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To explore the possible impact of river sediments on the endogenous pollution of water body under different dredging conditions, sediments in the Luling and Guanzui sections of Tuo River were selected as research object. On the basis of pollution assessment of typical heavy metals (i.e. Cd, Cr, Cu, Ni, Pb, Zn), the release characteristics of chemical oxygen demand (CODCr), total phosphorus (TP) and fluoride (F) in these two sediments were studied using an indoor disturbance test device. Results show that sediments of the Luling and Guanzui sections were unpolluted to moderately polluted by Cd and Cu. The comprehensive ecological risk of the selected heavy metals in the Luling and Guanzui sediments was low. However, the single potential ecological risk of Cd was at moderate risk level. Pollution level of heavy metals in Guanzui sediment is higher than that in Luling sediment. Owing to the influences of mineral composition, content of pollutants and chemical species of pollutants in sediments, CODCr, TP and F in the sediments of the two sections show different release characteristics. The Guanzui and Luling sediments showed release 'source' characteristics for CODCr and F, respectively, to overlying water. CODCr and F were the priority pollutants of endogenous pollution in the Guanzui and Luling sections, respectively, of Tuo River. [ABSTRACT FROM AUTHOR]

Areca-cooking wastewater is pretreated by aer-ation aluminum-carbon micro-electrolysis. By orthogonal experiments and single factor experiments, the study gets: when the initial pH value, colority, SS and COD index of the areca-cooking wastewater is 3.5, 1000(times), 647mg-L-1 and HeSSmg-L-1, respectively, the optimal operating parameter of aeration aluminum-carbon micro-electrolysis is as follows: aluminum shavings dosage is 70g-L-1, Al/C mass ratio is 1:1.5, and the reaction time is 240min. The average removal efficiency of colority, SS and COD index is 87.5%, 97.2% and 53.8%, respectively, and the biodegradability of the wastewater is improved from 0.28 to 0.68 of BOD5/COD so that it sets up the appropriate foundation for the sequent biodegradable treatment. The contrasting and analyzing results of pollutant components in the influent before micro-electrolysis and the effluent after micro-electrolysis by UHPLC-Q-TOF/MS show that aeration aluminum-carbon micro-electrolysis may remove the poisonous and non-degradable plant pol-yphenols by reduction, complexation, flocculation, absorption, coprecipitation and conglutination of micro-electric field to improve its biodegradability, and what's more improve the biodegradability of wastewater. [ABSTRACT FROM AUTHOR]

Pyrolusite leaching residue (PLR) was used as a low-cost adsorbent to remove methylene blue (MB) from aqueous solution by adsorbing MB and regenerating PLR in a H2O2/H2SO4 system. In this paper, the behaviors of adsorption and regeneration as well as the mechanisms of PLR were investigated. The experimental results showed that it took 180 min to reach adsorption equilibrium. The adsorption process was kinetically fitted to both pseudo-first-order and pseudo-second-order models. In isotherm equilibrium, it was better fitted to Langmuir isotherm model with a maximum adsorption capacity of 22.15 mg/g. The degradation process was influenced by degradation temperature and concentrations of H2SO4 and H2O2, whose best values were determined as 65 °C, 0.2% and 0.3%, respectively. PLR was proven to show good cycle performance by repeated adsorption-degradation process under appropriate conditions. In degradation process, MnO2 was extracted by sulfuric acid solution with hydrogen peroxide, which had a synergetic effect on the degradation of MB. The results will provide a novel approach for removal of dyes and resource utilization of PLR. [ABSTRACT FROM AUTHOR]