A potential new commercial method for processing leather to reduce environmental impact

Effect of co-culturing bacteria and microalgae and influence of inoculum ratio during the biological treatment of tannery wastewater

This present investigation is carried out to study the effect of algal and bacterial inoculum concentrations on the removal of organic pollutants and nutrients from the tannery effluent by the combined symbiotic treatment process. The bacterial and microalgal consortia was developed in laboratory setup and mixed together to perform this study. The Influence of algae and bacteria inoculum concentrations on the removal of pollutants such as Chemical Oxygen Demand (COD) and Total Kjeldahl Nitrogen (TKN) were studied using statistical optimization through Response surface methodology. For the design of experimental set up and optimization, full factorial Central composite design was used. The profiles of pH, Dissolved Oxygen (DO) and nitrate were also monitored and studied. The inoculum concentrations of microalgae and bacteria showed significant effect on Co-culturing on COD, TKN and nitrate removals as major response. The linear effect of bacterial inoculum has positive dominant influence on COD and TKN removal efficiencies. Nitrate utilization by microalgae increases with the increase in microalgal inoculum concentration. The maximum removal efficiencies of COD and TKN with 89.9% and 80.9% were obtained at optimum bacterial and algal inoculum concentrations of 6.7 g/L and 8.0 g/L respectively. These outcomes of this study are immensely favorable for maximizing the COD and nitrogen (nutrients) removal capabilities of microalgae-bacterial consortia in tannery effluent.

Occurrence of higher chlorinated benzenes in livers of grass carp and common carp collected from markets of Xinxiang, China

Five higher chlorinated benzenes (including hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and three isomers of tetrachlorobenzens) were measured in the livers of grass carp and common carp collected from five markets in Xinxiang city, China. HCB and PeCB were detected in all samples. The major component of the higher CBs residue was HCB and significant correlations existed between HCB and PeCB in both grass carp and common carp livers. The ratio range of HCB/PeCB in grass carp and common carp were 3.4-6.2 and 4.9-7.7, respectively, which implied the sources of higher CBs originate mainly from the revolatilization of industrial HCB with a minor impact from PeCB.

Distribution and characterization of higher chlorinated benzenes in outdoor dust collected from a fast developing city in North China

Five higher chlorinated benzenes (CBs), include hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and three isomers of tetrachlorobenzens, were analyzed in 20 outdoor dust samples collected from a fast developing city, Xinxiang. Only HCB was detected in all outdoor dust samples. The dominate part of the CBs residue in most samples was HCB and the mean HCB concentration (4.13 ng/g dry weight) in this study was in the range of global background soil HCB levels (ranging from 0.010 to 5.20 ng/g dry weight). The higher ratios of HCB/PeCB in the outdoor dust samples in the present study indicate that pesticide application may be an important source of HCB in China.