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In this work, potassium iodide (KI) and graphene oxide (GO) were utilized to promote the selectivity of photocatalytic process for alkali lignin oxidation over ZnO. Different concertation of GO was added during the microwave synthesis procedure of ZnO, and the characterization results revealed that graphene can shift the conduction band to more reducing potential, resulting to higher production of superoxide anion radicals (O2−) compared to OH. Response Surface Methodology revealed the most suitable interaction among loading of GO, KI and irradiation time on lignin and total phenolic compound (TPC) degradation. Specifically, the optimal conditions (i.e. maximum lignin (52%) and minimum TPC (55%) degradation) were at [KI] = 0.64 mM; GO content into ZnO 1.2 mg/mL; 240 min of irradiation time. The results showed that higher addition of graphene into structure of ZnO could preserve more phenolics from degradation due to less production of OH. Furthermore, the addition of KI at optimized conditions could enhance the selectivity of degradation of lignin and phenolics via producing I radicals and quenching the excess amount of generated OH, respectively. The lower generation of OH at optimized conditions was quantitatively confirmed by a photoluminescence simplified technique. In addition, the effect of the photocatalytic process on substrate's anaerobic degradability was examined in order to evaluate the suitability of the pretreated solution for energy recovery. Indeed, besides the higher TPC concentration, the biogas production of treated straw at optimized conditions was increased by 35% compared to the untreated sample. Keywords: UV/Iodide, Lignin degradation, Graphene, Phenolics

Globalization has led to a rapid rise in energy consumption, making climate change one of the world's most pressing issues. As wastewater treatment plants (WWTPs) contribute to climate change by emitting greenhouse gases (GHGs), this study estimated the total GHG emissions of WWTPs by classifying them as either direct or indirect carbon emissions. The effectiveness of the use of solar photovoltaic systems and biogas produced by WWTPs in increasing energy recovery and reducing GHG emissions was investigated. This study demonstrated that the use of an up-flow anaerobic sludge blanket (UASB) reactor with a biogas flow of 9 120.77 m3/d and an activated sludge processing system (ASPS) reactor with a biogas flow of 14 004 m3/d, in addition to the energy production from the UASB reactor (6 421.8 MW⸱h per year) and the ASPS reactor (9 860.0 MW⸱h per year), yielded a reduction of 3 316.85 and 5 092.69 t of CO2 equivalent per year, respectively. Furthermore, the co-design of wastewater processes could be utilized to optimize biogas energy recovery. Moreover, the use of solar photovoltaic systems reduced GHG emissions from WWTPs. This is important to the transition to renewable energy because it resulted in a 10%–40% reduction in carbon emissions from WWTPs. Integrating renewable energy sources, biogas, and solar energy could provide up to 88% of the annual energy requirements of WWTPs. Recommendations are provided for further research considering the limited availability of integrated resources for studying the simultaneous utilization of photovoltaic and biogas systems.

Abstract The aim of this study was to systemically evaluate how different pyrolysis temperatures (400, 550, and 700 °C) and particle sizes (1–2 mm and 63–75 µm) were influenced biochar evolution, made from urban pruning waste, during pyrolysis process and to establish their relationships with biochar potential for removal of lead (Pb), cadmium (Cd), and manganese (Mn) from real municipal solid waste landfill leachate. The effects of pH (2–7), contact time (30–300 min) and adsorbent dosage (0.1–5 g L−1) on heavy metals removal were also examined. The results showed that physicochemical properties of biochar were greatly influenced by pyrolysis temperature. Particle size, however, showed little influence on biochar characteristics (p > 0.05). The yield, volatile matter, hydrogen and oxygen contents, and surface functional groups decreased consistently with increasing pyrolysis temperature. An increase in the pH, electrical conductivity, ash, fixed carbon, and specific surface area values was also found. In biochar samples formed at high temperatures (i.e., 550 and 700 °C), Fourier transform infrared spectroscopy-FTIR studies confirmed the increase in aromaticity. Field emission scanning electron microscopy-FESEM images showed differences in the microporous structure and lower size pores at higher temperatures. Biochar pyrolyzed at 700 °C with a particle size of 63–75 µm (i.e., Lv700-63) showed the highest removal efficiency performance. Pb and Cd ions were completely removed (100%) by 0.2 g L−1 Lv700-63 at 7.0 pH and contact times of 120 and 90 min, respectively. The maximum percentage removal of Mn was 86.20% at optimum conditions of 0.2 g L−1 Lv700-63 dosage, 7.0 pH, and 180 min contact time. The findings suggests that the surface complexation, π-electron coordination, and cation exchange were the dominant mechanisms for the Pb, Cd, and Mn removal onto Lv700-63.

The goal of this study is the optimization and management of flare gases through the modification of knock-out drum HP flares. The optimization of the K.O.D. is to create a shell around it and inject water steam into the shell, so that a uniform temperature distribution has done inside the drum, so freezing does not occur, and liquid that drops inside the burner, does not burn. The result of the simulations showed that in the drainage part of the drum, humidity associated with inlet gas freezes upon entering it after pressure and temperature drop suddenly. In the drainage part of the drum and the entrance of water steam with a temperature of 438 K and relative pressure of 550,000 Pa, the freezing of the coating part of it is eliminated. Finally, the water steam with liquid water caused by the heat transfer between the steam, and the bottoms of the drum is out from its drainage part. In the following, two issues were examined. First, simulating the drum to prove the insufficient power of the electric heater at the entrance of the drum. Second, simulating the drum with its surrounding cover in order to eliminate possible freezing. As the result, this work simulated and optimized the K.O.D. flare system to reduce valuable and toxic gas which burned in the flare system and caused environmental, economic, and social effects. This modelling optimized 8 points to add optimum heat flux and used a water steam jacket to prevent the formation of a freezing zone. The optimum zone around the bottom of K.O.D. steam injected this zone and observed no ice formation occurred in this zone. The steam jacket creates uniform heating by using this design and steam injection to the outer wall of the drum. For many reasons, the implementation of this project will reduce smoke and flare pollution: Inhibition of freezing in the liquid outlet of the K.O.D., the liquid level inside the drum remains constant and prevents the transfer of liquid droplets associated with the exhaust gas to the flare.

Sludge is a by-product of urban wastewater treatment plants using a biological method, which needs to be properly processed and managed in order to avoid environmental pollution and maintain the health of society. The main goal of the current research is to analyze the amounts of sludge disposal and energy recovery in the wastewater treatment plant in south of Tehran, emphasizing the nexus between carbon and energy footprints. Biogas and electricity produced in the wastewater treatment plant were carefully examined. Their impact on reducing direct and indirect emissions and carbon footprint was calculated using relevant international coefficients based on the amount of methane gas and electricity produced. Also, the amount of waste sludge was analyzed during the period of eight years (2014 to 2021). During the investigated period, at least 2414 tons, maximum 22850 tons and an average of 7265.4 tons of sewage sludge were produced per month. The amount of waste sludge produced per million cubic meters of treated wastewater is 24.4, 99.8 and 57.1 tons, respectively. On average, 9.5 million m3 of methane are produced every year, which is equivalent to 146347.54 tons of CO2/ year. On average, 1.1 MW/hr is produced in the power plant of the treatment plant, which is equivalent to preventing the emission of 3612 to 6472 tons of CO2/ year. The total direct and indirect emissions prevented are equal to 149,960 to 152,820 tons of CO2 equivalent. The production of biogas and its consumption to produce electricity in the investigated wastewater treatment plant has a significant effect on reducing greenhouse gas emissions.

Abstract The main objective of this study was to investigate the effect of biochar on the composting process of the organic fraction of municipal solid waste (OFMSW) under real conditions. Different doses of biochar (1%, 3%, and 5%) were mixed with compost piles to evaluate the variation of temperature, moisture content (MC), organic matter (OM), carbon (C), nitrogen (N), C/N ratio, and heavy metal (HM) contents in comparison with the control treatment (with 0% biochar addition). The results of this study showed that the compost piles combined with different doses of biochar had higher MC. The use of biochar as an additive, even at low doses (1%), was able to increase the compost quality through the reduction of N losses during the composting process. The highest reduction of OM during the composting process was observed in the control pile (without biochar addition) by 48.06%, whereas biochar affected the biodegradability of OM and prevented the reduction of nutrients during the composting process under real conditions. The contents of HMs (Pb, Zn, Ni, Cd, and Cu) showed a significant reduction in all of the compost piles combined with biochar in comparison with the control treatment. Considering that in terms of all compost quality indicators, the piles combined with biochar can regarded as high standard product, the composts obtained from combining the OFMSW with different biochar doses have desirable features to be used as an amendment agent to improve agricultural soil quality.

Background: One of the most challenging and critical processes in wastewater treatment is sludge treatment. This study aimed to investigate the effects of low frequency ultrasound and high level of energy on inactivation rate of total coliform of sludge and ascertain the optimal operating parameters of the ultrasound waves.Methods: In this research, the density of ultrasound (W/mL) and time (minutes) were investigated. The effect of these parameters on the inactivation of total coliform in sludge was also investigated.Results: The results revealed that the optimum operating time and ultrasound density were 30 minutes and 2.5 W/mL, respectively. Also, the frequency of 20 kHz of total coliform removal rate in these conditions was 99.44% .Conclusion: Ultrasound waves as well as micro and nano bubbles could remove total coliform and decontaminate the sludge, thereby incrementing the rate of treatment.

Nowadays, the contamination of water resources with antibiotics are known as one of the major pollutants in the environment due to their widespread use, toxicity, causing drug resistance, and lasting effects. This study was designed to evaluate the efficiency of the advanced oxidation process of sodium persulfate activated with steel industry slag in the presence of ultraviolet rays, solution temperature, and pH aimed at eliminating the Azithromycin antibiotic from aqueous and effluent media. In the present study, the effect of the variables, including pH, solution temperature, reaction time, initial concentration of antibiotics, sodium persulfate concentration, and UV ray intensity was examined on the process efficiency. A High-Performance Liquid Chromatography (HPLC) machine was also used to measure the concentration of the Azithromycin antibiotic. According to the study results, under optimal and certain conditions in which sodium persulfate: 2 mM, pH: 2, iron ions level in the steel industry slag: 0.4 g/l, UV intensity: 8 watts, and during 60 minutes, the elimination efficiency rates of Azithromycin antibiotic, COD, and TOC were obtained as 91%, 57/4%, and 43/8%, respectively with a mineralization level higher than 55%. The rate of Azithromycin antibiotic removal was directly related to the concentrations of iron ions, sodium persulfate, UV intensity, and the temperature. However, increase in the pH from 2 to 10 led to decrease in the process efficiency from 81% to 43%, and enhance in the initial concentration of Azithromycin antibiotic from 5 to 50 mg/l also reduced the removal rate of the antibiotic from 73% to 43%. The research revealed that the advanced oxidation process of sodium persulfate activated by steel industry slag in the presence of ultraviolet rays can be used as a proper method with high efficiency to eliminate the high concentration of antibiotics found in a real sewage sample.

Today, antibiotics are known as one of the major environmental pollutants, particularly of water, due to their widespread use, toxicity, causing drug resistance and their lasting effects. This study was designed to evaluate the efficiency of the advanced oxidation process of sodium monopersulfate activated with steel industry slag in the presence of ultraviolet rays aimed at eliminating the tetracycline antibiotic from aqueous and effluent media. We examined the effect of the variables of pH, solution temperature, reaction time, initial concentration of antibiotics, sodium monopersulfate concentration, and the UV ray intensity on the process efficiency. A high-performance liquid chromatography machine was used to measure the concentration of the tetracycline antibiotic. According to the study results, under optimal and certain conditions (sodium monopersulfate: 2 mM, pH: 2, iron ions level in the steel industry slag: 0.4 g/L, UV intensity: 8 watts) and during 60 minutes, the elimination efficiency rates of tetracycline antibiotic, COD, and TOC were obtained as 98%, 61.8%, and 48.9%, respectively, with a mineralization level higher than 55%. The rate of tetracycline antibiotic removal was directly related to the concentrations of iron ions, sodium monopersulfate, UV intensity, and the temperature, while increasing the pH from 2 to 10 decreased the process efficiency from 98% to 46%; and enhancing the initial concentration of tetracycline antibiotic from 5 to 50 mg/L also reduced the removal rate of the antibiotic from 86% to 47%. The research revealed that the advanced oxidation process of sodium monopersulfate activated by steel industry slag in the presence of ultraviolet rays can be used as a proper method with effective efficiency to eliminate the high concentration of antibiotics found in a real sewage sample.

The aerobic wastewater treatments depend on the aeration. Hence, the size of the bubbles used in the aeration system may play a crucial role in this regard. This study attempted to investigate the effects of aeration bubble size on wastewater treatment efficiency of a “sequence batch reactor” (SBR) system at a laboratory scale using a novel designed fine/nanobubble forming instrumentation system. Based on the presence of microorganisms in the stationary phase, chemical oxygen demand removal efficiency on the 15th day (80.0 and 95.0%) was majorly better than on the 10th and 15th days in fine and nanobubble aeration systems. Moreover, with increasing sludge age, the “sludge volumetric index” (SVI) increased up to 170.0 ml g−1 on the 15th day. In addition, sludge rate and F/M ratio were much higher and expressively less in the nanobubble system rather than in the fine-bubbles system in which sludge was majorly denser. Therefore, the sludge was more easily deposited and the percentage of dry sludge was higher compared with the fine-bubble system. Thus, oxygen and specific oxygen uptake rate consumption were significantly reduced. The efficiency of the phosphorus removal was estimated to be between 54.0–60.0% for nanobubble aeration, compared to the general systems such as the SBR (10–20%) under similar conditions. In addition, the efficiency of the nitrogen removal in the nanobubble aeration system with different densities of 40.0, 50.0, and 60.0 ml g−1 was found as 99.0%, relatively higher compared to fine bubble with 96.0% nitrogen efficiency. In conclusion, a nanobubble aeration system could give considerably promoted efficiencies in all terms of the tested treatment effective parameters.

In this study, a novel integrated Hybrid Airlift Membrane Bioreactor (HAMBR) composed of oxic, anoxic, and anaerobic zones was developed to simultaneously remove organic matter and nitrogen from real paper-recycling wastewater. The removal efficiencies of Chemical Oxygen Demand (COD), ammonium, nitrite, nitrate and Total Nitrogen (TN) for permeate and supernatant were in the range of 88-99%, 54-83%, 70-90%, 65-95% and 61-90%, respectively. In addition, the membrane fouling was evaluated by Trans-Membrane Pressure (TMP) monitoring during the experimental period at a constant flux of 12 L/m2h,and the rate of TMP increase was 1.75 mbar/day. The results showed that the hybrid airlift membrane bioreactor can be applied effectively to the simultaneous removal of organic and nutrient from real wastewater and the performance of the membrane bioreactor was satisfactory in terms of resistance against membrane fouling phenomenon, which is an important parameter during HAMBR operation.

A hybrid silica-gel (3-glycidoxypropyl)trimethoxysilane/(3-aminopropyl)triethoxysilane magnetic graphene oxide (GPTMS/APTMS-MGO) nanocomposite was synthesized and used as an adsorbent for the magnetic removal of naproxen from water samples. The adsorbent was characterized using Fourier transform-infrared (FT-IR) spectroscopy, field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) spectroscopy, and transmission electron microscopy (TEM). The isotherm and kinetic studies showed that the data were fitted with Langmuir isotherm and pseudo-second-order kinetic models. The high adsorption capacity of 196 mg g−1 was obtained that indicated a monolayer sorption mechanism. The method was successfully applied for the removal of naproxen from wastewater samples and the removal efficiencies of 84–95% were obtained.

Low efficiency of conventional aeration techniques and the excessive production and disposal of sludge are great concerns in biological wastewater treatment systems. The present study aimed to evaluate the active sludge method using batch reactors under continuous operation to determine the efficiency of aeration and sludge production through microbubble and nanobubble aeration. The results indicated that compared to microbubble aeration, nanobubble aeration increased the concentration of dissolved oxygen in the mixed liqueur of the reactor (from 2 to 4.5 mg/l), while reducing the production of excess sludge from 100 to 40 ml/g (SRT: 15-40 d). With the same SRT duration, these values were within the range of 160-70 ml/g using fine-bubble aeration. According to the results, nanobubble aeration could increase the efficiency of aeration, thereby increasing the capacity of the treatment plant and reducing the costs of biological wastewater treatment.

Natural disasters in various forms have been identified as destructive phenomena during the life of earth planet and are also a serious threat to the inhabitants of the planet. Therefore, this issue leaded to the formation of a process called crisis management which includes activities occurring before, within and after the event to reduce the vulnerability. The country of Iran is considered as one of the world's affected countries from natural disasters due to its geographical location and climate diversity. In this research, the role of crisis management in reducing the socio-psychological vulnerability of affected citizens in 2003 earthquake of Bam city was investigated. Library and field study methods have been used to collect information in this study. Also, a qualitative-quantitative method was used to analyze the data by employing the theme method and consequently the most important factors affecting the citizen's socio-psychological vulnerabilities of Bam city after the earthquake were identified.

Background and purpose: Application of nanomaterials is growing in removing various contaminants, pharmaceuticals, and in deactivation of water or sewage bacteria. However, the ability to degrade or eliminate the genetic components of bacteria by nanoparticles and preventing the increasing trend of antibiotic resistance from sewage treatment plants needs to be further investigated. This study aimed at eliminating the genetic components (antibiotic resistance genes) of heterotrophic bacteria from wastewater by Zero Valent Iron Nanoparticles. Materials and methods: To eliminate genetic components of bacteria, the ability of nZVI was measured by cellular and molecular methods to remove the genetic components of the bacteria. Selected genes included TetW (tetracycline) Ctx-m-32 (Ceftazidime), and CmlA1 (Chloramphenicol). Polymerase chain reaction (PCR) and specific primers were used to detect resistant genes. Results: The average concentrations of HPC and ARBs were 1.68 × 105 and 2.58 × 104 cfu/mL in primary effluent. The mean values for ARGs were (TetW)=33.71 ±10.66, (CmlA1)=57.71 ±11.60, and (Ctx-m-32)=37.71 ±4.85 ng/μl after the experiments. The proposed software model for HPC and ARBs included nZVI= 20-23 mg/l, QN2=7-7.8l/min, and time=23-30 min and for ARGs it included nZVI=28-30 mg/l, QN2=7-7.8l/min, and time=30-38 min. Conclusion: Zero Valent Iron Nanoparticles can degrade and eliminate heterotrophic bacteria, and decompose and eliminate the genetic components of bacteria and antibiotic resistance genes. Unlike the chlorination units of sewage treatment plants that increase antibiotic resistance among effluent bacteria, iron significantly reduces the populations of antibiotic resistant bacteria. Compared to TetW and CmlA1, the Ctx-m-32 genes have high stability and durability against nZVI.

In order to increase the quality of industrial wastewater treatment and better manage of them, their approach should be simple and accurate for estimating process. Treatment processes for black box systems are due to the influence of many factors that involved in the system. Because of problems in using physical models, the use of statistics and regression methods could be helpful. Therefore, whatever model is simpler and less input variables so the model will be more important. Influent of the proposed model includes output data of biological unit and effluent is chemical oxygen demand of the clarifier. To compare the models performance three indicators of R-square, Correlation Coefficient(R) and Mean Square Error (MSE) are used. The aim of this study is creating linear data mining model and comparing them with similar methods for quality data. Finally, a linear robust regression with MSE = 0.089054, R = 0.784727 and R-Square = 0.6096 is proposed.

Background and purpose: Microbial desalination cells are the new technologies that can be used for wastewater treatment, desalination of seawater and electricity production simultaneously. Materials and methods: This experimental study was performed on a laboratory scale as a batch mode. The anode was flat carbon graphite that were heat treated, and the cathode was carbon cloth with 0.5 mg/cm2 of Pt on the water side and four PTFE diffusion layers on the air side. Output voltage was measured and power and current density were calculated. Changes in pH, COD, EC and chloride in the solution of the reactor vessel were evaluated and based on these changes, the parameters such as efficiency in COD reducing, the rate reduction of EC of salt-water and COD of wastewater and then columbic efficiency were calculated. Results: About half of EC in saltwater was reduced. Change percent in chloride ion in 25, 50 mM PBS and municipal wastewater was 175±21, 217±2 and 311±53 respectively. COD removal efficiency in 25, 50 mM PBS and municipal wastewater was 86±1, 80± 1and 76±4 mg / L, and the rate of COD removal was 10.74 ± 0.62, 6.95 ± 0.74 and 6.77 ± 0.25 mg / L.hr respectively. Columbic efficiency in 25, 50 mM PBS and municipal wastewater was 24±2, 51± 3and 25±0 respectively. Conclusion: Due to the significant reduction in COD and about half of the EC in wastewater, this technology can be used for municipal wastewater treatment and water desalination without the need to use energy.

Sand filters are a physical treatment unit in water treatment plants that have considerable potential for removing large suspended matter. However, these filters are somewhat inefficient in removing micro-pollutants. In this study, using waste leachate, carbon nanoparticles were coated on the silica particles to increase the surface adsorption capacity on silica substrates of rapid sand filters. The surface properties of nano-adsorbents produced by scanning electron microscopy, Raman spectroscopy and EDS test were investigated. Furthermore, the adsorption capacity of 4-Nonylphenol was examined using a new nanocomposite under different operational conditions (contact time, temperature and initial concentration) and after obtaining pHzpc, the effect of pH, total dissolved solids (TDS) and total organic carbon (TOC) on the efficacy of 4-Nonylphenol removal was tested. The adsorption isotherms in three temperature amounts of 15, 25, and 50 °C were also studied and Langmuir isotherm well fit the experimental data. To evaluate the thermal effect on the adsorption process, the thermodynamic study was also conducted. The results demonstrated that this reaction is spontaneous, endothermic and thermodynamically desirable. The experimental data also showed that the new engineered material is a good reusable adsorbent in water treatment.

Background: Considering the toxic effects of heavy metals and microbial pathogens in industrial wastewaters, it is necessary to treat metal and microbial contaminated wastewater prior to disposal in the environment. The purpose of this study is to assess the removal of heavy metals pollution and microbial contamination from a mixture of municipal and industrial wastewater using membrane bioreactor. Methods: A pilot study with a continuous stream was conducted using a 32-L-activated sludge with a flat sheet membrane. Actual wastewater from industrial wastewater treatment plant was used in this study. Membrane bioreactor was operated with a constant flow rate of 4 L/hr and chemical oxygen demand, suspended solids concentration, six heavy metals concentration, and total coliform amounts were recorded during the operation. Results: High COD, suspended solids, heavy metals, and microbial contamination removal was measured during the experiment. The average removal percentages obtained by the MBR system were 81% for Al, 53% for Fe, 94% for Pb, 91% for Cu, 59% for Ni, and 49% for Cr which indicated the presence of Cu, Ni, and Cr in both soluble and particle forms in mixed liquor while Al, Fe, and Pb were mainly in particulate form. Also, coliforms in the majority of the samples were

Arsenic which is present in the underground and surface water is one of the most toxic elements threating human health and animals. Arsenic has been removed in different type of ways. In this study Arsenic removal from drinking water and its decreasing rates were investigated by NZVI (nanoparticle zerovalent iron) to standard limit (I.e. 0.01 mg/lit) . The tests were conducted on reactor containing 100 ml water containing 1mg/L. Arsenic by virtue of Batch method. The mixture was executed in mixing was done an Oultrasnic device in order to have better mixture and complete distribution of nanoparticles in water. Then the arsenic was removed from the water by VATMAN paper of 0.45 Hm. The remained arsenic in the water was measured by ICP device. In this article the influence of the parameters including mixture time , PH ,NZVI and arcenic doses were examined . Having perfomed many tests the results showed that 1 mg arsenic can be removed 100 percent by 0.05 g NZVI in 8 min. It is possible to remove by 98 percent arsenic in 5-10 PH range. Iron nanopaticle way is an effective and rapid way to remove arsenic from water and various conditions have not considerable effect on it.

The efficiency of particle settling in tube settlers can be improved by reducing tube diameter; however, this has limits due to the clogging at low diameters. In this study, effect of reduced tube diameters on enhanced efficiency of tube settlers was investigated. This improvement was achieved by staging of the operation and reducing tube diameter in the last stage of the multi-stage tube settlers. Theoretical analysis indicated that the efficiency of tube settlers would improve if tube settlers were used in different stages in series and that if their diameter was reduced in the last stage. The predictions from the theoretical analysis were tested in a pilot study. One- and two-stage tube settler pilot plants were used to remove water turbidity caused by clay in the first and second phases of tests with and without adding coagulant, respectively. The tube diameter in the one-stage tube settler were 5.0 cm, and those in those the first and second stages of the two-stage tube settler was 5.0 and 1.2 cm, respectively. The results of both phases showed that the two-stage tube settler was more efficient than the one-stage for turbidity removal with no clogging observed because the majority of the particles had been removed in the first stage.

Phytoremediation is an emerging environmental-friendly technology that can be a promising solution to remediate oil-polluted soils. The impact of high amount of hydrocarbons on growth characteristics of burningbushand common flax was evaluated in this survey. The influence of organic fertilizers was also assessed on growth of plant species in oil-contaminated soil. Soil samples in which plants showed the best growth were analyzed for residual total petroleum hydrocarbons (TPHs) by GC-FID. Burningbush was employed for the first time in the history of phytoremediation of oil-polluted soils in this research. The two studied plant species demonstrated promising remediation efficiency in highly contaminated soil; however, petroleum hydrocarbon contamination depressed growth of surveyed plants significantly. Utilization of peat fertilizer improved plants’ growth parameters in highly oil-contaminated soil. Flax and burning bush reduced TPHs levels in contaminated soil by 87.63 and 65.29 percent, respectively, in comparison to initial concentration.

Natural organic matter (NOM) forms the group of principal precursors to organic disinfection by-products (DBPS), which have been recognized to be human carcinogens. In fact, a high TOC concentration, used as an indicator of NOM, indicates a high potential for DBP formation. The aim of the present work was to investigate the effects of nanofiltration with and without preozonation on TOC removal. Nanofiltration alone at operating pressures of 4 and 8 bars could reduce TOC levels to slightly less than 2 mgL-1, which recorded a profile of success for all the experiments. This is while preozonation at a concentration of 2 mgL-1 recorded an effluent TOC level of 3.3 mgL-1, which is not an acceptable record. Preozonation at a concentration of 4 mgL-1 increased effluent TOC to 4.2 mgL-1, which indicates that preozonation could convert NOM from higher- to lower-MW fractions, thus increasing effluent TOC. It was also shown that preozonation-nanofiltration increased effluent TOC, as compared to nanofiltration alone.

This study was conducted to investighate the adsorption of Cadmium from aqueous solutions by using the powder of excess sludge (biosolid) from municipal wastewater, at 24 to 26°C, a pH value of 2 to 6, over a contact time of 5-420 minutes, and at 50 to 300 rpm stirring rate in a batch reactor on the laboratory scale. The pretreatment of biosolids consisted of dewatering, grinding, and grainsizing with sieves (mesh dimensions between 50 and 120). According to the results, the best conditions for biosolids to adsorb Cadmium was pH=4, 120 minutes of contact time, and a stirring rate of 200 rpm. Cadmium adsorption kinetics followed the pseudo second order model. Maximum equilibrium adsorption was observed after two hours. The adsorption isotherm was in accordance with the Langmuir model. Maximum Cadmium adsorption capacity of biosolids (qmax) was estimated at 0.38 m-mol/g of dry biosolid (41.5 mg/g) and the Langmuir constant (kd) was found to be 0.1044 m-mol/lit (11.37 mg/lit).

The aim of present work was to investigate effects of the water pressure and ion compound present in water to be treated on nitrate removal efficiency of a nanofiltration membrane. Experiments were performed using sodium salts (NaNO3, Na2SO4, NaF), KNO3, Ca(NO3)2, and Mg(NO3)2 added to tap water. The effects of operating pressures were investigated for a pressure range of 4-10 bars for a nitrate concentration of 150 mg.L-1(NO3-). The effects of concentration levels were studied for the levels 50, 100, 150, 200, 250 and 300 mg.L-1(NO3-). Finally,the effects of anions were investigated for concentration levels of 50, 100, 150, 200 and 250 mg.L-1 of F- and SO42-. The results showed that nitrate removal increased with increasing pressure by up to 8 bars beyond which removal goes steady. Increased nitrate salt concentrations in monovalent salts led to reduced nitrate removal but in divalent salts led to increased nitrate removal. The effect of associated cation on nitrate removal was observed to be higher in the case of NaNO3 compared to KNO3. It was further observed that increasing sulfate ion concentrations reduced nitrate removal while increasing fluoride levels increased nitrate removal.