Drinking Water Industry Solutions PDF

Drinking Water Industry Solutions Safe and Reliable Liquid Analysis  We Start With One Idea in Mind: Make it Safe Water is the most crucial Poor Water Quality: Comprehensive Solutions element needed for human Understandi...

Drinking Water Industry Solutions Safe and Reliable Liquid Analysis  We Start With One Idea in Mind: Make it Safe Water is the most crucial Poor Water Quality: Comprehensive Solutions element needed for human Understanding the Problem For Your Application activity on the planet, including Water treatment plants come in a Some smaller treatment plants using agricultural, industrial and wide variety of sizes, with no two ground water systems can meet the domestic use. Unfortunately, plants exactly alike. But whether local and national requirements publicly owned or privately held, without any treatment, but many water quality around the world they all share the same goal — to other systems need additional treat- is poor and getting worse. provide a source of safe and reliable ment and disinfection. While over 70% of the Earth is drinking water to their Governmental agencies communities. such as the US covered in water, only about Environmental Production 0.01% is usable fresh water. Water treatment varies Agency (USEPA) protect And since water demand based on the quality of the public health by speci- the water source, size of fying water treatment increases with population, the the plant, and if ground components and re-use of water and proper water or surface water is used. appropriate disinfection levels. To treatment methods have Smaller systems are likely to use meet these requirements, a variety become a critical necessity. ground water, while larger systems of water treatment methods are rely on surface water sources such used to remove contaminants from as rivers, lakes, and reservoirs. drinking water, and are arranged in a With so much at stake, you sequence or a treatment train. 2 As water travels through the need a partner that can deliver ground, or sits in lakes and rivers, it A combination of appropriate water the best in knowledge and comes in contact with organic treatment processes is selected by systems, and do it quickly, thor- materials, which dissolve in water. the water utilities to treat the oughly and cost-effectively. The These organics in water become a contaminants in the raw water food source for microorganisms. source used. Commonly used liquid analysis professionals at Even the most minute nutrient processes include pre-treatment, Emerson Process Management sources will support growth. While coagulation, flocculation, are ready to put their 60-plus that’s good news for microorgan- sedimentation, filtration, and isms, it spells disaster for people, disinfection. Other treatment meth- years of experience to work for since these microorganisms (like ods could include ion exchange, you. We’ll evaluate your Giardia lamblia or the protozoa reverse osmosis, and adsorption. application and deliver an Cryptosporidium) can be harmful or optimal, real-world, customized even lethal to humans. For these applications and more, count on Emerson. Our full line of solution for your specific Rosemount Analytical sensors and requirements, utilizing world- measurement solutions for drinking class Rosemount Analytical water are proven solutions. When you bring your problem to Emerson, sensors and instrumentation. consider it solved. E M E R S O N. C O N S I D E R I T S O LV E D.™ Drinking Water Treatment Overview Pretreatment Primary Disinfection (Ozone or Chlorine Treatment) Page 4 Plant Intake Flash Mixers Filter Wastewater Flocculation Basin Page 5 Backwash Settling Basin Page 5 Filter Beds Page 6 Industries Secondary Disinfection Chlorine Addition (Ammonia Addition) Page 7 Water Tower Clear Well Homes 3 To Distribution System Page 8 Booster Station Here’s a typical drinking water monitored and controlled by plant. It takes water from a lake, continuous measurement of CO N T E N T S river or well and treats it ozone and/or chlorine. Particles Pretreatment 4 through primary disinfection, are removed and filtered out, Primary Disinfection 4 coagulation, sedimentation, and require continuous turbidity Coagulation, Flocculation filtration and secondary disin- measurement for reporting pur- and Sedimentation 5 fection to purify it into safe poses and indicate filter Filtration 6 drinking water. performance. Particle Counters are gaining more acceptance Secondary Disinfection 7 Harmful organisms are killed by since they provide a quantitative Distribution Monitoring 8 a combination of ozone, chlorine measurement of drinking water Desalination 9 and ammonia addition. The clarity and are being used to Instrumentation 10 disinfection process is anticipate filter breakthrough.  Pretreatment Primary Disinfection To better define the dynamics of Since water is a universal free oxygen radi- Chemical Oxidation Potential (volts) the raw water source being used cal, which Ozone 2.08 solvent, it comes in contact Hydrogen Peroxide 1.78 by a water treatment plant, a survives less number of liquid analytical with several different Hypochlorous Acid 1.48 than 30 minutes. Chlorine Gas 1.36 measurements are made prior to pathogens (bacteria, viruses, The rate of Hypobromous Acid 1.33 entering the treatment process. and parasitic protozoa), some degradation Chlorine Dioxide 0.95 Influent monitoring measure- depends on the Hypochlorite 0.81 of which are well know and ments could include pH, water chemistry, Relative Oxidation Power of Various Chemicals conductivity, temperature, potentially lethal. Both surface pH and temp- turbidity, dissolved oxygen, and water and groundwater sources erature. Since ozone is unstable, it Total Organic Carbon (TOC). is generated on site. can be contaminated by these Some plants also keep a permanent record of each of pathogens, and inactivation is Ozone is a very powerful oxidant these measurements for future accomplished through chemical and it disinfects in less time than is reference or for detecting season- required with chlorine. Ozone disinfection and mechanical al changes in the source water. attacks the chemical bonds of filtration treatment. pathogens in the water, reducing Before water is clarified, it passes the concentration of organic mate- through coarse filters to remove rial, iron, manganese, sulfur, and Chlorine was used first used in the sticks, leaves, fish, and other large reducing or eliminating odor and USA in 1908 as a chemical objects, preventing them from taste problems. Chlorine is a slow disinfectant of drinking water. entering the water treatment oxidizer, has limited effect on 4 plant. Pre-treatment also includes Ozone (O3) is also a powerful bacteria, and Cryptosporidium and primary disinfection using either disinfectant first used in water treat- Giardia are extremely resistant to chlorine or ozone to treat algae ment in Europe in 1886. Ozone chlorine disinfection. Ozone growth and for oxidation of consists of three oxygen atoms and treatment is gaining popularity as a chemicals and microorganisms. degrades back to oxygen forming a fast and effective treatment technology for disinfection in the primary disinfection stage. Ozonated air is bubbled up through the water in contact chambers. By the time the water reaches the end of the contact chambers, primary disinfection is complete and the ozone has converted back to oxygen. For proper ozone disinfection to occur, suitable contact time and the proper ozone dosage are required. The Ozone sensor Model 499AOZ is used to monitor ozone dosage and residuals in the contact chamber. Coagulation, Flocculation and Sedimentation After pretreatment and primary Coagulation and Focculation If the raw water source has an disinfection, the clarification of unusually high hardness, chemicals Smaller particles combine or coagu- are added such as lime and soda ash raw water is usually a multiple late into larger fluffy particles called to reduce the levels of calcium and step process for reducing floc and settle out of the raw water magnesium. Lime softening can turbidity and suspended solids. source as sediment. The coagulation produce water from 60 to 120 ppm process is promoted by the addition hardness, but will result in a higher of chemical coagulant such as alum, pH. Therefore, the treated water is iron salts or synthetic organic buffered to reduce the pH to make polymers. After chemical addition, it acceptable for further processing. the water flows through a mixing channel where the water and chemi- Sedimentation cals are flash mixed. Floc settles to the bottom to form a The floc is mechanically stirred to sludge in sedimentation basins. The attract suspended solids and combined weight of the dirt and A pH sensor, Model microorganisms. The pH chemical agent become heavy 399, is used to measurement plays an important enough to sink to the bottom, and monitor and control the addition role in the coagulation process. the settling or sedimentation occurs of chemicals for pH Keeping the pH at the proper levels naturally as larger particles settle adjustment. improves the coagulation process, out. Sludge is removed by mechani- lowers the turbidity and also cal scrapers and disposed of proper- improves TOC removal as the ly. Water is skimmed from the 5 pH is lowered. surface of the settling basins and flows into settled water channels. >>> While the Earth’s population is now twice the 1960 total, the amount of fresh water available is unchanged.  Filtration The sedimentation process Item EPA 180.1 IS0 7027 Light Source Tungsten Lamp LED or removes particles 25 microns Tungsten Lamp and larger, but the process is Wavelength 400-600 nm 860 ± 30 nm Characteristics Long Warm- Low Stray not 100% efficient, and filtra- Up Time Light tion is required. The turbidity More Sensitive Less Sensitive to Smaller to Smaller Particles Particles is between 1 and 10 NTU as it Color Low Color enters the filtration stage. Interferences Interferences The Clarity II On-Line Turbidimeter is used Comparison of USEPA 180.1 and ISO 7027 to monitor and report the turbidity of the filter effluent. Water flows through sand filters and percolates down through a monitor and report the turbidity of compliance monitoring purposes, combination of sand, gravel, the filter effluent. Turbidity the USEPA Method 180.1 and the ISO anthracite coal, and a mixture of measurements also help monitor Method 7027. USEPA method is used support gravel fine sand. Larger par- and improve plant efficiency. in the United States and some other ticles become trapped first and countries. The ISO method is used smaller particles such as clay, iron, High turbidity levels are an indication outside of the United States, such as manganese, microorganisms, that the filter is not operating proper- in Canada, Europe, Latin America and organic matter, precipitates from ly, and back washing is necessary. Asia. A comparison of the two meth- other treatment processes, and silt ods is shown in the table above. are also removed resulting in crystal Government rules and regulations 6 clear water. apply to public water systems, and Keeping water systems safe is a water treatment plants are required national priority. To monitor online The filtration stage also removes to achieve a minimal reduction of multiple parameters, Emerson has a residual matter resulting from the harmful microorganisms and configurable system, the Water oxidation of organic chemicals and viruses. Filtration systems are Quality System, model WQS, to meet microorganisms in the primary presumed to achieve the minimal your particular system and regulatory disinfection stage. Finally, micro- percent reduction of harmful requirements. The system assists in organisms resistant to chlorine or Cryptosporidium, Giardia and virus- meeting the requirements of the ozone disinfection in the es by meeting certain turbidity Surface Water Treatment Rule. pretreatment stage are effectively limits in combination with adequate removed during filtration. disinfection. The adequacy of the fil- tration process and the removal of Periodically, the filter must be back these microorganisms are washed to remove the fine suspend- determined by measuring the ed matter and accumulated turbidity of the combined filter sediment that collects in the filter effluent water to meet media. As an indication of filter per- governmental criteria. This criteria formance and the need to includes the turbidity monitoring backwash filters, the effluent from frequency, the maximum turbidity the filter beds is continuously moni- limit, and the approved turbidity tored with a turbidimeter. Turbidity measuring methods. is the clarity of the sample, and the The WQS provides constant surveillance of cloudy appearance is caused by tiny Two approved measuring methods water quality events to help ensure that particles in the water. The Clarity II have been accepted for making tur- acceptable water quality parameters are On-line Turbidimeter can be used to bidity measurements for maintained. Secondary Disinfection In compliance with the also a stronger disinfectant and regulations requiring post oxidizer. Hypochlorous acid is 80 to 100 times more effective than residual disinfection, plants use hypochlorite ion. chlorination as secondary disinfection in the final To accurately measure free chlorine concentrations, the Rosemount treatment step. Ozone does Analytical three electrode chlorine not provide germicidal or a sensor Model 498CL can be used for long-lasting disinfection continuous measurement of free chlorine. Neither a pH sensor, residual to inhibit or prevent sample conditioning, nor reagent The Monochloramine Measuring System re-growth of pathogens in the is required. Model MCL directly measures monochloramine without chemical water distribution system. reagents to condition the sample. Chlorine diffuses through a semi-per- meable membrane and develops a Monochloramine is the most desir- Today, chlorine is added as chlorine current proportional to the chlorine able of the three forms, since it gas (Cl2), sodium hypochlorite concentration inside the sensor. contributes little or no taste or (NaOCl), or chlorine dioxide (ClO2) odor, and is considered to be the as the secondary disinfection agent. Chlorination by-products were most effective at disinfecting water. Secondary disinfection prevents discovered in drinking water in the re-growth of certain pathogens 1974, and can form when chlorine Plant operators using chlora- that may enter the treatment reacts with bromide and natural mination for disinfection need to 7 plant or be introduced by back- organic materials present in the accurately determine monochlora- flow contamination. water source. These by-products mine levels in the water treatment have a potential health effect on systems. Rosemount Analytical When chlorine is added to water, humans. Fears that these by- offers a complete Monochloramine free chlorine forms a mixture of products could be potential human Measuring System Model MCL hypochlorous acid (HOCl) and carcinogens has led the USEPA to capable of directly measuring hypochlorite ion (OCl-). The relative establish maximum levels for these monochloramine. No chemical amount of each is dependent on disinfection by-products. reagents are needed to condition the pH, and the total of HOCl and the sample. OCl- is defined as free chlorine. Alternates to chlorine disinfection exist, such as chloramines. This For customers that want to For disinfecting water, hypo- process involves adding chlorine measure Total Chlorine, we chlorous acid is not only more reac- and ammonia compounds to the have the Total tive than hypochlorite ion, but is water that, when properly Chlorine Measuring controlled, form chloramines. System, the Model TCL. The TCL uses Compared to chlorine, chloramines household vinegar produce fewer disinfection byprod- and potassium iodide ucts and exist as monochloramine, as reagent. dichloramine or trichloramine. The ratios of these three depend on the Model TCL Total Chlorine Sample pH, physical properties of the water Conditioning System source, chlorine contact time, and the ratio of chlorine to ammonia.  Distribution Monitoring The prevention of contamina- Because pathogens can enter the Water quality within the distribution tion in the distribution system, distribution system through cracks system can be monitored on a and joints in pipes, water systems continuous basis, and several large thereby reducing the risk of are also required to provide water utilities have installed water borne diseases, requires continuous disinfection of the automatic sampling systems regular monitoring for disinfec- drinking water entering the throughout their district. distribution system, and maintain a tant levels, microbial levels, and detectable residual level within the A continuous on-line chlorine meas- corrosion products. Although distribution system. urement is especially important in water may be safe upon leaving ensuring adequate disinfection Regular monitoring includes micro- levels throughout the distribution the treatment plant, it is bial monitoring to meet public system; it can be accomplished by important to monitor for health standards. Chlorine residuals using one of three measurement contamination by growth of in the distribution system also need systems available from Rosemount: to be checked. The pH is monitored free chlorine, monochloramine or microorganisms, pressure prob- to confirm that the proper total chlorine. The monitoring data lems, and water main breaks. applications of corrosion control can be transmitted back to the plant Monitoring can also indicate for- chemicals are being applied at the and automatically stored for future mation of biofilms, malfunction- treatment plant. reference, historical trends, and detection of seasonal fluctuations. ing piping and valves or other A minimum of 0.2 mg/L of chlorine threats to the system. residual is advisable at the last tap 8 on the distribution system, and prompt investigation is required to correct a low or no residual reading. Free Chlorine Measuring System Model FCLi is a complete package that does not require a pH sensor. >>> In a large water system, hundreds of miles of piping serve thousands of people. Desalination Desalination refers to the water of the incoming sea-water. The main treatment process of removing benefit of this dual-purpose plant is the reduction of fuel used. salts from water. Of all the earth’s water, 94% is salt water Multi-Stage Flash Distillation is one and less than 1% is accessible of the most commonly used types. Typically, the salt water is heated in fresh surface water. the brine vessel for the separation of water and salt. The heated water is With the improvements in sent to another vessel where it boils desalination technologies over rapidly and flashes to create steam. the past 50 years, and the The steam is then captured and growing demand for fresh immediately cooled to convert it back into a liquid that has been water, there are over 16,000 Contacting Conductivity desalinated and is ready for use. ENDURANCE™ Sensors are used desalination plants worldwide. Desalination plants can have to monitor the reverse osmosis This compares to only 5 plants anywhere from four to 40 different treatment process and are available in a stages of flashing. Scaling is one of variety of mounting options. in 1960. Cities and major indus- the biggest problems in multi-stage tries have developed with the distillation applications. Maintaining availability of fresh water a pH balance of 5.7 or less is crucial desalination. RO is a technique in to minimize scaling. This can be which water is forced through semi- produced from seawater. achieved by using a Rosemount permeable membranes, and 9 Analytical pH/ORP sensor model 399 requires pretreatment consisting of Thermal techniques, such as multi- with the 1056 dual channel analyzer. coagulation and filtration. stage flash desalination (MSF) distil- lation, and membrane technologies, Scaling also causes a problem when The passage of dissolved salts and such as reverse osmosis (RO), are the feed solution becomes saturated microscopic particles is blocked, the two major competing tech- with calcium sulfate. It is important and relatively ion-free water (called- niques used in the desalination to maintain a concentration level permeate), passes through the of seawater, and both make below the saturation point. Using the membrane. Contacting conductivity seawater drinkable. Rosemount Analytical toroidal sensors placed in the feed-water conductivity sensor model 228 along and permeate let operators monitor About half the world's desalting with a 1056 two channel analyzer, the overall water quality and plants produce fresh water using will insure that no excessive build up efficiency of the RO treatment. heat to distill water from sea water. of dissolved solids takes place and Hybrid plants combine a steam minimizes fouling in the evaporator. Chemical attack can occur on the power plant and a desalination cellulose acetate RO membranes plant. The latent heat of conden- Seawater Reverse Osmosis (SWRO) when the pH is outside the acidic sation from the power plant is using membrane technology is range. To protect the membrane, reused to increase the temperature another way of accomplishing the acidity of the feed source is adjusted with the use of a pH meas- urement. A general-purpose sensor such as Model 399 can complete this measurement.  Rosemount Analytical Instrumentation The optimum solution for the process relies most control, and communication requirements, in heavily on selecting the right sensor to match the addition to other desired features, such as HART®, process needs. In most cases the instrument is FOUNDATION fieldbus®, preventative diagnostics, simple to select and depends on the power, and more. Choose the one that meets your needs. Features 1056 Series 54e Series 5081 Series SoluComp Xmt Series Power 115 - 230 VAC or 115 - 230 VAC or 24 VDC 24 VDC 24 VDC Requirement 24 VDC* Number of Two One One One Sensor Inputs 10 Number of 4-20 Two Two One One mA Outputs Available Select any two: pH/ORP/ISE, Select one: pH, ORP, Select one: pH, ORP, Select one: pH, ORP, Measurements Conductivity, Resistivity, Conductivity, Resistivity, Conductivity, Resistivity, Conductivity, Resistivity, % Concentration,Dissolved Oxygen, Dissolved Oxygen, Dissolved Oxygen, Dissolved Oxygen, Ozone, Flow,* Turbidity,* Ozone, Chlorine Ozone, Chlorine Ozone, Chlorine Chlorine (Total, Free, Monochloramine, pH Independent Free Chlorine) HART Yes* Yes Yes Yes Compatible FOUNDATION fieldbus No No Yes Yes Compatible Multi-lingual menus Yes Yes No Yes Relays 4* 4 0 0 PID Control No Yes Yes/Ff Yes/Ff Advanced Diagnostics Complete Complete Complete Complete Capability Area Pending Class I, Div. 2 Class I, Div. 1 and Div. 2, Class I, Div. 1 and Div. 2 Classifications Explosion proof Available Approvals CE approval (others pending) FM, CSA, CE FM, CSA, CE, ATEX FM, CSA, CE, ATEX * Future option Emerson Process Management: The Proven Source Emerson Process Management is Producing a source of safe and the proven supplier of Rosemount reliable drinking water and the Gas Chromatography Analytical on-line electrochemical removal of harmful microorganisms & Process Gas Analysis sensors and instrumentation with are the primary goals of every over 60 years experience in drinking water treatment plant. Emerson is the world’s largest drinking water treatment, waste Thousands were killed each year due provider of gas treatment and process control. In to cholera, typhoid fever, dysentery chromatography, process gas, recognition of our and hepatitis before cities began combustion and environmen- dedication to customer treating drinking water with tal analysis solutions. We feature products service, product chlorine. Today, chlorine, with unmatched accuracy, superior perform- excellence, and quali- ozone and UV are being ance and worry-free dependability. ty we have received used in primary disinfection at the #1 Readers Choice the pre-treatment stage and Emerson’s leading edge instruments and Award from Control Magazine for secondary disinfection in the final applications expertise, along with the tenth consecutive year. stage to inhibit or prevent regrowth unbeatable customer service and support of pathogens in the water worldwide help our customers maximize With a fixed amount of fresh water distribution system. process performance, productivity, and prof- available for consumption and our itability. Our solutions provide reduced worldwide increased demand for Accurate on-line process instrumen- installation and maintenance costs while access to safe water, continuous tation, such as pH, conductivity, improving process quality. monitoring and measuring of the chlorine, dissolved ozone, turbidity, water treatment process and water and particle counters, plays a critical quality becomes one of the most role in achieving the plant objective 11 important elements to prevent and meeting regulatory compliance solutions you need in an ever-chang- water-related diseases caused by at the local and federal level. Count ing, dynamic world. See us on the pathogens. on Emerson for the systems and web at RAIhome.com. PlantWeb® Brings It All Together Rosemount Analytical’s instru- process solutions. The PlantWeb and distribute ments are part of Emerson Process architecture consists of intelligent information and Management’s PlantWeb® field- field devices, scalable platforms process control data. based architecture: a scalable way and standards, and integrated to use open and interoperable modular software, all working This architecture can reduce your devices and systems to build together to create, capture, use, capital and engineering costs, reduce operations and maintenance costs, increase process availability, reduce process variability, and streamline regulatory reporting. To see what PlantWeb can do for your operation, call or visit us at PlantWeb.com/RunSafe  Offices Worldwide Emerson Process Management’s field sales offices are your source INTERNATIONAL SALES OFFICES: for more information on the full Angola Ethiopia Mexico Spain line of Rosemount Analytical Argentina Finland Netherlands Sweden products. Field sales personnel will Australia France New Zealand Switzerland Austria Germany Nigeria Syria work closely with you to supply Bahrain Ghana Norway Taiwan technical data and application Belgium Greece Oman Thailand information. Bolivia Hong Kong Pakistan Trinidad Brazil Hungary Peru Tunisia For more information on any of the Brunei India Philippines Turkey products listed in this brochure and Canada Indonesia Poland Ukraine Chile Ireland Portugal United Arab Emirates their applications, please contact China Israel Puerto Rico United Kingdom your nearest Rosemount Analytical Colombia Italy Qatar United States sales office. To request copies of our Costa Rica Jamaica Romania Uruguay literature, call 800.854.8257 or visit Croatia Japan Russia Venezuela Czech Republic Jordan Saudi Arabia Yemen our website. Denmark Korea Singapore Yugoslavia Ecuador Kuwait Slovak Republic www.raihome.com Egypt Malaysia South Africa Online ordering available. Emerson's Rosemount Analytical Liquid Division provides technologies and services for the analysis of liquid processes. For a wide range of applications, Emerson provides more than 60 years of expertise in high-precision analytical sensors, instrumentation and services. For information, call 800.854.8257. Emerson Process Management, Rosemount Analytical, PlantWeb, DeltaV, TUpH, ENDURANCE, ACCU-GLASS, and Solu Comp are marks of Emerson Process Management group of companies. All other marks are the property of their respective owners. The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure its accuracy, they are not to be construed as warranties or guarantees, expressed or implied, regarding the products or services described herein or their use or applicability. All sales are governed by our terms and conditions, which are available on request. We reserve the right to modify or improve the designs or specifications of such products at any time without notice. © Rosemount Analytical Inc. 2007. All rights reserved. Printed in the U.S.A. HEADQUARTERS ASIA-PACIFIC EUROPE, MIDDLE EAST, LATIN AMERICA Emerson Process Management Emerson Process Management AND AFRICA Emerson Process Management Rosemount Analytical Asia Pacific Private Ltd. Emerson Process Management 9753 Pinelake Drive Liquid Division 1 Pandan Crescent Services Ltd. Houston, TX 77055 2400 Barranca Parkway Singapore 0512 Heath Place T 713.827.3301 Irvine, CA 92606 Republic of Singapore Bognor Regis F 713.827.3329 T 949.757.8500 T 65.777.8211 West Sussex PO22 9SH T 800.854.8257 F 65.777.0947 England F 949.474.7250 T 44.1243.863121 F 44.1243.845354 91-6030 4.07