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2017 2

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Improvement of sludge dewaterability with modified cinder via affecting EPS

Weichao Ma, Lei Zhao, Huiling Liu, Qianliang Liu, Jun Ma

《环境科学与工程前沿（英文）》 2017年第11卷第6期 doi: 10.1007/s11783-017-0967-x

摘要： The relationship between the improvement of sludge dewaterability and variation of organic matters has been studied in the process of sludge pre-conditioning with modified cinder, especially for extracellular polymeric substances (EPS) in the sludge. During the conditioning process, the decreases of total organic carbon (TOC) and soluble chemical oxygen demand (SCOD) were obviously in the supernatant especially for the acid modified cinder (ACMC), which could be attributed to the processes of adsorption and sweeping. The reduction of polysaccharide and protein in supernatant indicated that ACMC might adsorb EPS so that the tightly bound EPS (TB-EPS) decreased in sludge. In the case of ACMC addition with 24 g·L , SRF of the sludge decreased from 7.85 × 1012 m·kg to 2.06 × 1012 m·kg , and the ﬁlter cake moisture decreased from 85% to 60%. The reconstruction of “floc mass” was confirmed as the main sludge conditioning mechanism. ACMC promoted the dewatering performance through the charge neutralization and adsorption bridging with the negative EPS, and provided firm and dense structure for sludge floc as skeleton builder. The passages for water quick transmitting were built to avoid collapsing during the high-pressure process.

关键词： Sludge conditioning Acid or alkali modified cinder TB-EPS Floc mass Floc reconstruction

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Isolation and application of predatory

Ran Yu, Shiwen Zhang, Zhoukai Chen, Chuanyang Li

《环境科学与工程前沿（英文）》 2017年第11卷第1期 doi: 10.1007/s11783-017-0900-3

摘要： Indigenous predatory BALO strains were successfully isolated from activated sludge. Sludge SRF and CST were significantly reduced by BALOs induced biolysis process. The increase of BALO input dosage promoted the sludge biolysis efficiency. Sludge biolysis disintegrated flocs and lysed cells for internal water release. The optimal sludge biolysis time was 24 h and no pH adjustment was needed. -and-like organisms (BALOs) are a group of ubiquitous and obligate predatory bacteria and commonly used as biocontrol agents. In this study, an efficient, environmental-friendly, and convenient BALOs encouraged municipal waste sludge biolysis pretreatment technique was developed and investigated for dewaterability enhancement of excess waste sludge. The indigenous predatory BALOs were successfully isolated from the sludge for biolysis treatment. Without any chemical addition or pH adjustment, the sludge specific resistance (SRF) and capillary suction time (CST) were significantly reduced by as high as 53.4% and 23.8%, respectively within 24 h’s treatment, which would further be lowered with the increase of BALOs input dosage. However, the continuous extension of reaction time would worsen the sludge dewaterability. The decreases of SRF and CST accompanied with the increases of sludge disintegration degree and soluble chemical oxygen demand, nitrogen, and phosphorus concentrations all emphasized the contributions of BALOs’ predation activities to sludge disturbance, cell lysis, and consequently the release of sludge intracellular water to finally effectively improve the sludge dewaterability and disposal efficiency.

关键词： Bdellovibrio-and-like organisms (BALOs) Biolysis Activated sludge Dewaterability Predation