scholarly journals Study on Shock Disinfection in a Fire Extinguishing Water Supply System

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 2967
Author(s):  
Kun Xiang ◽  
Pan Geng ◽  
Xuan Sun ◽  
Shasha Yuan ◽  
Peng Du ◽  
...  

The biofilms generated in a fire extinguishing water supply system can cause corrosion and a reduction in the water supply capacity; thus, degrading the system performance. To mitigate microbial corrosion, appropriate disinfection measures are necessary. In this study, the secondary addition of chlorine is employed to investigate the kinetics of chlorine decay, and shock disinfection is applied to investigate the removal efficiency of corrosion bacteria, and the microbial composition of a biofilm on the pipe wall was also clarified. The results show that the residual chlorine content in the secondary chlorination process was directly correlated with the decay rate of residual chlorine and the corrosion rate of the pipe wall. Additionally, the chlorine impact disinfection method could reduce the electrochemical corrosion phenomenon of the pipe wall. When the concentration of chlorine was 3 mg/L, the removal rate of corrosion bacteria was higher in 60 min than in 30 min. Specifically, most of the bacteria were inactivated in 60 min and the biofilm was severely damaged. Shock disinfection could significantly inactivate all microflora in the biofilm; the relative abundances of microflora varied significantly, while the change of microflora at the phylum level was insignificant. This study can provide theoretical support for the secondary addition of chlorine and shock disinfection in a fire extinguishing water supply system.

The study presents the hydraulic design and analysis of Rural Water Distribution System (WDS) for Nava shihora region of zone 1 of the state of Gujarat, India. Water supply distribution system is designed for this study for population estimated for future 30 years. LOOP 4.0 and Water Gems v8i software have been used and the results are compared to determine the economical size of pipes for water distribution system. The economical size of pipes of water supply distribution system is designed by considering the constraints; residual pressure at each node, velocity of flow in pipe, head loos in pipes, material of pipes, elevated service reservoir level, peak factor and available commercial pipe diameters. Further water distribution system has been analyzed for extended period simulation (EPS) for the present population scenario for intermittent water supply using Water Gems v8i. Further water supply system is analyzed the residual chlorine concentration at nodes and in the pipe links and also the total cost of water supply system of rural region is estimated.


Author(s):  
Е.Д. Нефедова ◽  
О.Д. Галактионова

Затронуты вопросы, связанные с организацией контроля качества питьевой воды, в том числе производственного контроля, в соответствии с действующими санитарными и отраслевыми нормативными документами. Приведен опыт ГУП «Водоканал Санкт-Петербурга» по формированию программ производственного контроля, выбора контрольных точек в распределительной сети с учетом оценки риска при ухудшении качества воды у потребителя. Обозначены инициативы по внесению в нормативные акты, касающиеся организации производственного контроля, обязательности использования автоматизированных систем контроля качества воды по основным индикаторным показателям (температура, мутность, цветность, рН, общий органический углерод, остаточный хлор). Это позволит повысить эффективность управления системой водоснабжения, оперативно реагировать на изменения состава воды, проводить постоянный мониторинг состояния устойчивости системы с переходом на цифровые технологии («умный водоканал»). The issues related to the arrangement of the drinking water quality control, including in-process monitoring, in accordance with the current sanitary and sectorial regulations are touched upon. The experience of SUE «Vodokanal of St. Petersburg» in developing production control programs, selecting control points in the distribution network with account of the risk assessment in case of water quality deterioration at the consumer’s tap, is presented. Initiatives for including into the statutory regulations on the arrangement of production control, the mandatory use of automated water quality control systems for the main indicator values (temperature, turbidity, color, pH, total organic carbon, residual chlorine) are outlined. The amendments will provide for improving the efficiency of the water supply system management, responding promptly to the changes in water composition, and continuously monitoring the state of the system sustainability with the transition to digital technologies («smart water utility»).


2018 ◽  
Vol 8 (2) ◽  
pp. 349-358 ◽  
Author(s):  
Andrés Araya ◽  
Luis D. Sánchez

Abstract This study presents the behavior of residual chlorine using computer modeling for a small water supply system located in La Sirena, Cali, Colombia. The study included field work to calibrate and validate the model together with lab determinations. Results show that the kinetics of first and second order together with the kinetics of mixed order can adequately describe the behavior of residual chlorine in this type of network. The research showed the variables that influence the behavior of residual chlorine in the network are: the quality of the input water, chlorine dosing, the effect of storage that increases the water age, and the presence of dead zones in the tanks. The study revealed that 95% of the reaction occurs in the storage tanks due to the small variation in the water level and the negligible reactions at the pipe walls. This study proved that the residual chlorine modeling in this small network in particular is a valuable tool for monitoring the water quality in the distribution network, which is useful to comply with water quality guidelines.


2021 ◽  
Vol 13 (24) ◽  
pp. 13913
Author(s):  
Feng Sun ◽  
Peng Yu ◽  
Chenhui Xu ◽  
Hongfei Yu ◽  
Fengyi Wang ◽  
...  

As a kind of high-organic-content contamination source, extracellular polymeric substances (EPS) secreted by cyanobacteria have become an important factor restricting the safety of supply water. In the dynamic batch mode water supply system, cyanobacterial EPS accelerated the decay rate of residual chlorine, resulting in a 21–26 times increase of the total viable bacteria count within 72 h. The water turbidity exceeded upper limit of the standards for drinking water quality within 4 h, with an increase of 306–332% within 72 h. The biological stability was reduced with BDOC and AOC increased by 41.4–43.8% and 331–396%, respectively. The main cause is that cyanobacterial EPS act as nutrients and metabolic energy for microorganisms, promoting their metabolic activity and secretion of extracellular organic components. This leads to the metabolic accumulation of tryptophan, fulvic acids and humic acids in the pipeline, thus further promoting the regeneration of bacteria. Compared with the influence of biofilm on pipe wall caused by long-term use of water supply network, the contribution of cyanobacterial EPS to the water contamination of pipe network is increased several times. Therefore, even in the presence of residual chlorine, the secondary contamination caused by cyanobacterial EPS in the water supply system could not be neglected.


2018 ◽  
Vol 28 (4) ◽  
pp. 1259-1264
Author(s):  
Kiril Lisichkov ◽  
Katerina Atkovska ◽  
Neven Trajchevski ◽  
Orce Popovski ◽  
Nadica Todorovska

The presence of some chemical compounds at higher levels than maximum permissible concentrations (MPC) in the drinking water, suggests of water resources pollution. In this paper the following elements were analyzed: total arsenic, cadmium, lead, cooper and zinc. Twelve samples of water from the water supply system from the city of Skopje were examined during one year from three different springs. Also, ten samples of bottled water from three producers from the Macedonian market were tested.The determined average mass concentrations of total As, Cd(II), Pb(II), Cu(II) and Zn(II) in the analyzed water samples from the water supply system are 1.35 μg/l, 0.06 μg/l, 0.6 μg/l, 0.9 μg/l and 1,12 μg/l, respectively, and for the tested bottled water, the mean values ranges from 0.56 - 0.83 μg total As / l, 0.053 - 0.056 μg Cd(II)/l, 0.51 - 0.54 μg Pb(II)/l , 0.6 - 0.87 μg Cu(II)/l and 0.68 - 0.8 μg Zn(II)/l water.The following instrumental analytical methods and techniques were used for the analysis of the tested samples of drinking water: flame atomic absorption spectroscopy (AAS), atomic absorption spectroscopy with hydride cеll, electrothermal atomic absorption spectroscopy.The obtained results are shown in tables and graphic form. According to the obtained results a comparative analysis was carried out indicate that it is a water of good quality that can be used in different branches of the process industry.The obtained results in this paper do not exceed the values of the MPC of the Republic of Macedonia prescribed by the legal regulations for the drinking water, which confirm the health safety of the drinking water from the water supply system in the city of Skopje and the packed waters from the Macedonian market in relation to the tested elements.


Sign in / Sign up

Export Citation Format

Share Document