Amin Mojiri

Powdered ZELIAC augmented sequencing batch reactors (SBR) process for co-treatment of landfill leachate and domestic wastewater.

Sequencing batch reactor (SBR) is one of the various methods of biological treatments used for treating wastewater and landfill leachate. This study investigated the treatment of landfill leachate and domestic wastewater by adding a new adsorbent (powdered ZELIAC; PZ) to the SBR technique. ZELIAC consists of zeolite, activated carbon, lime stone, rice husk ash, and Portland cement. The response surface methodology and central composite design were used to elucidate the nature of the response surface in the experimental design and describe the optimum conditions of the independent variables, including aeration rate (L/min), contact time (h), and ratio of leachate to wastewater mixture (%; v/v), as well as their responses (dependent variables). Appropriate conditions of operating variables were also optimized to predict the best value of responses. To perform an adequate analysis of the aerobic process, four dependent parameters, namely, chemical oxygen demand (COD), color, ammonia-nitrogen (NH3-N), and phenols, were measured as responses. The results indicated that the PZ-SBR showed higher performance in removing certain pollutants compared with SBR. Given the optimal conditions of aeration rate (1.74 L/min), leachate to wastewater ratio (20%), and contact time (10.31 h) for the PZ-SBR, the removal efficiencies for color, NH3-N, COD, and phenols were 84.11%, 99.01%, 72.84%, and 61.32%, respectively.

Phytoremediation of heavy metals from municipal wastewater by Typhadomingensis

The use of plants for the removal of heavy metals from spillage sites, sewage waters, sludges and polluted areas has become an important experimental and practical approach. A study was carried out to investigate the phytoremediation of heavy metals from municipal wastewater by Typhadomingensis according to randomized complete block design (with three replications). Every Typhadomingensis was planted in pots containing 7 liter of municipal wastewater, and aeration was done. After 24 and 48 h, the samples were taken for testing. The concentrations in the root and shoot tissues were found in the order of Fe>Mn>Zn>Ni>Cd. The evidences provided by this experiment indicated that the Typhadomingensis was capable to remove heavy metals from urban wastewater. These results also showed that most metal removal from wastewater by Typhadomingensis was after 48 h.

Metals removal from municipal landfill leachate and wastewater using adsorbents combined with biological method

Different physical, chemical, and biological treatment methods are used to eliminate heavy metals and pollutants from wastewater and landfill leachate. Sequencing batch reactor (SBR) is a type of biological treatment. This study was conducted to study heavy metals elimination from urban wastewater and landfill leachate using an adsorbent, namely powdered ZELIAC (PZ) that improved SBR. PZ consists of portland cement, limestone, rice husk ash, activated carbon, and zeolite. Response surface methodology and central composite design were used to elucidate the nature of the response surface in the experimental plan and determine the optimum settings of the independent variables [aeration rate (L/min), contact time (h), and leachate to wastewater ratio (%; v/v)] and their reactions. To study the aerobic process, four dependent factors (Fe, Mn, Ni, and Cd) were evaluated as reactions. The results indicated that compared with SBR, PZ-SBR removed heavy metals more efficiently. At the optimum contact time (11.70 h), aeration rate (2.87 L/min), and leachate to wastewater ratio (20.13%) in PZ-SBR, removal efficiencies for Fe, Mn, Ni, and Cd were 79.57, 73.38, 79.29, and 76.96%, respectively.

Adsorption isotherms in landfill leachate treatment using powdered activated carbon augmented sequencing batch reactor technique: Statistical analysis by response surface methodology

Abstract Landfill leachate was treated using non-powdered activated carbon sequencing batch reactor (NPAC-SBR) and powdered activated carbon (PAC) augmented SBR (PAC-SBR) processesto examine Langmuir and Freundlichadsorption isothermsin the SBR technique.Response surface methodology (RSM) was used for the experimental design and statistical analysis.Based on the obtained results, the maximum adsorption capacitiesof ammonia nitrogen (NH3-N), color, and chemical oxygen demand (COD) for the Langmuir adsorption isotherm were 5.63 mg/g, 25.30 Pt.Co/g, and 13.21 mg/g,respectively, whereas for the Freundlichadsorption isotherm, thesewere 6 mg/g, 46.29Pt.Co/g, and 15.41 mg/g, respectively.Generally, Freundlich isotherm values for NH3-N, color, and COD were higher than Langmuir isotherm values.The NH3-N adsorption on PAC was lower than the color and COD adsorptions because a great part of NH3-Nwas biologically removed in the SBR process.Increasing aeration rate and contact times in the SBR processes increased the adsorption isotherms of NH3-N, color, and COD on PAC

Landfill Leachate Treatment by Bentonite Augmented Sequencing Batch Reactor (SBR) System

As a developing country and one of the tropical tourism industry leaders, Malaysia is faced with environmental problems, such as the conversion of municipal solid waste landfill leachate into hazardous wastewater in mega cities. High concentrations of pollutants, toxic refractory component, and complex composition of landfill leachate have serious environmental impact. This study investigated a novel rapid treatment method to remove turbidity, suspended solid, color, and ammonia nitrogen. Bentonite augmented sequencing batch reactor with miscellaneous aeration (0.5–7.5 L/min) and contact time (1–3 h) is applied via response surface methodology in 13 runs. Results of this study show that in optimum circumstances, 93.63% of turbidity, 90.42% of total suspended solid, 76.33% of ammonia nitrogen (AN), and 45.96% color were removed in only three hours. Furthermore, natural bentonite is a cost effective adsorbent for landfill leachate treatment.

Heavy Metals Phytoremediation from Urban Waste Leachate by the Common Reed (Phragmites australis)

The use of plants for remediation of soils and waters contaminated with heavy metals has gained acceptance in the past two decades as a cost-effective and noninvasive technique. In this study, the effectiveness of Common Reed for phytoremediation of heavy metals from municipal waste leachate was investigated. The plants were transplanted into pots containing 10 L of mixed urban waste leachate and water (mixed 80 percentages of waste leachate with 20 % of water; V:V) and aerated during experiments. Central composite design (CCD) and response surface methodology (RSM) were used in order to clarify the nature of the response surface in the experimental design and explain the optimal conditions of the independent variables. In the optimum conditions, the amount of removed Fe, Mn, Cu, and Ni were 25.049, 9.623, 6.112, and 0.900 mg/kg, and Translocation Factor (TF) in 24, 48, and 72 h experiment were 0.47, 0.45, 0.34, 0.38, 1.17, 0.89, 0.69, 0.42, 1.30, 1.12, 1.10, and 1.01 for each heavy metal (Fe, Mn, Cu, and Ni), respectively. The findings showed that Phragmites australis is an effective accumulator plant for phytoremediation of these metals.

Enhancing BOD/COD Ratio of POME Treatment in SBR System

Palm oil mill effluent (POME) contains high biological oxygen demand (BOD) and chemical oxygen demand (COD) Agra base wastewater is the concern of biodegradable treatment methods. Consequently, the BOD / COD ratio has a significant effect on the biodegradability of wastewaters. This study investigates effects of aerated sequencing batch reactor (SBR) system augmented by zeolite used for treatment of POME. Not only, the BOD / COD ratio increased from 0.11 in raw POME to mean 68.15% increase after aeration in the SBR system, but also, the most obvious finding to emerge from this study is that, aerated SBR could be considered as an effective method for enhancing BOD/COD ratio for qualifying post treatment by biotreatment methods.

The effects of salinity and alkalinity of soil on growth of Haloxylon sp. in Segzi plain (Iran)

This study evaluated the effects of salinity and alkalinity of soil on growth of Haloxylon sp. in Segzi plain. Segzi plain is located in the Eastern part of Isfahan province in the center of Iran and is about 40 kms from Isfahan center. The phenomena of salinity and alkalinity are the key factors in the process of desertification that are mainly created in semiarid and arid regions. One way to prevent the spread of desert areas from blowing sand is to apply the biological fixation by means of resistant plant species which haloxylon sp. is the most suitable plant for this purpose. In order to do this research, Total 10 profiles as a vertical transect were studied and from each depth profiles of 0–30, 30–60 and 60–90 cm sampling was conducted. For each soil sample, chloride ion, pH, electrical conductivity and sodium absorption ratio were measured in the extract 1:1. Plant parameters, including plant height, Top environment and Top diameter were measured. It should be noted that in the study area all of Haloxylon sp. were the same age and nearly 18 years old. After preparing the data, measure were taken to analysis and compare the statistics and averages using the SPSS software. The results showed that the effects of salinity and alkalinity of soil on growth and development of Haloxylon sp. are negative. The electrical conductivity and sodium absorption ratio in the third depth are most negative correlation with plant parameters.

Pollutant Removal from Synthetic Aqueous Solutions with a Combined Electrochemical Oxidation and Adsorption Method

Eliminating organic and inorganic pollutants from water is a worldwide concern. In this study, we applied electrochemical oxidation (EO) and adsorption techniques to eliminate ammonia, phenols, and Mo(VI) from aqueous solutions. We analyzed the first stage (EO) with response surface methodology, where the reaction time (1–3 h), initial contaminant concentration (10–50 mg/L), and pH (3–6) were the three independent factors. Sodium sulfate (as an electrolyte) and Ti/RuO2–IrO2 (as an electrode) were used in the EO system. Based on preliminary experiments, the current and voltage were set to 50 mA and 7 V, respectively. The optimum EO conditions included a reaction time, initial contaminant concentration, and pH of 2.4 h, 27.4 mg/L, and 4.9, respectively. The ammonia, phenols, and Mo elimination efficiencies were 79.4%, 48.0%, and 55.9%, respectively. After treating water under the optimum EO conditions, the solution was transferred to a granular composite adsorbent column containing bentonite, limestone, zeolite, cockleshell, activated carbon, and Portland cement (i.e., BAZLSC), which improved the elimination efficiencies of ammonia, phenols, and molybdenum(VI) to 99.9%. The energy consumption value (8.0 kWh kg−1 N) was detected at the optimum operating conditions.

Pollutants removal from synthetic wastewater by the combined electrochemical, adsorption and sequencing batch reactor (SBR)

Wastewater filtration is considered the main solution to water shortages. Here, we treated synthetic wastewater by combining treatment techniques, namely, electrochemical oxidation and adsorbent added sequencing batch reactor (SBR). One beaker with a working value of 1500 mL was applied in this contemporary study. In the upper part of the beaker, an anode and a cathode (Ti/RuO2-IrO2) were arranged in parallel for the electrochemical oxidation process. Sodium sulfate (Na2SO4) with a concentration of 2.5 g/L was added as the electrolyte. The voltage and current were set to 7.50 V and 0.40 A, respectively. Aeration was conducted at the bottom of the beaker. Then, 15% working value of the reactor was filled by activated sludge, and 85% working value of the reactor was added with synthetic wastewater. In addition, 1.50 g/L of powdered cockleshell was added in the reactor. Response surface methodology was used for statistical analysis. In synthetic wastewater, concentrations of COD, ammonia, phenols and chromium were 2500 mg/L, 2500 mg/L, 100 mg/L and 100 mg/L, respectively. pH and reaction time (h) were considered as independent factors. A total of 2430 mg/L biochemical oxygen demand, 2500 mg/L ammonia, 90.0 mg/L phenols, and 84.0 mg/L chromium were eliminated at the optimum reaction time (72.9 min) and pH (6.5). The energy consumption value was 6.5 (kWh kg-1) at the optimum operating conditions. This study indicated that this combined treatment system exhibited high performance.