Influence of sludge disintegration by high pressure homogenizer on microbial growth in sewage sludge: an approach for excess sludge reduction

Lajapathi, Chockalingam; Rao, Paruchuri G.

doi:10.1007/s10098-009-0202-y

Cited by 51 publications

(15 citation statements)

References 23 publications

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“…Therefore, the incinerated gas needs an extensive cleanup system. Generally, 19,000-23,000 Water, varying from a few percent to more than 95% incineration systems required much higher cost and longer payback periods and still produced the solid waste residue which requires further management (Rai and Rao 2009). Incineration generates the ash and discharges heavy metals and, CO 2 and N 2 O to the atmosphere.…”

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confidence: 98%

“…It is estimated that about 10 million dry tons of sewage sludge are produced every year in United States (Bandosz and Block 2006). The expected increase in sludge generation is itself a challenge for waste management authorities and the choices of treatment and disposal methods will have large economic and environmental implications (Rai and Rao 2009). New stringent regulations regarding sludge treatment and disposal as well as social and environmental concerns have resulted in a considerable impetus to develop strategies to reduce the excess sludge production (Wei et al 2003).…”

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confidence: 98%

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Application of physico-chemical pretreatment methods to enhance the sludge disintegration and subsequent anaerobic digestion: an up to date review

Tyagi

2011

Rev Environ Sci Biotechnol

229

106

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Anaerobic digestion of waste activated sludge (WAS) is most commonly used at wastewater treatment facilities to stabilize the sludge. However, poor biodegradation efficiency of sludge and longer retention times (20-30 days) are the major limitations of anaerobic digestion method, which can be overcome by disintegrate the sludge and make intracellular material readily available to anaerobic biodegradation. Several sludge disintegration techniques (Thermal, chemical and mechanical) and their combinations were studied previously in order to improve the anaerobic digestibility of sludge, reduce the sludge retention time and enhance the production of biogas. However, none of the pretreatment technique shows a real breakthrough in enhancement of anaerobic digestibility of WAS due to associated drawbacks, such as high operational and capital cost, poor sanitization and energy intensive. On the other hand, hybrid pretreatment techniques endow with promising outcomes through neutralizing the associated drawbacks with individual pretreatment techniques. Nevertheless, the research on the application of hybrid pretreatment techniques is in its infant stage, presently. Therefore, the satisfactory research in this direction can lead to policy maker and environmental protection agency to select more robust and sustainable solution for sludge treatment. This review encompasses the up-to-date information about the thermal, chemical and mechanical sludge disintegration techniques (principle, performance at lab, pilot and full scale, advantages and disadvantages). A comparative evaluation of these techniques are also presented in terms of COD solubilization, dewaterability, pathogens removal, lab/pilot/full scale application, capital and, operation and maintenance cost involved and energy requirement.

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confidence: 98%

mentioning

confidence: 98%

Application of physico-chemical pretreatment methods to enhance the sludge disintegration and subsequent anaerobic digestion: an up to date review

Tyagi

2011

Rev Environ Sci Biotechnol

229

106

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“…Dispersion is the disbanding and dissemination of a solid, fluid or gaseous stage. Latterly, this has been suggested as a WAS disruption method, which transforms the speed as well as degree of sludge disintegration in the AD process (Rai and Rao 2009;Kavitha et al 2016a). It has been chiefly used for making firm the stuffs from food and dairy suspensions and has paved way for progressively innovative relevance fields (Jacquel et al 2008).…”

Section: Reaction Mechanism Of Dispersion Treatmentmentioning

confidence: 98%

“…t/V . TS where P power in KW t treatment time V volume of sample TS initial total solids concentration in kg Among the various terminology used to represent ultrasonic dosage, SE is reliable and most widely used (Rai and Rao 2009). It can be applicable to measure energy requirement for disintegration for all types of sludge samples since input parameters for its measurement are simple and reliable.…”

Section: Reaction Mechanism Of Ultrasonic Treatmentmentioning

confidence: 99%

Various Sludge Pretreatments: Their Impact on Biogas Generation

Banu

Kavitha

2017

Waste Biomass Management – A Holistic Approach

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Biogas produced through anaerobic degradation of waste activated sludge (WAS) in wastewater treatment plants has gained much more attention as it is a renewable energy resource. An apparent advantage of anaerobic digestion is the generation of biogas that presents a renewable substitute for utilization of fossil fuels. It was observed that pretreatment has to be done prior to anaerobic degradation (AD) to enhance the biogas generation. This review deals with various pretreatments-chemical, physical, mechanical, combinative, phase-separated pretreatment, their mode of action, advantages and their impact on biogas generation. An extensive review of these pretreatment techniques could plausibly aid in increasing the biogas production and thus rises the sustainable energy generation.

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“…This means that CO2 will preferentially dissolve into liquid at elevated pressures, and that increased pressure will result in a higher biogas methane composition. Several studies have been conducted at high pressure conditions, which were mostly focussed on either sludge hydrolysis or biogas upgrading (Bamberger, Sieder et al 2000, Rai and Rao 2009, Lindeboom, Fermoso et al 2011, Keymer, Ruffell et al 2013, Zhang, Zhang et al 2013, Chen, Rößler et al 2014, Wahidunnabi and Eskicioglu 2014. Some of these studies found methane content up to 95% of biogas at a pressure range of 2 -90 bar, this also resulted in a two fold increase in methane production.…”

Section: High Pressurementioning

confidence: 99%

Enhanced phosphorus solubility during anaerobic digestion

Latif¹

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Worldwide phosphorus (P) consumption has increased massively over the last century, to overcome soil nutrient constraints, and to feed an increasing population with an increasing level of urbanization.However, current P reserves are limited and are expected to deplete in 50-120 years. Hence, new techniques to source P from alternative resources are essential. Waste streams are the largest alternative resource of P, with much of the organic wastes containing P treated by anaerobic digestion (AD). However, P recovery from the digested waste streams is limited by in-reactor P precipitation, and inaccessibility of soil available P in sludge biosolids. In-reactor P precipitation increases the operational costs of a treatment facility due to scaling and precipitation, there are strong advantages in being able to recover P as a purified mineral product. In such circumstances, keeping high PO4 concentration during AD is vital to enhance its recovery post AD.This thesis aims to assess two different techniques to enhance PO4 concentration during AD from waste activated sludge (WAS): low pH and high pressure (enabling low pH). Low pH single stage AD was tested in both batch and continuous mode. In the batch study, biochemical methane potential tests were conducted for 51 days at a pH range of 5.0 to 7.2 in two separate sets (two different WAS samples collected from municipal WWTP). Low pH (< 5.7) caused a significant loss in the methane potential (B0) of up to 33%, with 3.6 times increase in PO4 concentration compared to the neutral pH (7 -7.7), but with no major change in methane production rate coefficient (khyd). The loss in methane yield was mainly due to decrease in hydrolytic capability rather than inhibition of methanogenesis with volatile fatty acids (VFAs) being < 300 mgCOD L -1 and soluble COD < 1300 mgCOD L -1 even at low pH. While pH did not influence the acetoclastic community (Methanosaeta dominated), it was the primary driver for the remaining community, and caused a loss of diversity and shift to Clostridia.To validate the results from batch conditions, continuous low pH AD was performed using similar substrate and pH conditions. The influence of the pH on PO4 concentration was similar in continuous and batch. It was found that the low pH (5.5) caused a significant increase in PO4 concentration up to 79% of the total P, while methane yield was reduced by 50%. VFAs and SCOD concentrations increased from 40 to 504 mg L -1 and 600 to 2017 mg L -1 respectively, as the pH was reduced from 7.0 to 5.5. Higher concentration of propionic acid (370 -430 mg L -1 ) was recorded at low pH (< 5.5).The reduction in methane yield was associated with a shift in microbial community and decreased destruction of particulate organics. Acidogens dominated at low pH (< 6.0), while methanogens decreased by 88% at pH 5.5 compared to neutral pH. Apart from the loss in methanogenic and hydrolytic capacity, continuous acid dosing to maintain low pH condition was identified as a key limitation with this technology. To assess an...

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Influence of sludge disintegration by high pressure homogenizer on microbial growth in sewage sludge: an approach for excess sludge reduction

Cited by 51 publications

References 23 publications

Application of physico-chemical pretreatment methods to enhance the sludge disintegration and subsequent anaerobic digestion: an up to date review

Application of physico-chemical pretreatment methods to enhance the sludge disintegration and subsequent anaerobic digestion: an up to date review

Various Sludge Pretreatments: Their Impact on Biogas Generation

Enhanced phosphorus solubility during anaerobic digestion

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