Evaluation of the disinfection potential of low chlorine concentrations in tap water using immobilised enterococcus faecium in a continuous flow device

1997 ◽  
Vol 35 (11-12) ◽  
pp. 77-80 ◽  
Author(s):  
A. Wiedenmann ◽  
M. Braun ◽  
K. Botzenhart
Keyword(s):  
Distribution System ◽  
Enterococcus Faecium ◽  
Continuous Flow ◽  
Tap Water ◽  
Test System ◽  
Batch Experiments ◽  
Membrane Filters ◽  
Upper Limit ◽  
Flow Device ◽  
Faecal Streptococci

A simple continuous flow device in which bacteria were immobilised on membrane filters and flushed with tap water with free chlorine residuals of 0.05, 0.1, 0.2 and 0.4mg/L at pH 7.7 and 10°C, has been used for disinfection experiments with faecal streptococci. A 99.99% reduction of Enterococcus faecium was observed between 3.4–5.2min (0.05mg/L), between 2.8–4.1min (0.1mg/L), between 1.7–3.1min (0.2mg/L) and between 0.8–2.1min (0.4mg/L). CT-products covered a range of 0.17 (0.05mg/L, lower limit) up to 0.85mg/L/min (0.4mg/L, upper limit). The test system is suggested as a more reliable alternative to batch experiments when the disinfection potential of low chlorine concentrations acting for several minutes has to be evaluated. The system cannot be used to demonstrate exact reduction kinetics but it allows the calculation of CT values and the evaluation of the disinfection potential of chlorinated water at any point of a distribution system where initial chlorine concentrations may have already remarkably declined.

scholarly journals Leveraging a Genetic Algorithm for the Optimal Placement of Distributed Generation and the Need for Energy Management Strategies Using a Fuzzy Inference System

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 172
Author(s):  
Sunny Katyara ◽  
Muhammad Fawad Shaikh ◽  
Shoaib Shaikh ◽  
Zahid Hussain Khand ◽  
Lukasz Staszewski ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Energy Management ◽  
Fuzzy Inference System ◽  
Distribution System ◽  
Fuzzy Inference ◽  
Management Strategies ◽  
Test System ◽  
Optimal Placement ◽  
Inference System ◽  
Simulated Environment

With the rising load demand and power losses, the equipment in the utility network often operates close to its marginal limits, creating a dire need for the installation of new Distributed Generators (DGs). Their proper placement is one of the prerequisites for fully achieving the benefits; otherwise, this may result in the worsening of their performance. This could even lead to further deterioration if an effective Energy Management System (EMS) is not installed. Firstly, addressing these issues, this research exploits a Genetic Algorithm (GA) for the proper placement of new DGs in a distribution system. This approach is based on the system losses, voltage profiles, and phase angle jump variations. Secondly, the energy management models are designed using a fuzzy inference system. The models are then analyzed under heavy loading and fault conditions. This research is conducted on a six bus radial test system in a simulated environment together with a real-time Power Hardware-In-the-Loop (PHIL) setup. It is concluded that the optimal placement of a 3.33 MVA synchronous DG is near the load center, and the robustness of the proposed EMS is proven by mitigating the distinct contingencies within the approximately 2.5 cycles of the operating period.

Coupling compositional data analysis (CoDA) with hierarchical cluster analysis (HCA) for preliminary understanding of the dynamics of a complex water distribution system: the Naples (south Italy) case study

2021 ◽  
Author(s):  
Pooria Ebrahimi ◽  
Stefano Albanese ◽  
Leopoldo Esposito ◽  
Daniela Zuzolo ◽  
Domenico Cicchella
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Compositional Data ◽  
Tap Water ◽  
Hierarchical Cluster ◽  
Compositional Data Analysis ◽  
Anthropogenic Pressure ◽  
South Italy ◽  
Global Concern

Providing safe tap water has been a global concern. Water scarcity, the ever-increasing water demand, temporal variation of water consumption, aging urban water infrastructure and anthropogenic pressure on the water...

DEVELOPMENT OF A RAPID CONTINUOUS FLOW SALT LEACHING KIT FOR FABRICATION OF POLY(3-HYDROXYBUTYRIC ACID-CO-3-HYDROXYVALERATE) (PHBV) POROUS 3-D SCAFFOLD

2015 ◽  
Vol 75 (1) ◽  
Author(s):  
Syazwan Aizad ◽  
Badrul Hisham Yahaya ◽  
Saiful Irwan Zubairi
Keyword(s):  
Conventional Method ◽  
Continuous Flow ◽  
Tap Water ◽  
Chemical Properties ◽  
Porous Scaffolds ◽  
Time Saving ◽  
Salt Particle ◽  
Salt Leaching ◽  
Leaching Process ◽  
Highly Efficient

Polyhydroxyalkanoates (PHAs) that are synthesized from bacteria that are predominantly produced by microbial fermentation processes on organic waste, such as palm oil mill effluent (POME), olive oil and kitchen waste, contribute to a sustainable waste management. A great variety of materials from this family can be produced, however the application of PHAs in the production of scaffolds in tissue engineering has been mainly constrained to poly(hydroxybutyrate-co-valerate) (PHBV) due to its highly adjustable physico-chemical properties. One of the common methods in making the 3-D scaffolds is by performing solvent-casting particulate-leaching (SCPL) process, but this process requires a long period of soaking in water to extract the entire salt particle in the 3-D scaffolds. Therefore, the objective of this study is to develop a new method to the conventional method of salt leaching process via a highly efficient continuous flow leaching kit. The salt leaching process was carried out by (1) immersing the 3-D porous scaffolds in a fabricated static container containing tap water and (2) by allowing a pre-setting continuous flow rate of water. The concentration of sodium chloride (NaCl) was calculated periodically for both processes based on the salt standard calibration curve. The results showed that the exhaustive salt leaching of the conventional process occurred at 48 ± 5 hrs with the needs of changing the water twice a day. In contrast, the exhaustive salt leaching process via continuous flow leaching kit occurred at 40 ± 5 mins, 72 times faster than the conventional method (p<0.05). Therefore, the salt leaching process using continuous flow leaching kit can be considered a highly efficient and time saving procedure as compared to the conventional method.  

Presence and formation of disinfection by-products in Cairo residential water supply

2009 ◽  
Vol 9 (2) ◽  
pp. 113-120 ◽  
Author(s):  
E. H. Smith ◽  
K. E. El-Deen
Keyword(s):  
Natural Organic Matter ◽  
Distribution System ◽  
Tap Water ◽  
Residential Community ◽  
Chlorine Disinfection ◽  
Sampling Program ◽  
The Impact ◽  
By Products ◽  
The U.S ◽  
Residential Water

A sampling program was conducted in a residential community in Cairo, Egypt in order to determine the presence of chlorine disinfection by-products (DBPs) in treated water and to observe the impact of the distribution system on DBP levels. Five campaigns were conducted over a 15-month period during 2005–2006. Trihalomethanes (THMs) and haloacetic acids (HAAs) exceeded local and international limits depending upon the season. Tap water concentrations of THMs were considerably higher in summer than during the rest of the year. In the Summer 2005 event, the average for the 20 tap water locations was 158 μg/l Total-THMs, well in excess of the U.S. EPA limit of 80 μg/L and the current Egyptian standard of 100 μg/l; all 20 locations exceeded the 100 μg/l limit. For the following event in late Fall 2005, the average dropped to 84 μg/l with 11 and 6 sites exceeding the U.S. EPA and Egyptian limits, respectively. HAA levels tended to be complementary to Total-THM values in that they were lower in summer but higher during fall and spring. The U.S. EPA limit on a select set of 5 HAAs (HAA5) is 60 μg/l (Egypt does not currently regulate HAAs). The average for HAA5 in the Summer 2005 event was 52 μg/l with 8 of the 20 tap samples equalling or exceeding the 60 μg/l standard. By contrast, in Fall 2005, the HAA5 average increased to 89 μg/l, with 15 of 20 sites exceeding the limit. THM and HAA concentrations generally increased with distance from the WTP along a targeted distribution main, while chlorine and natural organic matter tended to decrease.

Continuous Flow Device Support in Children Using the HeartWare HVAD

ASAIO Journal ◽  
2015 ◽  
Vol 61 (5) ◽  
pp. 569-573 ◽  
Author(s):  
Joshua Sparks ◽  
Deirdre Epstein ◽  
Sirine Baltagi ◽  
Mary E. Mehegan ◽  
Kathleen E. Simpson ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Flow Device

scholarly journals Near-IR squaraine dye–loaded gated periodic mesoporous organosilica for photo-oxidation of phenol in a continuous-flow device

2015 ◽  
Vol 1 (8) ◽  
pp. e1500390 ◽  
Author(s):  
Parijat Borah ◽  
Sivaramapanicker Sreejith ◽  
Palapuravan Anees ◽  
Nishanth Venugopal Menon ◽  
Yuejun Kang ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Heterogeneous Catalysts ◽  
Near Infrared ◽  
Periodic Mesoporous Organosilica ◽  
Photo Oxidation ◽  
Mesoporous Organosilica ◽  
Squaraine Dye ◽  
Flow Device ◽  
Catalytically Active ◽  
Oxidation Of Phenol

Periodic mesoporous organosilica (PMO) has been widely used for the fabrication of a variety of catalytically active materials. We report the preparation of novel photo-responsive PMO with azobenzene-gated pores. Upon activation, the azobenzene gate undergoes trans-cis isomerization, which allows an unsymmetrical near-infrared squaraine dye (Sq) to enter into the pores. The gate closure by cis-trans isomerization of the azobenzene unit leads to the safe loading of the monomeric dye inside the pores. The dye-loaded and azobenzene-gated PMO (Sq-azo@PMO) exhibits excellent generation of reactive oxygen species upon excitation at 664 nm, which can be effectively used for the oxidation of phenol into benzoquinone in aqueous solution. Furthermore, Sq-azo@PMO as the catalyst was placed inside a custom-built, continuous-flow device to carry out the photo-oxidation of phenol to benzoquinone in the presence of 664-nm light. By using the device, about 23% production of benzoquinone with 100% selectivity was achieved. The current research presents a prototype of transforming heterogeneous catalysts toward practical use.

scholarly journals The Seasonality of Nitrite Concentrations in a Chloraminated Drinking Water Distribution System

2018 ◽  
Vol 15 (8) ◽  
pp. 1756 ◽  
Author(s):  
Pirjo-Liisa Rantanen ◽  
Ilkka Mellin ◽  
Minna Keinänen-Toivola ◽  
Merja Ahonen ◽  
Riku Vahala
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Tap Water ◽  
Drinking Water Distribution System ◽  
Ammonium Oxidation ◽  
Water Age ◽  
Sampling Campaign ◽  
Drinking Water Distribution

We studied the seasonal variation of nitrite exposure in a drinking water distribution system (DWDS) with monochloramine disinfection in the Helsinki Metropolitan Area. In Finland, tap water is the main source of drinking water, and thus the nitrite in tap water increases nitrite exposure. Our data included both the obligatory monitoring and a sampling campaign data from a sampling campaign. Seasonality was evaluated by comparing a nitrite time series to temperature and by calculating the seasonal indices of the nitrite time series. The main drivers of nitrite seasonality were the temperature and the water age. We observed that with low water ages (median: 6.7 h) the highest nitrite exposure occurred during the summer months, and with higher water ages (median: 31 h) during the winter months. With the highest water age (190 h), nitrite concentrations were the lowest. At a low temperature, the high nitrite concentrations in the winter were caused by the decelerated ammonium oxidation. The dominant reaction at low water ages was ammonium oxidation into nitrite and, at high water ages, it was nitrite oxidation into nitrate. These results help to direct monitoring appropriately to gain exact knowledge of nitrite exposure. Also, possible future process changes and additional disinfection measures can be designed appropriately to minimize extra nitrite exposure.

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