scholarly journals Profiling chlorine residuals using DPD and amperometric field test kits in a chlorinated small drinking water system with ammonia present in source water

2018 ◽  
Vol 61 (2) ◽  
pp. 39-49
Author(s):  
Sunil Beeharry ◽  
Simon Sihota ◽  
Chris Kelly

Effective chlorine residual monitoring of water treatment systems that have ammonia in the raw source water is crucial to ensure adequate disinfection. Understanding the limitations related to monitoring chlorine in these systems is important to help reduce risk from microbiological hazards. The presence of ammonia and the resulting chlorine demand can be very challenging to address in drinking water treatment, especially for small water systems. This study profiles a number of situations where erratic chlorine dosing, operational, and testing conditions create a false-positive free available chlorine result. This study identified that the field test kit using amperometric testing methodology is superior to the traditional DPD (N,N-diethyl-p-phenylene-diamine) tests in a water system that has the presence of ammonia with erratic chlorine dosage.

2019 ◽  
Vol 15 (1) ◽  
pp. 48-65 ◽  
Author(s):  
Stephen Siwila ◽  
Isobel C. Brink

Abstract A low-cost multi-barrier drinking water system incorporating geotextile fabric for pre-filtration, silver-coated ceramic granular media (SCCGM) for filtration and disinfection, granular activated carbon (GAC) as an adsorption media and a safe storage compartment for treated water has been developed and tested. The developed system offers a novel concept of point-of-use drinking water treatment in rural and suburban areas of developing countries. The system is primarily aimed at bacterial and aesthetic improvement and has been optimised to produce >99.99% E. coli and fecal coliforms removal. Although particular emphasis was placed on the elimination of bacteria, improvement of the acceptability aspects of water was also given high priority so that users are not motivated to use more appealing but potentially unsafe sources. This paper discusses key system features and contaminant removal performance. A system using SCCGM only was also tested alongside the multi-barrier system. Strengths and weaknesses of the system are also presented. Both the developed and SCCGM-only systems consistently provided >99.99% E. coli and fecal coliforms removal at an optimum flow of 2 L/h. The developed system significantly recorded improvements of aesthetic aspects (turbidity, color, taste and odor). Average turbidity removals were 99.2% and 90.2% by the multi-barrier and SCCGM-only systems respectively.


2019 ◽  
Vol 19 (7) ◽  
pp. 2098-2106
Author(s):  
Chelsea W. Neil ◽  
Yingying Zhao ◽  
Amy Zhao ◽  
Jill Neal ◽  
Maria Meyer ◽  
...  

Abstract Source water quality can significantly impact the efficacy of water treatment unit processes and the formation of chlorinated and brominated trihalomethanes (THMs). Current water treatment plant performance models may not accurately capture how source water quality variations, such as organic matter variability, can impact treatment unit processes. To investigate these impacts, a field study was conducted wherein water samples were collected along the treatment train for 72 hours during a storm event. Systematic sampling and detailed analyses of water quality parameters, including non-purgeable organic carbon (NPOC), UV absorbance, and THM concentrations, as well as chlorine spiking experiments, reveal how the THM formation potential changes in response to treatment unit processes. Results show that the NPOC remaining after treatment has an increased reactivity towards forming THMs, and that brominated THMs form more readily than chlorinated counterparts in a competitive reaction. Thus both the reactivity and quantity of THM precursors must be considered to maintain compliance with drinking water standards, a finding that should be incorporated into the development of model-assisted treatment operation and optimization. Advanced granular activated carbon (GAC) treatment beyond conventional coagulation–flocculation–sedimentation processes may also be necessary to remove the surge loading of THM-formation precursors during a storm event.


2021 ◽  
pp. 117296
Author(s):  
Émile Sylvestre ◽  
Michèle Prévost ◽  
Jean-Baptiste Burnet ◽  
Patrick Smeets ◽  
Gertjan Medema ◽  
...  

2005 ◽  
Vol 71 (2) ◽  
pp. 1042-1050 ◽  
Author(s):  
Gerald Sedmak ◽  
David Bina ◽  
Jeffrey MacDonald ◽  
Lon Couillard

ABSTRACT Reoviruses, enteroviruses, and adenoviruses were quantified by culture for various ambient waters in the Milwaukee area. From August 1994 through July 2003, the influent and effluent of a local wastewater treatment plant (WWTP) were tested monthly by a modified U.S. Environmental Protection Agency Information Collection Rule (ICR) organic flocculation cell culture procedure for the detection of culturable viruses. Modification of the ICR procedure included using Caco-2, RD, and HEp-2 cells in addition to BGM cells. Lake Michigan source water for two local drinking water treatment plants (DWTPs) was also tested monthly for culturable viruses by passing 200 liters of source water through a filter and culturing a concentrate representing 100 liters of source water. Reoviruses, enteroviruses, and adenoviruses were detected frequently (105 of 107 samples) and, at times, in high concentration in WWTP influent but were detected less frequently (32 of 107 samples) in plant effluent and at much lower concentrations. Eighteen of 204 samples (8.8%) of source waters for the two DWTPs were positive for virus and exclusively positive for reoviruses at relatively low titers. Both enteroviruses and reoviruses were detected in WWTP influent, most frequently during the second half of the year.


2015 ◽  
Vol 51 (11) ◽  
pp. 8741-8756 ◽  
Author(s):  
Matthew T. Heberling ◽  
Christopher T. Nietch ◽  
Hale W. Thurston ◽  
Michael Elovitz ◽  
Kelly H. Birkenhauer ◽  
...  

2015 ◽  
Vol 7 (1) ◽  
pp. 1-15 ◽  
Author(s):  
I. Delpla ◽  
A. Scheili ◽  
S. Guilherme ◽  
G. Cool ◽  
M. J. Rodriguez

In Québec, Canada, shifts in climate patterns (i.e., rainfall increase) could have consequences on source water quality due to the intensification of surface/groundwater runoff contamination events, leading to a decline in drinking water treatment efficiency and ultimately disinfection by-products (DBPs) formation following treatment. To assess the impacts of climate change (CC) scenarios on DBP formation, a suite of models linking climate to DBPs was used. This study applies three emissions scenarios (B1, A1B and A2) for three 30-year horizons (2020, 2050 and 2080) in order to produce inputs to test several DBP models (total trihalomethanes (TTHMs), haloacetic acids and haloacetonitriles). An annual increase is estimated for all DBPs for each CC scenario and horizon. The highest seasonal increases were estimated for winter for all DBP groups or species. In the worst-case scenario (A2-2080), TTHMs could be affected more particularly during winter (+34.0%), followed by spring (+16.1%) and fall (+4.4%), whereas summer concentrations would remain stable (−0.3 to +0.4%). Potentially, small water utilities applying only a disinfection step could be more affected by rising TTHMs concentrations associated with CC than those having implemented a complete water treatment process (coagulation–flocculation, filtration and disinfection) with +13.6% and +8.2% increases respectively (A2-2080).


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