scholarly journals Robustness analysis of technological units for drinking water clarification: Normal and emergency operating conditions

2020 ◽  
Vol 74 (2) ◽  
pp. 91-102
Author(s):  
Slobodanka Zoric ◽  
Milena Becelic-Tomin ◽  
Bozo Dalmacija
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Treatment Plant ◽  
Robustness Analysis ◽  
Operating Conditions ◽  
Water Turbidity ◽  
Target Value ◽  
Robustness Index ◽  
Emergency Operating Conditions ◽  
Emergency Operating

The primary goal of a water supply system is the protection of human health by providing microbiologically and chemically safe drinking water. Significant changes in water quality require sufficiently robust systems for water preparation, performances of which are unaffected by present variations and changing operational conditions. Water turbidity is an important parameter for the water filtration control and efficiency of disinfection. The efficiency of turbidity removal in the drinking water treatment plant ?Vodovod? in Banjaluka under normal and emergency operating conditions was examined in this paper. At normal conditions the maximal detected value was 25 NTU while at emergency operating conditions it was above 240 NTU. Robustness evaluation of the water clarification system was performed separately for periods of normal and emergency operating conditions (during and after emptying the accumulation). The robustness index was calculated based on a more stringent target turbidity value (0.5 NTU) than that specified by the current legislation, which represents a new criterion in the risk analysis in the existing practice. Data processing results indicate high operational stability of technological units under normal conditions. The filtered water quality was below the target value during most of the time of filter operation in all cycles. The recorded turbidity value was ? 0.3 NTU for 92.9 % of filtered water samples. Analysis of the water turbidity data has shown that 17% of all taken measurements under emergency operating conditions (336 samples) had higher turbidity than the target value (0.5 NTU). Large variations in raw water turbidity over short periods of times during the emergency operating conditions, present a problem for prompt response in the drinking water plant. Calculated robustness index values point to inadequate efficiency of the water clarification process in a certain number of filter operating cycles. We have found a significant impact of the plant operating conditions on the filtered water turbidity under emergency conditions, such as suboptimal coagulation and flocculation conditions as well as the nature of suspended and colloid particles inducing turbidity and insufficient particle interactions with the coagulant. Along with the negative influence on water turbidity, excessive coagulant dosage leads to increased concentrations of residual aluminum in filtered water. Optimization of emergency working conditions could be performed based on adequate monitoring of water sources, which would further decrease potential risks of pathogen appearance in drinking water.

scholarly journals Membrane-Based Processes to Obtain High-Quality Water From Brewery Wastewater

2021 ◽  
Vol 3 ◽  
Author(s):  
Marc Sauchelli Toran ◽  
Patricia Fernández Labrador ◽  
Juan Francisco Ciriza ◽  
Yeray Asensio ◽  
André Reigersman ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Reuse ◽  
Public Perception ◽  
Treatment Plant ◽  
Ceramic Membranes ◽  
Operating Conditions ◽  
Brewery Wastewater ◽  
High Quality ◽  
Filtration Time ◽  
Treated Water

Water reuse is a safe and often the least energy-intensive method of providing water from non-conventional sources in water stressed regions. Although public perception can be a challenge, water reuse is gaining acceptance. Recent advances in membrane technology allow for reclamation of wastewater through the production of high-quality treated water, including potable reuse. This study takes an in-depth evaluation of a combination of membrane-based tertiary processes for its application in reuse of brewery wastewater, and is one of the few studies that evaluates long-term membrane performance at the pilot-scale. Two different advanced tertiary treatment trains were tested with secondary wastewater from a brewery wastewater treatment plant (A) ultrafiltration (UF) and reverse osmosis (RO), and (B) ozonation, coagulation, microfiltration with ceramic membranes (MF) and RO. Three specific criteria were used for membrane comparison: 1) pilot plant optimisation to identify ideal operating conditions, 2) Clean-In-Place (CIP) procedures to restore permeability, and 3) final water quality obtained. Both UF and Micro-Filtration membranes were operated at increasing fluxes, filtration intervals and alternating phases of backwash (BW) and chemically enhanced backwash (CEB) to control fouling. Operation of polymeric UF membranes was optimized at a flux of 25–30 LMH with 15–20 min of filtration time to obtain longer production periods and avoid frequent CIP membrane cleaning procedures. Combination of ozone and coagulation with ceramic MF membranes resulted in high flux values up to 120 LMH with CEB:BW ratios of 1:4 to 1:10. Coagulation doses of 3–6 ppm were required to deal with the high concentrations of polyphenols (coagulation inhibitors) in the feed, but higher concentrations led to increasing fouling resistance of the MF membrane. Varying the ozone concentration stepwise from 0 to 25 mg/L had no noticeable effect on coagulation. The most effective cleaning strategy was found to be a combination of 2000 mg/L NaOCl followed by 5% HCl which enabled to recover permeability up to 400 LMH·bar−1. Both polymeric UF and ceramic MF membranes produced effluents that fulfil the limits of the national regulatory framework for reuse in industrial services (RD 1620/2007). Coupling to the RO units in both tertiary trains led to further water polishing and an improved treated water quality.

Management of the Occoquan River basin: a 20-year case history

1995 ◽  
Vol 32 (5-6) ◽  
pp. 235-243 ◽  
Author(s):  
C. W. Randall ◽  
T. J. Grizzard
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Drinking Water ◽  
Wastewater Treatment ◽  
Water Supply ◽  
Land Use Changes ◽  
Treatment Plant ◽  
Water Reservoir ◽  
Land Use Management ◽  
Early Results

The high dam on the Occoquan River of Northern Virginia, United States of America, was constructed in 1957, forming a drinking water reservoir with a capacity of 37.1 × 106m3 formed by drainage from a 1 460 km2 watershed, and providing a safe yield of 189 251 m3 per day. Deteriorating water quality in the late 1960s led to a special “policy” for the watershed, designed to preserve the reservoir as a drinking water supply. Key provisions of the policy mandated replacement of the watershed's 11 publicly owned wastewater treatment works with a single advanced wastewater treatment plant (AWT), and establishment of the Occoquan Watershed Monitoring Programme. Early results from the programme established non-point nutrient pollution as a major cause of water quality deterioration and resulted in the implementation of non-point pollution controls throughout the watershed during the late 1970s. The AWT plant went on-line in July 1978. Continuous monitoring since 1973 has demonstrated both the necessity and the effectiveness of point and non-point nutrient controls for the preservation of the reservoir's water quality. The AWT plant provides excellent removal of organics and phosphorus, plus complete nitrification. The nitrates are discharged to the receiving stream to enhance conditions in the reservoir. Control policies include land-use management for the preservation of this essential water supply for 750 000 people in the Washington, D.C. suburbs. Land-use management decisions are based on the results obtained with a watershed-reservoir linked computer model which predicts water quality changes resulting from land-use changes.

An approach for determining the most critical among a suite of chemical contaminants at a drinking water intake

2013 ◽  
Vol 13 (3) ◽  
pp. 835-845
Author(s):  
Fei Chen ◽  
William B. Anderson ◽  
Peter M. Huck
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Intake ◽  
Treatment Plant ◽  
Quality Data ◽  
Exceedance Probability ◽  
Raw Water ◽  
Water Quality Data ◽  
Treatment Processes ◽  
Raw Water Quality

An integrated approach for the identification and assessment of the most critical chemical contaminant(s) at a drinking water intake has been developed. It involves the determination of a threshold or critical raw water concentration (CRWC) for target contaminants using the observed overall removal efficiency of a specific water treatment plant (WTP) and regulated drinking water concentrations for the target contaminants. The exceedance probability relative to the CRWC based on historical raw water quality monitoring data is then calculated. Finally, the integration of the raw water quality data and the overall efficiency of a particular WTP sequence allows for identification of the most critical contaminant(s) as well as an advance indication of which contaminants are most likely to challenge a plant. The proactive nature of this approach gives a utility the impetus and time to assess current treatment processes and potential alternatives. In addition, it was found that three- or four-parameter theoretical distributions are more appropriate than two-parameter probability distributions for the fitting of raw water quality data. This study reveals that the reliance on raw and/or treated water contaminant concentrations in isolation or on theoretical removals through treatment processes can, in some circumstances, be misguided.

An Assessment Of Drinking Water Quality In Parts Of Skudai, Johor Bahru

1992 ◽  
pp. 1-9
Author(s):  
Ir. Abd. Rasid Othman Othman ◽  
Mohd Asri Mohd Nor ◽  
Azmi Aris ◽  
Teng Keat Hui ◽  
Jagjit Singh Jora Singh
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Distribution System ◽  
Treatment Plant ◽  
Drinking Water Quality ◽  
World Health ◽  
Piped Water ◽  
Pipe Water ◽  
Result Show ◽  
Health Organization

In a assessment of drinking water quality in Skudai Johor Bahru, piped water samples in the distribution system from three different standpipe locations in Taman Sri Skudai, Taman Sri Pulai and Universiti Teknologi Malaysia (UTM) campus were collected and tested for selected ions and bacteriological quality. The result show that pipe water supplied from a treatment plant at Gunung Pulai in Pontian was low in mineral content. No Eschericia Coli were detected expected at the UTM Campus with concentration of 3 counts/100 mL in one out of 12 sample tested. Total coliforms were found at each site with concentration ranging from 1 to 13 counts/100 mL in 15 out of 6 samples. Except for the coliforms and the fluoride levels exceeding a little over 1.5 mg/L in 8% of the samples, drinking water in the distribution system in the study area can generally be said to have met the World Health Organization (WHO) guidelines during the study period. However, with the detection of coliforms and E. Coli at the household standpipes, the possibility of the distribution system in Skudai having pathogen contamination from time to time cannot be dismissed. Keywords: drinking water quality

scholarly journals Trihalomethane precursor reactivity changes in drinking water treatment unit processes during a storm event

2019 ◽  
Vol 19 (7) ◽  
pp. 2098-2106
Author(s):  
Chelsea W. Neil ◽  
Yingying Zhao ◽  
Amy Zhao ◽  
Jill Neal ◽  
Maria Meyer ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Plant Performance ◽  
Storm Event ◽  
Source Water ◽  
Treatment Unit ◽  
Source Water Quality

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.

A Case Study on the Automatic Control of Chemical Dosing Processes for Full-Scale Drinking Water Treatment

2012 ◽  
Vol 209-211 ◽  
pp. 1981-1985 ◽  
Author(s):  
Dong Sheng Wang ◽  
Xing Peng Zhou ◽  
Xiao Ming Mo ◽  
Yi Wang
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Automatic Control ◽  
Water Flow ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Constant Attention ◽  
Operational Conditions ◽  
Quality Water

During drinking water treatment, the chemical dosing processes, such as coagulant dosing process, ozone dosing process and chlorine dosing process are usually manually operated based on the operator knowledge and experience. However, due to the variations of water quality, water flow and process operational conditions and characteristics of large time-delay and nonlinear for the chemical dosing processes, it is difficult to adjust the chemical dosages in time by operators to keep the treated water quality stable, especially during the periods of rapid and frequent variations of water quality, water flow and process operational conditions. Thus, the improvements of control methods for the chemical dosing processes are essential to the operation of drinking water treatment plants. The Xiangcheng Water Treatment Plant in Suzhou, China has been utilizing the automatic control for chemical dosing processes since February 2012. Automatic controllers are designed respectively for the coagulant dosing process, ozone dosing process and chlorine dosing process. After the implementation of automatic control, operators are not necessary to keep constant attention. In addition, due to the improvements of control accuracies for the chemical dosing processes, the chemical dosages are reduced on the premise of ensuring safe water. Thus, both of the human resource costs and material costs can be saved. The practical control results demonstrate the efficiencies of proposed methods.

scholarly journals Investigation of water quality changes in drinking water supplied from Sitlee water treatment plant on River Tawi to Old Jammu City, Jammu, J&K, India

2018 ◽  
Vol 10 (2) ◽  
pp. 601-607
Author(s):  
Poonam Kundan ◽  
Deepika Slathia
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Water Samples ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Quality Parameters ◽  
Faecal Coliform ◽  
Quality Changes ◽  
Distribution Point

In the present study, an attempt has been made to evaluate the water quality changes in River Tawi water treated at Sitlee water treatment plant, and supplied for drinking to Old Jammu City, Jammu, J&K, India. Water samples from the treated water unit of Sitlee water treatment plant and around ten houses from the distribution point (Old Jammu City) were analyzed monthly for various physicochemical parameters for a period of one year (February 2014 to January 2015). The study indicated deterioration of drinking water quality during its passage through the distribution network which has been attributed to the leakages and defects in the old pipe system supplying water to the Jammu city. Comparison of analyzed water quality parameters with the drinking water standards prescribed by World Health Organization (WHO) and Bureau of Indian Standards (BIS) indicated that parameters like DO (7.49-8.24mg/l), calcium(49.93-67.08mg/l), magnesium(16.14-25.21mg/l) and potassium(6.99-7.93mg/l) were almost nearing the desirable limits but were within the permissible limits and parameters like turbidity(3.5-8.17 NTU) and total hardness(78.87-120.50mg/l) were above the desirable limits in the water samples collected from the distribution point. The collected primary data for the thirteen water quality parameters has been used to calculate the Arithmetic Water Quality Index(WQI) which has shown monsoon increase with higher values at distribution point(65.65). One time microbial analysis (MPN/100ml) for total and faecal coliform has indicated presence of faecal coliform (<1/100ml) in water samples from eight households at distribution point which indicates contamination of water with human faecal matter during its passage through the distribution network. According to microbial standards laid down by Central Pollution Control Board (2008), water contaminated with faecal coliform is unfit for drinking without conventional treatment.

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