scholarly journals The AquaNES Project: Coupling Riverbank Filtration and Ultrafiltration in Drinking Water Treatment

Water ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 18 ◽  
Author(s):  
Robert Haas ◽  
Ruediger Opitz ◽  
Thomas Grischek ◽  
Philipp Otter

Natural water treatment techniques combined with engineered solutions were investigated at demonstration sites in Europe within the AquaNES project. Ultrafiltration is well-established in water treatment, but is not feasible for many water utilities due to its high operational costs compared to conventional treatment. These differences in cost are caused by membrane fouling and the associated cleaning required. This study aims to assess the economic and energetic operation factors based on studies of an out/in ultrafiltration treatment plant for river water and bank filtrate. The fouling potential of both raw water sources was investigated as well as the quality of the resulting water. In addition, the results show the potential utility of a combined approach utilizing bank filtration followed by ultrafiltration in drinking water treatment. In a separate consideration of the treatment process, the water quality does not fulfill the requirements of the German drinking water ordinance. A new method for the removal of dissolved manganese from the bank filtrate is presented by inline electrolysis. While this improves water quality, this also has a significant influence on fouling potential and, thus, on operating costs of ultrafiltration. These aspects lead to a fundamental decision for operators to choose between more costly ultrafiltration with enhanced microbiological safety compared to cost-effective but less stringent drinking water treatment via open filtration.

Author(s):  
Nguyet Thi-Minh Dao ◽  
The-Anh Nguyen ◽  
Viet-Anh Nguyen ◽  
Mitsuharu Terashima ◽  
Hidenari Yasui

The occurrence of pesticides even at low concentrations in drinking water sources might induce potential risks to public health. This study aimed to investigate the removal mechanisms of eight pesticides by the nitrifying expanded-bed filter using biological activated carbon media at the pretreatment of a drinking water plant. The field analysis demonstrated that four pesticides Flutolanil, Buprofezin, Chlorpyrifos, and Fenobucard, were removed at 82%, 55%, 54%, and 52% respectively, while others were not significantly removed. Under controlled laboratory conditions with continuous and batch experiments, the adsorption onto the biological activated carbon media was demonstrated to be the main removal pathway of the pesticides. The contribution of microorganisms to the pesticide removals was rather limited. The pesticide removals observed in the field reactor was speculated to be the adsorption on the suspended solids presented in the influent water. The obtained results highlighted the need to apply a more efficient and cost-effective technology to remove the pesticide in the drinking water treatment process. Keywords: biological activated carbon; drinking water treatment; nitrifying expanded-bed filter; pesticide removal.


2019 ◽  
Vol 19 (8) ◽  
pp. 2330-2337
Author(s):  
Susumu Hasegawa ◽  
Yasuhiro Tanaka ◽  
Naokazu Wake ◽  
Ryosuke Takagi ◽  
Hideto Matsuyama

Abstract Recently, membrane filtration systems have become increasingly common in drinking water treatment plants. In this industry, preventing membrane fouling is of utmost importance. Many studies on the relationship between raw water components and membrane fouling have been performed in laboratory conditions. However, very few studies have analyzed the components of foulants on the fouled membrane as operated in actual drinking water treatment plants. By analyzing these components in plant-conditions, membrane fouling will be more effectively prevented. In this study, we analyzed the components of foulants extracted with 0.1 N NaOH from a fouled membrane operated in a drinking water treatment plant in Japan. Our analysis revealed that the main foulants were humic substances. In order to dissolve the accumulated humic substances, additional chemical cleaning was attempted with 500 ppm sodium hypochlorite. As a result, it was found that humic substances were dissolved and filtration resistance significantly decreased. Additionally, the removal of inorganic foulants was also greater after chemical cleaning with 500 ppm sodium hypochlorite, as inorganic foulants trapped within humic substances were released to the membrane surface as hydroxides by the additional sodium hypochlorite cleaning and were dissolved by the periodic citric acid cleaning.


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.


2012 ◽  
Vol 209-211 ◽  
pp. 1981-1985 ◽  
Author(s):  
Dong Sheng Wang ◽  
Xing Peng Zhou ◽  
Xiao Ming Mo ◽  
Yi Wang

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.


2016 ◽  
Vol 17 (2) ◽  
pp. 597-605
Author(s):  
Zhiquan Liu ◽  
Yongpeng Xu ◽  
Xuewei Yang ◽  
Rui Huang ◽  
Qihao Zhou ◽  
...  

The overall purpose was to assess the feasibilities of recycling filter backwash water (FBWW) and combined filter backwash water (CFBWW) in a drinking water treatment plant in south China. The variations of regular water-quality indexes, metal indexes (Al, Mn and Cd), polyacrylamide and disinfection by-product indexes (trihalomethanes and their formation potentials) along with the treatment and the recycling processes were monitored. Results showed the recycling procedure caused increases of turbidity, total solids, ammonia nitrogen (NH3-N), permanganate index (CODMn), and dissolved organic carbon, Al, Mn and Cd concentrations in a mixture of raw water and FBWW or CFBWW compared to those in raw water. However, the recycling procedure had negligible impacts on the qualities of settled water and filtered water because most of the contaminants could be effectively removed by the conventional water treatment process. Although recycling did cause slight increases of NH3-N and CODMn levels in settled water and filtered water, the quality of finished water always conformed to Chinese standards for drinking water quality according to the surveyed indexes in the present study. Thus, it is appropriate to recycle waste streams in water-stressed areas if the source water is well managed and the water treatment processes are carefully conducted.


2008 ◽  
Vol 8 (3) ◽  
pp. 297-304 ◽  
Author(s):  
A. W. C. van der Helm ◽  
L. C. Rietveld ◽  
Th. G. J. Bosklopper ◽  
J. W. N. M. Kappelhof ◽  
J. C. van Dijk

Optimization for operation of drinking water treatment plants should focus on water quality and not on environmental impact or costs. Using improvement of water quality as objective for optimization can lead to new views on operation, design and concept of drinking water treatment plants. This is illustrated for ozonation in combination with biological activated carbon (BAC) filtration at drinking water treatment plant Weesperkarspel of Waternet, the water cycle company for Amsterdam and surrounding areas. The water quality parameters that are taken into account are assimilable organic carbon (AOC), dissolved organic carbon (DOC) and pathogens. The operational parameters that are taken into account are the ozone dosage and the regeneration frequency of the BAC filters. It is concluded that ozone dosage and regeneration frequency should be reduced in combination with application of newly developed insights in design of ozone installations. It is also concluded that a new concept for Weesperkarspel with an additional ion exchange (IEX) step for natural organic matter (NOM) removal will contribute to the improvement of the disinfection capacity of ozonation and the biological stability of the produced drinking water.


2017 ◽  
Vol 18 (1) ◽  
pp. 279-287 ◽  
Author(s):  
E. Bertone ◽  
K. O'Halloran ◽  
M. Bartkow ◽  
K. Mann

Abstract The Mudgeeraba drinking water treatment plant, in Southeast Queensland, Australia, can withdraw raw water from two different reservoirs: the smaller Little Nerang dam (LND) by gravity, and the larger Advancetown Lake, through the use of pumps. Selecting the optimal intake is based on water quality and operators' experience; however, there is potential to optimise this process. In this study, a comprehensive hybrid (data-driven, chemical, and mathematical) intake optimisation model was developed, which firstly predicts the chemicals dosages, and then the total (chemicals and pumping) costs based on the water quality at different depths of the two reservoirs, thus identifying the cheapest option. A second data-driven, probabilistic model then forecasts the volume of the smaller LND 6 weeks ahead in order to minimise the depletion and spill risks. This is important in case the first model identifies this reservoir as the optimal intake solution, but this could lead in the long term to depletion and full reliance on the electricity-dependent Advancetown Lake. Both models were validated and proved to be accurate, and with the potential for substantial monetary savings for the water utility.


Water ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 57 ◽  
Author(s):  
Abderrezzaq Benalia ◽  
Kerroum Derbal ◽  
Antonio Panico ◽  
Francesco Pirozzi

In this study, the use of acorn leaves as a natural coagulant to reduce raw water turbidity and globally improve drinking water quality was investigated. The raw water was collected from a drinking water treatment plant located in Mila (Algeria) with an initial turbidity of 13.0 ± 0.1 NTU. To obtain acorn leaf powder as a coagulant, the acorn leaves were previously cleaned, washed with tap water, dried, ground and then finely sieved. To improve the coagulant activity and, consequently, the turbidity removal efficiency, the fine powder was also preliminarily treated with different solvents, as follows, in order to extract the coagulant agent: (i) distilled water; (ii) solutions of NaCl (0.25; 0.5 and 1 M); (iii) solutions of NaOH (0.025; 0.05 and 0.1 M); and (iv) solutions of HCl (0.025; 0.05 and 0.1 M). Standard Jar Test assays were conducted to evaluate the performance of the coagulant in the different considered operational conditions. Results of the study indicated that at low turbidity (e.g., 13.0 ± 0.1 NTU), the raw acorn leaf powder and those treated with distilled water (DW) were able to decrease the turbidity to 3.69 ± 0.06 and 1.97 ± 0.03 NTU, respectively. The use of sodium chloride solution (AC-NaCl) at 0.5 M resulted in a high turbidity removal efficiency (91.07%) compared to solutions with different concentrations (0.25 and 1 M). Concerning solutions of sodium hydroxide (AC-NaOH) and hydrogen chloride (AC-HCl), the lowest final turbidities of 1.83 ± 0.13 and 0.92 ± 0.02 NTU were obtained when the concentrations of the solutions were set at 0.05 and 0.1 M, respectively. Finally, in this study, other water quality parameters, such as total alkalinity hardness, pH, electrical conductivity and organic matters content, were measured to assess the coagulant performance on drinking water treatment.


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