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Excess Sludge

Bo Wang, Yuanyuan Guo, Mengyue Zhao, Baikun Li, Yongzhen Peng
Energy savings via achieving the reduction of aeration and excess sludge is required to realize energy self-sufficiency in wastewater treatment plants. A novel partial nitritation + simultaneous anammox denitrification and sludge fermentation (PN + SADF) process was operated for nearly two years, during which simultaneous energy-efficient nitrogen removal and waste activated sludge (WAS) reduction was achieved, with a stable nitrogen removal efficiency of 80% and external WAS reduction of 40%-50%. In the PN reactor, presence of ammonia oxidizing bacteria and absence of nitrite oxidizing bacteria ensured the stable nitritation...
November 27, 2018: Chemosphere
Hongbo Liu, Ling Wang, Xuedong Zhang, Bo Fu, He Liu, Yajie Li, Xiaoyou Lu
A novel strategy of liquid fermentation using anaerobic dynamic membrane reactor (AnDMBR) was proposed to enhance volatile fatty acids (VFAs) production from sewage sludge. Results indicated that liquid sludge fermentation in AnDMBR had the potential in commercial VFAs production. VFAs productivity and concentration as well as substrate conversion rate could reach as high as 7.8 kg VFA-COD/m3  d, 60 g/L and 0.38 kg VFA-COD/kg VS, respectively. Moreover, dynamic membrane was stably operated for approximately 70 days...
November 22, 2018: Journal of Hazardous Materials
Marta Nierychlo, Aleksandra Milobedzka, Francesca Petriglieri, Bianca McIlroy, Per Halkjær Nielsen, Simon Jon McIlroy
Filamentous bacteria belonging to the phylum Chloroflexi have received considerable attention in wastewater treatment systems for their suggested role in the operational problem of impaired sludge settleability known as bulking. Their consistently high abundance in full-scale systems, even in the absence of bulking, indicates that they make a substantial contribution to the nutrient transformations during wastewater treatment. In this study, extensive 16S rRNA amplicon surveys of Danish wastewater treatment plants (WWTPs) with nutrient removal were screened to identify numerically important Chloroflexi genera...
November 22, 2018: FEMS Microbiology Ecology
Min Zhang, Yi Zhang, Zhengwen Li, Chen Zhang, Xuejun Tan, Xiang Liu, Chunli Wan, Xue Yang, Duu-Jong Lee
The process of anaerobic co-digestion is vital importance to resource recovery from organic solid wastes such as food waste and municipal sludge. However, its application is hindered by the limited understanding on the complex substrates-products transformation reactions and mechanisms therein. In this study, food waste (FW) and excess sludge (ES) from municipal wastewater treatment were mixed at various ratios (ES/FW 5:0, 4:1, 2:1, 1:1, 1:2, 1:4, w/w), and the co-digestion process was studied in a batch test...
November 22, 2018: Journal of Environmental Management
Hairong Yuan, Ruolin Guan, Akiber Chufo Wachemo, Chao Zhu, Dexun Zou, Ying Li, Yanping Liu, Xiaoyu Zuo, Xiujin Li
Methane production of excess sludge (ES) and dewatered sludge (DS) were investigated with low frequency CaO-ultrasonic pretreatment. The results showed that the concentrations of SCOD and VFAs in pretreated ES (P-ES) and DS (P-DS) were 212.11% and 75.26%, 270.30% and 159.52% higher than those of untreated ES and DS, respectively. The contents of acetic acid and ethanol comprised 83.87%-92.88% of the total VFAs. The cumulative methane production (CMP) of P-ES and P-DS were 167.08 and 162.96 mL/g·VS, respectively, which resulted in 40...
October 19, 2018: Bioresource Technology
Santo Fabio Corsino, Marco Capodici, Francesca Di Pippo, Valter Tandoi, Michele Torregrossa
Biological nutrient removal performances and kinetics of autochthonous marine biomass in forms of activated sludge and aerobic granular sludge were investigated under different salinity and sludge retention time (SRT). Both the biomasses, cultivated from a fish-canning wastewater, were subjected to stepwise increases in salinity (+2 gNaCl L-1 ), from 30 gNaCl L-1 up to 50 gNaCl L-1 with the aim to evaluate the maximum potential in withstanding salinity by the autochthonous marine biomass. Microbial marine species belonging to the genus of Cryomorphaceae and of Rhodobacteraceae were found dominant in both the systems at the maximum salinity tested (50 gNaCl L-1 )...
October 30, 2018: Water Research
Francesca Petriglieri, Marta Nierychlo, Per Halkjær Nielsen, Simon Jon McIlroy
Anaerobic digestion is a key process for the conversion of waste organics to biogas for energy and is reliant on the synergistic activities of complex microbial communities. Members of the phylum Chloroflexi are often found to be abundant in these systems, yet little is known of their role, with most members yet to be cultured or identified. The aim of this study was to characterize the Chloroflexi communities present in full-scale anaerobic digesters receiving excess sludge from wastewater treatment plants...
2018: PloS One
Chunhui Zhao, Yong Wang, Yue Wang, Feijie Wu, Jiageng Zhang, Ruiyi Cui, Liguo Wang, Hui Mu
In this study, the influences of earthworms on the structure of microbial community as well as the metabolic function in vermicomposting (VPs, with earthworms) for excess sludge stabilization were investigated. Comparison between the dynamic variation of PLFA profiles in VPs and common composting (CPs, with no earthworms) was conducted. The Shannon index was increased in VPs, while it was decreased in CPs with time, indicating earthworm activity enhanced microbial community diversity. The fungal and protozoal biomasses were significantly increased in VPs compared with CPs...
September 2018: Waste Management
Masashi Hatamoto, Tsutomu Okubo, Kengo Kubota, Takashi Yamaguchi
The activated sludge (AS) process has been the most widely used process for wastewater treatment despite it has several limitations for its further application and adoption worldwide, owing to unsustainable properties such as high-energy consumption and the production of large amount of excess sludge. To overcome the drawbacks of the AS process, the downflow hanging sponge (DHS) has been developed as an energy-saving and easy-to-maintain alternative. To date, six types of different sponge configurations have been developed and their performances have been evaluated in practical- to full-scale DHS reactors...
October 20, 2018: Applied Microbiology and Biotechnology
Zhe Kong, Lu Li, Yu-You Li
Wastewater containing N, N-dimethylformamide (DMF) was treated by artificially mixing the anaerobic granular sludge (AGS) with DMF-degrading activated sludge (DAS) in this study. An up-flow anaerobic sludge blanket (UASB) successfully treated wastewater containing approximately 2000 mg L-1 DMF during an operation period of 215 days. An inoculation of DAS brought about remarkable results: a rapid start-up with effective DMF methanogenic degradation on the first day, and under a low organic loading rate (OLR) of 1...
January 15, 2019: Science of the Total Environment
Li Hua, Lu Li, Chun-Yan Yang
The study investigated abundance and distribution of three sulfonamides and sulfonamide-resistant bacteria in the wastewater treatment processes of two tannery wastewater plants, as well as the extent of their removal in different treatment units of the plants. Results showed that the three sulfonamides were detected in two different tannery wastewater treatment processes, with total content in water samples of 59.1-706.7 ng·L-1 . The content of sulfonamides in excess sludge samples from the two plants was 4388 ng·kg-1 and 2979...
September 8, 2018: Huan Jing Ke Xue= Huanjing Kexue
Wenzhe Zhang, Benyi Xiao, YanBo Li, Yu Liu, Xuesong Guo
Three alkaline treatments (pH 10, 11, and 12 for 1 h) were used to treat return sludge alone to reduce sludge production in laboratory-scale anaerobic-anoxic-oxic processes. After 99 days of operation, alkaline treatments at pH 10 and 11 led to accumulative excess sludge production and sludge yield reduction of 18.8%-31.7% and 14.7%-27.8%, respectively. However, alkaline treatment at pH 12 led to system breakdown because of sludge bulking. The alkaline treatment at pH 10 did not affect the chemical oxygen demand and NH4 + -N removals of the system and sludge volume index (SVI) of aerobic activated sludge...
November 10, 2018: Journal of Biotechnology
Dong Ou, Wei Li, Hui Li, Xiao Wu, Cheng Li, Yangyang Zhuge, Yong-di Liu
The aerobic granular sludge (AGS) dominated by halophilic microorganisms, was successfully cultivated in a lab-scale sequencing batch reactor (SBR) under varying salinity levels (from 0% to 6% (w/v)). Removal performance of AGS improved with the increase of salinity and increased up to 42.86 mg g-1 VSS h-1 at 6% salinity. Increased salinity resulted in better settling performance of AGS in terms of the sludge volume index (SVI), which was initially 148.80 mL/g at 0% salinity and gradually decreased to 59...
December 2018: Chemosphere
Martin H Andersen, Simon J McIlroy, Marta Nierychlo, Per H Nielsen, Mads Albertsen
Settleability of particles in activated sludge systems can be impaired by an overgrowth of filamentous bacteria, a problem known as bulking. These filaments are often members of the phylum Chloroflexi, sometimes reaching abundances in excess of 30% of the biovolume. The uncultured Chloroflexi phylotype, Candidatus Amarolinea, has been observed in high abundances in Danish full-scale activated sludge systems by 16S rRNA gene amplicon surveys, where it has been associated with bulking. In this study, fluorescence in situ hybridization was applied to confirm their high abundance, filamentous morphology, and contribution to the interfloc bridging that characterizes filamentous bulking...
August 16, 2018: Systematic and Applied Microbiology
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...
October 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...
November 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...
November 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...
November 1, 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
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