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Excess Sludge

Wanrong Hu, Yi Xie, Yu Zeng, Panyu Li, Yabo Wang, Yongkui Zhang
A considerable amount of excess sludge, a kind of hazardous waste, is produced from the conventional wastewater treatment systems such as activated sludge process, and efficient sludge reduction processes are needed. A new chemical method for sludge reduction was proposed by using manganese dioxide as oxidant in this study. A favorable condition for sludge reduction is determined as manganese dioxide dosage of 0.165 g g-1 wet sludge, sulfuric acid concentration of 3 mol L-1 , and reduction temperature of 90 °C for 90 min, where the sludge reduction efficiency can reach 73...
August 18, 2018: Environmental Science and Pollution Research International
Pompilio Vergine, Carlo Salerno, Giovanni Berardi, Alfieri Pollice
Two lab-scale Self Forming Dynamic Membrane BioReactors (SFD-MBR), equipped with 50 µm nylon meshes were set up and operated for the treatment of real municipal wastewater. Plastic carriers were added in one of the two bioreactors to generate a combination of the Integrated Fixed-film Activated Sludge (IFAS) and the SFD-MBR technologies. Overall, the two systems performed very well, achieving excellent effluent quality under steady state conditions and showing good resilience to extreme organic loading conditions...
July 25, 2018: Bioresource Technology
Jonathan W C Wong, Guneet Kaur, Sanjeet Mehariya, Obulisamy Parthiba Karthikeyan, Guanghao Chen
Potential of methane production by co-digestion of food waste with saline sludge produced from sewage receiving seawater toilet flushing was investigated to determine its suitability for food waste management in Hong Kong by making use of excess design capacity of sludge digesters. High salinity of saline sludge (12.8 mS/cm) affected degradation of organic compounds resulting in an increase in sCOD by 135% as compared to an increase by 283% in treatments with non-saline sludge (4.2 mS/cm) co-digestion. This inhibitory effect was also evident by lower VS removal efficiency of 32...
July 25, 2018: Bioresource Technology
Jinte Zou, Yaqiang Tao, Jun Li, Shuyun Wu, Yongjiong Ni
A continuous-flow reactor with two-zone sedimentation tank (CFR-TST) was developed to evaluate the formation of aerobic granular sludge (AGS). Micropowder made of excess sludge was added for a while in the CFR-TST, and selection pressure associated with settling time was created by the two-zone sedimentation tank. To avoid AGS disintegration, an airlift system for sludge return was used. The results show that AGS (mean particle size of 105μm; sludge volume index of approximately 26mL/g) was formed successfully in the CFR-TST...
January 2018: Bioresource Technology
P Wilfert, A I Dugulan, K Goubitz, L Korving, G J Witkamp, M C M Van Loosdrecht
Phosphate recovery from sewage sludge is essential in a circular economy. Currently, the main focus in centralized municipal wastewater treatment plants (MWTPs) lies on struvite recovery routes, land application of sludge or on technologies that rely on sludge incineration. These routes have several disadvantages. Our study shows that the mineral vivianite, Fe2 (PO4 )3  × 8H2 O, is present in digested sludge and can be the major form of phosphate in the sludge. Thus, we suggest vivianite can be the nucleus for alternative phosphate recovery options...
July 20, 2018: Water Research
(no author information available yet)
Over 60 percent of all wastewater treatmentplants in the developed countries use the activated sludgeprocess as secondary treatment system. About 50 to 85 percentof the total energy consumed in a biological wastewatertreatment plant is in aeration. The activated sludge process, themost common process, is performed in large aeration basins toprovide air for microorganisms, through biodegradation, toremove nutrients and pollutants. Very often excess factor ofsafety used in design for the air supply to meet sustained peakorganic loading and to avoid endogenous situations may lead tounsatisfactory treatment performance and even plant failure...
July 9, 2018: Water Environment Research: a Research Publication of the Water Environment Federation
Stefania Bilardi, Paolo Salvatore Calabrò, Rosa Greco, Nicola Moraci
The possibility of a landfill leachate pre-treatment, aiming at heavy metals removal, by means of either zero valent iron (ZVI), or granular activated carbon (GAC) or by a mixture of the two materials, was investigated in this paper through batch and column tests. For this purpose, a synthetic landfill leachate containing heavy metals (i.e. Cu, Ni, Zn), chloride, sulphates, ammonium and organic matter was prepared. Batch tests results demonstrated the efficiency of ZVI, GAC and ZVI/GAC mixture in heavy metals removal (efficiency > 90%) and their negligible effect on the other contaminants...
August 2, 2018: Environmental Technology
Łukasz Skórkowski, Ewa Zielewicz
The objective of this research was to examine the influence of energy input on the particle size distribution of disintegrated sludge. The change of particle size distribution indicates the deagglomeration of flocs and disruption of micro-colonies. As the digestibility of sludge increases with dispersion, particle size analysis is an important factor in evaluating the disintegration process. Four different levels of energy input were used in the research: 10-100 kWh·m-3 . All samples showed significant changes as far as dispersion (kdCST = 22...
July 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Maroua Haddad, Sami Abid, Moktar Hamdi, Hassib Bouallagui
Dye mass balance study at full-scale industrial textile wastewater (ITW) treatment plant showed that 1.5 ton of excess waste sludge, containing 304.5 Kg of dyes, are daily produced and discharged in landfills. Therefore, this by-product of activated sludge process (ASP) presents a serious environmental problem. In this work, a laboratory and pilot scale investigations were carried out to optimize aerobic biodegradation efficiency to reduce the amount of residual adsorbed dye that will be found in the waste sludge...
October 1, 2018: Journal of Environmental Management
Difang Zhang, Wenhai Luo, Yun Li, Guoying Wang, Guoxue Li
In this study, the co-composting performance of sewage sludge (SS) and organic fraction of municipal solid waste (OFMSW) at different proportions was investigated. Cornstalk was added at 15% (of total wet weight) to improve the co-composting process. Results show that higher SS proportion could rapidly initialize the co-composting process; while increasing OFMSW percentage enhanced organic content for biodegradation, thus prolonging the thermophilic period and increasing the humification degree during co-composting...
February 2018: Bioresource Technology
Guangyu Cui, Fusheng Li, Shuailei Li, Sartaj Ahmad Bhat, Yasushi Ishiguro, Yongfen Wei, Toshiro Yamada, Xiaoyong Fu, Kui Huang
Antibiotic resistance genes abundant in municipal excess sludge reduce the agricultural value of vermicompost. However, little attention has been paid on the fate and behavior of the problem-causing agents in vermicomposting. In this study, the fate and behavior of quinolone resistance genes in excess activated sludge during vermicomposting were studied with reactors introduced with Eisenia fetida for three different densities. The substrate pile without earthworms was operated as control in parallel. The results showed that earthworms could significantly reduce the absolute abundance of quinolone resistance genes in the excess sludge, with a reduction ratio of 85...
July 6, 2018: Science of the Total Environment
Yanfei Tang, Xiaowei Li, Bin Dong, Junjie Huang, Yanhong Wei, Xiaohu Dai, Lingling Dai
Humification plays an important role in the sewage sludge stabilization treatment and probably influences the end-product ecotoxicity, which are not fully understood for high-solid anaerobic digestion (AD) process. This study monitored the aromaticity degree of humic acid-like fraction (HA) and detected digestate phytotoxicity during a 48-d high-solid AD. Significant repolymerization of aromatic structures in HA. Electrical conductivity (EC) of digestate changed negatively with the aromaticity degree in HA, and the digestate with high EC had low seed germination index (SGI)...
July 3, 2018: Water Research
Bilardi Stefania, Paolo Salvatore Calabrò, Greco Rosa, Moraci Nicola
The pre-treatment of landfill leachate prior to its co-treatment in the municipal plants of waste water processing could represent an appropriate and cost-effective solution for its management. Pre-treatment is necessary especially to remove heavy metals, which may be transferred to the excess sludge preventing its valorisation. In the present paper, we propose a chemical-physical pre-treatment of leachate using four different granular reactive media able to selectively remove the contaminants present in the leachate...
July 5, 2018: Science of the Total Environment
Wenbin Liu, Hui Jia, Jie Wang, Hongwei Zhang, Changchun Xin, Yingjie Zhang
Membrane bioreactor (MBR) and microbial fuel cell (MFC) are new technologies based on microbial process. MBR takes separation process as the core to achieve the high efficient separation and enrichment the beneficiation of microbes during the biological treatment. MFC is a novel technology based on electrochemical process to realize the mutual conversion between biomass energy and electric energy, in order to solve the problems of serious membrane fouling and low efficiency of denitrification in membrane bioreactor, the low power generation efficiency, and unavailability of bioelectric energy of MFC...
July 3, 2018: Environmental Science and Pollution Research International
Jia-Wei Sun, Wei-Nan Ding, Zhan-En Zhang, Jun-Xia Wang, Hai-Dong Gu
Sewage water, the influent of the secondary sedimentation tanks, the final effluent, sludge from biological pools, and dewatered excess sludge samples from eight wastewater treatment plants (WWPTs) in Suzhou, including those from seven A2 /O processes and one oxidation ditch process, were collected in 2017 to study the pollution characteristics of organophosphorus flame retardants (OPFRs) in WWPTs. Accelerated solvent extraction (ASE) combined with a solid-phase extraction method was used to detect the concentration of 10 organic phosphorus flame retardant (OPFRs)...
May 8, 2018: Huan Jing Ke Xue= Huanjing Kexue
Dong Li, Yan-Ju Wang, Yu-Feng Lü, Rui-Hua Cao, Shuai Li, Jie Zhang
The effect of organic carbon on the start-up and operation of the CANON granular sludge process was investigated in two SBR reactors with different strategies:gradually increased organic carbon concentration (R1) and without organic carbon (R2). The results showed that adding 50 mg·L-1 organic carbon accelerated the start-up of the CANON granular sludge process. R1 and R2 were started up in 23 d and 32 d, respectively. Moreover, the appropriate organic carbon enhanced the activity of AOB, AnAOB, and denitrification, increasing the ammonia removal rates and total nitrogen (TN) removal rates...
March 8, 2018: Huan Jing Ke Xue= Huanjing Kexue
Gang Lü, Tian Li, Le-Zhong Xu, Yao-Liang Shen, Peng Wu, Ting Zhang, Thomas Samwine
In order to determine the optimal sludge source of anaerobic ammonium oxidation (ANAMMOX) and the rapid formation of ANAMMOX granular sludge, two CAMBRs (combined ABR and MBR) were compared for ANAMMOX enrichment with different inoculated sludge types, the anaerobic granular sludge (R1) and flocculent denitrifying sludge (R2). The results showed that ANAMMOX was successfully initiated after 45 d (R1) and 60 d (R2) in both reactors, respectively. The enrichment processes are divided into three different phases, lag phase, activity elevation phase, and stationary phase but the removal rules of nitrogen in each phase were different...
October 8, 2017: Huan Jing Ke Xue= Huanjing Kexue
Lu Wang, Wei-Wei Ben, Yan-Gang Li, Zhi-Min Qiang
Two sequencing batch reactors were established at bench-scale, with one used as an in-situ sludge ozone-reduction system and the other as a control system. Both systems were continuously operated for 90 days to comparatively investigate the elimination of nine typical antibiotics (i.e., tetracycline, oxytetracycline, doxytetracycline, norfloxacin, ofloxacin, ciprofloxacin, lomefloxacin, enrofloxacin, and azithromycin) during the in-situ sludge ozone-reduction process. Results indicated that the presence of target antibiotics in the influent (100 μg·L-1 each) had an insignificant influence on the removal of COD, total nitrogen, ammonia, and total phosphorus by the activated sludge...
April 8, 2018: Huan Jing Ke Xue= Huanjing Kexue
Xiang Li, Xing Lin, Fan Wang, Yan Yuan, Yong Huang, Yi Yuan, Zhen Bi, Xin Liu, Peng-Bing Yang
The ammonium oxidation by potential electron acceptors(NO2 - , Fe3+ and SO4 2- ) in ANAMMOX sludge was studied by inoculating nitrite-dependent ANAMMOX sludge. The results showed that nitrite was the most suitable electron acceptor for ANAMMOX bacteria, which could completely react within a short time. Nitrate was converted into nitrite by ANAMMOX sludge using the organic as electron donor and then participated in ammonia conversion, in the absence of nitrite. Fe3+ and SO4 2- conversion occurred at the end of ammonium oxidation, but its direct or indirect participation requires further study...
July 8, 2017: Huan Jing Ke Xue= Huanjing Kexue
Junfeng Wang, Hai Li, Yaqi Liu, Changming Zhong, Zhijiang Luo, Dan Li
As a byproduct of activated sludge process, excess sludge has become one of the current problems in the field of environmental protection for its yield huge、high moisture content and easy to pollution. In this study, the joint technology combining ozone with ultrasonic was applied in treatment of excess sludge by strong ozone oxidation and prominent ultrasonic cavitation. The effect on lysis excess sludge cells was explored comprehensively. The lysis mechanism of excess sludge cells degraded by ozone + ultrasonic was revealed by analysis of three-dimensional spectral fluorometer, optical microscope and scanning electron microscopy (SEM)...
July 30, 2018: Environmental Technology
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