Photochemistry of Colloids and Surfaces in Natural Waters and Water Treatment

Author(s):  
T. David Waite
1998 ◽  
Vol 37 (12) ◽  
pp. 263-267 ◽  
Author(s):  
Henry O. Edwards

The development of a sensor to measure colour and turbidity of natural waters is described. Filtration of the water is not required, so maintenance intervals and costs will be reduced. A four-beam intensity compensation technique is used for robust measurement and resistance to fouling. Results of the operation of a prototype at a water treatment works are presented.


Author(s):  
Sоfiia Haidash ◽  
◽  
Viktor Kostenko ◽  

Introduction. In the process of coal mining and beneficiation, a large amount of wastewater is formed at enterprises. Sewage has a variety of origins, which can be classified into: natural (mine, quarry, drainage); technological (water for carrying out technological process, water for cooling of cars and devices); surface (water from rain, snow and maintenance of the enterprise); household (water is formed from showers, bathrooms, dining rooms). Wastewater from mines and factories is highly polluted and can have toxic effects on the environment. Problem Statement. Natural waters have a high rate of mineralization, salts of heavy metals, iron. Waters are polluted with organic matter, large and small particles of coal and rock. Surface and process effluents are contaminated with coal dust and petroleum products. Domestic waters are contaminated with surfactants, fats, animal and plant food residues, alkali, cadmium, nickel. Purpose. The aim is to study in detail the sources of pollution of mine effluents, to determine their composition and properties. Identify the seasonality of sources. Describe the method of water treatment and suggest possible improvements to existing technology. Materials and methods. The water must undergo some purification before it enters the environment. One of the main processes of wastewater treatment is filtration. This process is the most common and effective, so it should be part of the cleaning technology. The filter element can be a thin partition with pores or three-dimensional elements with a porous filler. This paper presents a technology with a granular filter, also called fast. The fast filter works on the principle of volume filtration, impurities are retained in the entire volume of the filter medium, in the pores and on the surface of the grains. Before filtration, the water is treated with coagulants. Types of granular materials: quartz sand, anthracite, expanded clay, expanded polystyrene, ceramic sand, mesoporous coal. Mesoporous coal is a promising material for filtration. Results. In the result of consideration of the composition and properties of wastewater, the appropriate technological scheme of mine wastewater treatment is selected and described. The technology provides purification from large impurities in open hydrocyclones, water treatment with flocculant, provides a filter and clarifier, enhanced purification from petroleum products in the oil trap and carbon filter. Filling the filter is sent to the coal warehouse, which is a cost-effective solution. Conclusions. The effluents of mining enterprises are saturated with pollutants and have a very aggressive composition, so it is unacceptable to release them into the environment without prior lighting. Should attention be paid to the purification of petroleum products that fall into the water as a result of the operation of machines and devices. As one of the possible methods, the technological scheme, improved by the department with oil trap and filter, is presented. Filter backfill is mesoporous coal, which is a very promising sorbent. Water treated with this technology can be used for recirculating water supply. This is justified not only by the economic aspect, but also by the environmental one. Keywords: mine drains, mining, pollution, petroleum products, filtration, technological scheme.


2020 ◽  
Vol 24 (3) ◽  
pp. 19-23 ◽  
Author(s):  
A.S. Kutergin ◽  
T.A. Nedobukh

The possibilities of using natural granular glauconite in standard water treatment schemes have been investigated. Resource tests of the studied material were carried out in dynamics, simulating possible conditions of use. As a result of the experiments, it was established: during the filtration process, alkalization of water occurs, but the result does not exceed pH = 6÷9, which are the norm for drinking water; the use of a sorbent based on natural glauconite does not impair the hardness indicator of the treated water. The dynamic exchange capacity was: for iron – 3.09 mg/g of absorbent, copper – 19.15 mg/g of absorbent, zinc – 4.82 mg/g of absorbent. The resource of the filter was determined with the loading of granulate with a volume of 1 dm3: for iron – 2918 dm3, for copper – 5425 dm3, for zinc – 273 dm3. The mechanical strength acquired by the sorbent as a result of granulation made it possible to wash the load by the countercurrent method, freeing intergranular pores from the sediment accumulated in them. The revealed capabilities of granular glauconite will allow its use in drinking water treatment schemes for purifying natural waters from heavy metals: iron, zinc, copper.


1988 ◽  
Vol 34 (7) ◽  
pp. 907-910 ◽  
Author(s):  
Pierre Payment ◽  
Eric Morin ◽  
Michel Trudel

The present study was undertaken to determine if indigenous enteric viruses and coliphages are free or associated with suspended particulate matter in natural waters. River water was filtered on filters of decreasing porosities (100–0.25 μm) that were pretreated with detergent to eliminate viral adsorption while retaining particulates. This filtered water was refiltered in virus-adsorbing conditions to retain free viruses. The virus-adsorbing filter retained most of the enteric viruses (77.4%) and coliphages (65.8%), which indicated that these viruses were probably free or associated with particles with a diameter of less than 0.25 μm. These observations are important because in water treatment plants small particulates are often the most difficult to eliminate.


Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2019 ◽  
Author(s):  
Legin ◽  
Zadorozhnaya ◽  
Khaydukova ◽  
Kirsanov ◽  
Rybakin ◽  
...  

The paper describes a wide-range practical application of the potentiometric multisensor system (MS) (1) for integral safety evaluation of a variety of natural waters at multiple locations, under various climatic conditions and anthropogenic stress and (2) for close to real consistency evaluation of waste water purification processes at urban water treatment plants. In total, 25 natural surface water samples were collected around St. Petersburg (Russia), analyzed as is, and after ultrasonic treatment. Toxicity of the samples was evaluated using bioassay and MS. Relative errors of toxicity assessment with MS in these samples were below 20%. The system was also applied for fast determination of integral water quality using chemical oxygen demand (COD) values in 20 samples of water from river and ponds in Kolkata (India) and performed with an acceptable precision of 20% to 22% in this task. Furthermore, the MS was applied for fast simultaneous evaluation of COD, biochemical oxygen demand, inorganic phosphorous, ammonia, and nitrate nitrogen at two waste water treatment plants (over 320 samples). Reasonable precision (within 25%) of such analysis is acceptable for rapid water safety evaluation and enables fast control of the purification process. MS proved to be a practicable analytical instrument for various real-world tasks related to water safety monitoring.


Author(s):  
Lívia Duarte Ventura Melo ◽  
Elizângela Pinheiro da Costa ◽  
Carolina Cristiane Pinto ◽  
Gabriela Rodrigues Barroso ◽  
Sílvia Corrêa Oliveira

2019 ◽  
Vol 13 (1) ◽  
pp. 387-396 ◽  
Author(s):  
Gideon A. Idowu ◽  
Ashleigh J. Fletcher

AbstractMarabu (Dichrostachys cinerea) from Cuba and aspen (Populus tremula) from Britain are two rosid angiosperms that grow easily, as a weed and as a phytoremediator, respectively. As part of scientific efforts to valorise these species, their barks and woods were pyrolysed at 350, 450, 550 and 650 °C, and the resulting biochars were characterised to determine the potential of the products for particular applications. Percentage carbon composition of the biochars generally increased with pyrolysis temperature, giving biochars with highest carbon contents at 650 °C. Biochars produced from the core marabu and aspen wood sections had higher carbon contents (up to 85%) and BET surface areas (up to 381 m2 g−1) than those produced from the barks. The biochar porous structures were predominantly mesoporous, while micropores were developed in marabu biochars produced at 650 °C and aspen biochars produced above 550 °C. Chemical and thermal activation of marabu carbon greatly enhanced its adsorption capacity for metaldehyde, a molluscicide that has been detected frequently in UK natural waters above the recommended EU limit.


2018 ◽  
Vol 245 ◽  
pp. 12007
Author(s):  
Tatiana Germanova

This study was conducted with the aim of preliminary assessment of the total use of the working exchange capacity of cation-exchangers during ion-exchange filtration of surface waters. The chemical composition of natural waters in Russia depends on many factors, which affects the performance indicators during operation of water treatment equipment. Comparison of geochemical indicators of natural waters of the Ob River basin at specific locations of water withdrawal in the Ural Federal District of Russia was carried out. For several compositions of natural waters, the calculation of two-stage ion-exchange filtration in the water treatment scheme for heat and power plants has been carried out. The possibility of rational use of ion-exchange filtration at the first stage of water purification and low efficiency of the use of ion-exchange filtration at the second stage of filtration for these plants is shown.


2008 ◽  
Vol 8 (6) ◽  
pp. 615-623 ◽  
Author(s):  
William J. Cooper ◽  
Weihua Song ◽  
Michael Gonsior ◽  
Daina Kalnina ◽  
Barrie M. Peake ◽  
...  

The goal of our research is to better understand the structure and reactivity of natural dissolved organic matter (DOM) in aquatic environments. A more detailed knowledge of these DOM characteristics would lead to a better understanding of carbon cycling in natural waters and processes associated with water treatment using free radical chemistry. Our specific interest in DOM in natural waters is several-fold: 1) the photochemical formation of reactive oxygen species, 2) photobleaching of the DOM in coastal oceans, and 3) using chromophoric DOM (CDOM) as a tracer of water masses and in carbon cycling. Our interest in water treatment is that DOM is the major sink of hydroxyl radicals employed in advanced oxidation processes for the destruction of pollutants and thus adversely affects the efficiency of the process. We are using the techniques of radiation chemistry to explore the fundamental free radical and redox chemistry of DOM. We have initiated a study of the free radical reactions of DOM using isolated fractions of Suwannee River fulvic and humic acids and isolates from various anthropogenic sources. We are also investigating the use of model compounds in an attempt to understand the free radical transients formed from DOM either as a result of free radical reactions or photochemical reactions.


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