Slaughterhouse wastewater contains various and high amounts of organic matter (e.g., proteins, blood, fat and lard). In order to produce an effluent suitable for stream discharge, chemical coagulation and electrocoagulation techniques have been particularly explored at the laboratory pilot scale for organic compounds removal from slaughterhouse effluent. The purpose of this work was to investigate the feasibility of treating cattle-slaughterhouse wastewater by combined chemical coagulation and electrocoagulation process to achieve the required standards. The influence of the operating variables such as coagulant dose, electrical potential and reaction time on the removal efficiencies of major pollutants was determined. The rate of removal of pollutants linearly increased with increasing doses of PACl and applied voltage. COD and BOD5 removal of more than 99% was obtained by adding 100 mg/L PACl and applied voltage 40 V. The experiments demonstrated the effectiveness of chemical and electrochemical techniques for the treatment of slaughterhouse wastewaters. Consequently, combined processes are inferred to be superior to electrocoagulation alone for the removal of both organic and inorganic compounds from cattle-slaughterhouse wastewater.

Dyes are one of the most hazardous chemical compound classes found in industrial effluents and need to be treated since their presence in water bodies reduces light penetration, precluding the photosynthesis of aqueous flora. In the present study, single-walled carbon nanotubes (SWCNTs) was used as an adsorbent for the successful removal of Reactive Red 120 (RR-120) textile dye from aqueous solutions. The effect of various operating parameters such as initial concentration of dye, contact time, adsorbent dosage and initial pH was investigated in order to find the optimum adsorption conditions. Equilibrium isotherms were used to identify the possible mechanism of the adsorption process. The optimum pH for removing of RR-120 dye from aqueous solutions was found to be 5 and for this condition maximum predicted adsorption capacity for RR-120 dye was obtained as 426.49 mg/g. Also, the equilibrium data were also fitted to the Langmuir, Freundlich and BET equilibrium isotherm models. It was found that the data fitted to BET (R2=0.9897) better than Langmuir (R2=0.9190) and Freundlich (R2=0.8819) model. Finally it was concluded that the single-walled carbon nanotubes can be used for dye removal from aqueous solutions.

Background: Composting process is a feasible biological treatment for the recycling of municipal solid wastes as a soil amendment. The principal requirement of compost for it to be safely used in soil is a high degree of stability or maturity, which implies stable organic matter content as well as the absence of phytotoxic compounds and plant or animal pathogens. Objectives: At the present study, the maturity and stability of composted municipal solid wastes at a biocompost plant was evaluated. Materials and Methods: For the assessment of compost maturity, important parameters including temperature, moisture content, pH, electrical conductivity, carbon-to-nitrogen (C/N) ratio, microbial parameters including Salmonella, total and fecal coliforms were measured during the composting process (80 days). In addition, phytotoxicity as seed germination index and heavy metals concentration (Zn, Cu, Cr, Ni, Cd and Pb) was determined at the end of the composting time. Results:The results showed that the C/N ratio decreased during the composting process (reached to 15.6) due to the loss of carbon and the increase in nitrogen content per unit material; also, the NH 4 + /NO 3 ratio decreased with increase in the time of composting and reached

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A total of 78 street dust samples (75 within city and 3 from suburban) were collected from different areas with various land use within the city of Zahedan in November 2013 at the end of a long dry period. After digestion, the concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were measured by using ICP-OES. The degree of pollution by heavy metals was assessed with respect to the background concentration by calculation and comparison of the pollution index, integrated pollution index (IPI) and enrichment factor (EF). The mean IPI values (aggregate of six heavy metals) in commercial, high traffic, industrial, urban park, and residential were 3.65, 2.76, 1.68, 1.53 and 1.25, respectively. The results of EF analysis showed almost all sampled urban land use types to be enriched in heavy metals compared with sampled background levels, suggesting heavy metals contamination of street dust in the urban center is from anthropogenic sources.