Anaerobic treatment of high-saline wastewater using halophilic methanogens in laboratory-scale anaerobic filters.

The presence of a high concentration of sodium in wastewater is considered inhibitory for anaerobic biological treatment. This research was designed to investigate the potential use of halophilic methanogens and a mixed culture of halophilic methanogens and digester sludge, in anaerobic filters, for treatment of organic pollutants in high-saline wastewater at 35 degrees C. Data related to startup of the filters are presented. Both halophilic and mixed-culture anaerobic filters were able to operate at a sodium chloride concentration of 35 g/L, at organic loading rates (OLRs) of 6.2 and 5 kg chemical oxygen demand (COD)/m(3) x d, respectively. The COD removal efficiency was as high as 80%, and the systems were able to maintain a low volatile fatty acids concentration of 500 mg/L. No significant difference in COD removal was observed between the halophilic filter and the mixed-culture filter. Increasing the salt concentration to 37 g/L at an OLR of 3 kg/m(3) x d caused system failure.     

Female CEO succession and corporate social disclosure in China: unveiling the significance of ownership status and firm performance

Environmental Science and Pollution Research - This study intends to examine the effect of CEO succession with gender change from male to female (i.e., female CEO succession) on corporate social...     

Removal of Fe(II) from the wastewater of a galvanized pipe manufacturing industry by adsorption onto bentonite clay

Bentonite clay has been used for the adsorption of Fe(II) from aqueous solutions over a concentration range of 80-200 mg/l, shaking time of 1-60 min, adsorbent dosage from 0.02 to 2 g and pH of 3. The process of uptake follows both the Langmuir and Freundlich isotherm models and also the first-order kinetics. The maximum removal (>98%) was observed at pH of 3 with initial concentration of 100 mg/l and 0.5 g of bentonite. The efficiency of Fe(II) removal was also tested using wastewater from a galvanized pipe manufacturing industry. More than 90% of Fe(II) can be effectively removed from the wastewater by using 2.0 g of the bentonite. The effect of cations (i.e. zinc, manganese, lead, cadmium, nickel, cobalt, chromium and copper) on the removal of Fe(II) was studied in the concentration range of 10-500 mg/l. All the added cations reduced the adsorption of Fe(II) at high concentrations except Zn. Column studies have also been carried out using a certain concentration of wastewater. More than 99% recovery has been achieved by using 5 g of the bentonite with 3M nitric acid solution.     

The level and distribution of selected organochlorine pesticides in sediments from River Chenab,Pakistan

Organochlorine pesticides (OCPs), viz. β-hexachlorocyclohexane (β-HCH), γ-HCH, aldrin, dieldrin, endrin, heptachlor, endosulfan-I, endosulfan-II, heptachlor endoepoxide, heptachlor exoepoxide, mirex, dicofol, o,p′-dichlorodiphenyltrichloroethane (o,p′-DDT), p,p′-dichlorodiphenyltrichloroethane (p,p′-DDT), dichlorodiphenyldichloroethane (DDD), and dichlorodiphenyltrichloroethylene (DDE) and 12 other physicochemical parameters were measured in surface sediments from River Chenab during two sampling seasons (summer and winter, 2007) to evaluate spatial and temporal trends of sediment pollution. Hierarchical agglomerative cluster analysis identified three groups of sites based on spatial similarities in physicochemical parameters and OCP residual concentrations. Spatial discriminant function analysis (DFA) segregated 14 parameters, viz. dicofol, endosulfan-I, heptachlor endoepoxide, dieldrin, DDD, DDE, endosulfan-II, o,p′-DDT, p,p′-DDT, pH, electrical conductivity (EC), Cl⁻¹, total P (%), and silt, which explained 96% of total variance between spatial groups. γ-HCH was the most frequently detected (63%) pesticide, followed by DDD (56%). The ratio of DDTs to their metabolites indicated current input and anaerobic biodegradation. Temporal DFA highlighted aldrin, heptachlor endoepoxide, Cl⁻¹, total P, and EC as important variables which caused variations between summer and winter. DDTs were relatively more prevalent as compared to other OCPs in the sediments samples during both seasons. DDT metabolites were detected at greater frequencies and concentrations in winter, whereas DDT isomers were more prevalent in summer sediment samples. Factor analysis identified agricultural and industrial activities as major sources of sediment OCP contamination. Concentrations of γ-HCH, heptachlor endoepoxide, dieldrin, and DDTs (isomers and metabolites) in all sediment samples were well above interim sediment quality guidelines (ISQGs) and probable effect limits (PEL) given by Canadian Sediment Quality Guidelines (CSQGs).     

Organochlorine residual concentrations in cattle egret from the Punjab Province, Pakistan

In this study, residual concentration of organochlorine pesticides (OCPs) in the sediments, prey, and eggs of Bubulcus ibis were measured from three breeding heronries from the Punjab province of Pakistan. Pattern of contamination in eggs followed the order: DDTs > HCHs > heptachlor > aldrin. Overall, pesticide residual concentrations were greater in eggs of cattle egrets collected from heronry on the River Ravi. Among HCHs, ??-HCH was more prevalent in eggs, whereas DDTs followed the order: DDD > DDE > p,p ^??-DDT > o,p ^??-DDT. Eggshell thinning was detected which showed negative relationship with residual concentration of DDE. In prey samples, residual concentration of POPs followed the order: DDTs > HCHs > dicofol > heptachlor; however, contamination pattern in sediments followed a slightly different order: DDTs > heptachlor > dicofol > HCHs > dieldrin > aldrin. Concentration of ??-HCH was more prevalent in sediments and comparatively greater concentrations of POPs were measured in sediments collected from the River Ravi. Dicofol was found for the very first time in the biological samples from Pakistan, and its concentration was measured as relatively high in eggs from heronry from the River Chenab. Residual concentrations measured in eggs were below the levels that could affect egret populations. Biomagnification of the total OCPs through the food chain was evident in three breeding heronries. The concentration of DDE measured in eggs of the cattle egret suggests the need for monitoring this contaminant in other bird species at different trophic levels.     

The Immobilization of Titanium Dioxide on Organic Polymers,for a Cost Effective and Energy Efficient Means of Improving Indoorair Quality

The formation and spray coating, with Degussa P25 titanium dioxide (TiO₂), of a room temperature curable resin to form a photocatalytically active material is described in this paper. The TiO₂ surface layers produced have been characteristed with the aid of scanning electron microscope analysis. The photocatalytic activity of the samples tested using a gas phase continuous flow type photoreactor, the test pollutant being propene. Analysis of the test results indicates the potential of TiO₂ coated polymers to form effective photocatalytic materials, with the potential to improve indoor air quality and reduce the energy consumption of ventilation systems.     

Metal biomonitoring using fractioned dust to investigate urinary and oxidative stress biomarkers among occupationally exposed chromite mine workers

Environmental Science and Pollution Research - Exposure to heavy metals has been associated with the generation of reactive oxygen species (ROS) among exposed individuals in occupational and...