scholarly journals Beach Sand Filtration as Pre-Treatment for RO Desalination

10.5772/53034 ◽  
2012 ◽  
pp. 1 ◽  
Author(s):  
Rico Bartak ◽  
Thomas Grischek ◽  
Kamal Ghodeif ◽  
Chittaranjan Ray
Keyword(s):  
Beach Sand ◽  
Sand Filtration ◽  
Pre Treatment

Treatment of Groundwater with Slow Sand Filtration

1988 ◽  
Vol 20 (3) ◽  
pp. 141-147 ◽  
Author(s):  
T. Hatva
Keyword(s):  
Biological Activities ◽  
Treatment Phase ◽  
Purification Process ◽  
Sand Filtration ◽  
Sand Filters ◽  
Slow Sand Filtration ◽  
Filtration Method ◽  
Pre Treatment ◽  
Full Scale Tests ◽  
Iron Manganese

The purification process and techniques of the slow sand filtration method for treatment of groundwater was studied on the basis of pilot plant and full scale tests and studies of waterworks, to obtain guidelines for construction and maintenance. The purification process consists in general of two principal phases which are pre-treatment and slow sand filtration. Both are biological filters. The main purpose of the pre-treatment is to reduce the iron content of raw water, in order to slow down the clogging of the slow sand filters. Different types of biofilters have proved very effective in the pre-treatment phase, with reduction of total iron from 50 % to over 80 %. During the treatment, the oxidation reduction conditions gradually change becoming suitable for chemical and biological precipitation of iron, manganese and for oxidation of ammonium. Suitable environmental conditions are crucial in the oxidation of manganese and ammonium which, according to these studies, mainly occurs in slow sand filters, at the end of the process. Low water temperature in winter does not seem to prevent the biological activities connected with the removal of iron, manganese and ammonium, the chief properties necessitating treatment of groundwater in Finland.

Assessment of a roughing filtration as a pre-treatment for slow sand filtration of canal water with highly variable feed water turbidity

2017 ◽  
Vol 79 ◽  
pp. 221-227
Author(s):  
Mohammad Yassin ◽  
Nidal Mahmoud ◽  
Kebreab Ghebremichael ◽  
Branislav Petrusevski
Keyword(s):  
Feed Water ◽  
Sand Filtration ◽  
Canal Water ◽  
Water Turbidity ◽  
Slow Sand Filtration ◽  
Pre Treatment

Comparison of sand and membrane filtration as non-chemical pre-treatment strategies for pesticide removal with nanofiltration/low pressure reverse osmosis membranes

2014 ◽  
Vol 14 (4) ◽  
pp. 532-539 ◽  
Author(s):  
Krzysztof P. Kowalski ◽  
Henrik T. Madsen ◽  
Erik G. Søgaard
Keyword(s):  
Organic Matter ◽  
Reverse Osmosis ◽  
Membrane Filtration ◽  
Treatment Strategies ◽  
Low Pressure ◽  
Sand Filtration ◽  
Sand Filter ◽  
Pesticide Removal ◽  
Pre Treatment ◽  
Uf Membranes

Pilot plant investigations of sand and membrane filtration (microfiltration (MF)/ultrafiltration (UF)/nanofiltration (NF)/low pressure reverse osmosis (LPRO)) have been performed to treat groundwater polluted with pesticides. The results show that simple treatment, with use of aeration and sand filtration or MF/UF membranes, does not remove pesticides. However, by reducing the content of key foulants, the techniques can be used as a pre-treatment for nanofiltration and low pressure reverse osmosis that has proved to be capable of removing pesticides. It was found that a lower fouling potential could be obtained by using the membranes, but that sand filter was better at removing manganese and dissolved organic matter. The results indicate that combining aeration, sand filtration and membrane techniques might be a good option for pesticide removal without any addition of chemicals and minimized membrane maintenance.

Removal of microbes from municipal wastewater effluent by rapid sand filtration and subsequent UV irradiation

2003 ◽  
Vol 47 (3) ◽  
pp. 157-162 ◽  
Author(s):  
R.L. Rajala ◽  
M. Pulkkanen ◽  
M. Pessi ◽  
H. Heinonen-Tanski
Keyword(s):  
Uv Irradiation ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Water Source ◽  
Pilot Scale ◽  
Wastewater Effluent ◽  
Sand Filtration ◽  
Pre Treatment ◽  
Uv Transmittance ◽  
Rapid Sand Filtration

The elimination of wastewater microbes is often necessary when effluent receiving waters are reused for different purposes e.g. for irrigation or as a raw water source of drinking water. In the present study, rapid sand filtration (SF) combined with the use of polyaluminium chloride coagulation was used as a pre-treatment to improve the quality of wastewater effluent before further treatment with UV irradiation. Pilot-scale experiments were run in four treatment plants in Finland. Treatment performance was followed by measuring physical and microbial parameters. Rapid sand filtration reduced suspended solids, turbidity and colour of effluents by about 90%, 70-80% and 20-50% respectively. It also improved the UV transmittance of water by up to 20%. Microbes and phosphorus were reduced by 90-99% and to 0.05 mg/L respectively. UV irradiation further reduced the number of microbes up to 99.9%. The efficiency of UV doses in pilot UV reactors was confirmed with collimated-beam device determinations and with added FRNA phages. More than 99.9% reduction of MS2 was achieved with the dose of 140mWs/cm2 in pilot UV reactors. Rapid sand filtration and the subsequent UV irradiation reduced the number of all the tested microbes to a low level, often below the detection limit. Suspended solids and the water turbidity were reduced to 1-2 mg/L and ~1 NTU respectively.

Chemically enhanced gravel pre-filtration for slow sand filters: advantages and pitfalls

2006 ◽  
Vol 6 (1) ◽  
pp. 121-128
Author(s):  
C.C. Dorea ◽  
B.A. Clarke
Keyword(s):  
Negative Impact ◽  
Pilot Scale ◽  
Sand Filtration ◽  
Sand Filters ◽  
Slow Sand Filtration ◽  
Chemical Enhancement ◽  
Dissolved Organics ◽  
Efficiency And Effectiveness ◽  
Slow Sand Filter ◽  
Pre Treatment

The chemical enhancement of gravel (or roughing) filtration with coagulants, i.e. direct (gravel) filtration, has been proposed as a pre-treatment alternative for slow sand filters. However, studies have frequently focused on the efficiencies of the pre-filters in terms of reduction percentages. The effectiveness of the pre-treatment on the subsequent slow sand filtration is not usually cited or even evaluated. By incorporating a pilot-scale slow sand filter in our trials, both aspects of the pre-treatment process were assessed: efficiency and effectiveness. In terms of turbidity reductions, our results demonstrated that chemically enhanced pre-filtration was substantially more efficient (93.2 to 99.5%) than conventional pre-filtration (50.6 to 79.3); this was also observed in terms of reductions in the level of other parameters (i.e. thermotolerant faecal coliforms and dissolved organics). Yet, the use of a coagulant can have a negative impact on the slow sand filtration run.

Effect of slow sand filtration of treated wastewater as pre-treatment to UF

Desalination ◽  
2009 ◽  
Vol 249 (2) ◽  
pp. 591-595 ◽  
Author(s):  
X. Zheng ◽  
R. Mehrez ◽  
M. Jekel ◽  
M. Ernst
Keyword(s):  
Treated Wastewater ◽  
Sand Filtration ◽  
Slow Sand Filtration ◽  
Pre Treatment

EELS characterization of “Smut” layer films on steel surface prepared for chrome plating by anodic etching

1995 ◽  
Vol 53 ◽  
pp. 538-539
Author(s):  
E Y. Wang ◽  
J. T. Cherian ◽  
A. Madsen ◽  
R. M. Fisher
Keyword(s):  
Steel Surface ◽  
Surface Preparation ◽  
Treatment Method ◽  
Chrome Plating ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Pre Treatment ◽  
Hard Chrome ◽  
Electron Energy Loss

Many steel parts are electro-plated with chromium to protect them against corrosion and to improve their wear-resistance. Good adhesion of the chrome plate to the steel surface, which is essential for long term durability of the part, is extremely dependent on surface preparation prior to plating. Recently, McDonnell Douglas developed a new pre-treatment method for chrome plating in which the steel is anodically etched in a sulfuric acid and hydrofluoric acid solution. On carbon steel surfaces, this anodic pre-treatment produces a dark, loosely adhering material that is commonly called the “smut” layer. On stainless steels and nickel alloys, the surface is only darkened by the anodic pre-treatment and little residue is produced. Anodic pre-treatment prior to hard chrome plating results in much better adherence to both carbon and alloy steels.We have characterized the anodic pre-treated steel surface and the resulting “smut” layer using various techniques including electron spectroscopy for chemical analysis (ESCA) on bulk samples and transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) on stripped films.

Evaluating the effect of a group pre-treatment chemotherapy psycho-education session for chemotherapy-naive gynecologic cancer patients and their caregivers

2021 ◽  
Vol 160 (1) ◽  
pp. 234-243
Author(s):  
Diana Samoil ◽  
Nazek Abdelmutti ◽  
Lisa Ould Gallagher ◽  
Nazlin Jivraj ◽  
Naa Kwarley Quartey ◽  
...  
Keyword(s):  
Cancer Patients ◽  
Gynecologic Cancer ◽  
Education Session ◽  
Pre Treatment
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