Characterization of Non-Enteric Bacterial Regrowth in the Water Supply Distribution Network from a Eutrophic Reservoir

1989 ◽  
Vol 21 (3) ◽  
pp. 49-53 ◽  
Author(s):  
R. A. Gibbs ◽  
C. R. Hayes
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Pathogenic Bacteria ◽  
Seasonal Pattern ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Bacterial Regrowth ◽  
Organic Carbon Concentration ◽  
Plate Counts ◽  
Heterotrophic Plate Counts

An area of a distribution network receiving organically rich treated water was studied for a period of one year to gain further understanding of the regrowth of bacteria in a water distribution network. These bacteria are considered to be harmless to man. Surveys additional to this study confirmed that enteroviruses and pathogenic bacteria (as defined by EC directives) were absent, consistent with the general absence of coliforms. Fixed points were sampled regularly for bacteriological analysis and for relevant physical and chemical parameters. Heterotrophic plate counts were carried out using standard methods and a study was conducted to test alternative techniques. It was found that bacterial regrowth occurred close to the treatment works and longer retention resulted in little increase in plate counts. Monochloramine residuals of 0.26mg/l or less did not prevent regrowth. The assimilable organic carbon concentration decreased through the distribution system and increased following booster chlorination. Plate counts showed a seasonal pattern peaking in the spring and autumn and decreasing in the summer and winter. The predominant genera of bacteria were Pseudomonas, Alcaligenes and Aeromonas with maximum counts of 17,000, 23,000 and 1,700 CFU/ml respectively. Heterotrophic plate counts using the R2A medium, spread plate method and 7 day incubation period were on average 190 times greater than counts using the UK standard method. The increase in count gained by using the alternative method was greatest at the sampling points furthest from the treatment works.

scholarly journals DEVELOPMENT OF CLEAN WATER DISTRIBUTION NETWORK SYSTEM IN GENTENG SUB-DISTRICT BANYUWANGI USING EPANET 2.0 PROGRAM

2019 ◽  
Vol 3 (2) ◽  
pp. 172
Author(s):  
Ayu Rahmad Jayanti ◽  
Ririn Endah Badriani ◽  
Yeny Dhokhikah
Keyword(s):  
Discharge Capacity ◽  
Distribution System ◽  
Water Distribution ◽  
Water Discharge ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Public Works ◽  
Network System ◽  
Clean Water ◽  
Simulation Results

The clean water distribution in the Genteng Subdistrict, Banyuwangi Regency is included in the service area of the Zone 1 PDAM tile unit. The 60 liters/second reservoir discharge capacity is obtained from Sumber Umbul Sari in the Glenmore District. The distribution of clean water in Zone 1 is still less than 70% of the area served, as the installed discharge capacity is estimated to be insufficient. In order to achieve the distribution goal, a network system must be developed by adding direct debits and planning a new pipeline. The Epanet 2.0 program simplifies the calculation of pipeline networks by integrating elevation data, network maps, pipeline specification, and load. The analysis of the simulation results was conducted using the Public Works Minister's hydraulic parameter standards 2007. Planning of a distribution network and a cost budget in 2029 were done to estimate the water supply needs and budgets required. The hydraulic simulation results based on the analysis of the pressure of all joints are in accordance with the standard, while the analysis of the velocity in pipe is less standard. The need for water discharge in 2029 is 71.6 liters/second. In Kembiritan Village, the construction of distribution pipes with an additional reservoir unit was planned. The planned pipe dimensions in the development area were 25 mm at 796 meters, 50 mm at 4062 meters, and 75 mm at 1518 meters. The cost of planning a clean water distribution system in 2029 is Rp. 1,431,375,000.00. Distribusi air bersih di Kecamatan Genteng Kabupaten Banyuwangi merupakan wilayah pelayanan Zona 1 PDAM unit Genteng. Kapasitas debit reservoir sebesar 60 liter/detik berasal dari sumber umbul sari di Kecamatan Glenmore. Pendistribusian air bersih di wilayah Zona 1 masih kurang dari 70% wilayah yang terlayani, karena diperkirakan kapasitas debit yang terpasang kurang mencukupi. Untuk memenuhi target pemerataan distribusi perlu pengembangan sistem jaringan dengan penambahan debit dan perencanaan jaringan pipa baru. Program Epanet 2.0 memudahkan dalam perhitungan jaringan perpipaan dengan mengintegrasi data elevasi, peta jaringan, spesifikasi pipa dan debit. Analisis hasil simulasi menggunakan standar parameter hidrolis Permen PU 2007. Perencanaan pengembangan jaringan distribusi dan anggaran biaya pada tahun 2029 guna memperkirakan debit kebutuhan air dan anggaran biaya yang dibutuhkan. Hasil simulasi hidrolis berdasarkan analisis tekanan semua junction telah sesuai standar, sedangkan analisis kecepatan masih di bawah standar. Kebutuhan debit air tahun 2029 sebesar 71,6 Liter/detik. Pengembangan pipa distribusi direncanakan di Desa Kembiritan dengan tambahan satu unit reservoir. Dimensi pipa rencana di wilayah pengembangan digunakan diameter 25 mm sepanjang 796 m, diameter 50 mm sepanjang 4062 m dan diameter 75 mm sepanjang 1518 m. Biaya perencanaan sistem distribusi air bersih tahun 2029 sebesar Rp. 1.431.375.000,00.

Leakage management in a low-pressure water distribution network of Bangkok

2009 ◽  
Vol 9 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Mukand S. Babel ◽  
Md. S. Islam ◽  
A. Das Gupta
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Level Of Service ◽  
Operating Pressure ◽  
Asian Countries ◽  
Pressure Profiles ◽  
Pressure Water

Losses of water due to leakage occur in every distribution network, the only difference is in the amount of leakage. The leakage levels are relatively high in cities of developing Asian countries. Among the several factors, operating pressure is the most important affecting the leakage. This paper describes how the management of pressure can help reduce the leakage in the water distribution network. EPANET is used to develop the hydraulic model to analyse the effect of alternative pressure profiles on the leakage in a pilot area within the water distribution system of Bangkok. One of the alternatives is implemented in the field to verify the applicability of the model. Results indicate that the average reduction in pressure by 2.4 m can reduce the leakage by 12.5% of the system inflow without compromising the level of service.

scholarly journals Modelling the potable water quality in a distribution network based on the hydraulic conditions

2020 ◽  
Author(s):  
Jani Tomperi
Keyword(s):  
Water Quality ◽  
Distribution System ◽  
Water Distribution ◽  
Potable Water ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Quality Model ◽  
Pipe Surface ◽  
Hydraulic Conditions ◽  
Potable Water Quality

Abstract. Abnormalities in hydraulic conditions inside a water distribution network are strongly related to the deterioration of potable water quality. Leaking pipes and valves, for instance, cause changes in water hydraulic conditions and may allow the entry of microbes to the distribution system. Flow and pressure shocks can detach soft deposits and biofilms from the pipe surface which is shown among others as the elevated concentrations of bacteria, metals and turbidity in water. On that account, monitoring the hydraulic conditions in a distribution network and utilizing this information in developing a predictive water quality model assists providing a sufficient amount of potable water with an appropriate quality for the consumers use. In this paper, the water quality at the end part of the district metered area is modelled based on only the water flow and pressure measurements along the distribution network. The developed model can be utilized in proactive operation as it is able to show the potable water quality hours in advance before it is discovered at the end part of the distribution network.

Assimilable Organic Carbon Concentrations and Bacterial Numbers in a Water Distribution System

1993 ◽  
Vol 27 (3-4) ◽  
pp. 159-166 ◽  
Author(s):  
R. A. Gibbs ◽  
J. E. Scutt ◽  
B. T. Croll
Keyword(s):  
Seasonal Variation ◽  
Organic Carbon ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Seasonal Pattern ◽  
Agar Plate ◽  
Plate Count ◽  
Spatial And Seasonal Variation ◽  
Plate Counts

A three year study was conducted to investigate bacterial growth in a drinking water distribution system in the UK. Bacterial numbers were estimated using Yeast Extract Agar plate counts. Plate counts in the distribution system showed patterns of spatial and seasonal variation. The spatial pattern was that plate counts increased through the distribution system until approximately 30 to 40 hours retention time and remained constant further through the distribution system. The seasonal pattern was that plate counts were low in the winter and had large peaks in the summer and autumn. Assimi able organic carbon (AOC) concentrations were measured in the second and third years of the study using an adenosine triphosphate (ATP) assay. There appeared to be no relationship tietween AOC concentrations and the spatial and seasonal variation in plate counts. The lack of correlation may have been caused by a lack of sensitivity in the AOC technique. Another explanation is that the increase in plate counts through the distribution system was due to an increase in the culturability of bacteria on plate count media, rather than an increase in bacterial numbers. Bacteria may not have grown through the distribution system and therefore not utilised the AOC.

Application of Artificial Neural Network for Reducing of Chlorine Residual Concentration in Water Distribution Network

2008 ◽  
Vol 3 (2) ◽  
Author(s):  
Jayong Koo ◽  
Toyono Inakazu ◽  
Akira Koizumi ◽  
Yasuhiro Arai ◽  
Kyoungpil Kim ◽  
...  
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Residual Chlorine ◽  
Trial And Error ◽  
Ann Model ◽  
Residual Concentration ◽  
Dead End

It is difficult to estimate residual chlorine at the dead-end area of the water distribution network because chlorine consumption is influenced by various factors. Therefore, there are many water utilities that control the amounts of chlorine in reservoirs using empirical trial-and-error methods to maintain safe levels of residual chlorine in the distribution system. In this study, an ANN model of residual chlorine concentration is proposed which could be used to reduce in chlorine use in water distribution system. The ANN model with best performance was selected by training and verification. The five scenarios for the reduction in chlorine use were analyzed by setting the input chlorine as low as 0.05~0.25 mg/L compared with the input chlorine observed in the time series. Case 4 is the best to be satisfied with the input condition (0.4 mg/L or more) and output condition (0.34 mg/L or more) at the same time. It is possible to reduce chlorine in use up to 0.2 mg/L in the maximum amount.

Determination of Neutral Point in Water Distribution Network Pipes with Variable Discharge on Route

2014 ◽  
Vol 909 ◽  
pp. 428-432 ◽  
Author(s):  
Ioan Sarbu ◽  
Gabriel Ostafe
Keyword(s):  
Water Supply ◽  
Distribution System ◽  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Neutral Point ◽  
Water Supply Systems ◽  
Proposed Model

Distribution networks are an essential part of all water supply systems. Distribution system costs within any water supply scheme may be equal to or greater than 60% of the entire cost of the project. The reliability of supply is much greater in the case of looped networks. The pipe networks have concentrated outflows or uniform outflow along the length of each pipe. In some pipes with variable discharge of a looped distribution network, water velocity could be reversed between its extremities. Thus, it is a water stall point denominated neutral point in which the discharge is null. In this paper a mathematical model for the determination of water stall point location in the pipes with distributed consumption is developed. This model has been implemented in a computer program for PC microsystems. Numerical example will be presented to demonstrate the accuracy and efficiency of the proposed model.

scholarly journals Equivalent hydraulic resistance to simulate pipes subject to diffuse outflows

2011 ◽  
Vol 14 (1) ◽  
pp. 65-74 ◽  
Author(s):  
M. Ferrante ◽  
E. Todini ◽  
C. Massari ◽  
B. Brunone ◽  
S. Meniconi
Keyword(s):  
Hydraulic Resistance ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Distribution Network ◽  
Network Models ◽  
Water Distribution Network ◽  
Simulation Models ◽  
Gradient Algorithm ◽  
Present Generation

In water distribution network simulation models, pipes subject to diffuse outflow, either due to connections or to distributed demand or to leaks along their length, are generally converted into pipe elements only subject to lumped demand at their ending nodes. This approximation, which disregards the flow variation along the pipes, generates a loss of axial momentum, which is not correctly taken into account in the present generation of water distribution network models. In this paper a correction to the lumped demand approximation is provided and this equivalence is analyzed within the framework of the Global Gradient Algorithm. This is obtained through a correction of the pipe hydraulic resistance; this approach has proven to be more effective than the use of an asymmetrical lumped demand of the total distributed outflow at the pipe ending nodes. In order to assess the effect of the introduced correction, an application to a simple water distribution system is finally provided.

Chlorine requirement for biologically stable drinking water after nanofiltration

2013 ◽  
Vol 14 (3) ◽  
pp. 405-413
Author(s):  
Y. Ohkouchi ◽  
Y. Yata ◽  
R. Bun ◽  
S. Itoh
Keyword(s):  
Drinking Water ◽  
Water Distribution ◽  
Flow Reactor ◽  
Heterotrophic Bacteria ◽  
Tap Water ◽  
Biological Stability ◽  
Bacterial Regrowth ◽  
Chlorine Residual ◽  
Plate Counts ◽  
Heterotrophic Plate Counts

There is considerable interest in minimizing the chlorine residual in Japan's tap water because of increasing consumer complaints about the chlorinous odor of drinking water. However, minimization of the chlorine residual requires stricter control of biodegradable organics in finished water to ensure biological stability during water distribution. In this context, we investigated the improvement of biological stability of drinking water by nanofiltration (NF). The removal of assimilable organic carbon (AOC) was 52% on average, but showed large seasonal variation. It was found to be difficult to maintain the acceptable AOC level for biologically stable water by NF. In addition, significant bacterial regrowth in NF permeates was still observed without chlorination, although 52% AOC was removed. Then, the chlorine concentration required to prevent bacterial regrowth during distribution of nanofiltrated water was determined using continuous-flow reactor systems. The heterotrophic plate counts (HPC) densities in biofilm were monitored at different chlorine conditions. The results indicated that the NF process could significantly reduce the chlorine requirement of the finished water. The relationship between free chlorine residual and HPC in biofilm formed from 1 μgC AOC showed that a trace level of chlorine residual, <0.1 mg/L, could inactivate heterotrophic bacteria and prevent biofilm formation.

scholarly journals Optimizing the Formation of DMAs in a Water Distribution Network Applying Geometric Partitioning (GP) and Gaussian Mixture Models (GMMs)

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 601 ◽  
Author(s):  
Stavroula Chatzivasili ◽  
Katerina Papadimitriou ◽  
Vasilis Kanakoudis ◽  
Menelaos Patelis
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Gaussian Mixture ◽  
Optimal Placement ◽  
Water Age ◽  
Optimal Separation ◽  
Geometric Partitioning

In the last three decades, the need of achieving a reliable water distribution system has become more eminent for both the consumer’s satisfaction and the efficient management of water sources. The purpose of this paper is to provide an optimal separation of a water distribution network (WDN) into District Metered Areas (DMAs) in order to ensure that the delivered water is of proper age and pressure. At first, the water distribution network is divided into smaller areas via the method of Geometric Partitioning, which is based on Recursive Coordinate Bisection (RCB). Subsequently, Gaussian Mixture Modelling (GMM) solution is applied, obtaining an optimal placement of isolation valves and separation of the WDN into DMAs. The performance of the proposed system is evaluated on two different networks and is compared against the Genetic Algorithm (GA) tool, constituting a very promising approach, especially for sizeable water distribution networks due to the diminished running time and the noteworthy reduction of pressure and water age.

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