The characteristics of stepwise ultrasonic hydrolysates of sludge for enhancing denitrification.

The disposal of waste activated sludge (WAS) accounts for approximately 60 % of wastewater treatment plant operating costs. In this study, according to the reaction time and water quality parameters, ultrasonic hydrolysis of WAS is divided into three stages, including floc-disintegration (0-25.2 kJ/g TS), cell-disruption (25.

A Comparison of Heterogeneous/Homogeneous Crystallization for Phosphate Recovery from Biosolids.

  In this study, a fluidized bed reactor was used to compare heterogeneous and homogeneous crystallization for recovering magnesium ammonia phosphate (MAP) from the dewatering filtrate at a municipal water resource recovery facility. Investigating the factors affecting crystallization revealed that pH exerted a greater effect than the Mg/P molar ratio. The results of a heterogeneous crystallization experiment showed that removal efficiency of phosphate (RP%) and crystal efficiency of phosphate (CP%) were 68% and 66%, respectively, at a PO4-P concentration of 200 mg/L, pH of 8.

Dynamic fouling behaviors of submerged nonwoven bioreactor for filtration of activated sludge with different SRT.

The flux variations and resistances accumulated during filtration of activated sludge with sludge retention time (SRT) of 15, 30, and 60 days were analyzed to investigate the dynamic fouling behavior in a submerged nonwoven bioreactor. Different SRT values varied sludge condition and particle size distribution in the supernatants, which caused dissimilar fouling characteristics. Short-term fouling of the nonwoven bioreactor during filtration of activated sludge with SRT of 15 days was fully reversible, and the resistance percentages of solutes, colloids, and suspended solids were 6%, 27%, and 67%, respectively.

Effects of different carbon supplements on phosphorus removal in low C/P ratio industrial wastewater.

This study focuses on the effects of different carbon supplements on biological phosphorus removal in the optonics and semiconductor industrial wastewater treatment. Experimental results demonstrate that the addition of a carbon source (glucose, acetate, and digester supernatant) improved phosphorus removal effectively. When the COD/P ratios were controlled in the range of 18-20 (using glucose and supernatant as supplement), the acclimated sludge showed more than 98% removal of phosphorus.

Comparison of polyhydroxyalkanoates production by activated sludges from anaerobic and oxic zones of an enhanced biological phosphorus removal system: effect of sludge retention time.

This study compared the PHAs production behavior of sludges from the anaerobic and oxic phases of an enhanced biological phosphorus removal (EBPR) system. This was accomplished by using the kinetics and stoichiometric coefficients obtained from aerobic batch tests to evaluate the performance of these two sludges. Experimental results indicated that the metabolic behavior of the sludges for PHAs production depend significantly on the operating sludge retention time (SRT) of the EBPR system.

Comparative study on the degradation of I.C. Remazol Brilliant Blue R and I.C. Acid Black 1 by Fenton oxidation and Fe 0/air process and toxicity evaluation.

Degradation of Remazol Brilliant Blue R (anthraquinone dye) and Acid Black 1 (azo dye) by Fenton oxidation and low-cost Fe(0)/air process was compared. The doses of Fenton reagent needed for decolorization of Remazol Brilliant Blue R was much higher than for Acid Black 1. The Fe(0)/air process rapidly decolorized dyes within 5 min at the Fe(0) doses of 10 and 50 g L(-1) for Remazol Brilliant Blue R and Acid Black 1, respectively.

The effects of soluble organic matters on membrane fouling index.

This study investigated the effects of soluble organic matters on membrane fouling characteristics, using silt density index (SDI) and modified fouling index (MFI) to evaluate the fouling potential. Experimental results demonstrated that humic acid had significant effects on membrane fouling indexes. When its concentration was in the range of 0.