[Transformation of phosphorus forms in the construction process of phosphate reduction system of hypersaline and high-phosphorus wastewater].

Transformation of phosphorus forms in the construction process of biological phosphate reduction system was discussed in treating saline and high-phosphorus pickled mustard tube wastewater to resolve problems encountered with present phosphorus removal technology. A phosphate reduction system under hypersaline condition (salinity, 7% , measured by NaCl) was successfully constructed, when the reactor was started with 3% salinity wastewater and the salinity was increased through two stages, at influent organic loading (COD) 0.45 kg x (m3 x d)(-1), phosphorus loading (PO4(3-)-P) 5.0 g x (m3 x d)(-1), DO 6 mg/L, 30 degrees C and without sludge discharge. Phosphorus balance and transformation of phosphorus forms in sludge was studied on 26 running cycles of this phosphorus reduction system. Results show that averagely 41.8 mg x L(-1) of external phosphorus gets lost per day, and that 155 mg of internal phosphorus in sludge gets lost through the path of phosphorus forms transformation and phosphate reduction, which accounted for 14.2% of the external phosphorus loss and 12.5% of the total phosphorus loss, respectively. The transformation path of phosphorus forms in sludge is Org-P --> NaOH85-P --> HCl-P --> NaOH-P --> BD-P --> H2 O-P.

[Simultaneous chracterization of RBCOD and SBCOD in wastewater by hybrid respirometer].

Respirometry was made using wastewater and activated sludge from a WWTP of Chongqing through self-developed hybrid respirometer. And complete oxygen uptake rate (OUR) curves containing OUR of biodegradation process of RBCOD and SBCOD and endogenous process were obtained. A new method based on respirometry was proposed to characterize RBCOD and SBCOD in wastewater simultaneously, in which hydrolysis model was selected to analyze OUR curves of SBCOD according to the two-phases nature of exogenous OUR and trend-test method for endogens OUR. Compared with the traditional OUR-stages method, the new method reduces the man-made error and improves the accuracy of wastewater COD fractions characterization.

[Performance of biological phosphorus removal in anaerobic pre-fermentation and intermittent aerated biofilm system treating domestic wastewater].

A fixed-film system composed of anaerobic biofilter and intermittent aerated biofilter (IABF) was developed for enhanced biological phosphorus removal (EBPR) in treatment of domestic wastewater. Influence of hydraulic, organic, and phosphorus loading on performance of the system was investigated in this study. The result indicates that the system is efficient for the removal of organic and P in the treatment. At a hydraulic retention time of the system of 23.3-4.6 h, the effluent concentration and reduction efficiency of TP and COD are 0.59 mg/L, 68 mg/L in average and 85.2%, 73.6% in average, respectively. A stable performance of EBPR in the system is achieved with a good adaptability of fluctuations of the loadings. An innovative method instead of traditional backwashing was applied to remove P in biofilm from IABF. The use of the method improves P-uptake capacity in biofilm during long-term operation without wasting, which prolongs operation duration and reduces backwashing frequency in IABF. Pre-fermentation of domestic wastewater in anaerobic biofilter increases concentration of volatile fatty acids in the influent of IABF.

[Various effects on the activity of activated sludge by low intensity ultrasonic treatments with different parameter combinations].

Aerobic activated sludge was used as experimental material. Specific oxygen uptake rate (SOUR), mixed liquor suspended solids (MLSS), COD ratio and lambda (deltaMLSS/deltaCOD) were taken as experimental indexes to indicate the changes of sludge activity and metabolism. The influences on activated sludge induced by ultrasonic treatments with different parameter combinations were studied by equal-distribution experiments about frequency, ultrasound intensity and irradiation time. The results indicated that the best parameter combination (28 kHz, 20 W/L, 2 min) leaded to an evident enhancement of sludge activity and reduced the sludge production at the same time. MLSS, as a vital factor which influences the ultrasonic treatment, was concerned in this study. To the sludge used in these experiments, the results of multilevel experiments showed that the MLSS of 3 000 mg/L induced to a relative highest performance after ultrasonic treatment with the best parameter combination. This article also hypothetically presented the mechanism of sludge activity enhancement stimulated by low intensity ultrasound.

[Effects of Mn2+, Mo6+ and Zn2+ on the components change of extracellular polymeric substances in activated sludge].

By specific oxygen uptake rate, (SOUR) measurements of activated sludge with different metal ion concentration, the optimal stimulation concentrations of Mn2+, Mo6+ and Zn2+ were determined. Then within each metal ion stimulation concentration range, extracellular polymeric substances (EPS) were extracted from activated sludge and its components (protein, polysaccharide and nucleic acid) contents changes were investigated. The results showed that the optimal stimulation concentration of each metal ion is 1mg x L(-1). EPS components of activated sludge vary obviously with Mn2+ and Zn2+ concentration change but not with Mo6+. After storage at low temperature, EPS quantities in activated sludge are reduced with polysaccharide reduction is the most.

[Study on determination of trace copper(II) by catalytic kinetic discoloring spectrophotometry].

A kinetic spectrophotometric method for the determination of trace Cu(II) was developed in this paper. This method is based on the discoloring oxidation reaction between malachite green and hydrogen peroxide catalyzed by copper(II) in the medium of HCl solution. The influential factors of reaction and the optimum conditions for the determination of Cu2+ were investigated in detail. The decrease in absorbance was measured at 615 nm at fixed time intervals. The linear determination range is between 0 and 22 microg x L(-1) of copper(II). A detection limit of 1.92 microg x L(-1) is achieved. The catalytic and non-catalytic reactions are the first-order on copper(II), in the reaction time interval 15-20 min at 70 degrees C. The apparent activation energy of the catalytic reaction is 122.3 kJ x mol(-1). The apparent rate is 7.70 x 10(-4) s(-1). The Relative Standard Deviations (RSD) are 1.16% and the recoveries are 98.3%-100.3%. By masking Fe(III) ion with PO4(3-), the method can be applied to the determination of copper in water sample and foodstuffs with satisfactory results.