obtaining kinetic data that can then be used to design bioreactors. Figure 2. Equipment scheme (3) Biopile Biopile belongs to ex-situ bioremediation, which is a technology for decomposing contaminants by soil microorganisms by accumulating contaminated soil into a pile and providing the air, nutrients, and moisture needed by microorganisms in the soil. One of the advantages of biopile is that it can aerate according to the needs of aerobic microbes as a biological agent used and with a fairly high waste pile as long as the distribution of pipes for aeration is still possible (Munawar and Zaidan 2013). Another advantage of biopile is that it is one of the bioremediation technologies for petroleum-contaminated soil which has relatively low processing costs and is environmentally friendly, does not require a large area of land, humidity conditions and air utilization rates in the biopile can also be controlled, so that the growth and activity of bioremediation agent bacteria can be maintained. Biopiles require oxygen from the atmosphere or blowers because bacteria use oxygen during hydrocarbon metabolism. At least 2-5% of oxygen is needed in the soil to keep the biodegradation process going on (Arifudin 2020). If the soil texture is clean, then the distribution of oxygen in the biopile will be hampered. In conditions of high humidity, such as in biopiles, soil with a klei texture will have difficulty circulating air, so that the distribution of nutrients in the soil is uneven, thus affecting the growth and activity of degrading bacteria (Rasyid et al. 2021). Figure 3. Biopile process C. In Situ Bioremediation In situ bioremediation can be done with 2 efforts, namely Natural Attenuation and Enhancement which can be further divided into several methods, namely Phytoremediation, Bioventing, Bioaugmentation, Biosparging. Natural attenuation has several limitations, namely the bioremediation process lasts quite a long time because the presence of pollutant-degrading microbes in the soil is only 10% of the total microbes present. Methods in an effort to improve Bioremediation in situ: (1) Phytoremediation Phytoremediation is a bioremediation technology by utilizing plants to remove contaminants from soil and water. In the Proceedings entitled Combining the EAPR-Aeration (Electro-Assisted Phytoremediation Aeration) Process with Kiambang Plant (Salvinia molesta) for Cu and Zn Metal Wastewater Remediation, the meaning of Phytoremediation was explained again. Phytoremediation is a water remediation technique that is often used to reduce waste concentrations and environmental pollution problems. The technology does not require high costs and has the ability to remediate heavy metals such as cadmium (Cd), zinc (Zn), lead (Pb), copper (Cu), nickel (Ni) and arsenic (Ar). Phytoremediation can use accumulator plants to reduce the concentration of heavy metals in wastewater as well as soil. The Phytoremediation method described in the proceedings has advantages and disadvantages. The advantages of the Phytoremediation method are that it does not require high costs and has the ability to remediate heavy metals, while the disadvantages of the Phytoremediation method are the slow growth process of biomass and low reach of plant roots, so that the accumulation of pollutants in the plant parts is slow. The plants used in this method are Kiambang plants. Kiambang (Salvinia molesta) is an accumulator plant that is good in remediating organic and inorganic waste. Its fast-growing nature, able to grow in waters with low nutrient content, in addition, morphologically, Salvinia molesta has a relatively small leaf diameter (average 2-4 cm) but has a long root shape, fluffy and flooded into water. Based on this, it is hoped that Salvinia molesta can actively absorb pollutants, but not block the penetration of light into the waters Kiambang plants have been acclimatized and used for the remediation process with EAPR-Aeration, Phytoaeration, Phytoremediation Process. The process is carried out for 7 days for Cu metal and 4 days for Zn metal. After remediation is completed, analysis is carried out on the absorption of concentrations in the roots and leaves of plants. The leaves of the plant are cut and soaked in 10mL acetone for 24 hours then the concentration of chlorophyll in the leaves is analyzed with a spectrophotometer to determine the stress level in the plant. . Figure 4. (a) EAPR-Aeration reactor design and (b) EAPR-Aeration reactor photo. (2) Bioventing Bioventing is a minimally impactful recovery method by utilizing the activity of original bacteria and adding oxygen (air) to unsaturated soil areas. This makes the bacteria active in decomposing pollutants. In this case, it treats laundry wastewater that will be tested by molly fish as a bioindicator. The mortality rate of fish (fish mortality) is influenced by the dissolved oxygen present in the water, if the dissolved oxygen content is high then the fish can respirate properly, but if the oxygen content in the water is small, the fish cannot perform the function of the organs properly so that it causes death (Jupriyanto et al. 2021). The process of bioventing indigenous bacteria and exogenous bacteria from EM4 and applying Pistia stratiotes as phytoremediation in laundry wastewater. This plant has a good rate of metal absorption and translocation compared to normal plants when experiencing a decrease in metal poisoning. The parameters that are tested physically and chemically are pH, Temperature, DO, Color and Odor parameters. This step of the bioventing process uses an aquarium tub used for bioremediation with one inlet tub with bioventing and an outlet tub for wastewater filtration. Air is channeled into the inlet tub for nutrients bacteria, followed by laundry wastewater and Pistia stratiotes. After EM4 activation for two days, two treatments were carried out: the addition of EM4 to the first tub and no addition to the second tub. After three days, observation and measurement of test parameters were carried out after the administration of Pistia stratiotes plants, which involved rhyzofiltration, fythodegradation, and fytovolatil. The application of EM4 to laundry wastewater treatment causes parameter changes, such as a decrease in pH, an increase in DO, and a significant decrease in temperature. In addition, there was a change in the color parameters from deep white to clear white, and the odor parameter from pungent to non-pungent. This research is an ex-situ research. Ex-situ in bioremediation refers to the process of treating waste outside the source of contamination, such as in a waste treatment facility or laboratory (Irma 2020). The research was conducted at the Environmental Laboratory and Microbiology Laboratory of the Vocational School of IPB University. The material of this research is laundry wastewater taken from one of the laundry businesses in the city Bogor. (3) Bioaugmentation One of the remediation technologies with the addition of the same or different microorganisms is known as bioaugmentation. According to the journal Bioaugmentation Study to Reduce Heavy Metal Concentrations in Aquatic Areas Using Bacteria (Case Study: Mercury Pollution in the Krueng Sabee River, Aceh Jaya) Bioaugmentation is a way to improve the biodegradation process through the addition of microorganisms to the environment or polluted media. Bioaugmentation can increase the capacity of polluted media with the ability to degrade pollutants by microorganisms by converting pollutants from toxic compounds to non-toxic so as to reduce their impact on the environment. The bioaugmentation technique is very suitable for removing mercury heavy metal pollutants in river sediments by adding microorganisms in the form of bacteria. Bioaugmentation was chosen because it is an effective, cheap, easy-to-do, and environmentally friendly alternative to contaminant removal because it does not add chemicals that can pollute the environment. One of the microorganisms that can be used for the bioaugmentation of mercury heavy metals is bacteria. (4) Biosparging The biosparging technique is very similar to bioventing in that air is injected below the soil surface to stimulate microbial activity to increase the rate of degradation of pollutants from contaminated sites. (Melati. 2020). Biosparging is a bioremediation technique used with the aim of recovering groundwater contaminated or contaminated by benzene, toluene, ethylbenzene, and xylene (BTEX) (Jasmine 2020). The technique used for Biosparging is the In situ technique. In situ bioremediation is a bioremediation process that relies solely on the ability of indigenous microorganisms that already exist in the waste-contaminated environment to degrade it. This oxygen addition technique is also known as biosparging. This biosparging uses increased oxygen in groundwater, thereby increasing the rate of biodegradation of pollutants by microorganisms. The biosparging process requires the injection of low-pressure air below the surface of the water (Garcia and Purwanti 2022). (5) Reclamation Based on Law No. 4/2009, the definition of reclamation is "activities carried out throughout the stages of the mining business to organize, restore, and improve the quality of the environment and ecosystem so that it can function again according to its designation". The reclamation of former mining land is intended to restore the forest in accordance with its function. The key to the success of reclamation of ex-mining land is highly dependent on the ecological conditions of the reclaimed area. Ecological science can well explain the characteristics of former mine sites and the life that exists in them, including the types of vegetation that grow. In general, the outline of the stages of reclamation is: 1) Conservation of top soil 2) Land planning 3) Sediment management and erosion control 4) Cover crop planting 5) Planting pioneer plants 6) Heavy Metal Countermeasures. In general, reclamation carried out by mining companies today is found to have several obstacles, including requiring huge costs and technology modern, so that only large companies are able to do this and the area that is reclaimed is only a small part, is it proportional to the damaged land and the reclaimed land, and it seems that reclamation activities are not carried out seriously, it seems that it is wasted because it is constrained by the climate. Meanwhile, there are alternatives offered in the context of reclamation of ex-mining land with the concept of not requiring large costs and the reach of reclamation is wider, easier and cheaper; Namely with the concept of returning to nature or reclaiming ex-mining land biologically. (6) Polymer biodegradation Polymer degradation can occur in both aerobic and anaerobic conditions. Aerobic degradation will produce carbon dioxide and water while degradation in anaerobic conditions will produce carbon dioxide, water, and methane or H2S. The ability of enzymes produced by microorganisms to degrade microplastics is influenced by several environmental factors such as pH, temperature, weight and size of the substrate molecules. The working method is carried out by inoculating cleaned polyethylene plastic waste clippings into NA and TSA media. The incubation period is 10 days at 37⁰C. The growing colonies are then isolated and purified into the substrate to bevel NA and TSA for further testing. There are 27 types of isolates classified as genera Pseudomonas and Ochrobactrum which have the ability to degrade High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE) plastic polymers with the characteristics of bacillus form, gram negative, catalase positive and classified as non-fermentative bacteria. In addition, there is a species of Ochrobactrum anthropic with the ability to degrade HDPE by 20% and a species of Pseudomonas aeruginosa with the ability to degrade LDPE by 18.75%. Polymer biodegradation processing is carried out by attaching microorganisms to the surface of plastic that will form a biofilm. The growth of microorganisms utilizes degraded polymers as a source of energy and food (assimilation). Furthermore, polymer degradation or fragmentation is carried out through hydrolysis. Finally, the final disintegration of the polymer (mineralization) is carried out. The result of degradation causes changes in polymer properties such as producing polymer bond breaks, transformation or the formation of new chemical structure bonds (Anggiani 2020). BIBLIOGRAPHY Anggiani M. 2020. Potential of microorganisms as bioremediation agents of microplastics in the sea. Oceana. 45(2):40-49. Arifudin A. 2020. Planning of petroleum-contaminated soil tillage with biopile technique with a capacity of 2.2 M^3: tillage planning. Journal of Environmental Engineering. 13(2):85-95. Garcia AD, Purwanti IF. 2022. Bioaugmentation Study on Diesel Contaminated Groundwater in Sub-district Gedongtengen, Yogyakarta City. Jurnal ITS Engineering. 11(3). F105-F111. Gusprastomo N, Febrianto A, Wardana W, Pranoto K. 2018. Application of Bioremediation and Phytoremediation Methods in PIT Peri Low Wall Reclamation, PT Kaltim Prima Coal. 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