Sustainability of Wastewater Treatment and Excess Sludge Handling Practices in the Federated States of Micronesia

Author(s):  
Joseph Rouse
1994 ◽  
Vol 30 (8) ◽  
pp. 97-106 ◽  
Author(s):  
Angel Canales ◽  
Alain Pareilleux ◽  
Jean Luc Rols ◽  
Ge´rard Goma ◽  
Alain Huyard

With new EEC regulations, alternative treatment and disposal techniques of the excess sludge produced by Activated Sludge (AS) wastewater treatment plants have to be performed. In order to reduce the excess sludge produced, experiments have been carried out with a Membrane BioReactor (MBR) to study the maintenance and cryptic growth phenomena of Pseudomonas fluorescens culture taken as a model when grown on a limiting substrate complex medium similar to a synthetic urban wastewater. Experiments with various imposed wasting rates showed that viability and sludge production yield decreased when sludge age increased. Same variations were observed on the cell content ratio protein/polysaccharide by analysis of the cell lysis products released after discontinuous thermal treatment. Biomass growth on these cell lysis products was achieved to characterize cryptic growth and its impact on sludge production yield. Finally, a continuous sludge thermal treatment system was operating with MBR to amplify sludge breakage and consequently biomass growth on the lysis products. With the promising results obtained, this work gives a new outlook on the AS process and leads to the development of processes with control and reduction of sludge production.


2015 ◽  
Vol 768 ◽  
pp. 108-115
Author(s):  
Pan Yue Zhang ◽  
Tian Wan ◽  
Guang Ming Zhang

‘Sonication - cryptic growth’ technology can reduce 30-80% excess sludge in wastewater treatment systems. Various mechanisms contribute to the sludge reduction but the role of each one is unclear. This paper quantitatively studied the potential mechanisms in ‘sonication - cryptic growth’. The operation condition was: every day 20% sludge was sonicated under 1.2 Wml-1 for 15 min and then returned to the wastewater treatment reactor for cryptic growth. The results showed that under such conditions, ‘sonication - cryptic growth’ reduced the excess sludge by 57.3% and the effluent met the national discharge standard. Multiple mechanisms were involved in the process. Detailed analysis showed that the ‘lysis-cryptic growth’ mechanism was the most important one and accounted for 49.1% of sludge reduction. Biodegradation of residual sludge was the second important one and contributed 19.5%. Other potential mechanisms included the altered microbial community, longer sludge retention time, and accumulation of persistent materials. But organic load increase had virtually no impact.


2005 ◽  
Vol 95 (6) ◽  
pp. 447-455 ◽  
Author(s):  
Claudio Di Iaconi ◽  
Roberto Ramadori ◽  
Antonio Lopez ◽  
Roberto Passino

2005 ◽  
Vol 52 (10-11) ◽  
pp. 255-263 ◽  
Author(s):  
J. Chauzy ◽  
S. Graja ◽  
F. Gerardin ◽  
D. Crétenot ◽  
L. Patria ◽  
...  

In many cases, reducing sludge production could be the solution for wastewater treatment plants (WWTP) that here difficulty evacuating the residuals of wastewater treatment. The aim of this study was to test the possibility of minimising the excess sludge production by coupling a thermal hydrolysis stage and an anaerobic digestion with a very short HRT. The tests were carried out on a 2,500 p.e. pilot plant installed on a recycling loop between the clarifier and the actived sludge basin. The line equipped with the full scale pilot plant produced 38% TSS less than the control line during a 10 week period. Moreover, the rapid anaerobic digestion removed, on average, more than 50% of the total COD load with a hydraulic retention time (HRT) of 3 days. Lastly, the dryness of the remaining excess sludge, sanitised by the thermal hydrolysis, was more than 35% with an industrial centrifuge. This combination of thermal hydrolysis and rapid anaerobic digestion equally permits a significant gain of compactness compared to traditional anaerobic digesters.


2003 ◽  
Vol 37 (18) ◽  
pp. 4453-4467 ◽  
Author(s):  
Yuansong Wei ◽  
Renze T. Van Houten ◽  
Arjan R. Borger ◽  
Dick H. Eikelboom ◽  
Yaobo Fan

2006 ◽  
Vol 53 (9) ◽  
pp. 71-77 ◽  
Author(s):  
Anfeng Yu ◽  
Quan Feng ◽  
Zehua Liu ◽  
Yunan Zhou ◽  
Xin-Hui Xing

Activated sludge has been widely used in wastewater treatment throughout the world. However, the biggest disadvantage of this method is the by-production of excess sludge in a large amount, resulting in difficulties in operation and high costs for wastewater treatment. Technological innovations for wastewater treatment capable of reducing excess sludge have thus become research topics of interest in recent years. In our present research, we developed a new biological wastewater treatment process by repeated coupling of aerobes and anaerobes (rCAA) to reduce the excess sludge during the treatment of wastewater. During 460-day continuous running, COD (300–700 mg/L) and TOC (100–350 mg/L) were effectively removed, of which the removal rate was above 80 and 90%, respectively. SS in the effluent was 13 mg/L on average in the rCAA bioreactor without a settling tank. The on-site reduction of the excess sludge in the rCAA might be contributed by several mechanisms. The degradation of the grown aerobes after moving into the anaerobic regions was considered to be one of the most important factors. Besides, the repeatedly coupling of aerobes and anaerobes could also result in a complex microbial community with more metazoans and decoupling of the microbial anabolism and catabolism.


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