Optimum coagulant forecasting by modeling jar test experiments using ANNs

Abstract. Nowadays the proper utilization of water treatment plants and optimizing their use is of particular importance. Coagulation and flocculation in water treatment are among the common ways through which the use of coagulants leads to instability of particles and formation of larger and heavier particles, resulting in improvement of sedimentation and filtration processes. Determination of the optimum dose of such a coagulant is of particular significance. A high dose, in addition to adding costs, can cause the sediment to remain in the filtrate, a dangerous condition according to the standards, while a sub-adequate dose of coagulants can result in the reducing the required quality and acceptable performance of the coagulation process. While jar tests are used for testing coagulants, such experiments face many constraints with respect to evaluating the results produced by sudden changes in input water because of their significant costs, long time requirements, and complex relationships among the many factors (turbidity, temperature, pH, alkalinity, etc.) that can influence the efficiency of coagulant and test results. Modeling can be used to overcome these limitations, and in this research study, Artificial Neural Network (ANN) Multi-Layer Perceptron (MLP) with one hidden layer has been used for modeling the jar test to determine the dosage level of used coagulant in water treatment processes. The data contained in this research have been obtained from the drinking water treatment plant located in the Ardabil province. To evaluate the performance of the model, the parameters Mean Squared Error (MSE) and the Correlation Coefficient R2 have been used. The obtained values are within an acceptable range that demonstrates the high accuracy of the models with respect to the estimation of water quality characteristics and the optimal dosages of coagulants, so using these models will allow operators to not only reduce costs and time taken to perform experimental jar tests, but also to predict a proper dosage for coagulant amounts and to project the quality of the output water under real variable conditions.

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Treatment of Severely-Deteriorated Post-Fire Runoff: A Comparison of Conventional and High-Rate Clarification to Demonstrate Key Drinking Water Treatment Capabilities and Challenges

10.26434/chemrxiv.13350785.v1 ◽

2020 ◽

Author(s):

Jesse Skwaruk ◽

Monica Emelko ◽

Uldis Silins ◽

Micheal Stone

Keyword(s):

Water Treatment ◽

River Water ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Water Treatment Plant ◽

High Rate ◽

Case Scenario ◽

Worst Case ◽

Jar Test ◽

Doc Concentration

The ability to treat worst-case scenario, “black water” resulting from wildfire ash transport directly from hillslopes to source waters was investigated—this has not been reported previously. The treatment response capabilities of conventional chemical pre-treatment and high rate clarification processes were evaluated at bench scale; these included: sand-ballasted flocculation (SBF), SBF with enhanced coagulation, and SBF with powdered activated carbon (PAC).<div><br></div><div>Fresh ash was collected from the Thuya Lake Road (TLR) wildfire (+51.4098 latitude, -120.2435 longitude; burn area 556 ha), which was part of the Little Fort Fire Complex that burned in July 2017, near Little Fort, British Columbia, Canada. The ash was used to prepare a severely-deteriorated source water matrix. It was added to high quality river water (Elbow River, Calgary, Alberta) to reflect post-fire water quality conditions when ash is mobilized off the landscape to receiving waters during a major runoff event.</div><div><br></div><div><p>Prior to mixing, ash was sieved through a 1 mm screen to remove any large debris and conifer needles that typically would not be found in water treatment plant influent streams. Three concentrations of ash in river water were prepared (2.0, 10.0, and 20.0 g×L<sup>-1</sup> of ash; five replicates of each) by adding ash to 1000 mL of Elbow River water in 2-L plastic square beakers, and mixed using a jar test apparatus (Phipps & Bird, PB-900 Series Programmable 6-Paddle Jar Tester, Richmond, VA) at 120 RPM for 2 minutes. Turbidity and dissolved organic carbon (DOC) concentrations consistent with or slightly higher than the levels that have been reported following severe wildfire (i.e., >1000 NTU and >15mg×L<sup>-1</sup>, respectively) were targeted. These water matrices were black-colored, in a manner consistent with previous reports of severely-deteriorated water conditions after wildfire.<sup></sup></p><p> </p><p>Standard methods were used to evaluate turbidity (Method 2130B;<sup> </sup>Hach 2100 N turbidimeter, Loveland, CO), pH (4500-H<sup>+</sup>B Electrometric method; <sup> </sup>Orion 720A pH meter, Thermo Fisher Scientific, Waltham, MA), DOC concentration (filtration through pre-rinsed 0.45 µm Nylaflo membranes, Pall, Port Washington, NY; Method 5310C;<sup> </sup>Shimadzu TOC-V WP analyzer, Kyoto, Japan), and UVA<sub>254</sub> (Method 5910B;<sup> </sup>1 cm quartz cell; Hach DR 5000 Spectrophotometer, Loveland, CO). Specific ultraviolet absorbance at 254 nm (SUVA)<sub> </sub>was calculated by dividing UVA<sub>254</sub> absorbance by the DOC concentration.</p></div><div></div>

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Treatment of Severely-Deteriorated Post-Fire Runoff: A Comparison of Conventional and High-Rate Clarification to Demonstrate Key Drinking Water Treatment Capabilities and Challenges

10.26434/chemrxiv.13350785 ◽

2020 ◽

Author(s):

Jesse Skwaruk ◽

Monica Emelko ◽

Uldis Silins ◽

Micheal Stone

Keyword(s):

Water Treatment ◽

River Water ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Water Treatment Plant ◽

High Rate ◽

Case Scenario ◽

Worst Case ◽

Jar Test ◽

Doc Concentration

The ability to treat worst-case scenario, “black water” resulting from wildfire ash transport directly from hillslopes to source waters was investigated—this has not been reported previously. The treatment response capabilities of conventional chemical pre-treatment and high rate clarification processes were evaluated at bench scale; these included: sand-ballasted flocculation (SBF), SBF with enhanced coagulation, and SBF with powdered activated carbon (PAC).<div><br></div><div>Fresh ash was collected from the Thuya Lake Road (TLR) wildfire (+51.4098 latitude, -120.2435 longitude; burn area 556 ha), which was part of the Little Fort Fire Complex that burned in July 2017, near Little Fort, British Columbia, Canada. The ash was used to prepare a severely-deteriorated source water matrix. It was added to high quality river water (Elbow River, Calgary, Alberta) to reflect post-fire water quality conditions when ash is mobilized off the landscape to receiving waters during a major runoff event.</div><div><br></div><div><p>Prior to mixing, ash was sieved through a 1 mm screen to remove any large debris and conifer needles that typically would not be found in water treatment plant influent streams. Three concentrations of ash in river water were prepared (2.0, 10.0, and 20.0 g×L<sup>-1</sup> of ash; five replicates of each) by adding ash to 1000 mL of Elbow River water in 2-L plastic square beakers, and mixed using a jar test apparatus (Phipps & Bird, PB-900 Series Programmable 6-Paddle Jar Tester, Richmond, VA) at 120 RPM for 2 minutes. Turbidity and dissolved organic carbon (DOC) concentrations consistent with or slightly higher than the levels that have been reported following severe wildfire (i.e., >1000 NTU and >15mg×L<sup>-1</sup>, respectively) were targeted. These water matrices were black-colored, in a manner consistent with previous reports of severely-deteriorated water conditions after wildfire.<sup></sup></p><p> </p><p>Standard methods were used to evaluate turbidity (Method 2130B;<sup> </sup>Hach 2100 N turbidimeter, Loveland, CO), pH (4500-H<sup>+</sup>B Electrometric method; <sup> </sup>Orion 720A pH meter, Thermo Fisher Scientific, Waltham, MA), DOC concentration (filtration through pre-rinsed 0.45 µm Nylaflo membranes, Pall, Port Washington, NY; Method 5310C;<sup> </sup>Shimadzu TOC-V WP analyzer, Kyoto, Japan), and UVA<sub>254</sub> (Method 5910B;<sup> </sup>1 cm quartz cell; Hach DR 5000 Spectrophotometer, Loveland, CO). Specific ultraviolet absorbance at 254 nm (SUVA)<sub> </sub>was calculated by dividing UVA<sub>254</sub> absorbance by the DOC concentration.</p></div><div></div>

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Options to improve the coagulation process operation in a drinking water treatment plant. Case study

Romanian Journal of Ecology & Environmental Chemistry ◽

10.21698/rjeec.2021.214 ◽

2021 ◽

Vol 3 (2) ◽

pp. 114-119

Author(s):

Adina Pacala ◽

◽

Maria Laura Samonid ◽

Bogdan Murariu ◽

Keyword(s):

Water Treatment ◽

Test Procedure ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Water Treatment Plant ◽

Raw Water ◽

Aluminum Salts ◽

Flocculation Efficiency ◽

Jar Test

Aluminum salts are widely used across Romania in surface water treatment as coagulants. It is well-known that the efficiency of these coagulants has a complex dependency on the nature of the raw water, being affected by temperature, pH, and suspended solids. The objective of this case study was to compare the coagulation-flocculation efficiency process of raw water from the Bega River, at low temperature and turbidity, taking into account the use of alternative coagulating agents such as alum, poly aluminum chloride (PAC), and their mixing in 1:1 ratio. The raw water samples were treated using the "Jar Test" procedure, comparable with the current plant conditions at Timisoara Waterworks and taking into account possible operational improvements. For the mixture method applied in which was combined alum and PAC in 1:1 mixing ratio were achieved lower concentrations in aluminum residual, TOC, and turbidity.

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Optimizing the coagulation process in a drinking water treatment plant – comparison between traditional and statistical experimental design jar tests

Water Science & Technology ◽

10.2166/wst.2012.561 ◽

2012 ◽

Vol 65 (3) ◽

pp. 496-503 ◽

Cited By ~ 14

Author(s):

M. Zainal-Abideen ◽

A. Aris ◽

F. Yusof ◽

Z. Abdul-Majid ◽

A. Selamat ◽

...

Keyword(s):

Water Treatment ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Water Treatment Plant ◽

Water Source ◽

Optimum Dose ◽

Statistical Experimental Design ◽

Traditional Methods ◽

Rsm Optimization ◽

Standard Design

In this study of coagulation operation, a comparison was made between the optimum jar test values for pH, coagulant and coagulant aid obtained from traditional methods (an adjusted one-factor-at-a-time (OFAT) method) and with central composite design (the standard design of response surface methodology (RSM)). Alum (coagulant) and polymer (coagulant aid) were used to treat a water source with very low pH and high aluminium concentration at Sri-Gading water treatment plant (WTP) Malaysia. The optimum conditions for these factors were chosen when the final turbidity, pH after coagulation and residual aluminium were within 0–5 NTU, 6.5–7.5 and 0–0.20 mg/l respectively. Traditional and RSM jar tests were conducted to find their respective optimum coagulation conditions. It was observed that the optimum dose for alum obtained through the traditional method was 12 mg/l, while the value for polymer was set constant at 0.020 mg/l. Through RSM optimization, the optimum dose for alum was 7 mg/l and for polymer was 0.004 mg/l. Optimum pH for the coagulation operation obtained through traditional methods and RSM was 7.6. The final turbidity, pH after coagulation and residual aluminium recorded were all within acceptable limits. The RSM method was demonstrated to be an appropriate approach for the optimization and was validated by a further test.

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