Comprehensive insight of the performances of excess sludge reduction by 90°C thermal treatment coupled with activated sludge at pilot scale: COD and N removal, bacterial populations, fate of heavy metals

2011 ◽  
Vol 46 (9) ◽  
pp. 1808-1816 ◽  
Author(s):  
J. Laurent ◽  
K. Jaziri ◽  
R. Guignard ◽  
M. Casellas ◽  
C. Dagot
Keyword(s):  
Heavy Metals ◽  
Thermal Treatment ◽  
Activated Sludge ◽  
Pilot Scale ◽  
Sludge Reduction ◽  
Excess Sludge ◽  
Bacterial Populations ◽  
N Removal ◽  
Excess Sludge Reduction

Transformation and Migration of Heavy Metals by Aquatic Worms in Wastewater Treatment

2012 ◽  
Vol 573-574 ◽  
pp. 526-533
Author(s):  
Wei Fei Huang ◽  
Ying Gang Shu ◽  
Lu Cai ◽  
Sheng Liang Si
Keyword(s):  
Heavy Metals ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Environmental Risk ◽  
Sludge Reduction ◽  
Excess Sludge ◽  
Safe Disposal ◽  
Waste Sludge ◽  
And Migration ◽  
Sludge Settleability

L. hoffmeisteri was inoculated in reactor to investigate the effects on waste sludge and wastewater to reduce excess sludge and reduce the environmental risk of heavy metals in sludge and effluent in this study. The result showed a gravimetric sludge reduction of 53.8% and modification in the texture of the sludge. The residual form of heavy metals (As, Cd, Cr, Cu, Ni, Pb and Zn) was increased, which reduced the risk of the phytoaccumulation. An evident concentration of heavy metals in worm faece and a bioaccumulation of heavy metals in aquatic worms were also observed. Activated sludge is reduced significantly, sludge settleability is improved and the bioavailability of heavy metals in waste sludge is minimized, which are beneficial to wastewater treatment and safe disposal of waste sludge.

Comparison between ozonation and the OSA process: analysis of excess sludge reduction and biomass activity in two different pilot plants

2012 ◽  
Vol 66 (1) ◽  
pp. 185-192 ◽  
Author(s):  
Michele Torregrossa ◽  
Gaetano Di Bella ◽  
Daniele Di Trapani
Keyword(s):  
Municipal Wastewater ◽  
Process Analysis ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Anaerobic Sludge ◽  
Sludge Reduction ◽  
Excess Sludge ◽  
Biomass Activity ◽  
Excess Sludge Reduction ◽  
Ozone Contactor

The excess biomass produced during biological treatment of municipal wastewater represents a major issue worldwide, as its disposal implies environmental, economic and social impacts. Therefore, there has been a growing interest in developing technologies to reduce sludge production. The main proposed strategies can be categorized according to the place inside the wastewater treatment plant (WWTP) where the reduction takes place. In particular, sludge minimization can be achieved in the wastewater line as well as in the sludge line. This paper presents the results of two pilot scale systems, to evaluate their feasibility for sludge reduction and to understand their effect on biomass activity: (1) a pilot plant with an ozone contactor in the return activated sludge (RAS) stream for the exposition of sludge to a low ozone dosage; and (2) an oxic-settling-anaerobic (OSA) process with high retention time in the anaerobic sludge holding tank have been studied. The results showed that both technologies enabled significant excess sludge reduction but produced a slight decrease of biomass respiratory activity.

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