scholarly journals Reduction of naturally occurring enteroviruses by wastewater treatment processes

1984 ◽  
Vol 92 (1) ◽  
pp. 97-103 ◽  
Author(s):  
R. Morris
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Maximum Level ◽  
Process Efficiency ◽  
Individual Treatment ◽  
Sand Filtration ◽  
Treatment Processes ◽  
Naturally Occurring ◽  
Rapid Sand Filtration

SUMMARYThe levels of cytopathic enteroviruses at two wastewater-treatment works were monitored over a period of 9 months. The maximum level of virus at works 1 was 72500 p.f.u. l-1and at Avorks 2,57500 p.f.u. l-1. Examination of process efficiency showed an overall reduction of 63% for works 1 and 26 % for works 2 when used without lagooning. When lagooning was employed at the second works, virus reduction was 97%. Individual treatment processes showed poor reduction of virus levels. Sedimentation and rapid sand filtration had no significant effect on levels whilst both percolating filtration and activated sludge showed some reduction. Only lagooning resulted in substantial reductions of virus levels.

Savings with upgraded performance through improved activated sludge denitrification in the combined activated sludge–biofilter system of the Southpest Wastewater Treatment Plant

2008 ◽  
Vol 57 (8) ◽  
pp. 1287-1293 ◽  
Author(s):  
A. Jobbágy ◽  
G. M. Tardy ◽  
Gy. Palkó ◽  
A. Benáková ◽  
O. Krhutková ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Biological Treatment ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Process Efficiency ◽  
Initial Value ◽  
Initial Profile ◽  
Biological Treatment System

The purpose of the experiments was to increase the rate of activated sludge denitrification in the combined biological treatment system of the Southpest Wastewater Treatment Plant in order to gain savings in cost and energy and improve process efficiency. Initial profile measurements revealed excess denitrification capacity of the preclarified wastewater. As a consequence, flow of nitrification filter effluent recirculated to the anoxic activated sludge basins was increased from 23,000 m3 d−1 to 42,288 m3 d−1 at an average preclarified influent flow of 64,843 m3 d−1, Both simulation studies and microbiological investigations suggested that activated sludge nitrification, achieved despite the low SRT (2–3 days), was initiated by the backseeding from the nitrification filters and facilitated by the decreased oxygen demand of the influent organics used for denitrification. With the improved activated sludge denitrification, methanol demand could be decreased to about half of the initial value. With the increased efficiency of the activated sludge pre-denitrification, plant effluent COD levels decreased from 40–70 mg l−1 to < 30–45 mg l−1 due to the decreased likelihood of methanol overdosing in the denitrification filter

Intelligent control system based on blackboard concept for wastewater treatment processes

1998 ◽  
Vol 37 (12) ◽  
pp. 77-85 ◽  
Author(s):  
T. Ohtsuki ◽  
T. Kawazoe ◽  
T. Masui
Keyword(s):  
Wastewater Treatment ◽  
Control System ◽  
Activated Sludge ◽  
Intelligent Control ◽  
Software Agents ◽  
High Rate ◽  
Target System ◽  
Activated Sludge Process ◽  
Intelligent Control System ◽  
Treatment Processes

An intelligent control system for wastewater treatment processes has been developed and applied to fullscale, high-rate, activated sludge process control. In this control system, multiple software agents that model the target system using their own modeling method collaborate by using data stored in an abstracted database named ‘blackboard’. The software agents, which are called ‘expert modules’, include a fuzzy expert system, a fuzzy controller, a theoretical activated sludge model, and evaluators of raw data acquired by various online sensors including a respirometer. In this paper, the difficulties of controlling an activated sludge system by using a single conventional strategy are briefly reviewed, then our approach to overcome these difficulties by using multiple modeling methods in the framework of an ‘intelligent control system’ is proposed. Case studies of applications to a high-rate activated sludge process that treats BOD and nitrogen of human excrement are also presented.

scholarly journals The Effect of Electrolytes on the Photodegradation Kinetics of Caffeine

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 644
Author(s):  
Pedro M. Rendel ◽  
Giora Rytwo
Keyword(s):  
Wastewater Treatment ◽  
Ionic Strength ◽  
Water Systems ◽  
Process Efficiency ◽  
Rate Coefficients ◽  
Treatment Processes ◽  
Kinetics Of ◽  
Wastewater Effluents

Unsuccessfully treated by the existing wastewater-treatment processes, caffeine concentrations in wastewater effluents and natural reservoirs are constantly rising. Photodegradation treatment processes are drawing much attention due to their potential to oxidize and remove such, and similar contaminating compounds from treated waters. In continuation to our previous work on the photodegradation kinetics of caffeine in water by UV/H2O2 and UV/TiO2, this work evaluates the influence of various electrolytes, including NaCl, KCl, MgCl2, NaBr, and KBr, on the kinetics of the UV/H2O2 photodegradation of caffeine, aiming at estimating the efficiency of the method in more complex water systems. Results show that the efficiency of the UV/H2O2 photodegradation reactions is strongly affected by ionic strength and the presence of electrolytes in the solution. While chloride electrolytes were shown to optimize or reduce the process efficiency pending on their concentration. The sole presence of NaBr and KBr shows an immediate reduction in the efficiency of the photodegradation. Empirical apparent-rate-coefficients and curves describing the effect of the different electrolytes on the photodegradation kinetics of caffeine are presented.

Difference in behaviors of F-specific DNA and RNA bacteriophages during coagulation–rapid sand filtration and coagulation–microfiltration processes

2012 ◽  
Vol 12 (5) ◽  
pp. 666-673
Author(s):  
N. Shirasaki ◽  
T. Matsushita ◽  
Y. Matsui ◽  
T. Urasaki ◽  
K. Ohno
Keyword(s):  
Surface Charge ◽  
River Water ◽  
Treatment Process ◽  
Sand Filtration ◽  
Filtration Process ◽  
Dna And Rna ◽  
Treatment Processes ◽  
Particle Characteristics ◽  
Coagulation And Filtration ◽  
Rapid Sand Filtration

Difference in behaviors of F-specific DNA and RNA bacteriophages during coagulation–rapid sand filtration and coagulation–microfiltration (MF) processes were investigated by using river water spiked with F-specific DNA bacteriophage f1 and RNA bacteriophage f2. Because the particle characteristics of f1 (filamentous) and f2 (spherical) are quite different and the surface charge of f1 in the river water was slightly more negative than that of f2, the removal ratios of f1 were approximately 1-log lower than the removal ratio of f2 after any treatment process used in the present study. This result indicates that the behaviors of the two bacteriophages during the treatment processes were different, and that the removal of f1 by the combination of coagulation and filtration processes was more difficult than that of f2. The removal ratios for f1 and f2 were approximately 3-log and 4-log, respectively, in the coagulation–rapid sand filtration process, and 6-log and 7-log, respectively, in the coagulation–MF filtration process. Therefore, as expected, the coagulation–MF process appears to be more effective than the coagulation–rapid sand filtration process for the removal of not only spherical viruses but also filamentous viruses.

scholarly journals Loofah Sponges as Bio-Carriers in a Pilot-Scale Integrated Fixed-Film Activated Sludge System for Municipal Wastewater Treatment

2020 ◽  
Vol 12 (11) ◽  
pp. 4758
Author(s):  
Huyen T.T. Dang ◽  
Cuong V. Dinh ◽  
Khai M. Nguyen ◽  
Nga T.H. Tran ◽  
Thuy T. Pham ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Pilot Scale ◽  
Agricultural Product ◽  
Aeration Tank ◽  
Municipal Wastewater Treatment ◽  
Treatment Processes ◽  
Fixed Film ◽  
The Cost

Fixed-film biofilm reactors are considered one of the most effective wastewater treatment processes, however, the cost of their plastic bio-carriers makes them less attractive for application in developing countries. This study evaluated loofah sponges, an eco-friendly renewable agricultural product, as bio-carriers in a pilot-scale integrated fixed-film activated sludge (IFAS) system for the treatment of municipal wastewater. Tests showed that pristine loofah sponges disintegrated within two weeks resulting in a decrease in the treatment efficiencies. Accordingly, loofah sponges were modified by coating them with CaCO3 and polymer. IFAS pilot tests using the modified loofah sponges achieved 83% organic removal and 71% total nitrogen removal and met Vietnam’s wastewater effluent discharge standards. The system achieved considerably high levels of nitrification and it was not limited by the loading rate or dissolved oxygen levels. Cell concentrations in the carriers were twenty to forty times higher than those within the aeration tank. Through 16S-rRNA sequencing, the major micro-organism types identified were Kluyvera cryocrescens, Exiguobacterium indicum, Bacillus tropicus, Aeromonas hydrophila, Enterobacter cloacae, and Pseudomonas turukhanskensis. This study demonstrated that although modified loofah sponges are effective renewable bio-carriers for municipal wastewater treatment, longer-term testing is recommended.

Sign in / Sign up

Export Citation Format

Share Document