Ultrasonic reduction of excess sludge from the activated sludge system

Zhang, Guangming; Zhang, Panyue; Yang, Jianfeng; Chen, Yanming

doi:10.1016/j.jhazmat.2007.01.133

Cited by 106 publications

(49 citation statements)

References 14 publications

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“…Wśród stosowanych i badanych metod dezintegracji wykorzystuje się głównie: ozonowanie [3], alkalizowanie [10], zakwaszanie [24], użycie wysokiego ciśnienia [8], rozdrabnianie mechaniczne [16], enzymy [21], ultradźwięki [25], promieniowanie mikrofalowe [6] oraz zamrażanie/ rozmrażanie [15,19].…”

Section: Wprowadzenieunclassified

Improving the Gravitational Properties of Sewage Sludge by Pretreatments

Nowicka¹,

Grűbel²,

Machnicka³

2015

Inż. Ekolog.

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STRESZCZENIEPowstawanie osadów ściekowych jest nieuniknioną konsekwencją procesów oczyszczania ścieków, a ich unieszkodliwianie i utylizacja wymaga wiedzy, rozwiązań technologicznych i technicznych. Zastosowanie procesów wstępnej obróbki/kondycjonowania pozwala na uzyskanie poprawy własności mechanicznych osadów ścieko-wych. W ostatniej dekadzie można odnotować wiele prac badawczych z całego świata skoncentrowanych na nowych metodach kondycjonowania osadów tj. procesach dezintegracji, wśród których stosuje się destrukcję mechaniczną, chemiczną i biologiczną. Pomimo odmiennego działania każdej z metod (wprowadzona energia, zjawiska cieplne, zachodzące reakcje chemiczne, oddziaływania mechaniczne) ich wspólnym celem jest niszczenie struktury kłaczków osadu czynnego oraz mikroorganizmów, co skutkuje zmianami własności osadów i cieczy nadosadowej. W artykule przedstawiono wpływ dezintegracji mikrofalowej i zamrażania/rozmrażania suchym lodem na wybrane własności grawitacyjne osadu czynnego nadmiernego. Określono parametry charakterystyczne dla procesu sedymentacji osadu tj. prędkość opadania i zagęszczania, indeks gęstości osadu i indeks objętości osadu oraz zmiany zachodzące w cieczy nadosadowej. Przeprowadzone badania wykazały skuteczność stosowania wybranych metod dezintegracji osadu w odniesieniu do poprawy właściwości grawitacyjnych i stały się przyczynkiem do określenia skutecznej metodyki wstępnego kondycjonowania osadów.Słowa kluczowe: fala elektromagnetyczna, suchy lód, osad czynny nadmierny, własności grawitacyjne osadu. IMPROVING THE GRAVITATIONAL PROPERTIES OF SEWAGE SLUDGE BY PRETREATMENTS ABSTRACTThe formation of sludge is an inevitable consequence of wastewater treatment processes. Their disposal and utilization requires knowledge on technology and engineering. The application of pretreatment processes/conditioning allows to obtain better mechanical properties of sludge. In the last decade a lot of research from around the world focused on new methods of conditioning of sludge can be noticed, i.e. The processes of disintegration, of which the destruction of the mechanical, chemical and biological. Despite different activities of each method (introduced energy, thermal phenomena, chemical reactions, mechanical), their common goal is the destruction of activated sludge floc structure and micro-organisms, which result in changes of properties in sediment and supernatant liquid. The influence of the disintegration of the microwave and freezing/thawing dry ice on selected properties of gravitational surplus activated sludge were presented. Characteristic parameters determined sludge sedimentation processes, i.e. the rate of descent and compaction density index sediment and sludge volume index and changes in the supernatant liquid. The study showed the efficacy of selected methods of sludge disintegration with regard to improving the properties of gravity and becoming a contribution to the determination of the effective methods of deposits' preconditioning.

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Section: Wprowadzenieunclassified

Improving the Gravitational Properties of Sewage Sludge by Pretreatments

Nowicka¹,

Grűbel²,

Machnicka³

2015

Inż. Ekolog.

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“…When it is below 20 MJ/kg TS as in the present study, the trend was positive in comparison to the conventional system and when ES was higher, biomass activity showed a decreased. It is remarkable how other authors [19], [20] have reported that the performance of system was only irreversibly damaged with a much more intense ultrasound treatment than the one in US2. Indeed, in these studies, conditions of treatment were, respectively for [19] and [20]: fraction of sludge treated daily (SP) 30% and 28.5 % with an E S of 72 MJ/Kg and 108MJ/kg.…”

Section: Dehydrogenase Activitymentioning

confidence: 92%

“…It is remarkable how other authors [19], [20] have reported that the performance of system was only irreversibly damaged with a much more intense ultrasound treatment than the one in US2. Indeed, in these studies, conditions of treatment were, respectively for [19] and [20]: fraction of sludge treated daily (SP) 30% and 28.5 % with an E S of 72 MJ/Kg and 108MJ/kg. The synergic effect of the combined process of ultrasound treatment with OSA process exposure could lead to a more efficient energy consumption and thus to an economical advantage.…”

Section: Dehydrogenase Activitymentioning

confidence: 99%

Sludge Reduction and General Performance in a Combined US+OSA System

Romero-Pareja¹,

Aragon-Cruz²,

Quiroga-Alonso³

et al. 2017

IJESD

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Abstract-The reduction of sewage sludge generated in wastewater treatment plants is one topic of interest due to the high cost related to the management of this waste and the rising amount of volume at which sludge is produced worldwide. Within the techniques to reduce sludge, the Oxic-Settling-Anaerobic (OSA) process is one of the most promising due to its simplicity and to the absence of negative consequences for system. In the OSA process the recycled sludge is submitted to an anaerobic stage prior to flow again into the biological reactor. In this study, OSA process is run in a lab scale pilot plant together with a lysis step by ultrasound treatment, applied daily to a certain fraction of the total sludge of the system previously to the anaerobic holding tank. Results point to an enhancement of sludge reduction rate for the two sonication applied regimes (45.72% and 78.56%). Also the TN removal rate increases from 21.95% during control stage to 47.28% during the first of the two ultrasound regimes applied (US1). A too intense sonication treatment during the second synergic stage (US2) is reported to lead to a serious damage of system. Increases of dehydrogenase activity were described during both stages.

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“…A large proportion of biological sludge types include microorganisms which have cells, intracellular water, and a membrane (5). Since the main purpose of dewatering sludge is to remove the water trapped in cells, the process used should be able to remove interstitial water (6). When the water solution is exposed to the ultrasonic process, a high pressure gradient is generated in water, which leads to the expansion and contraction of some micron-sized bubbles.…”

Section: Introductionmentioning

confidence: 99%

Degradation of Organic Matter of Municipal Sewage Sludge Using Ultrasound Treatment in Shiraz Wastewater Treatment Plant

et al. 2015

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Background: Nowadays, the reduction of sludge production in the activated sludge process as well as disposal restrictions have drawn much attention. Objectives: The purpose of this study was to evaluate the feasibility of using ultrasound treatment in increasing the degradation of organic matter in sewage sludge from Shiraz Municipal Wastewater Treatment Plant and also to assess its effect on sludge dewatering. Materials and Methods:The samples were collected from the anaerobic digester of the Shiraz Wastewater Treatment Plant. The present study was conducted at the bench-scale method. The influence of different pH (3-9) and the effect of contact time (10-120 min) at the constant ultrasonic treatment (37 kHz) on degradation of organic matter were investigated. Since ultrasound is a cyclic sound pressure with a frequency greater than the upper limit of the human hearing range, this limit is approximately 20 kilohertz (20,000 hertz). In addition, the effect of ultrasonic treatment on the total solids (TS), volatile solids (VS), sludge volume index (SVI) and specific resistance to filtration (SRF) were determined. Results:The results of this study showed that the release of soluble chemical oxygen demand (SCOD) in the supernatant and SRF were in the range of 127.9-831 mg/L and 12.48-36.55 m/kg at 10 to 120 min ultrasonic contact time, respectively. In addition, TS and VS decreased from 57.98 and 56.31 to 52.69 and 49.87 mg/L, respectively. Despite the significant reduction in the solids, there was no considerable variation in SVI. Conclusions: This method can be used as a pretreatment method for the treatment of the sewage sludge. Moreover, a complementary treatment is necessary to reach the standard limit.

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Ultrasonic reduction of excess sludge from the activated sludge system

Cited by 106 publications

References 14 publications

Improving the Gravitational Properties of Sewage Sludge by Pretreatments

Improving the Gravitational Properties of Sewage Sludge by Pretreatments

Sludge Reduction and General Performance in a Combined US+OSA System

Degradation of Organic Matter of Municipal Sewage Sludge Using Ultrasound Treatment in Shiraz Wastewater Treatment Plant

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