Devolping Pre-treatment Strategy for SWRO Systems
Typically open-sea water intake structures are constructed in the shallow areas where sea water depth is in the range of 3m up to 10m. Due to this SWRO plant with open intake will have source water with high debris, suspended solids and aquatic organisms requiring a very elaborate pretreatment system. Thus Pretreatment design becomes an important part for a long term operation of the seawater desalination plants.
Pretreatment system depending on the source water characteristics may include one or more of the following:
- Intake screens
- Conventional or enhanced sedimentation
- Granular media filtration
- Membrane pretreatment filtration
Pretreatment evolves around the following objectives:
- Better filtered quality
- More consistent quality
- Less fouling of RO membranes
- Lesser quantity and number of process chemicals
- Less foot print area
- Lower operating and capital cost.
Key design criteria for the pretreatment facilities are as tabulated in Table 1.
High performance boron removal from seawater by two-pass SWRO system with different membranes
Boron in the desalinated water produced by the seawater reverse osmosis (SWRO) system is one of the most challenging issues for drinking or irrigation water uses. In recent years, many post-treatment methods and designs for boron elimination have emerged and attracted lots of attention, but only a few cases have demonstrated high performance and economic efficiency. The main aim of this work was to evaluate the efficiency of boron removal from seawater using a two-pass SWRO system employing different RO membranes...
Union county aquifer restoration
Client: Union County Water Conservation Board Completion Date: 2003 Services Provided 65-MGD river intake Mechanically cleaned bar screen Two traveling water screens Quarter-mile-long access bridge with service deck Four 15,050 gpm vertical turbine intake pumps 48-inch raw water transmission line Regulatory agencies coordination Project Summary South central Arkansas obtains its raw water supply from the Sparta Aquifer. Over the past 50 years, the Sparta has been declining with the...
Lake Taneycomo surface water intake
Client: City of Branson, Mo. Completion Date: 1997 Services Provided Microtunneling Public information program Permitting agency reviews Air backwash system Potassium permanganate feed system Inverted bulk drum storage Architectural features Architectural rendering Project Summary This intake receives water from Lake Taneycomo in Branson. It has an ultimate design capacity of 15 million gallons per day (MGD), with an initial firm capacity of 5 MGD. The intake was constructed by the sunken...
Experiences with the conventional pretreatment system in the seawater reverse osmosis plant at ...
A 1800 m³/day Seawater Reverse Osmosis (SWRO) plant was commissioned in October 2002 at Kalpakkam, India, as part of the Nuclear Desalination Demonstration Project (NDDP). The conventional pretreatment scheme was adopted consisting of a lamella clarifier, pressurised sand filter, activated carbon filter and cartridge filter. The dosing of pretreatment chemicals, ferrous sulphate and polyelectrolytes was done at optimum levels to keep the Silt Density Index (SDI) value between 3 and 4. Experimental trials indicated...
VSEP replaces crossflow membrane systems, filtering industrial wastewater at pulp and paper mills
Technological advances in membrane filtration systems have created an opportunity for pulp and paper mills to treat effluent streams in order to meet stricter environmental constraints. “Vibratory Shear Enhanced Processing” or VSEPÔ, developed by New Logic International makes it possible to filter effluent streams without the fouling problems exhibited by conventional membrane systems. The VSEP membrane system will significantly reduce BOD, COD, TDS, TSS and color bodies from effluent streams discharged from pulp...
Safety and reliability aspects of seawater reverse osmosis desalination plant of nuclear ...
Desalination systems are mostly based on membrane (RO) and thermal (MSF and MED) processes. High-pressure operation and high level of corrosion are the major aspects of concern in a Seawater Reverse Osmosis (SWRO) Plant. Selection of the appropriate material for construction and the following of the proper design, fabrication and testing codes, and safe operational procedures ensure the safety of the plant. Proper selection of feed seawater source, provision of standby equipment, proper instrumentation and...
Tuas Seawater Desalination Plant
Black & Veatch designed the largest membrane desalination plant in Southeast Asia to help Singapore reach a critical technical milestone in its drive to overcome drinking water supply issues.The island of Singapore is among the world`s 20 smallest countries in land area, but is one of the most densely populated. This highly developed city-nation enjoys a tropical climate with abundant rainfall, but population growth and economic development are placing great pressure on freshwater resources. Innovative treatment...
Experiences in the construction and operation of a nuclear desalination demonstration plant
A hybrid desalination system of 6300 m³/day capacity has been envisaged, comprising 4500 m³/day Multi-Stage Flash (MSF) and 1800 m³/day Seawater Reverse Osmosis (SWRO) plants, and sharing basic utilities with Madras Atomic Power Station. The SWRO plant has been commissioned and has been operating for more than two years. The MSF plant is under construction. The construction of the MSF plant has thrown up a number of challenges, particularly as it is being retrofitted to the existing power plant. The steam supply...
Treating Taste & Odor and Disinfecting Drinking Water with UV
Cornwall is a city of nearly 60,000 people in Ontario, Canada. It is located on the St. Lawrence River, approximately 1,700 km from the Atlantic Ocean and 2,000 km from Lake Ontario. The city draws its drinking water from the St. Lawrence, a reliable and generally good-quality source. However, in the late summer and early fall, dying algae from algae blooms during the warmest months often leave an earthy and musty taste in the water. The city’s conventional treatment process, consisting of coagulation,...
Nuclear desalination: harnessing the seas for development of coastal areas of Pakistan
Pakistan has a population of 140 million with more than 30% of the population living in cities and towns. Karachi, the major port city of the country, is the most densely populated with a population crossing the 11 million mark. The city receives 435 MGD of drinking water from the River Indus and other sources. However, the net demand for the year 2000 was 594 MGD thus there is a gap of 159 MGD in demand and supply. Statistics show that the water demand in Karachi is increasing at the rate of 100 MGD every five...
The pebble bed modular reactor, desalination challenges and options
The Pebble Bed Modular Reactor (PBMR) is a development lead by Eskom, the South African state power utility. The technology used is based on the previous German HTGR work linked to a direct cycle gas turbine (or Breyton Cycle) being developed in conjunction with Mitsubishi Heavy Industry. The initial commercial plant design has a thermal output of 400 MW with an electrical output (nett) of over 165 MW. The interesting feature of desalination is that the nature of the inter-cooled closed cycle is the rejection of...
Water desalination price from recent performances: modelling, simulation and analysis
The subject of the present article is the technical simulation of seawater desalination, by a one stage reverse osmosis system, the objectives of which are the recent valuation of cost price through the use of new membrane and permeator performances, the use of new means of simulation and modelling of desalination parameters, and show the main parameters influencing the cost price. We have taken as the simulation example the Seawater Desalting centre of Djannet (Boumerdes, Algeria). The present performances allow...
Comparing the efficiency of uaff and uasb with hybrid reactor in treating wood fiber wastewater
Some industrial wastewaters such as pulp and paper mills and chemicals are highly loaded with organic pollutants and can be treated advantageously by means of anaerobic processes. Anaerobic treatment converts the wastewater organic pollutants into a small amount of sludge and a large amount of biogas. Several operational problems have normally been experienced in both suspended growth and biofilm systems, which are widely used for wastewater treatment. More significant problems are long start-up periods, instabilit...
Air scouring - an alternative for water main cleaning
Eliminating sediment and debris from municipal water mains that deliver potable water to residences and businesses can help preserve water quality, increase flow and pressure - and maintain a municipality`s good reputation.
The role of solution chemistry in the stability and detachment of cohesive kaolinite particles
The effect of solution chemistry on the behavior of kaolinite in three different situations was investigated: (1) the detachment of kaolinite from glass beads in a fluidized bed, (2) the erosion of kaolinite deposits in a laboratory flume and (3) the determination of the stress-strain rate relationship of concentrated suspensions in a rheometer. The experimental results from these three different approaches could be explained in terms of changes in mode of particle associations which in turn could be characterized...
Advanced Water Treatment Technologies May Bring Purified Water to San Diego
`In four years, half of San Diego may be filling its glasses with tap water that once ran through its toilets,` reported the San Diego Union-Tribune recently. A plan to mix `repurified water` with the City`s raw drinking water reservoir could become a reality, thanks to the wonders of water treatment technology. Such a possibility elicits various reactions including disgust, marvel and fear. Although the public generally trusts and admires modern technology, politicians and even scientists fear the grave repercuss...
Introduction: In this process, vacuum extraction is used to remove contaminants from soils. After condensation, contaminants are mixed with a semiconductor catalyst such (e.g., titanium dioxide), and fed through a reactor which is illuminated by sunlight. Ultraviolet light activates the catalyst, which results in the formation of reactive chemicals known as `radicals`. These radicals are powerful oxidizers that break down the contaminants into non-toxic by-products such as carbon dioxide and water. A big...
Elemental Chlorine-Free (ECF): Pollution Prevention for the Pulp and Paper Industry
Imagine being in charge of a chemical company. One day a fire breaks out, and an employee, designated as a first responder, is killed fighting the blaze. Then OSHA investigators discover that the man died primarily because both his training and his equipment were inadequate. This scenario is why CPL 2-2.59A should put anyone who runs a HAZMAT facility into a state of introspection. These employers need to ask themselves: `When was the last time that our Emergency Response Plan was brought up to date? Do our...
Wood Preserving Industry - Pollution Prevention Guidelines
Introduction Pollution Prevention Guidelines to provide technical advice and guidance to staff and consultants involved in pollution-related projects. The guidelines represent state-of-the-art thinking on how to reduce pollution emissions from the production process. In many cases, the guidelines provide numerical targets for reducing pollution, as well as maximum emissions levels that are normally achievable through a combination of cleaner production and end-of-pipe treatment. The guidelines are designed to...
Explore the capabilities of nanofiltration and ultrafiltration. Filters have similar looks, ...
Introduction Even if you’re an expert in reverse osmosis (RO) membrane technology, you may be overlooking some applications using often neglected cousins of RO: nanofiltration (NF) and ultrafiltration (UF). Although virtually identical in looks to RO membranes, NF and UF membranes serve distinctly different separation functions. Dramatic levels of resource recovery, efficiency improvement and pollution prevention are compelling incentives for the industry to continue to use NF and UF. Membrane separation...
Ex Situ Physical/chemical Treatment for Ground Water, Surface Water, and Leachate
The main advantage of ex situ treatment is that it generally requires shorter time periods, and there is more certainty about the uniformity of treatment because of the ability to monitor and continuously mix the ground water. Ex situ treatment, however, requires pumping of ground water, leading to increased costs and engineering for equipment, possible permitting, and material handling. Physical/chemical treatment uses the physical properties of the contaminants or the contaminated medium to destroy (i.e,...
Common Treatment Technologies for Inorganics in Ground Water, Surface Water, and Leachate
It may be necessary to know other subsurface information to remediate inorganics in ground water, surface water, and leachate. Treatability studies are usually necessary to ensure that the contaminated ground water can be treated effectively at the design flow. A subsurface geologic characterization would be particularly important to characterize the effects of adsorption and other processes of attenuation. Ground water models are also often needed to predict flow characteristics, changes in contaminant mixes and...
Ex Situ Biological Treatment for Soil, Sediment, and Sludge
The main advantage of ex situ treatment is that it generally requires shorter time periods than in situ treatment, and there is more certainty about the uniformity of treatment because of the ability to homogenize, screen, and continuously mix the soil. However, ex situ treatment requires excavation of soils, leading to increased costs and engineering for equipment, possible permitting, and material handling/worker exposure considerations. Bioremediation techniques are destruction or transformation techniques...
Data Requirements for Ground Water, Surface Water, and Leachate
It is common for ground water to be contaminated with the water soluble substances found in overlying soils. Many of the required data elements are similar, e.g., pH, TOC, BOD, COD, oil and grease, contaminant identification and quantification, and soil and aquifer characterization. Additional water quality monitoring data elements include hardness, ammonia, total dissolved solids, and metals content (e.g., iron, manganese). Knowledge of the site conditions and history may contribute to selecting a list of...
Nanofiltration As a Post-Treatment at a Conventional Water Treatment Plant
Introduction The Clifton Water District (Colorado) covers roughly 20 square miles stretching east of Grand Junction to Palisade, and extending south from I-70 to the Colorado River. The District has approximately 7,400 service connections serving a population of 30,000. Utilizing the Colorado River as its primary source, the District`s Charles A. Strain Water Treatment Plant has a capacity of 12 million gallons per day (mgd). Conventional water treatment processes are employed including presedimentation, coagulati...
Drinking Water Aesthetics Improve with Ozone Treatment
High quality water sources for municipal use are dwindling, forcing utilities to seek alternate water sources. Many times, aesthetics are the only problem preventing the use of these alternate water sources for potable purposes. Although typically used as a disinfectant, ozone offers municipal water purveyors the benefits of being the strongest commercially available oxidizing agent (Table 1). Due to its oxidizing power, ozone is used successfully in applications requiring reduction of aesthetically unpleasant...
Application of Membrane Technology for the Recovery and Reuse of Water
Abstract As water and sewer costs are expected to increase over the next decade, membrane technology will continue to be a viable and economical option in the recovery and reuse of water. This paper describes the mechanism of membrane effected separation (specifically reverse osmosis, ultrafiltration and microfiltration), membranes commercially available, membrane element configurations, and how complete membrane systems are designed. The paper also discusses case histories of a variety of proven applications,...
Membranes, the Finest Filtration
Introduction The notion that salt could be removed from seawater without a phase change took hold of Dr. Sourirajan`s imagination in the late 1950`s. The actual invention of the reverse osmosis (RO) membrane took place in his laboratory at UCLA around 1960. (Thus Sourirajan could be called not only the `Father of Reverse Osmosis,` but the initiator of all crossflow membrane technology.) The full commercialization of RO and its sister crossflow technology, ultrafiltration (UF), occurred in the early 1970`s. About...
Methods of Water Purification
This article is excerpted from `Pure Water Handbook` published by Osmonics®, Inc. of Minnetonka, Minnesota USA and is printed with permission of Osmonics, Inc. Water treatment can be defined as any procedure or method used to alter the chemical composition or natural `behavior` of a water supply. Water supplies are classified as either surface water or groundwater. The majority of public or municipal water comes from surface water such as rivers, lakes, and reservoirs. The majority of private water supplies...