فهرست مطالب فرهاد قادری

Microalgae have the potential to produce valuable substances for pharmaceutical purposes as well as serve as a food source, providing bioactive compounds and ingredients for cosmetics. However, harvesting microalgae is a crucial step in the mass production of various high-value products derived from microalgae. This process often becomes a major bottleneck in downstream processing. It is essential to find effective and cost-effective harvesting methods for industrial applications. Among several harvesting methods, magnetic flocculation offers the benefits of modest operation, energy savings, and quick separation. This study investigates the harvesting process of Chlorella sorokiniana pa.91 microalgae using a novel flocculation process involving nano-Fe3O4 coated with PACl. In this research, we have used the chemical co-precipitation method to prepare nanoparticles. Using the response surface method to optimize the most important parameters of the magnetic flocculation harvesting process to check the microalgae removal efficiency, three variables of time, concentration of nanomaterials, and pH in the culture medium obtained from municipal wastewater have been investigated. The results demonstrated that the highest harvesting efficiency, nearly 90%, was achieved under the conditions of 3.5 g/L Fe3O4, a constant concentration of 0.075 g/L PACl, a harvesting duration of 40 minutes, and a pH level of 4. On the other hand, the lowest microalgae harvesting efficiency was observed under specific conditions: a composite nanoparticle concentration of 0.5 g/L per liter, a harvesting time of 27.5 minutes, and a pH of 6.5 resulting in a mere 22% efficiency. The rate of microalgal removal increased from 53% in the most alkaline condition to 75% in the most acidic environment. The highest harvesting efficiency, reaching 80%, was achieved under neutral pH conditions with a settling time of 53 minutes. Furthermore, the investigated combined method investigated enhances the flocculation effectiveness of microalgae. Based on the findings, it can be inferred that the efficiency of microalgae harvesting rises with longer duration, higher nanoparticle concentrations, and lower pH levels

The purpose of this study is to analyze the environmental risks of soil erosion in the runoff of the Shahid Rajaei Dam in Sari based on GIS and remote sensing approach. In this study, soil erodibility was assessed based on the global model of soil loss called RUSLE with rainfall erosion input parameters, soil erodibility, topographic factors: length and slope, land cover management, conservation operations. For this purpose, before producing the results of these factors, first the input data such as DEM, slope, geological layer, land use layer, precipitation, soil and vegetation index was prepared and their spatial distribution pattern in the study area was described and analyzed. In the next step, the potential for flooding and runoff production was measured using the criteria of distance from waterways, drainage density, slope, slope direction, land use, rainfall, geology, soil type. In this regard, while fuzzy the layers, different variables were applied in order to integrate the mentioned layers in the final step on the production of flood potential map and runoff production. After producing the main layers, namely flood potential and runoff production, soil erodibility was studied using Pearson correlation test and regression model of the relationship between these factors and the results were discussed. The results of this study showed that remote sensing and GIS techniques in combination with field measurement values of the studied parameters can have many applications in the field of environmental studies in the field of civil engineering and in modeling and estimating environmental parameters. Be very beneficial bio.

Industrial progress has ushered in the production of a diverse array of pollutants, encompassing both organic and non-biodegradable substances, such as hydrocarbon compounds derived from petroleum. As the discernible environmental ramifications of these pollutants continue to escalate, the quest for efficacious methodologies for wastewater remediation assumes paramount importance. Among the emergent technologies, plasma technology has garnered considerable acclaim due to its capacity to obliterate a myriad of pollutants. Plasma, which ensues from the application of high voltage to either a gaseous or liquid medium, engenders profoundly reactive species capable of dismantling intricate organic compounds. Similarly, ozone, an exceedingly potent oxidizing agent, has long commanded recognition for its aptitude in the degradation of pollutants. Its robust oxidative attributes render it an invaluable instrument in the realm of wastewater treatment. Ozone treatment entails the infusion of ozone gas into the contaminated aqueous medium, whereupon it engages pollutants in a transformative reaction, rendering them into less deleterious byproducts. By amalgamating the ozonation process with plasma technology, we can harness the merits of both modalities and achieve synergistic effects. This hybridized approach proffers several advantages vis-à-vis individual treatment methodologies, including augmented pollutant removal efficiency, diminished treatment duration, and amplified energy efficiency. The plasma-ozonation process exploits plasma's propensity for the generation of reactive species, capable of reacting with the organic constituents in wastewater. The ensuing ozonation phase augments the degradation of these constituents, engendering a more efficacious and comprehensive removal process. Prior investigations have scrutinized the efficacy of ozone and plasma in isolation for the eradication of p-nitrophenol, a ubiquitous organic pollutant encountered in industrial wastewater. These inquiries have methodically examined various parameters to ascertain their influence on pollutant removal efficiency. Factors such as applied voltage, ozone dosage, initial pH, reaction duration, and initial solution concentration have been subjected to meticulous scrutiny to optimize the treatment regimen. In the present study, we have devised an innovative mathematical model to probe the interplay between these two independent variables: plasma technology and ozonation. The model incorporates a quadratic equation and employs analysis of variance (ANOVA) to gauge the significance of each variable and discern the optimal conditions for pollutant removal. Through scrutiny of the model, we have ascertained that the pinnacle of removal efficiency, surpassing 95%, materializes under specific parameters. These parameters encompass an applied voltage of 14 kV, an oxygen flow rate of 6 L/min, an initial pH of 10, a reaction duration of 6 minutes, and an initial concentration of 200 mg/L. These revelations offer valuable insights into the operational parameters that yield superlative results for pollutant removal within the context of the plasma-ozonation process. The efficacious integration of ozone and plasma technologies in wastewater treatment proffers a promising panacea for the elimination of p-nitrophenol pollutants and sundry other organic constituents. By fine-tuning the process parameters in alignment with the model's recommendations, we can attain exceptional levels of pollutant elimination whilst concurrently minimizing energy consumption and treatment duration. This research significantly contributes to the perennial endeavors aimed at fashioning sustainable and efficient remedies for industrial wastewater treatment, endowing valuable perspectives for their future deployment and widescale application in industrial settings.

Offshore produced water (OPW), a type of wastewater rich in hazardous compounds such as polycyclic aromatic hydrocarbons (PAHs), requires effective treatment. This study presents a novel methodology utilizing TiO2 nanoparticles, ultraviolet (UV) lamps, and ozonation for the degradation of phenanthrene (PHE) from OPW. Various factors including UV lamp power (10W-50W), ozone dose (0.1 mg/L-0.5 mg/L), TiO2 concentration (0.5 g/m²-2.1 g/m²), ethanol fraction (25%-85%), pH (4.5-10.5), PHE initial concentration (5 mg/L-25 mg/L), and treatment time (15 min-45 min) were systematically investigated to understand their impact on PAH degradation in the OPW. The study employs Response Surface Methodology (RSM) for modeling and optimizing PHE removal efficiency. The results contribute to the development of a mathematical model, and through optimization, optimal conditions are proposed to maximize PHE removal efficiency. Experimental implementation of the optimized conditions in a physical model resulted in an impressive 98% PHE removal efficiency. The identified optimal conditions include UV lamp power of 40 W, ozone dose of 0.5 mg/L, TiO2 concentration of 2 g/m², ethanol fraction of 25%, pH of 5.2, initial PHE concentration of 15 mg/L, and a treatment time of 40 min. This optimized approach provides valuable insights for efficient and environmentally friendly treatment of PAHs in OPW, emphasizing on the potential for practical application in soil washing effluent treatment.

The biological treatment process is considered the most important method in wastewater treatment. The role played by a Biological treatment reactor is to prepare suitable conditions for biological growth of bacteria to remove the contaminants. Various types of reactors (attached growth (biofilm) and suspended growth) are used in biological treatment of wastewater. Moving bed biofilm reactor is the most important of biofilm reactors. Moving bed biofilm reactor (MBBR) was used rare for treatment of wastewater containing petroleum component like as produce water. In this research, MBBR was used for investigation of removal efficiency of crude oil component, those are in produce water.

The pHotocatalytic process is one of the most used chemical process in wastewater treatment. Proposing a method for decreasing treatment cost is one of current challenges in this field. The cost of wastewater treatment depends on the pollutant degradation rate. The kinetic parameters are the main indicators of the pollutant degradation pace in the pHotocatalytic processes; and the kinetic parameters of the pHotocatalytic process depend on various factors. Factors affecting the kinetic parameters of a pHotocatalytic process include hydraulic parameters and the pHysical properties of the pHotoreactor, that for the first time, those effects were investigated in this research. Titanium Dioxide was used for the pHotocatalytic process. The independent variables of pollutant initial concentration, flow rate, pH in the step pHotoreactors with different pHysical properties (slope and step heights) were studied. The differential method were used in this research for determining the kinetic parameters based on the laboratory data.

In the past few years, with the advances made in the production of geosynthetic products, the use of these products in the pavement reinforcement has increased dramatically. Among the geosynthetic products, geocell improves the performance of the pavement due to the proper 3D confining of aggregates materials inside its cells. In order to investigate the effect of base layer reinforced with the geocell, six different geometries with reinforced and unreinforced base layer were simulated in ABAQUS finite element software. The behaviour of aggregate base and subbase layers were consirdered nonlinear which is implemented in ABAQUS by a FORTRAN subroutine. In the next stage, the results of the ABAQUS program as well as FORTRAN subroutine were validated using the results of KENLAYER and MICHPAVE programs as well as a full scale test. The results showed that the results of the ABAQUS program are consistent with results of other programs and also with the results of the fieled test. According to this research, by reinforcement of base layer using geocell, the surface deflection responses decreases betwen 5 to 10.28%, the tensile strain responses at the bottom of the asphalt decreases between 7.15 to 12.24% and the vertical compression strain on the top of subgrade decreases between 5.1to 9.19%. Also, the damage analysis was conducted based on the Asphalt Institute relations and results showed that the reinforcement of base layer increase asphalt fatigue life by 21.68-34.94% and subgrade rutting life by 20.89-35%.

Environmental problems in tourist places is one of the major problems of tourism industry, also air pollution in tourist areas is one of the most important environmental problems. Tehran is capital of Iran and it has plenty of tourist sites. The air pollution has hit the tourism in this city. Therefore, this research was carried out for modeling, control and manage of air pollution in Tehran. Based on the previous models presented for air pollution management, the possibility of simultaneous prediction of pollution based on time and place variables has been less considered. Therefore, in this research, for the first time, a spatial-temporal model for pollution management in Tehran was presented. In this research, the spatial model in the GIS environment for each pollutant was defined. Then, based on a Python program, modeling by neural networks in GIS environment for each pollutant at each arbitrary location of the city was implemented. According to validation of model, error values were acceptable. This research model can predict air pollutants, and therefore tourism desirability of each cities point can be estimated based on air pollutants concentration.

Astrazon Red GTL is one of chemical dyes that vastly used in various industries. According to effects of this dye, degradation of wastewater containing Astrazon Red GTL is vital. According to previous researches, suspended microorganisms reactor is one of economically methods. suspended biofilm microorganisms reactor can reach to optimal efficiency in suitable retention time. In this research, for the first time, two cylindrical reactor was used and a new reactor was designed and called as “circulating feed biofilm reactor”. Every of these cylindrical reactors had 2.75 litter volume, 10 cm area and 35 cm height. In this research “circulating feed biofilm reactor” was used for growing of mixed culture microorganism containing Bacillus and Aeromonas. This reactor was used for treatment of Astrazon Red GTL wastewater. In “circulating feed reactor”, two independent variables including retention time and input concentration of pollutant were measured and the effect of each variable were studied on the removal percentage of dye. Following that, modeling and determining the optimum conditions for operating the FB/FFMBBR was carried out based on Response Surface Methodology (RSM). The results showed that the optimum condition occurred at retention time of 6.21 h and input dye concentration of 74.77 mg/l. Based on this research, retention time has the greatest impact on the removal efficacy of this biological system.

The use of unconventional water is very effective in solving dehydration problems. The studies on these sources have shown that concentrations of some pollutants are higher than standard, but by employing different methods the researchers would eliminate the pollutants. The use of photocatalyst is a novel method for removing pollutants from aqueous solutions(Ehrampoosh et al., 2011, Konstantinou and Albanis, 2004).In this research, the photocatalytic process of titanium dioxide stabilized on the surface of plexiglass in the removal of phenol in different pH levels (3, 7 and 11) and different powers of ultraviolet radiation (25, 50, 75 and 100 watts) was comprehensively investigated.

Water resources pollution with petroleum hydrocarbons is one of the most important problems in clean water supply for drinking and sanitary purposes. In this study, the simultaneous reduction of salinity and PAH (benzene and toluene) from the contaminated water has been investigated with membrane process (Forward Osmosis) coupled with photocatalysis. The amount of membrane flux, and the treatment efficiency of toluene and benzene through three various membrane including PES, CTA and CTA/TiO2 have been investigated. Based on the results from three types of membrane, the amount of toluene and benzene removal in combined method has been seen 74% and 41% respectively. Also, membrane surface modification with nano-photo catalyst particles has reduced membrane fouling; moreover, the membrane surface has increased membrane flux, and removed benzene and toluene from feed water.

Determining the long-term qualitative conditions for water resources is very important in areas facing water shortage. By determining the quality of water resources, it is possible to examine the sustainability of resources and its importancein long-term planning. Iran is also considered to have a shortage of water due to its geographical location, including arid and semi-arid regions. Therefore, in this paper, determination of the quality of water resources of fertile plains around Musan village in Iran was studied.For this purpose, the data of watershed and aquifer were collected during 10 years period and the outlyingdata was removed using the box diagram.Statistical analysis carried out in Student'st-distributionat confidence levelof 95% showed that the maximum amount of hardness, TDS, EC, Ca, NO3, HCO3, SO4, CL, Mg and Na in the Telezi River are 70.5, 124.5, 201, 91.1, 7.5, 82.3, 15.2, 11.7, 3.8 and 14.9 mg/liter, respectively. According toWHO and the drinkingwater standards of Iran (No.1053), it can be used for drinking. This analysis also demonstrated the appropriate quality of groundwater resources. Based on the long-term collected data, changes in quality trend of the catchment and aquifer were investigated, which based on the Mann-kendall test, the decline trend in quality for all parameters of the catchment (except SO4and Mg) was obvious at 5% significance level, while in the aquifer, just reduction in the TDS quality of the groundwater resources was observed. According to the similar results between the catchment and aquifer, the hypothesis based on the relationship between these resources was raised which investigated by the finite element method. It was found that the aquifer of the plain has been influenced up to the high of 70 meters from the watershed.

Humankind’s demands on the biosphere were in a balance with the Earth natural resources, until the middle of 20th century. Ever since the natural resources increasingly exceeded the supply, and caused environmental destruction and ecological unsustainability (Szigetia et al, 2017). These environmental issues raised the concerns and made the sustainable development concept (He et al, 2016). Sustainable development states a long term development strategy, which considers the future generation needs for development. This kind of development should be the foundation of every region development, thus the protection of environment will be insured. Unsustainable development in a region will reduce biocapacity, jeopardize the environment, and it will cause a number of irrecoverable damages (Sardarabadi et al., 2014). Sustainable development could be assessed through various methods. The presented approach, evaluate the sustainable development of zone 22 of Tehran by calculation of Ecological Footprint. The Ecological Footprint is an accounting tool used to measure mankind’s demand for natural services and biocapacity is the natural ability of an ecosystem to regenerate those services (Wackerngel and Rees., 1996). Since 1961 the balance between biocapacity and Ecological Footprint of Earth has been lost (Ecological Footprint Atlas, 2016). Moreover, with the climate change caused by massive carbon emission (CO2 concentration changed from 270ppm to 400ppm since the industrial revolution), biocapacity is reducing more than before. Global consumption trends reduced the Earth biocapacity to 1.8 Global Hectares and raised the average Ecological Footprint to 2.7 Global Hectares. This peculiar situation leads the world to unbearable ecological condition (Ecological Footprint Atlas, 2016).
Methods and material: Study of sustainable development in Tehran zone 22 is the main aim in this research. The assessment is based on the calculation of Ecological Footprint and biocapacity metrics. Ecological Footprint is the overall usage of natural resources and the generate waste. EF is equivalent to consumption of water, land and all the use of other environmental services, in addition to released carbon and generated waste caused by this consumption. According to the assumptions and as the initial definition, the Ecological Footprint is obtained by dividing the annual demand of one product into its annual efficiency. Also, the Ecological Footprint unit is the Global Hectare. To obtain the world hectare, which depends on the efficiency coefficient (the average national efficiency of each hectare of land to the average global efficiency of that type of land) and the equilibrium coefficient (representing the relative productivity between water and land types), the amount of consumption of each person, Per ton per year, is divided into the final limit of the earth or the water zone, then the amount that is consumed or contaminated is the desire amount, which is called the world hectare. The biocapacity means the ability of the fertile land, which includes natural biotic areas that are used to produce consumable resources, and also to receive waste and residues from their consumption. To calculate the biocapacity, the efficiency coefficient and the equilibrium coefficient for each type of region of the earth is multiplied by its area. It should be noted that each of the zones of forest, pasture, farmland, built and sea, has it specific efficiency coefficient and equilibrium coefficients. Scientifically, when the two parameters are equal, the development of a region is stable. To calculate the biocapacity, two Google Earth and Arc GIS software were used and the area of available regions was calculated for each land use.

The difference between the amount of Ecological Footprint and biocapacity determines the level of instability in the area; so, if this difference is high, the development of the region is an acute and very concerning. According to the results obtained in this study, carbon footprint with a total amount of 2.57 units per world hectare, compared to land, forest, pasture products, agricultural products and seafood, which were 0.09, 0.11, 0.41, 0.83, and 0.1 world hectares respectively, are significant. Also, according to the results obtained in region 22 of Tehran, the distribution of carbon in the commodity sector is the highest in terms of the area and type of use per unit of world hectare. It is approximately 0.8 and this is a threatening. In transportation sector, the services and construction, which include the next higher values, are 0.62, 0.6 and 0.43 world hectares respectively, all of which cant be ignored. Finally, the carbon footprint in the food sector is considered to be 0.12 world hectare, and has less rank and actually less vulnerable than the other factors mentioned, but it needs to be considered fairly. In the following, comparing the Ecological Footprints of This region with other major parts of the world, the location of Tehran's 22nd region, after Kyoto with 2.38, Campo Grande with 3.14 and Hong Kong with a value of 4 world hectares, which is equal to 4.11 world hectares, Sao Paulo, New York, San Francisco, Ontario and Calgary have values of 4.38, 6.1, 7.1, 8.4 and 9.86 world hectares, respectively, have a higher Ecological Footprint than Tehran's 22nd area, and the Ecological Footprint of all cases are higher than the acceptable global limit for the Ecological Footprint of the world, and this is a threat, and it is required to take action to reduce and perhaps eliminate the damages. Biocapacity of Tehran's 22nd district, which includes the total capacity of all areas, was estimated at 5549 world hectares. By dividing this amount into the population of the region in 2015 (equal to one million and one hundred thousand), biocapacity was estimated at 0.005 world hectares per capita. By comparing it with Iran, Asia and the world, it was determined that Tehran's 22nd region has a much lower capacity than the mentioned ones. To estimate the Ecological Footprint of the 22nd district of Tehran, population density and information related to lifestyle were used and the rate of this parameter was 4.1 world hectare per capita. Comparing the Ecological Footprint of the 22nd district of Tehran with the average of this index in Iran (2.67), Asia (1.8) and also in the world (2.7), it was determined that the 22nd district of Tehran has a more Ecological Footprint amount than all these. There is a need to reduce the Ecological Footprint by changing the pattern of life and reducing population in the region.

Cause of immoderate difference between Ecological Footprint and biocapacity in this region it’s accurate to assess the development, in an unsustainable situation. The main reason of this difference is lack of infrastructures in zone 22. With two times more population than master plan, biocapacity is less than half of the predicted amount. As a region with high mid-income level, in case of mismanagement Ecological Footprint of Tehran zone 22 could reach to 6.2 Global Hectares. Zone 22 needs an immediate management on population density with decrease in urban construction, especially near the Chitgar artificial lake. It worth mentioning that Ecological Footprint decrease is an achievable goal. Germany was successful to change the people Ecological Footprint from 6.8 Global Hectares in 1990 to 5.2 Global Hectares in 2012.

In this research, treatment of wastewater containing azo dye of acid orange 7 was investigated. According to low capability of conventional photocatalytic process in treating colored wastewater in comparison to ozonation, and high ability of ozone in discoloration, system of ozonation/ photocatalytic processes was used for treatment. Nano TiO2 was used as photocatalyst. The effect of pH (3, 5, 7, 9) and initial concentration (5, 35, 50 mg/L) on removal efficiency of organic pollutant was investigated by ozonation/photocatalytic system and phtocatalytic process. An experimental design based on the response surface method was applied to assess the optimum level of operating parameters on the treatment energy consumption in textile industry wastewater. Based on experimental design data, optimum conditions were achieved at 2.95 day of retention time, pH of 5, ozone injection rate of 1.2 g/h, 128 mg/L of nano TiO2 and 120 Wt UV-A light source.

Most of dyes used in production processes caused serious environmental pollution when discharged into the environment. Azo dyes are the most used synthetic compounds in the textile، food، leather and cosmetic industries. Due to their toxicity and hard degradation، these kinds of compounds are classified as environmental hazardous materials that have to be treated before discharging to the environment. Acid orange 7 (AO7) is one of azo dyes that is resistant to aerobic degradation and under anaerobic condition is reduced to potential carcinogenic aromatic amines. Different physical methods such as adsorption، ultrafiltration، reverse osmosis، coagulation and electro coagulation are widely used for efficient dye removal but they just transport contaminants from water to sludge and generate secondary wastes which need more treatment. Advanced oxidation processes (AOPs) are suitable to mineralize dye wastewater. They are almost characterized by the efficient production of hydroxyl radicals. Radicals are highly reactive oxidant. Ozonation and photocatalytic treatment are often applied for decolorization of dye wastewaters. It is reported that ozone is an effective agent for reducing the color of wastewater especially azo dyes. TiO2 photocatalytic process is safe and does not require expensive oxidants، against ozonation. This process classified as an AOP method and can be carried out at mild temperature and pressure. The purpose of this study was to investigate hybrid photocatalytic and ozonation processes. Therefore، according to debarment of light penetration in dye wastewater، decoloration ability of ozone was used for improving photocatalytic process efficiency in a hybrid process. The effect of pH، dye and nano catalyst concentration، irradiation source power and ozone injection rate were investigated on removal efficiency in this process. Dye removal efficiencies decreased with increase in dye concentration and decrease in pH، ozone injection rate، catalyst concentration and irradiation source power. Optimum conditions of the process was occurred in pH of 9، UV-A lamp of 120 W، and nano material concentration of 128 mg/L with 50 mg/L of dye concentration and 20 mg/min of ozone injected (with 1 bar pressure and 1 lit/min of gas flow). In these conditions، dye removal was completed after 65 minutes. The result confirm the cleavage of the azo bonds، benzene and naphthalene rings as a result of treatment. The intensities of the absorbance peak at 485nm decrease rather fast than 230 and 310 nm. This shows that faster degradation of azo band in comparison with benzene and naphthalene rings. GC-MS analysis was performed to identify the intermediate products of process. According to GC-Mass test، 5-amino-1-naphthol، 1-naphthol and benzene compound (phenol، aniline and phthalic acid) were in decolorized solution. These compounds concentration increased in the first hour and then decreased. 3 and 7 hour were needed to reach optimum condition for removing naphthalene and benzene compounds، respectively. Reaction was followed by first order kinetic and was fitted to langmuir–hinshelwood model in optimum condition in all cases. First order reaction rate of decoloration (K) decreased with increase in dye concentration and decrease in pH، catalyst concentration and irradiation source power.

Formaldehyde is used in many industrial activities such as adhesives, resins, paper producing and pharmaceutics industries. Due to formaldehyde toxicity for microorganisms, aerobic biological methods were less studied for its treating. Chemical and anaerobic biological methods are often applied for treating wastewaters containing formaldehyde. Recently, some methods such as Fenton and photo-Fenton, photo catalytic degradation, combination of chemical-biological and anaerobic-aerobic biological have been investigated. In this research, formaldehyde removal efficiencies using aerobic biological treatment systems including moving bed biofilm reactor (MBBR) and sequencing batch airlift reactor (SBAR) were compared.Temperature, pH, and dissolved oxygen were adjusted every 6 hours for preparing suitable condition for microorganisms activity. Mixed liquor suspended solid and sludge volume index were measured daily. COD, BOD5, granular diameter, and velocity settling were used for illustrating reactors situation. All of the experiments were accomplished in accordance with the instructions presented in the "Standard Methods for the Examination of Water and Wastewater" [1]. After investigating all methods, the best one was selected regarding to the laboratory facilities. Removal efficiency was determined using COD results. COD removal efficiency The results showed both systems can be used for treating formaldehyde wastewater in low concentrations. The most removal efficiencies were 100% that occurred in concentration of 100 mg/L (Fig. 2). The results of this research in pilot scale showed both systems were capable in removing formaldehyde from wastewater in concentration of less than 300 mg/L with a 24-hour retention time. SBR and MBBR systems can be used as pretreatment units for the treatment of formaldehyde CODs more than 500 mg/L. 5.