Efficiency of the Combined Chemical Precipitation -Reduction Process to Remove Dye and Chromium from Industry Wastewater of Home Appliance

Background: Industrial wastewater is one the most important pollutants of environment. This study aimed to evaluate the efficiency of the combined chemical precipitation-reduction process for removal of dye and chromium from wastewater of home appliance factories. Methods: This experimental study was performed in laboratory scale on wastewater from the dying unit of the home appliance factory. The process used was a combination of the chemical precipitation-reduction process. Combine sampling was done and 214 samples were analyzed. COD, dye, and chromium were measured in samples. MgCl2, Polyaluminium Chloride (PAC), and FeCl3, cationic polymer and bentonite were used for chemical precipitation; and sodium meta bi sulfite was used for chemical reduction. Data were analysed by ANOVA and Tukey tests and by SPSS 16 software. Results: The results show that PAC had the highest color removal efficiency (90.92%). Also, the highest COD removal was related to the combination of magnesium chloride (1.4 mg/l), poly aluminum chloride (0.6 mg/l), and the coagulant aid cationic polymer (0.4 mg/l) with an efficiency of 89.11%. Moreover, total efficiency of the combined chemical precipitation and reduction process in chromium removal was 94%. Conclusion: The chemical precipitation- reduction process as a pre-treatment method has high efficiency in removal of COD, dye and chrome from wastewater of home appliance factories

The Efficiency of Peroxone Process in Packed Reactor for Removal of Anionic Surfactants and COD from Carwash Wastewater

Background: Carwash is an industry that consumes large amounts of water and its wastewater contains a variety of pollutants. The aim of this study was to investigate the efficiency of the Peroxone process as a method for wastewater treatment of carwashes. Methods: This study was conducted at laboratory scale. A total of 54 samples were collected from a carwash in Yazd city and COD and anionic surfactants removal percentages were respectively determined by using the standard vial and anionic surfactants method and Methylene Blue Active Substances (MBAS). The process was conducted with an ozone dose of 0.7 mg per min, H2O2 concentrations of 10, 20 and 40 mmol per liter, reaction times of 30, 60 and 90 min and pH of 7, 9 and 11 in a cylindrical reactor respectively. Data were analyzed using ANOVA and through SPSS 18. Results: The removal efficiencies of COD and anionic surfactants increased with increasing pH and reaction time; so that, at pH =11 and after a reaction time of 90 minutes for an ozone dose of 0.7 mg/min and H2O2 concentration of 40 mmol/l, removal efficiency of COD and anionic surfactants were respectively 74.77% and 74.27%. Conclusion: The peroxone process has a good ability for removal of COD and anionic surfactants. Similar studies confirm the findings of this study. Meanwhile, pretreatment methods are recommended for further evaluation of this process

Investigating the Concentration of Heavy Metals in Bottled Water and Comparing with its Standard: Case Study

Introduction: Today, bottled waters have attracted the assurance of consumers as one of the important drinking water supply resources, such that in some regions, the use of bottled waters has replaced the drinking water distribution system. The present study was carried out with the aim of measuring and determining the heavy metals in bottled water across a number of brands produced in Iran and comparing it with the drinking water standard. Materials and Methods: In this descriptive-cross-sectional study, two different brands of bottled water were randomly sampled from the supermarket. To measure the heavy metals of interest, the samples were concentrated and then the concentration of some heavy metals such as copper, zinc, nickel, iron, aluminum, lead, and cadmium ions were measured by atomic absorption spectrophotometer. The mean concentration of ions was calculated in each brand and then compared with amount of standards. Results: Brand No. 1, the concentration of zinc ion was larger in Brand 2 while in Brand No. 2 had larger copper, nickel, and aluminum ions. The results indicated that the concentration of the measured metal ions were below the allowable limit of drinking water standard across all of the studied samples. Conclusion: Based on the obtained results from the investigated parameters, it can be concluded that the bottled water of both brands poses no health issue and is drinkable. Considering the changes in the concentration of ions and the increasing trend of consumption of bottled waters, their monitoring and qualitative control of pollutants are very crucial in terms of public health

Determination of a Statistical Model to Predict COD and TKN from the BOD5 and NH4+ Results

Introduction: The development of an appropriate model for the quality control of an industrial wastewater treatment system can save the time as well as the cost. This study was performed to determine an appropriate model in order to predict the COD and TKN parameters by BOD5 and NH4+ in the Meybod industrial estate wastewater treatment plant (WWTP).  Materials and Methods: This descriptive – analytical study was performed on 120 samples of the influent and effluent of the industrial estate wastewater treatment plant in Jahan Abad, Meybod, Yazd in 2015. The studied parameters were BOD5, TKN, COD, and NH4+. After measuring, they were imported to SPSS and Excel software to determine the relationship between them and then the linear regression model of the statistical method was used. Results: The predictive results of COD values on the basis of BOD5 in the regression model showed that the coefficient of determination was 0.88 and the correlation coefficient was 0.93 (p = 0.00) for this relationship. The prediction of TKN values on the basis of NH4+ in the regression model showed that for this relationship the determination coefficient of TKN and NH4+ influent parameters was 0.87 and the correlation coefficient was 0.93 (p = 0.00). Conclusion: This study represented that using the linear regression model for predicting COD and TKN values through BOD5 and NH4+ was in close accordance with the laboratory data and can thus be applied when the Meybod industrial estate WWTP faces time limitations or sampling problems

The Efficiency of Typha Latifolica in Subsurface Flow Constructed Wetland for Wastewater Treatment

Background: Natural methods of wastewater treatment, such as wetlands, are simple, cheap and acceptable for developing countries, especially small and remote cities. The aim of this study was to evaluate the efficiency of Typha Latifolica in subsurface flow constructed wetland for wastewater treatment. Methods: In this experimental research, the efficiency of Typha Latifolica in subsurface flow wetland for removing chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), nitrate-N (NO3-N), ammonia-N (NH3-N), orthophosphate (PO4-P), total coliform and fecal coliform was evaluated in Yazd, Iran. Two reactors (without the plant and with plant) were made, as pilot study, by subsurface flow constructed wetland with the dimensions of 2 × 1.5 × 0.6 m and with a retention time of 4 days. In two months, samples were taken from the incoming and outgoing flow of the reactors and were analyzed according to standard methods. Results: The efficiency of Typha Latifolica wetland for removing COD, BOD5, TSS, NO3-N, NH3-N, PO4-P, total coliform and fecal coliform was 72, 72, 85, 31, 25, 40, 94 and 59 percent, respectively, via 44, 34, 77, 15, 0.3, 1, 17 and 29 percent for the control weland, respectively; all the differences were statistically significant, except for NH3-N and fecal coliform. Conclusion: According to the result of this study, Typha Latifolica has a high efficiency in removing organic material and suspended solids; the treated wastewater by Typha Latifolica can achieve the environmental standards for agriculture and irrigation use. Keywords: Subsurface flow constructed wetland, Typha Latifolica, Wastewater treatmen

Investigating the efficiency and kinetic coefficients of nutrient removal in the subsurface artificial wetland of Yazd wastewater treatment plant

Background: Investigating the performance of naturally operated treatment plants may be due to the fact that they cannot be operated as desired, or that they should be modified to achieve good performance e.g. for nutrients removal. The advantage of kinetic coefficient determination is that the model can be adjusted to fit data and then used for analyzing alternatives to improve the process. This study investigates the efficiency of subsurface artificial wetland and determines its kinetic coefficients for nutrient removal. Methods: The present study investigated the kinetics of biological reactions that occurred in subsurface wetland to remove wastewater nutrient. Samples were taken from 3 locations of wetlands for 6 months. The nutrient content was determined through measuring Total Kjehldahl Nitrogen (TKN), ammonium, nitrate, and phosphate values. Results: Average levels for TKN, ammonium, nitrate, and phosphate in effluent of control wetland were 41.15, 23.59, 1.735, and 6.43 mg/L, and in wetland with reeds were 28.91, 19.99, 1.49 and 5.63 mg/L, respectively. First-order, second-order, and Stover-Kincannon models were applied and analyzed using statistical parameters obtained from the models (Umax, KB). Conclusion: The nutrients removal at Yazd wastewater treatment plant was remarkable, and the presence of reeds in wetland beds was not very efficient in improving system performance. Other more efficient plants are suggested to be evaluated in the system. Stover-Kincannon kinetic model provided predictions having the closest relationship with actual data obtained from the field

Comparing the Efficiency of Stabilization Ponds and Subsurface Constructed Wetland in Domestic Sewage Treatment in City of Yazd

Wastewater is one of the most important contributors to water pollution on the one hand, while it has the potential to serve as an alternative source of water if subjected to proper treatment, on the other. The present study was designed to compare the removal efficiencies of stabilization ponds and subsurface constructed wetlands in the treatment of urban wastewater in Yazd. For this purpose, 72 samples were collected at the inlet and outlet of a constructed wetland as well as 72 from the inlet and outlet of stabilization ponds over a period of one year. The samples were subjected to identical tests and the results were compared. The removal efficiencies for BOD5, COD, TSS, NH4-N, NO3-N, and PO4 in the stabilization ponds were 79.7, 79.6, 44.4, 57, 0, and 42.5 percent, respectively. The same parameters for the constructed wetland system were 80.7, 81.5, 77.7, 9.9, 34, and 59.4, respectively. Moreover, BOD5, COD, TSS, and PO4 removal efficiencies were higher in autumn and summer. From these results, it may be concluded that constructed wetlands are more commercially viable than stabilization ponds both in terms of performance and cost-effectiveness

Performance Evaluation of Tile Wastewater Treatment with Different Coagulants

Introduction: The objective of this study was to investigate wastewater quality and the efficiency of removal of wastewater contaminants produced by a tile factory by using ferric chloride, ferrous sulfate, ferric sulfate, aluminum sulfate (alum) and poly-aluminum chloride (PAC) coagulants. Materials and Methods: This is an applied study. A composite sample was taken of the wastewater production line of the factory. Wastewater characteristics including pH, EC, temperature, turbidity, TSS, TDS, TS and COD were measured in accordance with the standard methods. In the next step, the jar-test experiment was used to investigate the effect of changing doses of coagulants (0.15, 0.2, 0.25, 0.3, 0.35 g/L) and pH values (7, 9, 11) on the removal of contaminants. The effective dose and optimal pH were thus selected and the best coagulant was later determined. Results: The optimum pH of 11 was obtained for removal of contaminants by ferric chloride, ferric, ferrous sulfate and 7 for alum and PAC. The optimum concentration of the five coagulants was obtained at 0.3, 0.3, 0.3, 0.25, 0.25 g/L respectively. PAC, with the turbidity removal EC, TSS, TS and COD removal of 99.92%,17.74%, 99.93%, 89.8%, 75% respectively, had best performance at lower doses and alum, ferrous sulfate, chloride, ferric and ferric sulfate were placed in the next rankings. Conclusion: Among the five studied coagulants, PAC is the most effective coagulant, and then alum, ferrous sulfate, ferric chloride and ferric sulfate are placed. Given that PAC is more expensive than other materials, care should be taken to select the most appropriate coagulant. &nbsp

Removal Efficiency of Linear Alkyl Benzene Sulfonate (LAS) in Yazd Stabilization Pond

Surfactants are organic chemicals with wide applications as detergents. Linear alkyl benzene sulfonate (LAS) is an anionic surfactant most commonly used. Discharge of raw or treated wastewater containing this chemical into the environment causes major public health problems. In this study, 64 samples were taken from the effluent of Yazd Wastewater  Treatment Plant over a period of one year. The samples were analyzed according to standard methods. The results obtained from the samples taken in different seasons showed that the highest efficiency of anionic surfactant removal was achieved in the summer in the secondary facultative stabilization pond. The least efficiency was observed in the autumn in samples from the anaerobic stabilization pond. It was also found that treated wastewater discharged into surface waters, reused for agricultural irrigation, or discharged into absorbent wells had significant differences with Pvalu

Biodegradation and nutrients removal from greywater by an integrated fixed-film activated sludge (IFAS) in different organic loadings rates

Abstract In this study, the efficiency of Integrated Fixed-film Activated Sludge (IFAS) system in synthetic greywater treatment and nutrients removal was studied in duration of 105 days according to different Organic Loadings Rates (OLRs). The study was operated in pilot-scale and OLRs of 0.11–1.3 gCOD/L.d. Scanning Electron Microscope (SEM) image showed that the biofilm with a proper thickness was formed on IFAS reactor’s media. The results indicated that the best removal efficiency of BOD5, COD, and TSS were 85.24, 92.52 and 90.21%, respectively, in an organic loading of 0.44 gCOD/L.d. Then, with the OLR increased, the removal efficiencies of BOD5, COD, and TSS increased as long as the organic loading reached 0.44 gCOD/L.d. But with the OLR increased more, the removal efficiency of these parameters decreased. The ANOVA statistical test results showed that the mean difference of removal efficiency in organic loadings for BOD5 (p ≤ 0.001) and COD (p = 0.003) was significant, while it was insignificant for TSS (p = 0.23). The best removal efficiencies of Total Nitrogen (TN) and Total Phosphorus (TP) were 89.60 and 86.67%, respectively, which were obtained at an OLR of 0.44 gCOD/L.d. By increasing OLR up to 0.44 gCOD/L.d, removal efficiencies of TN and TP increased, while the removal efficiency decreased with the OLR increased more, and this difference was statistically significant (p = 0.021). Finally, the results showed that the IFAS system provided a proper efficiency in treatment of the synthetic greywater and it could be used in a full scale