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Titolo:
Complete decomposition of biological waste sludge by thermophilic aerobic bacteria
Autore:
Sakai, Y; Aoyagi, T; Shiota, N; Akashi, A; Hasegawa, S;
Indirizzi:
Japan Sewage Works Agcy, Res & Technol Dev Div, Toda, Saitama 3350037, Japan Japan Sewage Works Agcy Toda Saitama Japan 3350037 Saitama 3350037, Japan Sewage Div Nakanojo Town, Gunma 3770494, Japan Sewage Div Nakanojo Town Gunma Japan 3770494 Town, Gunma 3770494, Japan Shinko Pantec Co Ltd, Dept Res & Dev, Nishi Ku, Kobe, Hyogo 6512241, JapanShinko Pantec Co Ltd Kobe Hyogo Japan 6512241 Kobe, Hyogo 6512241, Japan
Titolo Testata:
WATER SCIENCE AND TECHNOLOGY
fascicolo: 9, volume: 42, anno: 2000,
pagine: 81 - 88
SICI:
0273-1223(2000)42:9<81:CDOBWS>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIGESTION;
Keywords:
activated sludge process; enzyme; sludge; solubilization; thermophilic bacteria;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
5
Recensione:
Indirizzi per estratti:
Indirizzo: Sakai, Y Japan Sewage Works Agcy, Res & Technol Dev Div, 1541 Shimosasame,Toda, Saitama 3350037, Japan Japan Sewage Works Agcy 1541 Shimosasame TodaSaitama Japan 3350037
Citazione:
Y. Sakai et al., "Complete decomposition of biological waste sludge by thermophilic aerobic bacteria", WATER SCI T, 42(9), 2000, pp. 81-88

Abstract

Conventional activated sludge (AS) process is an economical and effective biooxidation process although a large amount of excess sludge is necessarily generated. We have developed a new zero-discharge AS process, in which noexcess sludge is generated. It was formed by combining the conventional ASprocess with thermophilic aerobic sludge digester in which excess sludge is solubilized by thermophilic enzyme, so we call it hereafter the digester S-TE reactor. The excess sludge withdrawn from the AS step is subjected to the S-TE reactor, followed by its circulation to an aeration tank. Completedecomposition of the excess sludge is carried out when the sludge is solubilized by thermophilic aerobic bacteria (e.g. Bacillus sp.) and mineralizedby mesophilic bacteria. The S-TE reactor is operated at 65 degreesC with hydraulic retention time of 1 day. Bench-scale test facilities of both the new process and conventional AS process were comparatively operated under the conditions of BOD-SS loading of 0.3 kg/kg/d and MLSS of 2,000 mg/L using artificial wastewater for over 100 days. The S-TE reactor was initially inoculated with the seedling culture of isolated Bacillus sp. bacteria. No additional inoculation seem to be needed under the steady condition since these bacteria can form spores and survive even under mesophilic conditions. The average rates of VSS solubilization and VM removal in the S-TE reactor were 40% and 15%, respectively. No excess sludge was generated when 3-fold amounts of the excess sludge generated in the conventional AS process were subjected to the S-TE reactor. in the new process, BOD was removed with high efficiency. Slight increase of SS and TOC was observed when compared with those of the AS process. A pilot-scale facility of the process has been operated with a petrochemical plant wastewater for a year. MLSS concentration was continuously kept around 3,000 mg/L without withdrawing the excess sludge. Inorganic salts seemed not to accumulate in the process. Therefore, it was demonstrated that excess sludge generation was completely reduced in thenew process. According to our estimates, total operating costs for the newprocess are reduced to 40-50% of those of the conventional wastewater dewatering process. An application to a municipal sewage sludge treatment is currently performed in its full-scale facility.

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Documento generato il 01/04/20 alle ore 01:57:45