Review of environmental aspects and waste management of stone cutting and fabrication industries

Iran is the second largest stockholder of construction stones with 10 % of world production ;and there are more than 4000 stone cutting and fabrication industries (SCFIs). In the processing of raw stones, a considerable part of stone is turned into waste. Generated wastes include excess parts of different stones and sludge. The present paper reviews the state of SCFIs waste management using multiple data sources including site, analysis of effluent and sludge samples, and conducting interviews with people who are involved in 286 SCFIs in Qom and Tabriz. The results revealed that currently almost 35 to 52.5 % of raw stones were converted to solid wastes depending on stone cutting and processing methods, type of stones and their quality, which seemed a high percentage. Also, the effluents between 0.8 and 2.8 m³ were generated per ton of processed stone. Based on the analysis of heavy metals with atomic absorption spectroscopy, sludge samples contained a considerable amount of Pb, Cu, Cr, and Cd. It was also found that the lack of specific recycling, reuse and disposal programs and suitable supervision has led to uncontrolled disposal of stone wastes and sludge in different areas. However, there are good opportunities for reuse and recycling of the SCFIs wastes.     

Cannibalism in the lifeboat �� collective movement in Australian plague locusts

Mass migration of locusts is an economically devastating and poorly understood phenomenon. Locust mass migration often follows rapid population growth because individuals must move to find new sources of locally depleted resources. In Mormon crickets and Desert locusts, cannibalistic interactions have been revealed as the driving force behind collective mass movement. Locusts are known to compensate for nutrient deficiencies and they themselves are a good source of nutrients such as protein. However, direct empirical evidence for an adaptive benefit of cannibalism in migratory bands has been lacking. Here, we first show that Australian plague locusts, Chortoicetes terminifera, will cannibalise vulnerable conspecifics to compensate for protein deprivation, supporting the notion that cannibalistic interactions among nutritionally deprived individuals drives collective mass movement. We then show that individuals in a group with the opportunity to cannibalise survive longer and move more than individuals without the opportunity to cannibalise. These results provide empirical support for the ??lifeboat mechanism??, which proposes that cannibalism offers the dual benefits to individuals in a group of surviving longer and travelling farther than a solitary individual without the opportunity to cannibalise.     

Assessment of hospitalization and mortality from exposure to PM10 using AirQ modeling in Ilam,Iran

Environmental Science and Pollution Research - The aims of this study were to assess the health impact of PM10 on inhabitants and to investigate the trend of PM10 concentrations in Ilam, Iran, from...     

Increased urinary arsenic concentration in newly diagnosed type 2 diabetes mellitus: a gender-independent,smoking-dependent exposure biomarker in older adults in Tehran

Environmental Science and Pollution Research - Arsenic is ranked in the top ten environmental toxicants but its impact on type 2 diabetes mellitus (T2DM) and its association with other human health...     

Performance of full-scale coagulation-flocculation/DAF as a pre-treatment technology for biodegradability enhancement of high strength wastepaper-recycling wastewater

Paper mill wastewater leads to a serious damage on the environment owing to the high content of organic matters, suspended solids, toxic substances, and lignin. Hence, exploring new treatment technologies is the passion of environmental engineers to minimize the effluent impact on the environment and cleaner production aspects. This research focused on the performance of full-scale coagulation-fluctuation/DAF system for pre-treatment of high strength wastepaper-recycling wastewater and its effect on biodegradability improvement. To optimize unit performance, optimum coagulant and flocculant doses were firstly determined by jar test without prior change and adjustment of pH in lab-scale experiments. The optimum dosages were obtained by 1500 mg L^?1 polyaluminum chloride (PACl) as coagulant coupled with 40 mg L^?1 cationic polyacrylamide (C-PAM) as flocculant. Percentage removals of 39?±?10, 6.8?±?3.6, 31.0?±?6.7, 24.0?±?3.8, and 33.0?±?20.0 were achieved for COD, sCOD, BOD₅, sBOD₅, and color, respectively. The average BOD₅ to COD ratio after pre-treatment increased from 0.44 to 0.5, whereas the ratio of sBOD₅/sCOD dropped from 0.65 to 0.53. A superior effectiveness in reduction of TSS (98.1%) and VSS (98.4%) was also achieved. The results show that the application process is able to prevent malfunction operation in the following bioreactors which is obtainable through bio-treatability enhancement of pre-treated wastewater and reducing the risks of clogging and sludge washout. Attached growth processes are suggested to be applied in the further anaerobic/aerobic processes because of high proportion of soluble fraction of COD in the effluent to avoid poor floc formation and dispersed growth problems.     

Characterization and Optimization of Persian Gum/Whey Protein Bionanocomposite Films Containing Betanin Nanoliposomes for Food Packaging Utilization

Journal of Polymers and the Environment - In this study, composite packaging films were produced from relatively inexpensive materials including Whey protein isolate (WPI) and Persian gum (PG),...     

Temporospatial variation and health risk assessment of trihalomethanes (THMs) in drinking water (northwest Iran)

Environmental Science and Pollution Research - Trihalomethanes (THMs) are one of the most common classes of disinfection by-products. In this study, the temporospatial trends and health risks due...     

The use of artificial neural networks and multiple linear regression to predict rate of medical waste generation

Prediction of the amount of hospital waste production will be helpful in the storage, transportation and disposal of hospital waste management. Based on this fact, two predictor models including artificial neural networks (ANNs) and multiple linear regression (MLR) were applied to predict the rate of medical waste generation totally and in different types of sharp, infectious and general. In this study, a 5-fold cross-validation procedure on a database containing total of 50 hospitals of Fars province (Iran) were used to verify the performance of the models. Three performance measures including MAR, RMSE and R² were used to evaluate performance of models. The MLR as a conventional model obtained poor prediction performance measure values. However, MLR distinguished hospital capacity and bed occupancy as more significant parameters. On the other hand, ANNs as a more powerful model, which has not been introduced in predicting rate of medical waste generation, showed high performance measure values, especially 0.99 value of R² confirming the good fit of the data. Such satisfactory results could be attributed to the non-linear nature of ANNs in problem solving which provides the opportunity for relating independent variables to dependent ones non-linearly. In conclusion, the obtained results showed that our ANN-based model approach is very promising and may play a useful role in developing a better cost-effective strategy for waste management in future.     

Breakthrough CO2 adsorption in bio-based activated carbons

In this work, the effects of different methods of activation on CO₂ adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, using three different activation methods of steam activation, CO₂ activation and Potassium hydroxide (KOH) activation. CO₂ adsorption behavior of the produced activated carbons was studied in a fixed-bed reactor set-up at atmospheric pressure, temperature range of 25–65°C and inlet CO₂ concentration range of 10–30 mol% in He to determine the effects of the surface area, porosity and surface chemistry on adsorption capacity of the samples. Characterization of the micropore and mesopore texture was carried out using N₂ and CO₂ adsorption at 77 and 273 K, respectively. Central composite design was used to evaluate the combined effects of temperature and concentration of CO₂ on the adsorption behavior of the adsorbents. The KOH activated carbon with a total micropore volume of 0.62 cm³/g and surface area of 1400 m²/g had the highest CO₂ adsorption capacity of 1.8 mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30 mol% CO₂ and 25°C. The performance of the adsorbents in multi-cyclic adsorption process was also assessed and the adsorption capacity of KOH and CO₂ activated carbons remained remarkably stable after 50 cycles with low temperature (160°C) regeneration.     

Vortex formation and foraging in polyphenic spadefoot toad tadpoles

Animal aggregations are widespread in nature and can exhibit complex emergent properties not found at an individual level. We investigate one such example here, collective vortex formation by congeneric spadefoot toad tadpoles: Spea bombifrons and Spea multiplicata. Tadpoles of these species develop into either an omnivorous or a carnivorous (cannibalistic) morph depending on diet. Previous studies show that S. multiplicata are more likely to develop into omnivores and feed on suspended organic matter in the water body. The omnivorous morph is frequently social, forming aggregates that move and forage together and form vortices in which they adopt a distinctive slowly rotating circular formation. This behaviour has been speculated to act as a means to agitate the substratum in ponds and thus could be a collective foraging strategy. Here we perform a quantitative investigation of the behaviour of tadpoles within aggregates. We found that only S. multiplicata groups exhibited vortex formation, suggesting that social interactions differ between species. The probability of collectively forming a vortex, in response to introduced food particles, increased for higher tadpole densities and when tadpoles were hungry. Individuals inside a vortex moved faster and exhibited higher (by approximately 27%) tailbeat frequencies than those outside the vortex, thus incurring a personal energetic cost. The resulting environmental modification, however, suggests that vortex behaviour may be an adaptation to actively create and exploit a resource patch within the environment.