Rehabilitation of water treatment plants with operational constrains: a study on turbidity removal

2013 ◽  
Vol 3 (4) ◽  
pp. 549-556 ◽  
Author(s):  
Kaveh Sookhak Lari ◽  
Morteza Kargar

High-rate lamella settlers in clarifiers and triple media filters have been implemented in Isfahan water treatment plant (known as ‘Baba-Sheikh-Ali’) in Iran to upgrade existing clarification/filtration processes during the recent years. The applied technologies are mainly used to reduce finished water turbidity as the primary regional criterion on water quality. However, application of both technologies faced some operational limitations since they began to work. These problems are due to the existing layout of the process units and available materials. The current study focuses on performance of restricted application of the two technologies with respect to turbidity removal. Online measured turbidity data from a two-year field observation (since March 2010) are used. In particular, results show a more promising and long-term effect on turbidity removal due to tripling filter media rather than application of the lamella settlers in clarifiers. The reasons for these observations are discussed.

Due to the rate increase for potable water need, the general market trend is the vertical expansions for water treatment plants instead of the horizontal ones. By upgrading the existing plants using new technology to reach the maximum capacity and conserve the water quality parameters as the Egyptian Code states. The most benefits of plant upgrading are no new land is needed also, low cost solution, as we could upgrade the WTP as mentioned before without adding major civil works comparing with the construction of new water treatment. This study aims to upgrade the existing water treatment plants using dissolved air floatation system, in order to reach the maximum possible capacity using several possible scenarios without adding major civil works. The study shows that, the scenario which involves DAF technology then sedimentation and filtration has the best removal efficiency because it has three treatment phases. The use of one treatment phase from floatation or sedimentation followed by filtration achieved lower efficiency. At last direct filtration, considering low removal efficiencies due to the high rate of filtration which allowed the suspended solids to escape.For the application upon Al Ameriyah water treatment plant, the first proposal which involves five combined tanks, two tube settler and one filter tank is the most convenient proposal to be achieved. Since it has quiet high value 72 points in the technical evaluation with the least estimated cost 85,769,200 LE. The use of DAF technology combined with sedimentation gives the chance to increase the existing plant capacity from 520000 m3 /day to 864815 m3 /day with rate of increase equals 66.31% which is a cheap and happy solution.


2019 ◽  
Vol 100 ◽  
pp. 00019 ◽  
Author(s):  
Renata Gmurkowska

During water treatment a large amount of sludge is created – in the form of sewage and sediments. The largest amounts of sludge are produced during coagulation, ozonation and backwashing rapid filters. The quality and quantity of treated water, the type and dose of used coagulants are factors affecting the quantity, composition and properties of the sludge. Sludge produced during processing of drinking water is important problem and their quantity has been increasing. The study focuses on characteristics of water treatment sludge from four water treatment plants in Cracow. It includes theoretical and experimental part. The first part is based on analysis of literature and information obtained from MPWiK [3]. The second experimental part, concerns the analysis of dry matter, organic dry matter, capillary suction time and visual parameters: the color and consistency of the sludge. Result shows that every sludge contains organic matter. The highest concentrations of organic compounds and the largest diversity has been observed in the sludge collected in the Water Treatment Plant Raba, reaching even up to 70% of organic compounds in the dry mass of sludge.


2019 ◽  
Vol 24 (1) ◽  
pp. 135-163
Author(s):  
Jader Martínez Girón ◽  
Jenny Vanessa Marín-Rivera ◽  
Mauricio Quintero-Angel

Population growth and urbanization pose a greater pressure for the treatment of drinking water. Additionally, different treatment units, such as decanters and filters, accumulate high concentrations of iron (Fe) and manganese (Mn), which in many cases can be discharged into the environment without any treatment when maintenance is performed. Therefore, this paper evaluates the effectiveness of vertical subsurface wetlands for Fe and Mn removal from wastewater in drinking water treatment plants, taking a pilot scale wetland with an ascending gravel bed with two types of plants: C. esculenta and P. australis in El Hormiguero (Cali, Colombia), as an example. The pilot system had three upstream vertical wetlands, two of them planted and the third one without a plant used as a control. The wetlands were arranged in parallel and each formed by three gravel beds of different diameter. The results showed no significant difference for the percentage of removal in the three wetlands for turbidity (98 %), Fe (90 %), dissolved Fe (97 %) and Mn (98 %). The dissolved oxygen presented a significant difference between the planted wetlands and the control. C. esculenta had the highest concentration of Fe in the root with (103.5 ± 20.8) µg/g ; while P. australis had the highest average of Fe concentrations in leaves and stem with (45.7 ± 24) µg/g and (41.4 ± 9.1) µg/g, respectively. It is concluded that subsurface wetlands can be an interesting alternative for wastewater treatment in the maintenance of drinking water treatment plants. However, more research is needed for the use of vegetation or some technologies for the removal or reduction of the pollutant load in wetlands, since each drinking water treatment plant will require a treatment system for wastewater, which in turn requires a wastewater treatment system as well.


2019 ◽  
Vol 8 (3) ◽  
pp. 93-101
Author(s):  
Paulami De

This article addresses methods to adjust operating requirements in water treatment plants (WTPs) in order to increase the efficiency of water treatment plants based on the nature of the water inflows into the systems. In the past, various studies have suggested that the quality of water inflow into the WTP has an impact on the efficiency and economic viability of operating treatment plants. Among all other quality parameters, the concentration of dissolved oxygen (DO) is one of the basic indicators about the overall quality of the water. Identification of a temporal pattern can help the engineers to adapt the WTP operations and can save the unnecessary wasting of plant resources. That is why the present article has proposed a new model that can predict the temporal patterns of various chemical parameters with the help of an analytic neuronal network. The model was applied to the case of a WTP that responds to a peri-urban catchment, leading to regular variations in the DO of water inflow. According to the performance metrics utilized the model was able to predict the temporal pattern at a lag of 1 hour.


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.


2013 ◽  
Vol 14 (2) ◽  
pp. 246-254 ◽  
Author(s):  
A. Abeynayaka ◽  
C. Visvanathan ◽  
S. Khandarith ◽  
T. Hashimoto ◽  
H. Katayama ◽  
...  

This long-term pilot-scale study on the performance of ceramic microfiltration (CMF) was conducted at the Bangkhen water treatment plant (BWTP), with the raw water from Chaophraya River, Thailand. Raw water turbidity and dissolved organic carbon (DOC) were varied in the ranges of 20–210 NTU and 3.0–8.5 mg/L respectively. The hybrid pilot-scale CMF (Pilot-CMF) operational parameters were optimized with the aid of jar-tests and laboratory-scale CMF (Lab-CMF) operations. The systems were operated with various polyaluminum chloride dosages and filtration cycle times. Pilot-CMF provided excellent steady turbidity removal compared to the conventional water treatment process. DOC removal percentages of Pilot-CMF and the conventional process at the BWTP were 49% and 30% respectively. With different coagulant dosages, unique patterns in transmembrane pressure (TMP) variations were observed. The daily TMP increment under low turbidity conditions was 0.08 kPa/day. During rainy periods (turbidity over 100 NTU) the TMP increment reached 0.79 kPa/day. However, once the turbidity of raw water reaches normal conditions (30–60 NTU at the BWTP) the Pilot-CMF system recovers the TMP increment due to efficient backwashing.


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