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Samples of typical street dust were collected from Jian-sheng Town, Chongqing City and classified into four groups on the basis of particle size: 0-75, 75-150, 150-300, and 300- 1000 lm. The pollutant content and heavy metal composition of the samples were investigated. The particles in the 0-75, 75-150, 150-300, and 300-1000 lm groups had mass fractions of 20.82% ± 8.86%, 24.68% ± 9%, 30.83% ± 9.76%, and 23.68% ± 15.56%, respectively. The highest concentration of nutritional pollutants was detected in the 300-1,000 mm group, with total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) concentrations of 3.07 ± 2.48, 0.64 ± 0.39, and 83.79 ± 65.28 g/kg, respectively. The lowest concentration of nutritional pollutants was observed in the 150- 300 lm group, with TN, TP, and TOC concentrations of 1.78 ±1.22, 0.51 ± 0.20, and 36.74 ± 24.64 g/kg, respectively. The nutritional pollutants presented similar mass fractions in the street dust samples with different particle sizes. Vegetation significantly affected the TOC content in the samples. The TOC content of the streets with rich vegetation was 1.90 ± 0.56 times that of the streets with less vegetation. The 150-300 µm group had the highest heavy metal mass percentage. Among the heavy metals detected in street dust, Cd, Cr, and Ni were mainly residuals; Cu and Pb were oxidizable; and Zn was mainly acid-extractable. [ABSTRACT FROM AUTHOR]

Anaerobic ammonia oxidation(Anammox) process is a novel and promising wastewater nitrogen removal process. The feasibility of transition of Anammox from denitrification and the performance of lab-scale Anammox biofilm reactor were investigated with sludge dewatering effluent. The results showed that Anammox process could be successfully started up after cultivation of denitrification biofilm and using it as inoculum. The transition of Anammox from denitrification was accomplished within 85 d. Anammox process was found suitable to remove ammonia from sludge dewatering effluent. The effluent ammonia concentration was detected to be 23.11 mgN/L at HRT of 28 h when influent ammonia concentration was fed 245 mgN/L, which was less than that for the national discharge standard II (25 mgN/L) of China. Volumetric total nitrogen loading rate was up to 584.99 mg TN/(L· d) at HRT of 17 h, while influent concentrations were kept 243.25 mg NH4+ -N/L and 288.31 mg NO2- -N/L. [ABSTRACT FROM AUTHOR]

Anammox was successfully transited from heterotrophic denitrification and autotrophic denitrification in two upflow biofilm reactors, respectively. The results showed that the volumetric loading rate and nitrogen removal efficiency in the reactor transited from heterotrophic denitrification were higher than that in its counterpart. When the hydraulic retention time was 12 h or so, the total nitrogen loading rate was about 0.609 kg N/(m^3·d), and the effluent ammonia and nitrite concentrations were less than 8.5 mg/L and 2.5 mg/L, respectively. The upflow anammox biofilm reactor was capable of keeping and accumulating the slow-growing bacteria efficiently. During operation of the reactor, the biomass color was gradually turned from brownish to red, and the ratio of ammonia consumption, nitrite consumption and nitrate production approached the theoretical one. These changes could be used as an indicator for working state of the reactor. [ABSTRACT FROM AUTHOR]

The effect of elemental sulfur concentration on bioleaching of Cu, Zn and Pb and loss of fertilizer value from sewage sludge was investigated in flasks by batch experiments. The results showed that the ultimate pH of sludges with 3-5 g/L of sulfur added was about 1.3 and the production of SO42+ had good correlation with the elemental sulfur concentration. The sensitivity of removal efficiency of metals to sulfur concentration was: Pb > Cu > Zn. The sulfur concentration except for 3 - 5 g/L had significant effect on the solubilization of Cu, Pb and Zn. The highest solubilization efficiency for sludge with 3 g/L of sulfur was 87.86% for Cu, 32.72% for Pb and 92.14% for Zn which could make the treated sludge easily meet the metal limitations for land application. The sulfur concentration of 3 g/L was enough for the solubilization of all three heavy metals. The influence of sulfur concentration on solubilization of total nitrogen and potassium from sludge was negligible. but that on solublization of total phosphorus was of great importance. The loss of nitrogen phosphorus and potassium of sludge with 3 g/L of sulfur by bioleaching was 38.2%, 52.1% and 42.8% respectively, and the sludge still remained satisfactory fenilizer value after bioteaching. [ABSTRACT FROM AUTHOR]

Abstract: The effects of nitrite concentration, organic carbon and pH on denitrifying dephosphatation over nitrite were studied with batch tests. The results showed that anoxic initial phosphate uptake rate increased as nitrite concentration increased. For an initial phosphate of 8.5mgPL−1 and an initial COD of 350mgL−1, a nitrite level of 15.2mgN(gMLSS)−1 was found to be appropriate. The anaerobic phosphate release rate decreased as anaerobic nitrite addition increased. The results suggest that to ensure effective phosphate release and subsequent phosphate uptake, anaerobic nitrite should be lower than 2mgNL−1. Very high and very low initial COD concentrations both resulted in an adverse effect on denitrifying dephosphatation. The anaerobic phosphate release with different carbon sources followed the order: acetate>butyric acid>glucose. The suitable pH for anaerobic phosphate release and anoxic phosphate uptake was approximately 7.0 and 8.0, respectively. [Copyright &y& Elsevier]