[Detection and risk assessment of musculoskeletal disorders among the staffs employed in a dish manufacturing company using the QEC method and Nordic questionnaire]

Background and aim: Due to the high production rate and the manual nature of the manufacturing of Arc opal dishes the probability of the musculoskeletal disorder onset is high. The aim of present study was to detect and assess the risk of musculoskeletal disorders and its relation to the work pace among the staffs in one of the dishes manufacturing companies.

Materials and Methods: This cross-sectional descriptive-analytical study was carried out on the 100 staffs employed on the decoration section of the company that had job experience equal to one year. They was selected randomly. . To detect the disorders in different parts of the body and to assess the risk of MSDs were used Nordic questionnaireand QEC method respectively. Using SPSS15 software, we analyzed data that used one way ANOVA and Independent Sample t- test.

Results: The results from Nordic questionnaire revealed that the most prevalent disorders in past year related to back [93%], neck[89%], and shoulder[82%] regions respectively. The QEC showed that level of worker exposure with risk factors in back[53%], shoulder[58%], Wrist – Hand[71%] and neck[58%] regions is high. Also 71 percent of worker employees have inappropriate posture during work. A significant relation was found between the MSDs and the work pace.

Conclusion: Considering the high prevalence of MSD and analyzing the related risk factors which signifying the risky condition of work environment, it proposed to apply the ergonomic intervention for reduction of work pace.

study of the chemical and physical properties obtained from the composition of live stock and poultry wastes in biogas system

Introduction: Unnecessary use of chemical manure in order to increase the crop production, particularly in the agricultural sector, causes environmental damages and disorder in terms of soil fertility. In the manure preparation method through the biogas, organic manure of high quality can be produced in addition to obtaining gas. The purpose of this study is to examine the physical as well as chemical properties of the manure produced by the combined wastes of livestock and poultry using biogas system

Research method: In order to put the pilot project into operation, livestock and poultry wastes were primarily collected and were added to the planned pilot in a proportional ratio of 1:2. After about two months, the produced gas was measured and the parameters of the manure were analyzed according to the pilot sample and subsequently, they were compared with the existing standards. Using EXCEL, the gathered data were analyzed

Results: PH rate obtained from the manure was estimated to be 7.2. Reportedly, the electrical conductivity of the sample was equal to 29.53 ml. Siemens/cm. and the humidity was 5%. The organic compounds in the sample were 8.19% and ash was 8.58%. Furthermore, the rate of the organic carbon for the sample was 40% and the size of the uniformed particles was of the highest mesh, i.e. 50. The manure obtained has a phosphorous concentration of 1 mg/l and the sodium concentration obtained were 94 mg/l and potassium 74 mg/l

Discussion and conclusion: Findings indicate that the rate of organic materials, phosphorus, ash and organic carbon are consistent with the standards set by WHO. With regard to low cost, availability, being danger-free and enriched as well as the simultaneous use of the gas produced, the manure obtained through the biogas can be considered a suitable kind of manure for agriculture

Removal of Reactive Orange 3 dye from aqueous solution by biosorption technology

Background: The biosorption process has found numerous applications due to low cost, availability, biosorbent reuse, and utilization of excess sludge from wastewater treatment facilities. The aim of the present study was to evaluate the efficiency of dried activated sludge in removing Reactive Orange 3R dye

Materials and Methods: For this experimental, laboratory study, dye solutions were prepared in three concentrations: 50, 100, and 150 mg/L. The solutions were then subjected to adsorbent in weights 0.2, 0.4, 0.6, 0.8, and 1.0 g for various durations [0.5, 1, 1.5, 2, 2.5, and 3 hours] in different pH levels [4, 7, and 12]. Data was analyzed using Excel software

Results: Increasing contact time from 0.5h to 3h, the dye removal efficiency increased from 56% to 76%. When the weight of the biomass increased from 0.2g to 0.8g, the dye removal efficiency increased from 58% to 72%. High initial iron concentration had an adverse effect on iron removal efficiency

Increasing initial dye concentration from 50 to 150 mg/L decreased iron removal efficiency from 71% to 62%. Freundlich isotherm models could describe the adsorption equilibrium of the dye onto the activated sludge. Freundlich isotherm represented a better correlation compared to other isotherms [R2>0.952]. Also, second-order models fit well with experimental data [R2>0.979]

Conclusion: This technology for dye removal from industrial wastewater, in addition to the optimal use of biomass from wastewater, can help resolve the environmental problem of wastewater dye excretion

Hamadan landfill leachate treatment by coagulation-flocculation process

In most countries, sanitary landfilling is the common way to dispose municipal solid wastes. In the operations, leachate treatment is a difficult and expensive process. Although, leachate can be treated by biological processes, COD removal efficiency is usually low due to high ammonium ion content and the presence of toxic compounds such as metal ions. This experimental study was conducted to investigate the effect of coagulation-flocculation process on the Hamadan landfill leachate treatment in the city of Hamedan. Also the effects of different coagulants with various dosages and pH values in the removal of chemical oxygen demand [COD] and total suspended solids were studied. Results showed that the efficiency for COD removal by Poly Aluminum Chloride at pH=12 and 2500 mg/L of coagulant, by alum at pH=12 and 1000 mg/L of coagulant dose and by ferrous sulfate at pH=12 and 1500 mg/L of ferrous sulfate dose were 60%, 62.33% and 70.66%, respectively. Also results showed that, the efficiency for Total Suspended Solids removal by Poly Aluminum Chloride that was obtained at pH=12 and 2500mg/L concentration of Poly Aluminum Chloride, by alum at pH=2 and 1500 mg/L concentration of alum and by ferrous sulfate at pH=7 and 2500mg/L of ferrous sulfate, were 39.14%, 58.37% and 35.58%, respectively. Based on results of this study, the best coagulant for COD removal was ferrous sulfate and the physico-chemical process may be used as an effective pretreatment process, especially for young leachate, prior to post-treatment [polishing] for partially stabilized leachate

[Performance of simple nano zeolite Y and modified nano zeolite Y in phosphor removal from aqueous solutions]

Phosphate discharges from domestic and industrial waste water to water bodies. High concentrations of phosphate in water stimulate the eutrophication phenomenon that causes taste and odor in water, losing dissolved oxygen and aquatic life in rivers or surface waters. Aim of this study is survey of phosphate adsorption on simple nano zeolite Y and nano zeolite Y that was modified with a cationic surfactant [HDTMA-Br]. In This study we used simple nano zeolite Y and nano zeolite Y in form of Surfactant Modified Zeolites [SMZs] using batch tests to adsorption of Phosphate from Aqueous Solutions. The adsorbants were contacted with different initial phosphor concentrations [5, 10 and 15 mg/l], pH [4, 7, 12], contact time [30, 60, 90, 120, 150 and 180 minutes] and weight of adsorbant [0.2, 0.4, 0.6, 0.8 and 1g]. the extracted solution was determined for Phosphate concentration by the ammonium molybdate and tin chloride method with spectrophotometric detection at 680 nm. Results of this study show that, with increase in contact time, decrease in pH, increase in zeolites concentration and decrease in initial phosphate concentration, the removal efficiency increased. And the Both isotherm of Langmuir and Freundlich models [r[2]>0.997 and r[2]>0.996 respectively] were agreement with adsorption equilibrium of phosphate. Reduced Chi-Sqr For Langmuir and Freundlich models were [0.00079] and [0.0011] respectively. Pseudo first-order kinetic models fits well with experimental data [r[2]>0.963]. From this survey, it is concluded that performance of modified nano zeolite Y for adsorption of phosphate in same conditions is better than non-modified zeolite Y. In general the modified nano zeolite Y presented a good profile for removal of phosphate. Therefore SMZs is a suitable candidate for removal of Phosphate molecules from contaminated solutions in contaminated waters

[Comparison of diffrent coagulants efficiency for treatment of Hamedan landfills leachate site]

In Iran, indicated that the municipal landfill leachate has been one of the major problem for environment. In the operations, leachate treatment is a very difficult and expensive process. Although, young leachate can be treated easily by biological treatment, COD removal efficiency are usually low due to high ammonium ion content and the presence of toxic compounds such as metal ions. Treatment of leachate is necessary.The aim of this study is reduction of Chemical Oxygen Demond [COD] and Total Suspended Solids [TSS] from hamedan city sanitary landfill leachate by three coagulants: alum, PAC and ferrous sulfate. This experimental study was conducted to investigate the effect of treatment of landfill leachate by a coagulation-flocculation process. The effects of different amounts of coagulant and different pH values on the coagulation processes were compared. result of this survey show that the high efficiency for COD removal by PAC in pH=12 and 2500[mg/l] concentration of PAC was 62.66%, by alum in pH=12 and 1000 [mg/l] concentration of alum was 60%, by ferrous sulfate in pH=2 and 1000 [mg/l] concentration of ferrous sulfate was 70.62%. Also result shown the high efficiency for TSS removal by PAC in pH=12 and 2500[mg/l] concentration of PAC was 58.37%, with alum in pH=2 and 1500 [mg/l] concentration of alum was39.14%, by ferrous sulfate in pH=7 and 2500[mg/l] concentration of ferrous sulfate was 35.58%. The best coagulant for COD removal is ferrous sulfate.The physico-chemical process may be used as a useful pretreatment step, especially for fresh leachates, prior to post-treatment [polishing] step for partially stabilized leachates

Biosorption of iron from aqueous solution by dried biomass of activated sludge

This study was conducted to investigate the removal of iron by dried biomass of activated sludge. Dried activated sludge, prepared as a powder, was tested as a sorbent for the removal of iron from aqueous solutions. The effects of various experimental parameters including initial iron concentration, mass of biomass and contact time were examined and optimal experimental conditions were obtained. The equilibrium time for iron adsorption onto biomass was determined as 150 min. The rate of iron removal was directly correlated to biomass amount and contact time. Increasing contact time from 0.5h to 2.5h resulted in 25% improvement in iron removal efficiency. When the weight of the biomass increased from 0.1g to 0.9 g, the iron removal efficiency increased from 62% to 95%. High initial iron concentration had an adverse effect on iron removal efficiency. Increasing initial iron concentration from 2 to 10 [mg/L] caused declining the iron removal efficiency from 70% to 56%. Freundlich, Langmuir, Dubinin-Radushkevich and Temkin isotherm models could describe the adsorption equilibrium of the iron onto the activated sludge. Meanwhile, Freundlich isotherm represented a better correlation compared to other isotherms [R2 > 0.999]. Also Elovich kinetic models fits well with experimental data [R2>0.997]