scholarly journals Cryptosporidium Oocysts Removal by Upflow Direct Filtration: Pilot Scale Assessment

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1328
Author(s):  
Marcely Ferreira Nascimento ◽  
Yovanka Pérez Ginoris ◽  
Cristina Celia Silveira Brandão

Studies on the removal of Cryptosporidium oocysts by direct filtration suggested that high removal efficiencies (>3.0 log) can be achieved, but the vast majority of the studies focused on the assessment of downflow direct filtration. However, in comparison with downflow direct filtration, filters in upflow direct filtration systems use lower filtration rates, deeper stratified bed, and water flows from coarse to fine sand grain, which may improve the removal of oocysts. In this context, we evaluated the removal of Cryptosporidium oocysts using upflow direct filtration, on a pilot scale, to treat Paranoá Lake water (Brazil) seeded with Cryptosporidium oocysts. The experiments were conducted with raw water with low turbidity (3.2–5.7 NTU) and induced higher turbidity (28–30 NTU). Non-parametric statistical analysis was used to verify correlations between the filtered water values and removal of oocysts, particles, and turbidity. In general, no correlation was observed between the parameters analyzed, nor between their removals. The exception was the correlation between residual values of Cryptosporidium oocysts and particles of 2 to 7 µm during ripening, an aspect that needs further evaluation. Under stable operation, average removal of Cryptosporidium oocysts by upflow direct filtration was >3.87 log. During ripening, removal of oocysts was around 1 log lower.

2010 ◽  
Vol 45 (3) ◽  
pp. 317-326 ◽  
Author(s):  
Murat Eyvaz ◽  
Hatice Deniz ◽  
Tuğrul S. Aktaş ◽  
Ebubekir Yüksel ◽  
Ahmet M. Saatçi

Abstract Pre-ozonation–coagulant interactions effects in relation to the coagulant type and dosage in direct filtration of surface waters were investigated. The performance of the process was evaluated by monitoring the effluent quality and head loss development through the filter bed. Two identical pilot scale filter columns filtering the same raw water were operated in parallel. The raw water was brought from Ömerli Reservoir in Istanbul. Before filtering, the raw water flow was split into two equal flows. One of the streams was pre-ozonated and the other was aerated using contact chambers with equal volumes equipped with same number and type of diffusers. In coagulation experiments, one of the filters was operated using aluminum sulfate as a coagulant while the other one was run with ferric chloride. For similar filter run times, the effluent quality was always better with pre-ozonation compared to aeration. It was also observed that, aluminum sulfate application gave more favorable results for both particle and turbidity removal compared to ferric chloride. Ives’ filterability index which incorporates the important filtration design parameters such as: effluent quality, the headloss and the velocity of filtration into a dimensionless number was used for the comparison of the experimental results.


2013 ◽  
Vol 448-453 ◽  
pp. 1169-1172
Author(s):  
Feng Ping Hu ◽  
Gui Zhou Hu

Through pilot scale test, inspection the effect of treatment of micro-polluted raw water of Kongmu Lake with vortex clarifier accomplished by the addition of coagulant PAC. After the stable operation of the vortex clarifier, in the 30 mg/L of dosage and 6.8 min of flocculation time conditions, the removal of turbidity, NH3-N, TP, UV254 and COD is 94.2%, 22.9%, 84.8%, 45.2% and 78.5%.


1993 ◽  
Vol 27 (11) ◽  
pp. 81-90 ◽  
Author(s):  
J. E. Tobiason ◽  
J. K. Edzwald ◽  
D. A. Reckhow ◽  
M. S. Switzenbaum

A pilot-scale study of the effects of pre-ozonation on the performance of in-line direct filtration was carried out. Performance measures included filtered water turbidity, unit filter run volumes, and organics in filtered waters: DOC, UV254, AOC and DBPs. Continuous operation of four dual media GAC/sand filters with and without pre-ozonation and chlorinated backwash and a dual media anthracite/sand filter were compared to full-scale performance. Pre-ozonation frequently results in longer filter runs, causes a twofold increase in raw water AOC and has little effect on raw water DOC. GAC/sand filters consistently reduced the AOC in the ozone train to levels below that of the full-scale plant and also provided 25 % lower DOC levels as compared to anthracite/sand filters. The effect of ozone and filtration on chlorinated DBPs followed overall DOC removal while DBPs created by ozonation followed AOC removal trends.


Author(s):  
Abdul Gani Akhmad

This study aims to evaluate the performance of a pilot-scale HSSF-CW utilizing Typha angustifolia and fine sand-gravel media in removing total coliform and TSS from hospital wastewater. Three pilot-scale HSSF-CW cells measuring 1.00 x 0.45 x 0.35 m3 were filled with gravel sand media with a diameter of 5 - 8 mm as high as 35 cm with a submerged media depth of 0.30 m. There were three treatments, namely the first cell (CW1) without plants, the second cell (CW2) was planted with a density of 12 Typha angustifolia plants, and the third cell (CW3) was planted with a density of 24 Typha angustifolia plants. The three HSSF-CW cells received the same wastewater load with total coliform and TSS contents of 91000 MPN / 100 mg and 53 mg / L, respectively, with Hydraulic Loading Rates 3,375 m3 per day. Wastewater was recirculated continuously to achieve the equivalent HSSF-CW area requirement. The experimental results show that the performance of CW3 is more efficient than CW1 and CW2 in total coliform and TSS removal for hospital wastewater. The pollutant removal efficiency at CW3 reached 91.76% for total coliform with one day hydraulic retention time and 81.00% for TSS with two days of hydraulic retention time. This study concludes that the HSSF-CW system using sand-gravel media with a diameter of 5 - 8 mm with a submerged media depth of 0.30 m and planted with Typha angustifolia with a tighter spacing proved to be more efficient in removing total coliform and TSS from hospital wastewater.


1999 ◽  
Vol 40 (9) ◽  
pp. 55-62 ◽  
Author(s):  
Bjørnar Eikebrokk

Optimisation of coagulation-direct filtration processes with respect to efficient removal of humic substances, i.e. natural organic matter (NOM) has gained a lot of focus in many countries over the last years. This paper presents experimental results from pilot scale research studies aimed at optimising the coagulation-direct filtration process applied to soft and humic raw waters with low turbidity and alkalinity levels. Comprehensive tests of 3 types of raw waters with different NOM content, 5 types of coagulants, and 3 calcium sources for the purpose of corrosion control have been conducted. Removal efficiencies with respect to relevant water quality parameters are presented, with typical relationships between raw water NOM content, coagulant dose requirements and pH. Generally, when applying metal-based coagulants, residual metal concentration was the critical parameter regarding minimum coagulant dose requirements. Typical NOM removal efficiencies were in the range of 75-90% and 40-70% with respect to colour and organic carbon, respectively. Optimum pH conditions for the removal of NOM and/or residual metals do not always coincide with that of turbidity. The experiments also showed that poly-aluminium and ferric chlorides might have some benefits over alum in terms of dose requirements and range of optimum pH values, and that chitosan may be used for colour removal with good results.


2001 ◽  
Vol 43 (8) ◽  
pp. 43-49 ◽  
Author(s):  
M. A. P. Raeli ◽  
M. Marchetto

This paper presents the results of an experimental investigation about the performance of a horizontal flow high-rate pilot scale Dissolved Air Flotation (HRDAF) unit containing inclined parallel plates for treating a coloured and low turbidity raw water. Experiments were performed with the DAF unit in order to verify the influence on flotation of : (i) the water velocity (Vh) between the plates, in the range 18 to 96.5 cm.min−1 with corresponding Reynolds numbers between 240 and 1060; (ii) the supplied air (S*) value ranging from 2.2 to 8.5 g of air/m3 of water ; (iii) the angle of the plates (60° or 70°). The best pilot plant operational condition was obtained applying only 4.0 g/m3 (S*) with Vh around 18 cm.min−1 for treatment of water coagulated with a Al2(SO4)3 dosage of 40 mg.l−1. In these conditions, the unit presented very good removal efficiencies of colour (90%, residual of 10 uC), turbidity (88%, residual of 0.8 NTU ) and TSS (94%, residual of 1.8 mg.l−1). Furthermore, the unit could operate at higher Vh values up to 76 cm.min−1 and still present good results. The DAF unit thus behaved as a high rate unit presenting good performance with low air requirement.


2001 ◽  
Vol 43 (12) ◽  
pp. 89-92 ◽  
Author(s):  
A. Hashimoto ◽  
T. Hirata ◽  
S. Kunikane

A one-year monitoring of Cryptosporidium oocysts and Giardia cysts was conducted at a water purification plant. A total of thirteen 50 L samples of river source water and twenty-six 2,000 L samples of filtered water (treated by coagulation-flocculation, sedimentation and rapid filtration) were concentrated using a hollow fibre ultrafiltration membrane module at a purification plant. Cryptosporidium oocysts were detected in all raw water samples with a geometric mean concentration of 400 oocysts/m3 (range 160-1,500 oocysts/m3). Giardia cysts were detected in 12/13 raw waters (92%) with a geometric mean concentration of 170 cysts/m3 (range 40-580 oocysts/m3). Probability distributions of both Cryptosporidium oocyst and Giardia cyst concentration in raw water were nearly log-normal. In filtered water samples, Cryptosporidium oocysts were detected in 9/26 samples (35%) with a geometric mean concentration of 1.2 oocysts/m3 (range 0.5-8 oocysts/m3) and Giardia cysts in three samples (12%) with 0.8 cysts/m3 (range 0.5-2 oocysts/m3). The estimated removal of Cryptosporidium oocysts and Giardia cysts was, respectively, 2.54 log10 and 2.53 log10 on the basis of geometric means, 3.20 and 3.57 log10 on the basis of 50% observation level and 2.70 and 2.90 log10 on the basis of 90% observation level.


2004 ◽  
Vol 48 (11-12) ◽  
pp. 473-479 ◽  
Author(s):  
E. Yüksel ◽  
Ö Akgiray ◽  
E. Soyer

The possibility of applying preozonation followed by direct filtration without the use of a coagulant is investigated. Filtration experiments have been carried out using four different water sources within Istanbul. A 1 m deep bed of 0.8-1.2 mm silica sand was used as the filter medium. The filter was operated at a rate of 11.5 m/hr. Raw water turbidities ranged from 2.3 NTU to 10.0 NTU. Effluent turbidity and particle count values were monitored using an on-line turbidimeter and an on-line particle counter. With all the waters studied in this work, preozonation improved particle removal in direct filtration. With three of the mentioned waters, it was possible to achieve turbidity values below 1.0 NTU without a coagulant by applying ozone at a rate between 1.7-1.8 mg/L. It was not possible to reduce the turbidity of one of the waters to below 2.7 NTU even with very high ozone dosages. The need for pilot testing before deciding if this treatment method is applicable to a given water is underlined.


2012 ◽  
Vol 12 (6) ◽  
pp. 918-925 ◽  
Author(s):  
Y. Sangu ◽  
H. Yokoi ◽  
H. Tadokoro ◽  
T. Tachi

An automatic coagulant dosage control technology for water purification plants was developed to deal with rapid changes of raw water quality parameters. Control logic was developed to decide coagulant dosage based on aluminum concentration in rapid mixing tank water based on results of semi-pilot scale experiments. This logic enabled quick feedback on the excess or lack of coagulant. It was found that the aluminum residual rate, which was proposed as an indicator of coagulation reactions, could be given as a function of coagulant dosage and turbidity. The effectiveness of the control logic was verified in semi-pilot scale experiments. Settled water turbidity was within ±0.5 NTU of target value even when raw water turbidity increased rapidly up to 100 NTU.


Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 495 ◽  
Author(s):  
Kornecki ◽  
Schmidt ◽  
Lohmann ◽  
Huter ◽  
Mestmäcker ◽  
...  

An experimental feasibility study on continuous bioprocessing in pilot-scale of 1 L/day cell supernatant, that is, about 150 g/year product (monoclonal antibody) based on CHO (Chinese hamster ovary) cells for model validation is performed for about six weeks including preparation, start-up, batch, and continuous steady-state operation for at least two weeks stable operation as well as final analysis of purity and yield. A mean product concentration of around 0.4 g/L at cell densities of 25 × 106 cells/mL was achieved. After perfusion cultivation with alternating tangential flow filtration (ATF), an aqueous two-phase extraction (ATPE) followed by ultra-/diafiltration (UF/DF) towards a final integrated counter-current chromatography (iCCC) purification with an ion exchange (IEX) and a hydrophobic interaction (HIC) column prior to lyophilization were successfully operated. In accordance to prior studies, continuous operation is stable and feasible. Efforts of broadly-qualified operation personal as well as the need for an appropriate measurement and process control strategy is shown evidently.


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