microbiology of drinking water treatment

... the use of surface water, and (c) focus on water utilities and communities (e.g., water treatment plants) to improve source water quality to reduce further treatment of the filtrate If the watersheds ... purpose of water treatment drastically In India, charcoal was first used as a drinking water treatment technology in the seventeenth century as well Since then, technologies and tech- 2õ Drinking Water ... all instances, the quality of filtrate from these systems is still superior to that of the river water Provided in the book is a comparative analysis of drinking water treatment technologies that...

Ngày tải lên: 30/05/2014, 22:56

... Continuous Online? 14 Chapter A B C D E F Applications for Drinking Water Treatment Why Use Particle Counters for Drinking Water Treatment? 15 Cryptosporidium and Giardia 16 Particle ... be used in drinking water treatment, if some new applications are developed that require the unique features of this type of technology One potential application is the combination of light-blocking ... some drinking water research is done using Coulter counters A detailed description of this instrument is beyond the scope of this book This instrument is much too complex for typical drinking water...

Ngày tải lên: 18/06/2014, 19:20

... cause of any changes to various plant operations Figure 2.8 Particle counts anticipate filter breakthrough Þ G PROCESS OPTIMIZATION The goal of proper drinking water treatment is consistent water ... conventional treatment J WASTEWATER APPLICATIONS Although not within the scope of this book, it might be of interest to look briefly at some of the potential applications for particle counters in wastewater ... tertiary stage of treatment This filtration step is similar to that of conventional water treatment, and particle counters are used in the same manner The particle loading in wastewater filtration...

Ngày tải lên: 18/06/2014, 19:20

... for applications where the cost of the process can justify expensive instrumentation Needless to say, drinking water is not one of the them Tritech Enterprises of Grants Pass, Oregon, has recently ... especially wary of putting strainers on settled water lines, as the flocs can coat them, quickly, and create a lot of problems The velocity of the sample slows down through the strainer because of its ... bottom The differential pressure transducer is often used as a sample point for settled water It is important to avoid the “mudleg” of this device because of the excess particles that lodge there Short...

Ngày tải lên: 18/06/2014, 19:20

... the trend display of particle counts and removal efficiencies over time The goal of every drinking water treatment plant is the consistent production of high-quality drinking water Trends provide ... centerpiece of drinking water treatment plant data collection from now on Consider the reasons: A single personal computer can collect display and store all the data produced by a large water treatment ... resources of the individual drinking water treatment plant None of the information presented here is intended to be specific to any brand or product Those details are presented in Part III of the...

Ngày tải lên: 18/06/2014, 19:20

... high-concentration raw water sources This is because dilution is straightforward with a grab sampler The larger question of the usefulness of performing particle counting on conventional treatment raw water is ... prominent in drinking water treatment Costs have dropped a great deal in the few short years since particle counters were introduced to the industry on a wide scale The same goes for the utility of particle ... filtered and finished water These can produce less than 10 particles/ml at µm in some cases, so contamination is of primary concern Settled and raw water samples will usually be of high enough concentration...

Ngày tải lên: 18/06/2014, 19:20

... of cell width cidence is usually presented as the number of particles for which the measured counts fall within 10% of the actual number of particles present This number is the total number of ... is a good example of electronic noise Even the highest-fidelity audio system produces some of this type of noise, which becomes audible as the volume is increased Every type of electronic device ... representation of noise as displayed on an oscilloscope This noise level is measured with no particles in the water flowing through the particle counter sensor (This is not exactly true There are millions of...

Ngày tải lên: 18/06/2014, 19:20

... minimize reflections C SAMPLE FITTINGS A variety of sample fittings are available, and are usually of concern only as a matter of convenience or preference Ease of accessibility is important Plastic or ... far as optical quality is concerned It is a softer material than sapphire, and thus can be bored and polished to create the single window piece This softness accounts for the fact that it can be ... long time period Different grades of sapphire are available The entrance window (the side where the laser enters before passing through the flow cell) must be of a higher grade than the exit window...

Ngày tải lên: 18/06/2014, 19:20

... drinking water treatment The PHA is used to provide a histogram of all the particles in a given volume of water A “histogram” is a sort of graphical history of the particles present in that volume of ... due to the capacitance of the photodetector The impedance of a capacitor varies with the frequency content of the electronic signal applied to it, resulting in a loss of amplitude at higher frequencies.) ... other type of monitoring device We © 2001 by CRC Press LLC L1306/frame/pt02 Page 87 Friday, June 23, 2000 1:54 PM PARTICLE COUNTER ELECTRONICS 87 will begin a presentation of the types of counters...

Ngày tải lên: 18/06/2014, 19:20

... the flow from exceeding the acceptable limits of the particle counter C ANALOG INPUTS One of the most useful features of the more-advanced models of particle counters are the auxiliary analog ... result in offsets, which create erroneous signals Output Scaling Particle counters provide various means of scaling the count output to conform to the limitations of the to 20 mA signal Some of the ... have no use for them The number of analog inputs provided will vary from unit to unit Certainly turbidity and loss -of- head are useful inputs and others may be of importance depending on the process...

Ngày tải lên: 18/06/2014, 19:20

... between the SCADA software and the particle counters It consists of special software code which runs along with the SCADA software Control commands are issued from the SCADA software to the driver, ... the form of to 20 mA current loops Serial interfaces are becoming more common, with the growing complexity of newer instruments and the need for greater accuracy Most of the major SCADA software ... requirements of the particular application Since SCADA systems are normally used to collect data from most or all of the plant instrumentation, a number of instrument protocols must be supported Most of...

Ngày tải lên: 18/06/2014, 19:20

... in the drinking water treatment plant Serial data are transmitted at different rates, commonly referred to as the “baud” rate The speed of communication depends upon the capabilities of the other ... requirements of the particle counting system Particle counting software has improved a great deal in the last couple of years, but is still pretty far behind the curve in terms of available software ... Several forms of permanent storage media have been developed in the past few years Most of them are designed for backup of the hard-drive data, or for transporting large amounts of data Tape backup...

Ngày tải lên: 18/06/2014, 19:20

... increase the need for good maintenance instead of reducing it Treatment Process The type of treatment process employed may have a bearing on the type of particle counting system selected Conventional ... monitoring raw water will require evaluation of online dilution systems as well as the true coincidence limits of the available particle sensors For most applications, the physical location of the sample ... Some of them are of real value, while others involve mere “specmanship.” Except for electronic flowmeters, few of the various features add significant cost to the system Most are an integral part of...

Ngày tải lên: 18/06/2014, 19:20

... purchased for water treatment applications now that the much less expensive portable units are available Several of them are still in use in drinking water plants, so a brief description of the sample ... intermittent use If the window surfaces dry off, it is possible for water spots to form, affecting the optical clarity of the cell With many different types of samples being run through the same sensor, ... purchased for drinking water applications They are built for heavy-duty © 2001 by CRC Press LLC L1306/frame/pt02 Page 129 Friday, June 23, 2000 1:55 PM GRAB SAMPLERS 129 service, and many of the units...

Ngày tải lên: 18/06/2014, 19:20

... actually a succession of pulses of similar amplitude The brightness of that pulse occurs because it is actually several pulses “stacked” on top of each other The amplitude of the pulse is chosen ... indication of how accurately the particle counter sizes particles of the same size The width of the distribution relates to the resolution of the sensor It should be obvious that any type of consistent ... Although it would be of great value, it may not be worth a significant increase in the cost of the units F FIELD VERIFICATION OF CALIBRATION One area of increasing relevance is that of field verification...

Ngày tải lên: 18/06/2014, 19:20

... book, a thumbnail sketch of the history of the particle counting manufacturers involved in the water treatment industry follows The first particle counters were used in water treatment for research ... Department of Justice forced Pacific Scientific Instruments to sell off the Hiac Royco water treatment particle counting product line to another manufacturer, to prevent a “monopoly” in the drinking water ... currently marketing drinking water systems through US Filter in North America At the time of writing, the current manufacturers offering particle counting equipment in the drinking water industry...

Ngày tải lên: 18/06/2014, 19:20

... Page 149 Friday, June 23, 2000 2:15 PM PARTICLE SENSOR CONSTRUCTION 149 ARTI ARTI offers two sensors for drinking water application Each employs a standard aluminum flow cell housing with a monolithic ... well as the older Met One sensors The Met One drinking water sensor employs a quartz flow cell as described above This flow cell is a single bored piece of quartz, which is field replaceable ARTI uses ... LASER/OPTICAL ASSEMBLY All of the manufacturers employ a similar method of mounting the laser/optical assembly to the flow cell Mechanical configurations vary, as well as the method of alignment during...

Ngày tải lên: 18/06/2014, 19:20

... is more than enough for drinking water treatment applications The 2400D counting electronics is not used for calibration purposes It is currently limited to a maximum of 16 size channels in the ... are set with software The 2400D was initially intended to size particles up to the 1000 µm, but the circuitry to provide this was not implemented To maintain better resolution of the smaller ... eight size channels are supported by the software, but 64,000 are theoretically possible Once initialized, the 2400D is designed to run independently of any external control, and provides sample...

Ngày tải lên: 18/06/2014, 19:20

... length of the vertical PVC pipe that makes up the body of the weir The horizontal tube at the top of the Chemtrac weir is made of clear plastic, to allow visual indication of the amount of overflow ... Both of these devices allow the sample outlet stream to be seen by the operator, which makes quick checks of flow easy to accomplish These weir assemblies are designed to mount on the side of the ... signal events of some sort These are found on analog output units, to provide indication of instrument problems or alarm conditions Serial output units provide alarm information as part of the serial...

Ngày tải lên: 18/06/2014, 19:20

... almost all of the available SCADA software packages Chemtrac uses a modified version of the optomux protocol While the standard optomux protocol is supported by many SCADA packages, not all of the ... hardware, whereas the SCADA software programs perform these tasks themselves Often these commands are left out of the driver packages that come standard with the SCADA software Unfortunately, the ... in these arrangements is the slightly higher cost of four-conductor cabling B PROTOCOLS Each of the available units communicates data by way of a unique protocol When a standard turnkey system...

Ngày tải lên: 18/06/2014, 19:20