scholarly journals Pre-treatment before Slow Sand Filtration with Pebble Matrix Filtration at Kataragama Water Treatment Works, Sri Lanka

2007 ◽  
Vol 40 (2) ◽  
pp. 53
Author(s):  
J. P. Rajapakse ◽  
S. Sumanaweera
Keyword(s):  
Water Treatment ◽  
Sri Lanka ◽  
Sand Filtration ◽  
Slow 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.

scholarly journals Natural organic matter removal by ion exchange at different positions in the drinking water treatment lane

2013 ◽  
Vol 6 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
E. R. Cornelissen ◽  
L. C. Rietveld
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Organic Matter ◽  
Water Treatment ◽  
Organic Carbon ◽  
Natural Organic Matter ◽  
Drinking Water Treatment ◽  
Biological Stability ◽  
Sand Filtration ◽  
Slow Sand Filtration

Abstract. To guarantee a good water quality at the customers tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research was to improve the biological stability of the produced water by incorporating anion exchange (IEX) for NOM removal. Different placement positions of IEX in the treatment lane (IEX positioned before coagulation, before ozonation or after slow sand filtration) and two IEX configurations (MIEX® and fluidized IEX (FIX)) were compared on water quality as well as costs. For this purpose the pre-treatment plant at Loenderveen and production plant Weesperkarspel of Waternet were used as a case study. Both, MIEX® and FIX were able to remove NOM (mainly the HS fraction) to a high extent. NOM removal can be done efficiently before ozonation and after slow sand filtration. The biological stability, in terms of assimilable organic carbon, biofilm formation rate and dissolved organic carbon, was improved by incorporating IEX for NOM removal. The operational costs were assumed to be directly dependent of the NOM removal rate and determined the difference between the IEX positions. The total costs for IEX for the three positions were approximately equal (0.0631 € m−3), however the savings on following treatment processes caused a cost reduction for the IEX positions before coagulation and before ozonation compared to IEX positioned after slow sand filtration. IEX positioned before ozonation was most cost effective and improved the biological stability of the treated water.

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

Water treatment for rural areas by slow sand filtration

2010 ◽  
Author(s):  
Bruno Segalla Pizzolatti ◽  
Marcus Bruno Domingues Soares ◽  
Denise Conceição de Gois Santos Michelan ◽  
Luis Romero Esquivel ◽  
Maurício Luiz Sens
Keyword(s):  
Water Treatment ◽  
Rural Areas ◽  
Sand Filtration ◽  
Slow Sand Filtration

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.

Removal of cyanobacteria by slow sand filtration for drinking water

2012 ◽  
Vol 2 (3) ◽  
pp. 133-145 ◽  
Author(s):  
Silvano Porto Pereira ◽  
Fabiana de Cerqueira Martins ◽  
Lenora Nunes Ludolf Gomes ◽  
Manoel do Vale Sales ◽  
Valter Lúcio De Pádua
Keyword(s):  
Water Treatment ◽  
Rural Communities ◽  
Human Consumption ◽  
Industrialized Countries ◽  
Sand Filtration ◽  
Intact Cells ◽  
Slow Sand Filtration ◽  
Treatment Techniques ◽  
Slow Sand Filter ◽  
The City

Potential problems arising from the presence of cyanobacteria in water intended for human consumption have been reported by several researchers. Regarding water treatment plants, intact cells of cyanobacteria should be removed to avoid the release of cyanotoxins due to cell lysis. Water treatment techniques with different degrees of complexity can be employed but, whenever possible, the method of easiest installation, operation and maintenance should be selected, especially for non-industrialized countries and rural communities. In this context, research was carried out to evaluate the efficiency of slow sand filtration to treat water from Gavião reservoir in the city of Pacatuba, Ceara, Brazil, which has exhibited phytoplankton density of approximately 105 cells/mL with a prevalence of cyanobacteria representing over 90% of total cells. The results have demonstrated that slow sand filtration can be used to achieve water purification that meets federal standards. However, it was established that filtration through beds of gravel (prefilter) before the slow sand filtration is essential. The removal of phytoplankton reached values of approximately 97% and the filter run duration was more than 70 days. Furthermore, the slow sand filter was very efficient in removing total coliforms, with removal of up to 99.98%.

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