Preliminary Water Treatment Research Articles

Performance of the unified clarifier packed with filter media (UC-FM) as a preliminary water treatment step

The unified clarifier packed with filter media (UC-FM) is composed of three treatment tanks connected in series, and each tank is packed with porous filter media. As the downflow of untreated surface water is fed into the central cylinder of the tank, uniform upflow current in the outer area of the cylinder is concurrently made throughout the tank. The UC-FM system showed 80–90% removal in normal turbidity and above 90% removal in high turbidity. The average algae and COD removal by the system over 303 days operation were 80% and more than 90%, respectively. Precoagulation prior to the system improved the removal efficiency of the dissolved and particulate contaminants up to 99% without sand filtration or other consecutive treatment. The UC-FM system was operated any additional energy except for the intake of the raw water into the first tank. A negligible head loss was observed after almost 100 days operation and backwashing was not required.

부상여재 및 모래 여과장치에 의한 조류와 탁도 제거에 관한 연구

In Korea, almost every water treatment plant suffers from seasonal problem of algae and turbidity which result from eutrophication and heavy rainfall. To relieve this problem, experimental investigation was performed to study the applicability of a floating-media and sand filter to preliminary water treatment in terms of algae and turbidity removal. Experimental results using pure-cultured algae influent showed that the shape of algae species as well as filtration velocity affects the removal efficiency. From the experiments using natural river water, it was concluded that algae removal is more sensitive to floating-media depth but turbidity more sensitive to sand depth. As the filtration velocity increased, the removal of turbidity decreased but that of algae was not affected. The floating-media and sand filter removed more than 30 % of TP, TN, turbidity, Chl-a and CODcr, and less than 20 % of DOC and .

The elusive mechanism of the magnetic ‘memory’ of water

It has been claimed that preliminary water treatment with magnetic or electromagnetic (EM) fields can help descale metal surfaces, improve cement hydration, change ζ potential of colloids, make plants irrigated with such water grow faster, enhance efflux of calcium through biomembranes or influence the structure of model lyposomes. The effects persist minutes or hours after the water treatment. It is well known that relaxation phenomena in water occur on a picosecond to second timescale. The nature of these ‘mysterious’ and questionable phenomena uniquely known as the ‘magnetic memory of water’ has recently been scrutinized. Based on our recent work as well as other recent publications, we propose a model for the observed phenomena. We propose that the gas ∣ liquid interface is perturbed by the action of magnetic and electromagnetic fields. As in the case of the sonochemical gas ∣ liquid interface treatment, some free radicals and/or reactive oxygen species are observed after the treatment (ozone, superoxide, hydroxyl radicals, singlet oxygen, atomic hydrogen, hydrogen peroxide, hypochlorous acid, etc.). The perturbations of the gas ∣ liquid interface relax more slowly (minutes to hours). The presence of gases, such as carbon dioxide or noble gases which promote clathrate-like structures of water, significantly enhanced the observed effects. Some reactive oxygen species such as hydrogen peroxide are also stable for hours or days in the absence of heavy metals. The ‘magnetic memory of water’, we propose, is the combination of perturbations of the gas ∣ liquid interface and the production of reactive oxygen species. This model is still speculative and will be tested by other researchers. Numerous tests in different independent laboratories are needed before any final conclusions can be made.

Growth Inhibitory Effect of Certain Polysaccharides for Chickens

IT IS well-known that the growth of chickens is inhibited if their diet contains either linseed meal (Kratzer and Williams, 1948; MacGregor and McGinnis, 1948), or ground carobs (Kratzer and Williams, 1951; Bornstein et al., 1963), or guar meal (Borcher and Ackerson, 1950; Vohra and Kratzer, 1964). In each case, the feces of the chickens were extremely sticky and tended to paste up the vent. Linseed meal loses its growth-inhibitory properties if it is given a preliminary water treatment; or if the pyridoxine content of the diet is increased (Kratzer and Williams, 1948; MacGregor and McGinnis, 1948). Similar treatment of ground carobs gave either very slight but significant (Kratzer and Williams, 1951), or no growth improvement (Bornstein et al., 1963) of chicks. Our unpublished studies indicate that guar meal is not improved either by treatment with water or by the addition of pyridoxine.Linseed meal, carob and guar seeds are…

Coagulation conditions and bacterial efficiency of preliminary water treatment

Coagulation conditions and bacterial efficiency of preliminary water treatment

Experimental Studies of Water Purification: IV. Observations on the Effects of Certain Modifications in Coagulation-Sedimentation on the Bacterial Efficiency of Preliminary Water Treatment in Connection with Rapid Sand Filtration: A. Observed Effect of Variations in the Period of Sedimentation

Experimental Studies of Water Purification: IV. Observations on the Effects of Certain Modifications in Coagulation-Sedimentation on the Bacterial Efficiency of Preliminary Water Treatment in Connection with Rapid Sand Filtration: A. Observed Effect of Variations in the Period of Sedimentation

Experimental Studies of Water Purification: IV. Observations on the Effects of Certain Modifications in Coagulation Sedimentation on the Bacterial Efficiency of Preliminary Water Treatment in Connection with Rapid Sand Filtration: B. Observed Effect of Certain Modifications in the Conditions of Coagulation

Experimental Studies of Water Purification: IV. Observations on the Effects of Certain Modifications in Coagulation Sedimentation on the Bacterial Efficiency of Preliminary Water Treatment in Connection with Rapid Sand Filtration: B. Observed Effect of Certain Modifications in the Conditions of Coagulation