Effectiveness of Hydrogen Peroxide in H2S Removal by a Packed High Specific Surface Area Bed Scrubber

Removal of H2S from waste air streams was investigated in a chemical scrubber packed with new low-cost and high specific surface area media and in the presence of H2O2 in scrubbing liquid. The experimental conditions included superficial gas velocities of ν = 500 and ν = 840 m h-1, inlet H2S volume fraction in the range of φ = 50 to 250.10-6, scrubbing liquid flow rate ranging from QL = 1 to 10 L min-1 and liquid phase pH of 7 to 12. The results showed H2S removal efficiencies of η = 97.5 % to more than η = 99 % at liquid flow rate of QL = 5 L min-1 and pH of 10 to 11. Overall, it was determined that the media tested and H2O2 can be used in scrubbers for efficient H2S removal without the possibility of forming any toxic by-products

A framework for exploration and cleaning of environmental data : Tehran air quality data experience

Management and cleaning of large environmental monitored data sets is a specific challenge. In this article, the authors present a novel framework for exploring and cleaning large datasets. As a case study, we applied the method on air quality data of Tehran, Iran from 1996 to 2013. ; The framework consists of data acquisition [here, data of particulate matter with aerodynamic diameter ≤10 µm (PM10)], development of databases, initial descriptive analyses, removing inconsistent data with plausibility range, and detection of missing pattern. Additionally, we developed a novel tool entitled spatiotemporal screening tool (SST), which considers both spatial and temporal nature of data in process of outlier detection. We also evaluated the effect of dust storm in outlier detection phase.; The raw mean concentration of PM10 before implementation of algorithms was 88.96 µg/m3 for 1996-2013 in Tehran. After implementing the algorithms, in total, 5.7% of data points were recognized as unacceptable outliers, from which 69% data points were detected by SST and 1% data points were detected via dust storm algorithm. In addition, 29% of unacceptable outlier values were not in the PR.  The mean concentration of PM10 after implementation of algorithms was 88.41 µg/m3. However, the standard deviation was significantly decreased from 90.86 µg/m3 to 61.64 µg/m3 after implementation of the algorithms. There was no distinguishable significant pattern according to hour, day, month, and year in missing data.; We developed a novel framework for cleaning of large environmental monitored data, which can identify hidden patterns. We also presented a complete picture of PM10 from 1996 to 2013 in Tehran. Finally, we propose implementation of our framework on large spatiotemporal databases, especially in developing countries

Removal of Furfural From Wastewater Using Integrated Catalytic Ozonation and Biological Approaches

Furfural with a chemical formula of C5H4O2 is a toxic compound which has several health problems for both humans and environment. It has a few exposure routes for entering the human body such as oral, dermal or nasal. In the present study, the efficacies of an integrated catalytic ozonation process (COP) and novel cyclic biological reactor (CBR) were explored for the removal of furfural from aqueous solutions. Activated carbon was purchased from Merck Company. It had a Brunauer, Emmett, and Teller (BET) specific surface area of 1100 m2/g, with an average micropore volume and size of 0.385 cm3/g and 595 µm, respectively. The results indicated that 30% pretreatment with COP could increase furfural and chemical oxygen demand (COD) removal efficiency with CBR 5.56% and 27.01%, respectively. With 70% pretreatment by COP, 98.57% furfural and 95.34% COD removal efficiencies happen in CBR. Generally, batch and continuous experiments showed that the integrated COP/CBR could be efficient in eliminating furfural from wastewater and thus may be a promising technique for treating furfural-containing wastewater

Bioassay of Phenol and its Intermediate Products Using Daphnia magna

Phenol is one of the most common compounds found in many industrial effluents such as petroleum refining and petrochemicals, pharmaceuticals, pesticides, paint and dye industries, organic chemicals manufacturing, etc. The contamination of bodies of water with phenol is a serious problem in terms of environmental considerations due to its high toxicity. In this study, toxicity of phenol and its degradation mixtures by sonochemical, photochemical, and photosonochemical processes were investigated. Toxicity assay tests were carried out using Daphnia magna as a bio-indicator. The sonochemical and photochemical experiments were carried out using a bath sonicator (500 W) working at 35 and 130 kHz frequencies and with a 400 W medium pressure mercury lamp, respectively. Experiments were performed at initial concentrations of 100 mg L-1. Bioassay tests showed that phenol was toxic to D.magna and so resulted in quite low LC50 values. Comparison of toxicity units (TU) between phenol and effluent toxicity showed that TU value for photosonochemical effluent was lower than that obtained for phenol, photochemical effluent, and sonochemical effluent. It was found that the toxicity unit of photochemical effluent was lower than that obtained for sonochemical effluent. According to the D.magna acute toxicity test, it is concluded that photosonolysis and photolysis are capable of decreasing the toxicity of by-products formed during the degradation of phenol aqueous solutions. Photosonic and photolytic processes can, therefore, be recommended as a potential approach to the treatment of phenolic wastewater

Assessment of environmental health in the 2012 East Azerbaijan earthquake

Background and Objectives: On August 2012, two earthquakes measured 6 and 6.2 on the Richter scale took place in Eastern Azerbaijan province. Environmental Health Department is accounted as one of the main units for providing and supervising environmental sanitation services at the emergencies, therefore, the objective of this study was allocated to assess environmental health response performance in recent earthquake. Material and Methods: Through multi-stages stratified sampling, we selected 8 and 4 villages from the earthquake zones of Heris and Varzaghan respectively. The collecting data tools in this research were the WHO checklist in 7 categories, 14 subcategories, and 37 environmental health activities and also the minimum standards of Sphere Project checklist. The status of environmental health in each village was assessed using the mentioned checklists. This study was carried out with attendance of research team in earthquake zones 21 days after the occurrence of earthquake. Results: Among the 37 environmental health activities, 7 activities were the joint ones, which Environmental Health Department had to carry it out with the coordination of other related organizations. In other words, the environmental health has the supervising role in these activities. Totally, such activities had more nonconformities compared with the activities in which environmental health was administered as the main responder. The details of results have been expressed in the full text. Conclusion: Providing intra-sector coordination, prioritizing the needs of the affected population and considering the principles of community based management in the natural disaster are proposed as the recommendations of this study

Study of Aerated Lagoons in Treating Industrial Effluent from Industrial Bou-ali Zone in Hamedan

Aerated lagoon is a kind of the aerobic suspended growth process that can be used to treat domestic and industrial wastewater. Due to its considerable design flexibility, the aerated lagoon has gained wide applications in both developed and developing countries. This study aims to investigate the performance of aerated lagoons in the wastewater treatment plant in Bou-Ali industrial zone in Hamedan over a period of seven months from May to November 2004. Quality indexes such as pH, TSS, BOD5 ,COD, total coliform and fecal coliform, Cu, Pb, Zn, total Cr in plant influent and effluent were determined. The average values of pH, TSS, BOD5 ,COD, total coliform and fecal coliform, Cu, Pb, Zn, total Cr in plant effluent were measured to be 7.46, 84mg/l, 76mg/l, 176mg/l, 1.98´104MP N /100ml, 3.31´103MPN/100ml, 0.04mg/l, 0.13mg/l, 0.88mg/l, and 0.03mg/l, respectively. The removal efficiencies recorded for the contaminants studied were 73.56%, 91.58%, 89.95%, 99.968%, 99.713%, 62.24 %, 59.08%, 56.51%, 62.57%, respectively. Total and fecal coliform contents were greater than standard limits for irrigation recommended by Iranian Environmental Protection Organization while the rest were below the standard values. If the effluent from this plant should be reused for agriculture or landscape irrigation, reduction of microbial pollution to standard limits recommended by Iranian EPO or to guidelines set by WHO must be considered

Using Rainbow Trout to Measure Arsenic Toxicity in Water

The purpose of this study is to determine arsenic toxicity on rainbow trout. Acute toxicity of arsenic was determined by measuring the lethal effects on rainbow trout in static conditions. Five aquariums of 25×30×30 cm with five concentrations of 5,10,15,20 and 25 mg/L of arsenic were prepared and then ten fishes were added to each concentration. Also one aquarium with similar conditions was considered as a control with no arsenic solution. Hardness, temperature and dissolved oxygen of dilution water were determined by standard methods, and concentration of dissolved oxygen, pH and temperature of solution test in time periods of 2,4,6,8,24,48,72 and 96 hrs were measured. Water temperature of aquarium was regulated by circulation of water in refrigerator through indirect conduction with solution test. LC50 was measured at intervals of 24,48,72 and 96 hrs by SPSS software and respectively showed 28.13,21.77,15.78 and 12.72 mg/L.Probit curve was drawn by Harvard Chart XL software, and LC50 curve was drawn by Excel software