THEORY AND PRACTICE OF WATER AND WASTEWATER TREATMENT PDF
Theory and Practice of Water and Wastewater Treatment, 2nd Edition is an important text for undergraduate and graduate level courses in water and/or. Theory and practice of water and wastewater treatment/by Ronald. L. Droste. p. em. Includes index. ISBN (cloth: alk. paper). 1. Water-Purification . Theory and practice of water and wastewater treatment. Material. Type. Book. Language English. Title. Theory and practice of water and wastewater treatment.
|Language:||English, Spanish, Portuguese|
|ePub File Size:||28.66 MB|
|PDF File Size:||11.72 MB|
|Distribution:||Free* [*Register to download]|
Theory and Practice of Water and Wastewater Treatment, 2nd Edition: * Addresses physical/chemical treatment, as well as biological treatment, of water and. Design Principles and Practice .. water treatment and wastewater treatment facilities with conventional or membrane .. Theory of Granular Filter Hydraulics. Theory and Practice of Water and Wastewater Treatment by Ronald L. Droste, , available at Book Depository with free delivery.
These tailings contain a combination of not only undesirable leftover metals, but also sulphide components which eventually form sulphuric acid upon the exposure to air and water that inevitably occurs when the tailings are disposed of in large impoundments. The resulting acid mine drainage , which is often rich in heavy metals because acids dissolve metals , is one of the many environmental impacts of mining.
Petroleum refining and petrochemicals[ edit ] Pollutants discharged at petroleum refineries and petrochemical plants include conventional pollutants BOD, oil and grease, suspended solids , ammonia, chromium, phenols and sulfides. Plants that bleach wood pulp for paper making may generate chloroform , dioxins including 2,3,7,8-TCDD , furans , phenols and chemical oxygen demand COD.
Increased BOD or COD loadings, as well as organic pollutants, may require biological treatment such as activated sludge or upflow anaerobic sludge blanket reactors. For mills with high inorganic loadings like salt, tertiary treatments may be required, either general membrane treatments like ultrafiltration or reverse osmosis or treatments to remove specific contaminants, such as nutrients.
Textile Dyeing[ edit ] Textile dyeing plants generate wastewater that contain synthetic and natural dyestuff, gum thickener guar and various wetting agents, pH buffers and dye retardants or accelerators.
Industrial oil contamination[ edit ] Industrial applications where oil enters the wastewater stream may include vehicle wash bays, workshops, fuel storage depots, transport hubs and power generation. Often the wastewater is discharged into local sewer or trade waste systems and must meet local environmental specifications. Typical contaminants can include solvents, detergents, grit. Water treatment[ edit ] Many industries have a need to treat water to obtain very high quality water for demanding purposes such pure chemical synthesis or boiler feed water.
Nanotechnology in Water and Wastewater Treatment
Many water treatment produce organic and mineral sludges from filtration and sedimentation. Regeneration of ion exchange columns with strong acids and alkalis produces a wastewater rich in hardness ions which are readily precipitated out, especially when in admixture with other wastewater constituents. Animal fats may be present in the wastewater, which if not contaminated, can be recovered for the production of tallow or further rendering. Treatment of industrial wastewater[ edit ] The various types of contamination of wastewater require a variety of strategies to remove the contamination.
Although similarities to seawater or brackish water desalination exist, industrial brine treatment may contain unique combinations of dissolved ions, such as hardness ions or other metals, necessitating specific processes and equipment. Brine treatment systems are typically optimized to either reduce the volume of the final discharge for more economic disposal as disposal costs are often based on volume or maximize the recovery of fresh water or salts.
Brine treatment systems may also be optimized to reduce electricity consumption, chemical usage, or physical footprint. Brine treatment is commonly encountered when treating cooling tower blowdown, produced water from steam assisted gravity drainage SAGD , produced water from natural gas extraction such as coal seam gas , frac flowback water, acid mine or acid rock drainage , reverse osmosis reject, chlor-alkali wastewater, pulp and paper mill effluent, and waste streams from food and beverage processing.
Brine treatment technologies may include: membrane filtration processes, such as reverse osmosis ; ion exchange processes such as electrodialysis or weak acid cation exchange ; or evaporation processes, such as brine concentrators and crystallizers employing mechanical vapour recompression and steam. Reverse osmosis may not be viable for brine treatment, due to the potential for fouling caused by hardness salts or organic contaminants, or damage to the reverse osmosis membranes from hydrocarbons.
Evaporation processes are the most widespread for brine treatment as they enable the highest degree of concentration, as high as solid salt. They also produce the highest purity effluent, even distillate-quality. Evaporation processes are also more tolerant of organics, hydrocarbons, or hardness salts.
However, energy consumption is high and corrosion may be an issue as the prime mover is concentrated salt water. As a result, evaporation systems typically employ titanium or duplex stainless steel materials. Brine management[ edit ] Brine management examines the broader context of brine treatment and may include consideration of government policy and regulations, corporate sustainability , environmental impact, recycling, handling and transport, containment, centralized compared to on-site treatment, avoidance and reduction, technologies, and economics.
Brine management shares some issues with letéléchargemente management and more general waste management. Solids removal[ edit ] Most solids can be removed using simple sedimentation techniques with the solids recovered as slurry or sludge. Very fine solids and solids with densities close to the density of water pose special problems.
In such case filtration or ultrafiltration may be required.
Although, flocculation may be used, using alum salts or the addition of polyelectrolytes. Wastewater from industrial food processing often requires on-site treatment before it can be discharged to prevent or reduce sewer surcharge fees.
The type of industry and specific operational practices determine what types of wastewater is generated and what type of treatment is required. Reducing solids such as waste product, organic materials, and sand is often a goal of industrial wastewater treatment.
Table of Contents
Some common ways to reduce solids include primary sedimentation clarification , Dissolved Air Flotation or DAF , belt filtration microscreening , and drum screening. Oils and grease removal[ edit ] The effective removal of oils and grease is dependent on the characteristics of the oil in terms of its suspension state and droplet size, which will in turn affect the choice of separator technology. Oil in industrial waste water may be free light oil, heavy oil, which tends to sink, and emulsified oil, often referred to as soluble oil.
Emulsified or soluble oils will typically required "cracking" to free the oil from its emulsion. In most cases this is achieved by lowering the pH of the water matrix. Most separator technologies will have an optimum range of oil droplet sizes that can be effectively treated. Analysing the oily water to determine droplet size can be performed with a video particle analyser. Each separator technology will have its own performance curve outlining optimum performance based on oil droplet size.
Considered a dependable and cheap way to remove oil, grease and other hydrocarbons from water, oil skimmers can sometimes achieve the desired level of water purity. At other times, skimming is also a cost-efficient method to remove most of the oil before using membrane filters and chemical processes.
Theory of Practice Water
Skimmers will prevent filters from blinding prematurely and keep chemical costs down because there is less oil to process. More recently, Gambrill et al. Higher removal rates are possible with industrial wastes, particularly those containing significant quantities of organic settleable solids.
Of course, other environmental conditions in the ponds, particularly pH, must be suitable for the anaerobic microorganisms bringing about the breakdown of BOD.
In certain instances, anaerobic ponds become covered with a thick scum layer, which is thought to be beneficial but not essential, and may give rise to increased fly breeding.
Solids in the raw wastewater, as well as biomass produced, will settle out in first-stage anaerobic ponds and it is common to remove sludge when it has reached half depth in the pond. This usually occurs after two years of operation at design flow in the case of municipal sewage treatment.
Facultative Ponds The effluent from anaerobic ponds will require some form of aerobic treatment before discharge or use and facultative ponds will often be more appropriate than conventional forms of secondary biological treatment for application in developing countries.
Primary facultative ponds will be designed for the treatment of weaker wastes and in sensitive locations where anaerobic pond odours would be unacceptable.
Solids in the influent to a facultative pond and excess biomass produced in the pond will settle out forming a sludge layer at the bottom. The benthic layer will be anaerobic and, as a result of anaerobic breakdown of organics, will release soluble organic products to the water column above.
Organic matter dissolved or suspended in the water column will be metabolized by heterotrophic bacteria, with the uptake of oxygen, as in convential aerobic biological wastewater treatment processes. However, unlike in convential processes, the dissolved oxygen utilized by the bacteria in facultative ponds is replaced through photosynthetic oxygen production by microalgae, rather than by aeration equipment.
Especially intreating municipal sewage in hot climates, the environment in facultative ponds is ideal for the proliferation of microalgae. High temperature and ample sunlight create conditions which encourage algae to utilize the carbon dioxide CO2 released by bacteria in breaking down the organic components of the wastewater and take up nutrients mainly nitrogen and phosphorus contained in the wastewater.
This symbiotic relationship contributes to the overall removal of BOD in facultative ponds, described diagrammatically by Marais as in Figure 8. Figure 8: Energy flows in facultative stabilization ponds Marais To maintain the balance necessary to allow this symbiosis to persist, the organic loading on a facultative pond must be strictly limited.
Even under satisfactory operating conditions, the dissolved oxygen concentration DO in a facultative pond will vary diurnally as well as over the depth. Maximum DO will occur at the surface of the pond and will usually reach supersaturation in tropical regions at the time of maximum radiation intensity, as shown in Figure 9. From that time until sunrise, DO will decline and may well disappear completely for a short period.
Preview Unable to display preview. Download preview PDF. References 1. CrossRef Google Scholar 2. Ming, F. Mumpton eds.
Google Scholar 3. Mucsy, G. Google Scholar 4. Sherry eds. Google Scholar 5. Surf Sci Catal. CrossRef Google Scholar 6.Brine treatment systems are typically optimized to either reduce the volume of the final discharge for more economic disposal as disposal costs are often based on volume or maximize the recovery of fresh water or salts.
The relative numbers of different genera and their dominance in a facultative pond vary from season to season throughout the year but species diversity generally decreases with increase in loading. However, energy consumption is high and corrosion may be an issue as the prime mover is concentrated salt water. Mucsy, G. Iron and steel industry[ edit ] The production of iron from its ores involves powerful reduction reactions in blast furnaces.
Removal of toxic materials[ edit ] Toxic materials including many organic materials, metals such as zinc, silver, cadmium , thallium , etc.