Water Treatment Operator

What reasons would a water treatment operation employ microfilters ... 

Treatment of brackish waters in the production of potable supplies has been the largest application of electrodialysis. Costs associated with electrodialysis processes depend on such factors as the total dissolved solids (TDS) in the feed, the level of removal of TDS (percent rejection), and the size of the plant. In brackish water treatment, operating costs for very large ED installations (on the order of millions of gallons a day) have been between 40 cents to 50 cents per 1,000 gallons for brackish feed waters, which compares favorably with RO costs. 

The most important aspect of this is that profits can be increased by either an increase in revenues or a decrease in expenses. Water treatment operations are by and large end-of-pipe treatment technologies, and hence from the standpoint industry applications that must treat water, the investments required increase expenditures and decrease profit. Municipal facilities view their roles differently, because their end-product is clean water which is saleable, plus they may have addon revenues when biosolids are developed and sold into local markets. There are different categories of revenues and expenses, and it is important to distinguish between them. 

Other notaries are the Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemistry in Modem Industrial Boilers (1994 edition), published by the American Society of Mechanical Engineers, and BS 2486 1997 Recommendations for Treatment of Water for Steam Boilers and Water Heaters from the British Standards Institution. The 1994 Consensus (with its engineering background) and the 1997 version of BS 2486 (with its strength in operational chemistry) complement each other well. I consider that the tables and propositions contained in these two booklets jointly represent a true standard for boiler water treatment operational control. Consequently, I am pleased to be able to reproduce in this book all the tables from both publications, having received permission from the respective organizations to do so. 

The optimum wavelength for UV sterilization is around 260 nm. A suitable source for UV light in this region is a mercury lamp giving peak emission levels at 254 nm. These sources are generally wall- or ceiling-mounted for air disinfection, or fixed to vessels for water treatment. Operators present in an irradiated room should wear appropriate protective clothing and eye shields. 

The first step in most water-treatment operations is screening. Its purpose is to remove large articles like tree branches, dead animals, shoes, and bolts from the water. The first of these screens usually has openings that range from 1.5 to 6 in (4-15 cm). This is followed by another with openings from 0.25 to 1.5 in (0.6-4 cm). The flow through these screens should be around 2 ft/sec (0.6 m/sec).31 The solids are raked off and ground up before further treatment. 

Hydrogen peroxide is produced in moderately high volume and is widely used. Its primary uses are as a chemical intermediate, as a bleaching agent in the textile and paper and pulp industry and in water treatment operations. It occurs naturally at low levels in the air and water, in human and plant tissues and bacteria, and in food and beverages. 

The common water treatment operations can be classified into... 

Substances generated during water treatment operations... 

It is also true that many water treatment plants use ferric chloride as a coagulant in water treatment operations. Ferric ions are trivalent cations, much like aluminum ions. Since the DMP is driven by an electrochemical potential, it is thought that it might be possible to apply it to WTR generated from iron-based coagulants. It was therefore conceived that a single-step DMP could selectively recover ferric ions as well. 

Membrane filtration is used for treating high-turbidity waters, surface waters high in TOC and for tertiary water treatment, and provides a more stable and superior water quality than coagulation-sedimentation and media filtration. It is a simple and cost-effective alternative to conventional water treatment operations. 

Direct use of chlorine is in pulp and paper manufacturing and water treatment operations. Chlorine is used in the pulp and paper industiy to bleach the pulp to produce a high-quality whitened material, devoid of dark lignin and any other undesirable residuals. Chlorine has been the most common disinfectant and is still used by municipalities and others to treat potable, process, and waste water streams. Because of this specific use of chlorine, waterborne diseases such as typhoid and cholera have been eradicated in the industrialized world. Chlorine also removes hydrogen sulfide, iron compounds, and organic species that are responsible for objectionable tastes or odor associated with water. 

As these species are human carcinogens, the US EPA and the enviromnental agencies in other countries are seeking to limit the use of chlorine in drinking water. In the United States, Canada, and Western Europe, chlorine consumption will decrease as water treatment operations switch to different disinfectant technologies. However, chlorine consumption will increase in less-developed countries as more water treatment plants go in. 

Cheremisinoff, N. P. 2001. Handbook of Water and Wastewater Treatment Technologies. Boston, MA Butterworth-Heinemann. A handbook aimed at process and plant engineers, water treatment operators, and environmental consultants, this reference contains practical information for the treatment of drinking water and wastewater. 

Pizzi, Nicholas G., Water Treatment Operator Handbook, American Water Works Association, Denver, CO, 2005. 

Years of regulation have greatly lowered releases of water pollutants from industrial operations due largely to sophisticated water treatment operations that are applied to water before it is released from a plant. Desirable as these end-of-pipe measures are, the practice of industrial ecology goes beyond such pollution control, minimizing the use of water and preventing its pollution in the first place. One way to ensure that water pollutants are not released from an industrial operation is to completely recycle the water in the system—no water out, no water pollutants. 

Many water treatment operators consider liquid chemicals easy to feed and handle. Chemical suppliers deliver the chemicals in sealed containers, and the feed and delivery systems are contained. Accurate feed is assured when using properly sized, calibrated, and maintained chemical metering pumps and control systems. Liquids also mix easily into the process water stream. Table 7-1 hsts some of the more common liquid chemicals used in water treatment. In addition to these, there are many liquid polyelectrolytes sometimes used in coagulation and filtration. They are not listed in the table because their properties vary depending on the specific product. 

Giorgi, John. 2007. Math for Water Treatment Operators. Denver, Colo. American Water Works Association. 

---