[Investigation of effective factors for fenton like process in para-chlorophenol removal from aqueous solutions]

Chlorophenol compounds are used frequently in industries including: petrochemical, producing pesticide and herbicides, producing antimicrobial agents, pharmaceutical and refineries. These compounds can enter the environment through the wastewater industries. This investigation has studied the application of Fenton-like process [Fe[0]/H[2]O[2]] in removal of Parachlorophenol. A laboratory scale study was done on a synthetic wastewater containing Para-chlorophenol. Concentration of 10 mg/L of Para-chlorophenol was prepared then optimal values of affecting parameters such as pH, hydrogen peroxide, and iron powder and detention time in the process for Para-chlorophenol removal were determined. The optimum pH, molar ratio of hydrogen peroxide on Para-chlorophenol, hydrogen peroxide on iron powder and time were 4, 18.8, 0.4 and 5 minutes respectively. The results showed that removal efficiency in optimal conditions for concentrations of 10, 50 and 100 mg/L are 93.9, 94.4 and 94.3 respectively. The study showed the rate of mineralization of Para-chlorophenol is not completed. According to the results of this study and high resistance in degradation by biological processes, Fenton like process can be used for conversion Para-chlorophenol resistant compound to other compounds with ability of higher biological degradation and lower toxicity

[Investigation of iron powder, hydrogen peroxide and iron hydrogen peroxide for removal of acid yellow powder 36 dye from aqueous solutions]

A great part of organic compounds cause more pollution in natural waters meet, are chemical dye material. Azo dyes have more usage in different industries. Azo dyes not only give undesirable dye to the water but also have mutation potential and carcinogenesis effects in human and cause the production of toxic substances in water environments. The purpose of this study is investigation of iron powder, hydrogen peroxide and iron powder-hydrogen peroxide processes in removal of acid yellow 36 dye from aqueous solutions. This study was conducted in laboratory scale. At this experiment synthetic solution was made from acid yellow 36 dye, and the removal of acid yellow 36 dye was studied by iron powder, hydrogen peroxide and iron powder-hydrogen peroxide processes .Also effect of dye concentration, pH solution, hydrogen peroxide concentration, iron powder concentration and the time of contact on decolorization, were evaluated. The results showed that iron powder-hydrogen peroxide process, compared to two other process has high decolorization power. Removal efficacy of iron powder-hydrogen peroxide process with H[2]O[2]=23.33 ml / L, pH=3, iron powder 2000 mg/L and 60 minute, was about 97.9% In general this investigation showed that, this method [Iron powder-hydrogen peroxide process] has high efficiency for removal of Azo dyes. But application this method in the industry, should be economically evaluated

[Optimization of moving bed bioflim reactor using taguchi method]

In recent years, mobile bed biological reactors have been used progressively for municipal and industrial wastewaters treatment. Dissented experiment is a trial that significant changes will accrue for influent variables in the process, and generally used for identification of the effective factors and optimization of the process. The scope of this study was determination of the optimized conditions for the MBBR process by using of Taguchi method. Reactor start up was done by using of the recycled activated sludge from Ahwaz wastewater treatment plant. After that and passing the acclimation period, with hydraulic residence time equal to 9 hours matched for 1000, 2000 and 3000 mg/1 based on COD respectively, for optimization determination of the acclimated microbial growth, the variables change [p[H], nitrogen source, chemical oxygen demand and salinity] were determined in 9 steps, and all of the results were analyzed by Qualitek -4 [w32b]. In this study, organic load removal based on COD was 97% and best optimized condition for MBBR were [inf. COD 1000 mg/1, pH= 8, salinity = 5% and the Nitrogen source= NH4CL]. Based on our finding, we may conclude that Taguchi method is on of the appropriate procedure in determination the optimized condition for increasing removal efficiency of MBBR

Study on wastewater treatment systems in hospitals of Iran

Nowadays, water resources shortage is one of the most important issues for environmental engineers and managers as well as its conservation due to population growth and ever-increasing water demands. Besides, hospital wastewater has the same quality as municipal wastewater, but may also potentially contain various hazardous components. In this paper, physical and chemical specifications of produced wastewater in hospitals of Iran were investigated experiments. Results were compared with the effluent parameters of wastewater standards of Iranian Department of the Environment. 70 governmental hospitals from different provinces of Iran were selected by purposive [non-random] sampling method. For data analysis, SPSS and EXCEL softwares were applied. The findings of the study showed that 52% of the surveyed hospitals were not equipped and 48% were equipped with wastewater treatment systems. The mean of Biochemical Oxygen Demand, Chemical Oxygen Demand and Total Suspended Solids of the effluent of wastewater treatment systems were reported as 113, 188 and 99 mg/E respectively. Comparison of the indicators between effluents of wastewater treatment systems and the standards of Departments of the Environment, showed the inefficiency in these systems and it was concluded that despite the recent improvements in hospital wastewater treatment systems, they should be upgraded based on the remarks in this paper

Chemical denitrification of nitrate from groundwater via sulfamic acid and zinc metal

Nitrate contamination in drinking water can cause methemoglobinemia, which is especially detrimental to infants and nursing mothers. Batch experiments in two units for catalytic reduction of nitrate from groundwater with Zn catalyst and sulfamic acid were conducted. The system includes chemical denitriphication [ChemDen reactor] and electrolytic recovery reactoers. A batch study was conducted to optimize parameters like pH, sulfamic acid concentration, Zn concentration, temperature and reaction time governing the ChemDen process. The concentrations of remained nitrate and Zn were measured at the end of the reactions. Results showed that near to 100% of nitrate decreased and the quantity of remained nitrate was <1 mg/L. pH and agitation had great effect on denitrification, and the nitrate removal rate changed rapidly when pH value ranged between 3-4. Two water quality parameters which limit this process were sulfate and chloride ions concentrations in nitrate contaminated water

Study on the reuse of zamyad factory wastewater treatment plant effluent in irrigation

Considering the population increase in the cities and also the increase of per capita water consumption in these societies, the use of treated effluents for the green area irrigation has been taken into consideration. Human ever-increasing needs to green area in municipal societies and on the other hand the limitations in water supplies cause a new review in wastewater reuse. Also making use of treated effluents in irrigation has some limitations including clogging of the soil porosities, increasing of the chemicals and toxic substances to plants and increasing the probability of groundwater pollution. In this research, considering the indicators using recognition of the effluent's quality, at the first stage compound samples of domestic wastewater treatment effluents of Zamyad Factory were taken. The samples were tested from the viewpoint of quality. Results showed that the indicator of Sodium Adsorption Ratio, Sodium Percentage, amounts of chloride, and electrical conductivity comparing to Food and Agriculture Organization and Department of the Environment of Iran standards were higher than the standard levels. Also parameters such as TDS, TSS, BOD, COD, anions and cations were in standard levels. Results also showed that the increase of some of the undesirable parameters was not related to the operation of wastewater treatment plant. Therefore, in order to make the standard effluent, different methods may be proposed and the most practical and economical one is dilution by using 50% mixing with raw water

Characteristics of fenton's oxidation of 2, 4, 6 trichlorophenol

2, 4, 6 trichlorophenol [TCP] is one of the most toxic chlorophenols which is very difficult to biodegradation. Advanced Oxidation Processes [AOPs] is one of the most effective processes for degradation of persistent compounds. Since the mineralization of recalcitrant compound by AOPs often requires long reaction time and strong doses of oxidant, the combination of this process with biological one, is considered as an efficient and economic method. In this work degradation of 2, 4, 6 trichlorophenol in aqueous solution with Fenton reagent [H2O2 +Ferrous ion] was studied. The experiment was done in batch mode, and the initial concentration of TCP was 0.60mM. In pH=3, H202=1.8mM, Fe=0.6mM, more than 99% of TCP was degraded in 10 minutes after the reaction was started. Chloride ion generation as TCP degradation by product was investigated, and it was found that the scavenging effect of chloride is negligible. PH and UV215 absorbance analysis, after reaction completion, indicated that generated intermediates had the less chlorinated nature, acidic properties and nonphenolic structure. Chloride ion increases from 0 mg/L to 40 mg/L, pH decreased from 3 to 2.7 and UV215 absorbance decreased from 3.2 to 0.6, therefore it can be resulted that their biodegradability modified and their recalcitrance reduced. COD analysis indicated that TCP did not mineralize and in H2O2/TCP = 3 and oxidation time of 1 h, COD reduction was only 37%.

Removal of chrome and nickel from sewages-polluted water sources by using oak fruit

With respect to an increasing growth in city population and also an annual increase in the per capita consumption in the societies, particularly in the dry and semi-dry countries, the opportunity to use surface water sources to provide drinking water for the cities has decreased. In a such way, in 2001 more than 70 percent of the drinking water for the population of Tehran had been provided by underground water sources due to a decrease in the water reservoirs of Latian, Karag and Lar dam. The figure shows an increase for other cities of Iran as well. On the other hand, due to discharging industrial sewages with chrome and nickel contents in the absorptive wells and the penetration potentials of these compounds into underground waters, and with respect to the potential of these substances to accumulate in different tissues of the body and their sarcoma-generation characteristics as proved through various researches a strong need is felt to render a careful control on these sources. In this research, the plan is to omit and remove chrome and nickel from the sewage polluted underground water sources by using the essence of oak tree fruit for their condensed tannic acid, hydrolysable tannic acid, gaelic acid and Eeagic acid contents. First 60 water samples with a given amount of chrome and nickel contents were prepared and divided into 12 different groups with 5 concentration and environmental conditions. The experimental and non-probable sampling were applied sample taking and the counter effects of Tannin essence. Calcium hydroxide and sodium hydroxide were studied both in separated and simultaneous forms. With respect to the given initial concentration, the amount of remaining concentration was determined by flame application at the atomic absorption device. Among the measured specimen, 50 mg/1 of concentration of calcium hydroxide or 50 mg/1 of concentration of sodium hydroxide along with 50 mg/1 tannin-content essence with 80 to 86 percent output proved to render best conditions in omitting chrome and nickel from reaction environment. The results were evaluated through bi-factors variance analysis with one repletion in each box tests to ensure the accuracy and care rendered in performing the test. The results showed that simultaneous application of two chilling factors found in calcium hydroxide and tannin essence show significant differences as compared with other methods and also it was proved that the tannin content essence in an alkaline environment forms a full set of [OH] branches that are bound with chrome and nickel ions in the reaction environmental and due to the large size of tannin molecules and their saturation with the existing cations, they form a flocc mass that immediately deposits for its heavy weight. Also the essence in the tannin is able to take the mentioned ions form the reaction environment both in low and large concentrates and the ions concentrations have no significant differences in omission output

Comparison of phenol removal in anaerobic fluidized bed reactors with sand and gac media

In this study two identical anaerobic completely mixed fluidized bed reactors with GAC and sand media were employed for COD and phenol removal. At loading rate of 1.6 g phenol L-1d-1, the efficiency of phenol removal in GAC and sand reactors were 97.7% and 74%, respectively. At high loading rate of phenol [6.09 g phenol I: 1d1] the efficiency of phenol removal in GAC reactor was better than 95%. In GAC reactor, the main mechanism for phenol removal at steady state condition was biological process; this was concluded through balance of gas production and COD removal. Better efficiency of GAC reactor comparing with sand reactor was because of resistance to fluctuations, higher surface for biomass growth and adsorption capacity of activated carbon