scholarly journals Application of roughing filter to pre-treat 1,000 NTU raw water for slow sand filter

2019 ◽  
Vol 14 (2) ◽  
pp. 355-364 ◽  
Author(s):  
Yuichi Hashimoto ◽  
Hiroshi Takashima ◽  
Somasundaram Jayamohan
Keyword(s):  
Filtration Rate ◽  
Design Guidelines ◽  
Raw Water ◽  
Filter Media ◽  
Sand Filter ◽  
Treated Water ◽  
Slow Sand Filter ◽  
High Turbidity ◽  
Pre Treatment ◽  
One Year

Abstract It was confirmed experimentally that a Roughing Filter (RF) is effective as a pre-treatment system for Slow Sand Filter (SSF) with coagulant dosing and mixing with raw water. This RF system can pre-treat high turbidity raw water (1,000 NTU) to generate low turbidity (10 NTU) pre-treated water for SSF treatment. In the experiment, the types of filter media, height of the filter media, filtration rate and coagulant dosing were varied and the characteristics of each item were evaluated and the design guidelines were formulated. Water Treatment Plants (WTPs) consisting of pre-treatment with RF followed by SSF to treat river water were designed and constructed in Myanmar based on the design guidelines, and the operational performance was confirmed as effective to generate treated water with a turbidity under 5 NTU, which is in compliance with the WHO guideline despite the rather short working period of about one year. Sand scraping of SSF at a frequency of about once in every one to two months was implemented to maintain the design filtration rate.

Slow sand filtration pre-treatment with alum is efficient, but is it effective?

2013 ◽  
Vol 3 (2) ◽  
pp. 106-111 ◽  
Author(s):  
C. C. Dorea
Keyword(s):  
Process Control ◽  
High Efficiency ◽  
Sand Filters ◽  
Sand Filter ◽  
Limited Effectiveness ◽  
Scale Field ◽  
Slow Sand Filter ◽  
High Turbidity ◽  
Pre Treatment ◽  
Run Lengths

Enhancing the performance of slow sand filter pre-treatment with alum (i.e. direct or contact filtration) has been proposed as an alternative to overcome limitations of conventional gravel (roughing) pre-filtration. Experimental results revealed high turbidity reduction efficiencies in alum-dosed pre-filtration. However, due to the alum coagulation, the nature of the particulates in the pre-treatment effluent changed and had a potential to shorten the downstream slow sand filter run lengths by approximately 50% under the conditions tested. Hence, depending on the effluent turbidity levels the effectiveness of the alum-dosed pre-treatment could be compromised, despite its high efficiency. Relatively low turbidity levels (<2 NTU) were needed to minimise excessive headloss development in alum-dosed filters. However, the necessary resources to achieve such process control may not be available in developing country contexts. Furthermore, full-scale field experiences indicated the limited effectiveness of alum dosing prior to slow sand filters and the difficulties in maintaining an adequate chemical dosing in under-resourced settings.

Characterization of Particles in Slow Sand Filtration at North Caribou Water Treatment Plant

2003 ◽  
Vol 38 (1) ◽  
pp. 153-168 ◽  
Author(s):  
Beata Gorczyca ◽  
David London
Keyword(s):  
Water Treatment ◽  
Microscopic Analysis ◽  
Plant Design ◽  
Raw Water ◽  
Filter Media ◽  
Sand Filters ◽  
Sand Filter ◽  
Particle Counter ◽  
Filter Performance ◽  
Slow Sand Filter

Abstract Microscopic analysis of particles in water can indicate the size of filter media required, and can be used to monitor filter performance. This study investigated a malfunctioning slow sand filter in a water treatment facility on a First Nations community in Northern Ontario. There has been a boil-water advisory in the community due to high turbidity in the drinking water since the plant was put into operation. Also, the slow sand filters in the plant clog frequently resulting in outflow volumes significantly below the plant design capacity. On-line particle counts and microscopic analysis of water were conducted in the plant at various points before and after the slow sand filters. Microscopic analysis of the slow sand filter effluent showed that the high water turbidity was due to an increased concentration of particles smaller than 2 µm in size. This observation could not have been made with the particle counter data alone, as it is not capable of measuring particles of that size. Visual inspection of microscopic images of these small particles indicated that they were being washed out from the filter media, and did not originate from the raw water. Significant numbers of large filter-clogging diatoms (up to 50 µm in size) were identified under the microscope; yet, the particle counter did not report particles larger than 15 µm in raw water supply. Turbidimeters and particle counters were found to be unable to identify these diatoms, due to the transparent nature of the cell walls of these microorganisms. It is likely that most of these diatoms originated from sediment accumulated in the raw water intake pipe.

scholarly journals Verification of filter efficiency of horizontal roughing filter by Weglin's design criteria and Artificial Neural Network

2009 ◽  
Vol 2 (1) ◽  
pp. 21-27 ◽  
Author(s):  
◽  
◽  
◽  
◽  
Keyword(s):  
Genetic Model ◽  
Neural Model ◽  
Model Verification ◽  
Design Criteria ◽  
Experimental Setup ◽  
Mean Square ◽  
Raw Water ◽  
Neural Models ◽  
Sand Filter ◽  
Slow Sand Filter

Abstract. The general objective of this study is to estimate the performance of the Horizontal Roughing Filter (HRF) by using Weglin's design criteria based on 1/3–2/3 filter theory. The main objective of the present study is to validate HRF developed in the laboratory with Slow Sand Filter (SSF) as a pretreatment unit with the help of Weglin's design criteria for HRF with respect to raw water condition and neuro-genetic model developed based on the filter dataset. The results achieved from the three different models were compared to find whether the performance of the experimental HRF with SSF output conforms to the other two models which will verify the validity of the former. According to the results, the experimental setup was coherent with the neural model but incoherent with the results from Weglin's formula as lowest mean square error was observed in case of the neuro-genetic model while comparing with the values found from the experimental SSF-HRF unit. As neural models are known to learn a problem with utmost efficiency, the model verification result was taken as positive.

scholarly journals Influence of slow sand filter cleaning process type on filter media biomass: backwashing versus scraping

2021 ◽  
Vol 189 ◽  
pp. 116581 ◽  
Author(s):  
F.H. de Souza ◽  
P.B. Roecker ◽  
D.D. Silveira ◽  
M.L. Sens ◽  
L.C. Campos
Keyword(s):  
Cleaning Process ◽  
Filter Media ◽  
Sand Filter ◽  
Slow Sand Filter

Removal of particulates, natural organic matters, and microorganisms in a surface amended slow sand filter

2002 ◽  
Vol 2 (5-6) ◽  
pp. 387-394
Author(s):  
H.-B. Jun ◽  
Y.-J. Lee ◽  
S.-S. Shin
Keyword(s):  
Surface Treatment ◽  
Raw Water ◽  
Sand Filters ◽  
Water Turbidity ◽  
Turbidity Removal ◽  
Sand Filter ◽  
Organic Matters ◽  
Slow Sand Filter ◽  
Natural Organic Matters ◽  
Filter Bed

Removal characteristics of particulates, natural organic matters, and microorganisms with six slow sand filter units were measured with a diameter of 50 mm and packed with sand to a depth of 50, 150, 300, 600, and two 700 mm, respectively. One of the 700 mm depth filters was amended by covering the surface of the filter bed with a prefilter. The raw water turbidity and pH was in the range of 1.5-2.0 NTU, and 7.0-7.7, respectively. Turbidity in each filter effluent was decreased as the depth of filter medium increased. However, a greater part of influent turbidity was removed within the top layer of the slow sand filters. Turbidity removal in the 700 mm depth filter with prefilter was similar to that without the prefilter, however, the removal of particles smaller than 2 mm was improved with the prefilter. The particles greater than 10 mm could be removed within the upper 50 mm depth in the slow sand filter. A greater fraction of the particles smaller than 2 mm was removed within the upper 50 mm, however, they were also removed in the deeper sand bed. The removal efficiency of DBP precursors represented by DOC and UV-254 absorbance was 9.2-31% and 2-31%, respectively. pH drop in the 50 mm depth filter was 0.12, while that in the 700 mm depth filter was 0.19. The effects of surface treatment with prefilter on UVA and DOC were not apparent.

scholarly journals Pengujian Filter Fisik (Slow Sand Filter) Untuk Menurunkan Kadar Pestisida Golongan Organoklorin

SoilREns ◽  
2017 ◽  
Vol 15 (1) ◽  
Author(s):  
Siska Rasiska ◽  
Aditya Bintan Pratama ◽  
Fitri Widiantini
Keyword(s):  
Activated Carbon ◽  
Experimental Design ◽  
Organochlorine Pesticide ◽  
Plant Protection ◽  
Silica Sand ◽  
Pesticide Level ◽  
Filter Media ◽  
Sand Filter ◽  
Slow Sand Filter ◽  
Sand And Gravel

Organochlorine pesticide is one of the pesticide that has high persistency and toxic. One of the attempt to degrade organochlorine pesticide using cheaper and easier way is using the slow sand filter technology. The research aimed to test the slow sand filter and to obtain the best filter media combination for degrading organochlorine pesticide. The experiment was conducted at the Laboratory of Pesticide and Toxicology, Laboratory of Plant Protection Biotechnology and Laboratory of Chemical and Soil Fertility, Faculty of Agriculutre, Padjadjaran Univeristy from December 2016 – May 2017. The experimental design used the observative and descriptive design with 8 treatments and repeated twice. P1 (activated carbon and gravel), P2 (sand and gravel), P3 (silica sand and gravel), P4 (activated carbon and zeolite), P5 (sand and zeolite), P6 (silica sand and zeolite), P7 (activated carbon, silica sand and zeolite), P8 (activated carbon, sand and gravel). The result showed that all treatments of slow sand filter were able to degrade organochlorine pesticide and the best filter media combination was from P7 with ability to degrade the pesticide level by 82,86%.Key words: slow sand filter, activated carbon, silica sand, sand, gravel, zeolite

scholarly journals EFEKTIVITAS MEDIA FILTER DALAM MENURUNKAN TSS DAN LOGAM Fe PADA AIR SUMUR GALI

2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Euis Nurul Hidayah ◽  
Shofi Nasyi'atul Hikmah ◽  
Muhammad Firdaus Kamal
Keyword(s):  
Total Suspended Solid ◽  
Suspended Solid ◽  
Daily Activities ◽  
Well Water ◽  
Filter Media ◽  
Screening Process ◽  
Sand Filter ◽  
Percentage Decrease ◽  
Slow Sand Filter ◽  
The Media

Masyarakat Desa Tambak Rejo, Kecamatan Waru, Kabupaten Sidoarjo, masih mengunakan air sumur sebagai kebutuhan sehari-hari. Air sumur perlu dilakukan pengolahan agar layak dikonsumsi dengan menggunakan berbagai jenis media melalui proses filtrasi. Tujuan penelitian adalah mengetahui pengaruh jenis media terhadap penurunan TSS dan logam Fe yang terkandung pada air sumur gali dengan single media filter. Reaktor yang digunakan yaitu slow sand filter dengan aliran down flow kecepatan 0,4 m/jam. Parameter yang diuji adalah Total Suspended Solid (TSS) dan logam Fe. Variasi dalam penelitian ini yaitu jenis dan ketinggian media filter. Media yang digunakan yaitu pecahan gerabah, pasir bancar, dan manganese greensand dengan ketinggian media 20 dan 30 cm. Sampel yang digunakan adalah air sumur gali daerah Tambak Rejo, Waru Sidoarjo. Analisis TSS dengan metode Gravimetri dan Fe dengan Spektrofotometri. Hasil yang diperoleh menunjukan media pasir bancar mampu bekerja lebih baik daripada media yang lainnya. Persentase penurunan konsentrasi TSS pada ketinggian 20 dan 30 cm sebesar 76,92% dan 80,00% dan penurunan konsentrasi Fe pada ketinggian 20 dan 30 cm sebesar 80,00% dan 84,19%. Hal ini menunjukan bahwa variasi jenis dan ketinggian media berpengaruh terhadap penurunan konsentrasi TSS dan Fe. Air yang dihasilkan telah memenuhi baku mutu air bersih sehingga aman untuk memenuhi kebutuhan rumah tangga. Kata kunci: Fe, pasir bancar, pecahan gerabah, manganese greensand, total suspended solidThe citizen of Tambak Rejo Village, Waru District, Sidoarjo Regency, still use well water as their daily activities. Well water needs to be processed so that it is suitable for consumption by using various types of media through the screening process. The purpose of the study was to determine the effect of the type of media in decrease TSS and Fe contained in well water dug with a single media filter. The reactor used is a slow sand filter with a downflow speed of 0.4 m/hour. The parameters tested were Total Suspended Solid (TSS) and Fe. Variations in this study are the type and height of the filter media. The media used are pottery fragments, bancar sand, and manganese greensand with media heights of 20 and 30 cm. The sample used was well water dug in the area of Tambak Rejo Village, Waru District, Sidoarjo Regency. TSS analysis with Gravimetric and Fe methods with Spectrophotometry. The results obtained show that bancar sand media is able to work better than other media. The percentage decrease in TSS concentration at the height of 20 and 30 cm was 76.92% and 80.00% and a decrease in Fe concentration at the height of 20 and 30 cm was 80.00% and 84.19%.This shows that variations in the type and height of the media influence the decrease in TSS and Fe concentrations. The water produced meets the quality standards of clean water so it is safe to meet daily activities. Keywords: Fe, bancar sand, pottery fragments, manganese greensand, total suspended solid

Particle and microorganism removal in floating plastic media coupled with microfiltration membrane for surface water treatment

2005 ◽  
Vol 51 (10) ◽  
pp. 93-100 ◽  
Author(s):  
C. Chiemchaisri ◽  
W. Chiemchaisri ◽  
T. Kornboonraksa ◽  
C. Dumrongsukit ◽  
S. Threedeach ◽  
...  
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Filtration Rate ◽  
Coliform Bacteria ◽  
Transmembrane Pressure ◽  
Raw Water ◽  
Microfiltration Membrane ◽  
Treated Water ◽  
Surface Water Treatment ◽  
Plastic Media

Floating plastic media followed by hollow fiber microfiltration membrane was applied for surface water treatment. The performance of the system in terms of particle and microorganisms was investigated. The floating filter was examined at different filtration rates of 5, 10 and 15 m3/m2.h. Treated water was then fed into a microfiltration unit where different filtration rates were examined at 0.6, 1.0 and 1.4 m3/m2.d. It was found that polyaluminum chloride was the best coagulant for the removal of particle, algae and coliform bacteria. Average turbidity in treated water from the floating plastic media filter was 3.3, 12.2 and 15.5 NTU for raw water of 80 NTU and 12.9, 11.7 and 31.2 NTU for raw water of 160 NTU after 6 hours at the filtration rates of 5, 10 and 15 m3/m2.h, respectively. The microfiltration unit could further reduce the turbidity to 0.2–0.5 NTU with low transmembrane pressure development of 0.3–3.7 kPa. Microfiltration membrane could retain most of algae and coliform bacteria remaining in the effluent from the pretreatment unit. It was found that at higher turbidity, algae and coliform bacteria removal efficiencies were achieved at lower filtration rate of the system of 5 m3/m2.h whereas a higher filtration rate of 15 m3/m2.h yielded better coliphage removal.

scholarly journals Anthracite as filter Media in Filtration Process

2021 ◽  
Vol 6 ◽  
pp. 1-7
Author(s):  
Aashish Poudel
Keyword(s):  
Filtration Rate ◽  
Head Loss ◽  
Sieve Analysis ◽  
Filter Media ◽  
Filtration Process ◽  
Sand Filter ◽  
Uniformity Coefficient ◽  
Effluent Quality ◽  
Run Time

This research was carried out to see the performance of anthracite as filter media in filtration process. The study also aimed to compare two filter media in terms of turbidity it removed, head loss development with time and filter run with increase in influent turbidity. Two rapid gravity filter(RGF) columns were prepared having internal dimensions of 11x11x290 cm3, one with anthracite and another with sand as filter media. The uniformity coefficient of sand and anthracite of 1.54 and 1.4 were maintained from sieve analysis. Constant Filtration rate of 3m/h was set and other ancillary activities were made same for both filter models. The experiments were repeated seven times with different influent turbidity ranges of 0-25, 25-50, 50-100, 100-150, 150-200, 200-250, 250-300 NTU. Both the Filters were back washed with back washing velocity of 24 m/h, when the terminal head loss of 165.4 cm was obtained. The effluent quality of anthracite obtained was better for all the filter run. The head loss development with time was more for sand filter in all filter runs. The filter run time for sand vary from 150 to 8 hours and for anthracite, it varies from 172 to13 hours from first to seventh filter run.

Research on the Implementation and Analysis of High-Turbidity Raw Water Pre-Treatment with a Barrier Board

2012 ◽  
Vol 610-613 ◽  
pp. 1402-1408
Author(s):  
Jian Liang Chen ◽  
Yi Kuo Chang ◽  
Yun Hwei Shen ◽  
Kun Liao Chen
Keyword(s):  
Removal Rate ◽  
Experimental Result ◽  
Raw Water ◽  
Turbidity Removal ◽  
Gravity Settling ◽  
Bottom Mud ◽  
High Turbidity ◽  
Different Depths ◽  
Pre Treatment

The purpose of this Research is to simulate the water quality of varied High-turbidity Raw Water at different depths under the water’s surface. During the experiment, a Barrier Board was used to extend the flowing route and to change the overflow level for carrying out the pre-treatment of High-turbidity Raw Water through the changes of varied flow rates in order to study the changes and the removal rate of the turbidity for the influent and effluent; with the settled bottom mud surveyed, the operating requirements of the Surface Overflow Rate (SOR). The experimental result indicated that the turbidity of High-turbidity Water can be reduced by means of an inertia restrained flow, extending the flowing route and heightening the overflow level. The results indicated that the turbidity of the effluent was mostly between 380-1,000 NTU in presenting an over 50% removal rate and even up to 93%. When the SOR of the Sedimentation Basin is set at 19.l m/d, a 54-86% turbidity removal rate can be achieved; whereas, a 50-72% removal rate can be achieved when set at 38.3 m/ d. It has indicated that a significant effect could be achieved for turbidity treatment by employing the properties of high-turbidity substances and the convenient physical theory of gravity settling. As such, a visible removal effect could be achieved to exhibit the effect of pre-treatment.

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