PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Water Purification”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1991

[Production of mutagenic compounds during the water purification treatment of surface water].

In the last years many studies have reported the presence of mutagenic/carcinogenic compounds in treated waters. These substances can be present in raw water, but are also produced during drinking water purification. Mutagens are formed as by-products of chemical reactions between oxidants/disinfectants used in treatments and organic load of the raw water (humic and fulvic acids). The aim of this study was to evaluate the production of mutagenic substances during the main phases of the Po river water treatment ("PO3" plant) in Turin. Water samples (50 litres), collected from February 1989 to August 1990, were concentrated with XAD-2/XAD-8 resins mixture. Extracts were tested for mutagenicity at different doses (1, 2.5, 5 and 10 litres) by Ames Salmonella assay, using TA 100 and TA 98 strains, without microsome fraction (S9). Raw water was rarely mutagenic while, in particular at the highest doses (5 and 10 litres), sometimes showed toxic effect. After ozonation treatment only few samples were mutagenic with TA 100 strain, while 43% of the samples were mutagenic with TA 98. The following treatment of clariflocculation and chlorination with NaClO produced mutagens in 95% of the samples assayed with TA 100 and in 85% of the samples assayed with TA 98. The next GAC/sand filtration step seems to reduce the mutagenic load produced in the previous phases. Finally, drinking water after chlorination with ClO2 showed weak mutagenicity at 1 litre dose (26% and 21% of positive samples with TA 100 and TA 98 respectively) and this effect increased at the higher dosages.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinogenicity Tests↗
PubMed1990

Evaluation of traditional filters for water purification in Burkina Faso.

Most tropical water springs are polluted with microbial agents such as faecal coliforms and streptococci, so for the present and the forseeable future, boreholes are considered to be the most appropriate system for reducing the bacterial contamination of water. However, from source to consumer, safe drinking water usually becomes polluted with faecal bacteria. This observation which calls into question the success of the International Drinking Water Supply and Sanitation Decade should stimulate efforts to provide a reliable means of water purification. The use of traditional filters prepared with sand, gravel and charcoal has been proposed but our results reveal that they give no guarantee for the purification of bacteria-polluted water.

Burkina Faso↗
PubMed1978

A water purification system for laboratory use.

A water purification system is described, capable of producing Type I water upon demand at multiple locations up to 700 feet, from the purifying equipment. Tap water is initially treated employing reverse osmosis, followed by treatment with activated charcoal and mixed anion/cation exchange resins. The resultant Type I quality water is maintained by means of a recycling loop until removal upon demand. The current cost of producing water of this quality is $0.03 per liter, exclusive of capital and installation costs.

Dialysis↗
PubMed1990

[Bacterial regrowth in drinking water. IV. Bacterial flora in fresh and stagnant water in drinking water purification and in the drinking water distribution system].

Six dead end water pipes were installed inside a Zurich drinking water plant and five others over a distance of 12 km along the distribution system and the water was left stagnating in there for 2 weeks. A total of 1508 bacteria from fresh and stagnating water were isolated and identified. Of these, 241 bacterial isolates from the distribution system were examined using the nutrient-tolerance test, i.e. testing the ability to grow in tap water and in media with low and very high nutrient content. In the fresh water of the treatment plant specific bacterial populations were obtained, these occurring particularly after the filters. According to different chlorine dosage and chlorine demand, they were finally washed into the distribution system in varying amounts and compositions. It was shown that in the fresh water of the distribution system the genera of Pseudomonas, Azotobacter and Actinobacteria were each present at a level of approximately 30%. After two weeks stagnation non-fluorescing pseudomonads were dominating in the treatment plant as well as in the fresh water of the distribution system. All isolated Actinobacteria and Azotobacter and almost half of the Pseudomonads proved to be oligotrophic oligocarbotolerants or oligocarbophilic organisms in the nutrient-tolerance test. The other half of the Pseudomonads plus the Flexibacter species were mesotrophic oligocarbotolerants, since they could grow in tap water and in culture media with very high nutrient content. Attention is drawn to the unrecognized danger of recontamination of mesotrophic bacteria growing rapidly in stagnating drinking water, which is used as rinsing water for cleaning food processing equipment.

Acinetobacter↗
PubMedDate not supplied

Water purification systems and recommendations for fluoride supplementation.

In communities that do not fluoridate water supplies, or homes that have fluoride removed from their water, fluoride supplementation may be necessary. The AAPD guide is reviewed, with dosage recommendations provided. Water purifications are described and reviewed. Dentists should ask their patients about their drinking water.

Fluorides↗
PubMedDate not supplied

[Water purification from ethylene glycol by catalytic oxidation using hydrogen peroxide].

In order to select the method of water regeneration from air moisture condensate in a manned enclosed environment, the procedure of water decontamination from ethylene glycol was investigated. The process developed at t 20-22 degrees C and the following concentrations of C2H6O2 = 0.0125-0.5 mole/l, H2O2 = 1-5 mole/l, and catalyst = 1.7-50% wt. In the presence of 6.67 g/l of homogeneous catalyst FeSO4.7H2O, destructive oxidation of ethylene glycol to yield CO2 in the system 0.1 M C2H6O2 + 1M H2O2 proceeded effectively. However, the iron concentration in the decontaminated water exceeded significantly the maximally allowable concentration of iron in potable water as well as in industrial and non-industrial sewage. Heterogeneous MnO- and PbO-based catalysts provided no more than 20% ethylene glycol oxidation. Siderite, a natural mineral containing 33% wt. Fe2+, proved a more effective catalyst of ethylene glycol oxidation. When ethylene glycol and hydrogen peroxide were used at ratios of 1:30 and 1:80 with 5% wt. siderite, the degree of C2H6O2 to CO2 conversion was 99.2% and 99.8, respectively.

Aerospace Medicine↗