FA2022_CHE304_M3L2-Farahalduweesh-Water-Treatment.pdf

Introduction to Environment Engineering DR. FARAH M. AL-DUWEESH CHE 304 1 Understanding Water FARAH M. AL-DUWEESH 2 What is Water made of ? FARAH M. AL-DUWEESH 3 What is Water made of ? H atoms O atoms FARAH M. AL-DUWEESH à Freshwater 4 Components added to water are due to taste mai...

Introduction to Environment Engineering DR. FARAH M. AL-DUWEESH CHE 304 1 Understanding Water FARAH M. AL-DUWEESH 2 What is Water made of ? FARAH M. AL-DUWEESH 3 What is Water made of ? H atoms O atoms FARAH M. AL-DUWEESH à Freshwater 4 Components added to water are due to taste mainly as long as they meet Drinking Water Standards “The additives being put in water are those naturally found in water and the quantities of these additives are likely too small to be of much significance.” States Marion Nestle, professor of Sociology at New York University. “If you had pure water by itself, it doesn't have any taste,” says Bob Mahler, Soil Science and Water Quality professor at the University of Idaho. FARAH M. AL-DUWEESH 5 Water In reality has additional components due to conditions surrounding it H atoms O atoms (freshwater) From seawater, ponds, lakes, rivers - Disease + - Germs - Viruses - Bacteria - Parasites = Contaminated Water FARAH M. AL-DUWEESH 6 Some are beneficial and some are harmful Can be kept Have to be removed à Need to Treat It FARAH M. AL-DUWEESH 7 Before we Treat it we have Standards to follow for Safe Drinking Water Drinking Water Standards Primary To ensure safe water with no toxins - Federal enforced by US EPA - Tables 6.1A-6.1F in textbook FARAH M. AL-DUWEESH Secondary Not related to health; but to the physical form of water (i.e. color, odor and taste ) - Nonfederal enforced 8 Majority is Inorganic components and Microbial organisms FARAH M. AL-DUWEESH 9 Water Characteristics Constituents can be found in water, may be classified as • Physical •Chemical •Biological FARAH M. AL-DUWEESH 10 Inorganic Components Includes knowing about • pH Level (alkalinity and acidity) •Nitrogen •Phosphorus •Metals •Gas content FARAH M. AL-DUWEESH 11 pH Level and Understanding Acidity and Alkalinity Recap : List of major carbonate species : •Alkalinity : is the buffering capacity to resist a change in pH when an acid is added. (so neutralize an acid ) •Acidity: is the buffering capacity to resist a change in pH when a base is added. The Carbonate system is paramount in water chemistry - controls most of the natural waters pH level FARAH M. AL-DUWEESH 12 Other Important Components that cause alkalinity and their Occurrence in Water •Bicarbonate [HCO3-] •Hydroxide ion [OH-] Others present in water at lower concentrations are: •Ammonia, NH3 •Phosphates, HPO4-2, H2PO4•Hydrogen Sulfide, HS•Silicates, HiSiO3•Borates, H2BO3FARAH M. AL-DUWEESH 13 Some of those minerals can harm or dis-harm by becoming a contaminant 1) Nitrogen [N] •When present in excessive concentrations in surface water creates algae growth and cultural. •The primary drinking water standard for nitrate (NO3) is 10 mg/L •The process to remove ammonia (NH3) from wastewater is : - nitrification - denitrification - Ammonia stripping (using a solvent) FARAH M. AL-DUWEESH 14 Some of those minerals can harm or dis-harm by becoming a contaminant 2) Phosphorous [P] Are two Types : Organic-P and Inorganic P Proteins Orthophosphate Amino Acids Polyphosphate Metaphosphate Any compound that has a P or the phosphate ion PO43-. FARAH M. AL-DUWEESH 15 Some of those minerals can harm or dis-harm by becoming a contaminant 3) Metals – some are essential for microbial growth •The following metals are required for microbial growth: - Calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, potassium, sodium, tungsten, vanadium, and zinc. •Some can be toxic at high concentrations, therefore not all of them are acceptable in drinkable water FARAH M. AL-DUWEESH 16 Harmful Metals not allowed in Drinking Water FARAH M. AL-DUWEESH 17 Metals that are used in Water Quality Management and Treatment plants -Calcium (Ca) - Iron (Fe) -Magnesium (Mg) -Manganese (Mn) -Potassium (K) -Sodium (Na) FARAH M. AL-DUWEESH 18 Some of those minerals can harm or dis-harm by becoming a contaminant 4) Gases Some gases that may be dissolved in water or wastewater •Ammonia (NH3) - due to decomposition of bacteria -is toxic to fish at concentrations 0.02 mg/L •Carbon Dioxide (CO2) - primary carbon found in atmosphere as a result from respiration of humans and animals - remove it from water if concentrations ≥ 10 mg/L FARAH M. AL-DUWEESH 19 Some of those minerals can harm or dis-harm by becoming a contaminant •Hydrogen Sulfide (H2S) - colorless, flammable gas, with a rotten egg odor (death can occur at 300 ppm by volume in air) -occurs from the decomposition of organic matter that contain sulfur (S), or reduction of sulfates to sulfides under anaerobic conditions •Methane (CH4) - colorless, odorless, combustible gas forms primarily from the decomposition of organic matter under anaerobic conditions FARAH M. AL-DUWEESH 20 Some of those minerals can harm or dis-harm by becoming a contaminant •Fluorene (F2) - pale yellowish-brown, poisonous gas - Not used in its elemental form - Fluorides are compounds that combine fluorine (F) with other positively charged ions - fluorides have been added to drinking water in 1945 (recently) in U.S. , to prevent tooth decay - normal dose added 1mg/L if >1 mg/L à mottling teeth occurs FARAH M. AL-DUWEESH 21 Some of those minerals can harm or dis-harm by becoming a contaminant •Nitrogen (N2) - 78% of the atmosphere - found as N2 or N2O •Oxygen (O2) – the most essential element in water - some fish such as trout require 5 mg/L to survive FARAH M. AL-DUWEESH Human oxygen level 95% or higher 22 Biological and Microbiological Characteristics All natural bodies of water support biological ecosystems, some organisms are harmful or pathogenic (bacteria, virus or microorganism causing disease) Main microorganisms and most dangerous are: • Giardia lamblia , removal 99.9% • Cryptosporidium , removal required 99.9% FARAH M. AL-DUWEESH 23 There are two types of Bottled Water Spring Water Rich in trace minerals such as calcium and magnesium and is bottled at source. - Further treated at source to meet pollution standards - Surface water Mineral water Flows over and through rocks before reaching the bottling source. - More strict hygiene standards - Continuous regular testing (2 years of frequent biological testing) - Ground Water Source: Geological Survey, Ireland FARAH M. AL-DUWEESH 24 Water Treatment To provide Potable Water = water that is healthy for human consumption and free of harmful microorganisms and organic and inorganic compounds. FARAH M. AL-DUWEESH 25 Types of Water Treatments •Lime-Softening (Hardness Removal) •Sedimentation •Filtration •Adsorption and Desorption (separation units) FARAH M. AL-DUWEESH 26 Lime Softening Treatment (Hardness Removal) •Water Hardness is the amount of dissolved calcium (Ca+2) and magnesium (Mg+2) cations in water. •Hardness (precipitation of the divalent cations ) can be removed using lime-soda (CaO). •Removes As, Ba, Cd, Cr, F, Pb, Hg, radionuclides etc…] FARAH M. AL-DUWEESH 27 Water in the States vs. Kuwait Hard Soft FARAH M. AL-DUWEESH Kuwait’s water supply consists of distilled. sea-water and is “Soft.” Yet very saline. Source: Embassy of Kuwait-Rome 28 Sedimentation •Sedimentation : the process in which the majority of the particles will settle by gravity within a reasonable time and be removed. •Particles of density > 1000 kg/m3 will settle, < 1000 kg/m3 will float to the water surface. •Removes iron (Fe) FARAH M. AL-DUWEESH 29 Filtration Filtration : to remove small or precipitated particles. Two types of Water Filtration: 1) Granular Media Filtration 2) Membrane Filtration High-Rate filtration (large scale) Slow Sand filtration (e.x:homes) FARAH M. AL-DUWEESH 30 One of the Most Advanced Water Filtration Technology for large-scale is the Membrane Process •By 2007, over 20,000 membrane (including reverse osmosis ) plants were operating worldwide. •Membrane process: feedwater passes through a series of semipermeable filters/membranes, water gets purified and leaves a a permeate. •The driving force for constant water filtration through a membrane is Pressure gradient. FARAH M. AL-DUWEESH 31 Types of Membranes •Microfiltration (MF) •Ultrafiltration (UF) •Nanofiltration (NF) •Reverse Osmosis (RO) FARAH M. AL-DUWEESH Which is the best option and more expensive ? 32 RO is the tightest barrier that blocks all species combined or a Multistage Flash Distillation (MFS) is used to Desalinate Water Do we have a choice? FARAH M. AL-DUWEESH Decreasing Pore Size / Increasing Pressure 33 In 1951- Kuwait is the First Country in the World to Commission A Desalination Plant For Drinking Water Production using a Multistage Flash Distillation (MSF) The First Desalination Plant was a submerged tube plant located in Shuwaikh, in 1960 replaced with the first MSF desalination plant with capacity of 4546 m3/day. Source: MEW, 2019 FARAH M. AL-DUWEESH 34 Our Eight Desalination Plants in Kuwait •Most of the useable groundwater extracted in the southwest is brackish water. •Brackish water salinity of 2500- 5000 mg/L •Runoff infiltration occurs occasionally from intense rainstorms give rise to surface water in the northern part, at Raudhatain and Umm AlAish. FARAH M. AL-DUWEESH 35 Source: MEW, 2019 Our Eight Desalination Plants in Kuwait •Most of the useable groundwater extracted in the southwest is brackish water. •Brackish water salinity of 2500- 5000 mg/L •Runoff infiltration occurs occasionally from intense rainstorms give rise to surface water in the northern part, at Raudhatain and Umm Al-Aish. FARAH M. AL-DUWEESH 36 Source: MEW, 2019 We Consume A lot of Energy to Desalinate (Desalination is the most expensive water treatment in the World) = more electricity generation and extra heat The capacity of the power plant and desalination network in the country is estimated at 16,095 MW and 2 × 106 m3/day, respectively. Three major refineries process over 935,000 bbld, situated in the southern part of the country, collectively referred to as the refineries belt. Our desalination Plants consume 1,850,400 m3/day ~ 2 million m3/day 37 FARAH M. AL-DUWEESH 38 Source: MEW, 2019 Desalination •Video on desalination water treatment •https://youtu.be/xy-ZDZaetPY FARAH M. AL-DUWEESH 39 Source: MEW, 2019 Adsorption Process, Absorption and Desorption (Stripping) FARAH M. AL-DUWEESH 40 Adsorption Processes are widely used to remove organic and inorganic constituents from water and air. •Granulated Activated Carbon (GAC) and Powdered Activated Carbon (PAC) are widely used for removing Synthetic organic chemicals (SOCs) and odor compounds from drinking-water supplies. •Under Safe Drinking Water Act, the EPA has designed GAC as the best available technology for removing many organic and inorganic constituents from water supplies ( aresenic (As), SOCs and radionuclides.) FARAH M. AL-DUWEESH 41 Absorption Process is a process of adding a reactive gas to purify the liquid stream. •Removes dissolved gases such as NH3, CH4, H2S, CO2, VOCs and inorganics Fe2+, Mn2+. •Reactive gases added to water such as - Oxygen (O2); removes precipitated iron and manganese - Ozone (O3) ; removes iron, manganese, algae, color, odor and controls taste - Chlorine (Cl2) FARAH M. AL-DUWEESH 42 Desorption / Stripping •Removes gases such as radon, H2S, CO2, VOCs in the liquid stream. •By using a gas stream for removal usually air called Air Stripping. - Spray aerators -Nozzles Can be in multiple stages •EPA declared packed tower aeration as best available technology for removing VOCs and radon from groundwater. FARAH M. AL-DUWEESH 43 Desalination is said to be the future of water treatment technology •Desalination provides only around 1% of the world’s drinking water • Demand to desalination is growing annually since it is a drought-proof water supply and seawater is the most abundant (97% of earth’s water is ocean water) source of water supply. • Desalinated water is produced from either -Brackish water (salt content < 10,000 mg/L) or, -Seawater (salinity range 30,000 - 44,000 mg/L) FARAH M. AL-DUWEESH 44 Most Desalination Plants are in the Middle East and North Africa •At 2015, approximately 18,000 desalination plants worldwide with a capacity of 86.55 million m3/day. • 44% of this capacity is located in the Middle East and North Africa. It is growing in this region 7-9 % annually. •The main disadvantage for desalination is Cost FARAH M. AL-DUWEESH With advanced technologies and equipment cost has been cut down 80%. Source: iwa-network.org/desalination-past-presentfuture/ 45 Best Potable Tap Water in the World by Rank (Countries ) in 2017 1. Iceland 2. Greenland 3. Switzerland 4. Sweden 5. Australia 6. Denmark FARAH M. AL-DUWEESH 7. Canada 8. Finland 9. Austria 10.Norway Source: Sieni Kimalainen, Hidropolitik Akademi 46 Worst Potable Tap Water in the World by Rank (Countries ) 1. Uganda 2. Ethiopia 3. Nigeria 4. Cambodia 5. Nepal 6. Ghana 7. Bhutan 8. Pakistan 9. Congo 10.Mexico Source: US News , 2019 FARAH M. AL-DUWEESH 47 Being fortunate with energy (affluent countries) can recycle/ retreat their water systems •In 2020, 74% of global population (5.8. billion people) had a safe water source on premises •Remaining over 2 billion people live in water-stressed countries, having contaminated water with faeces. Source: WHO, Drinking Water FARAH M. AL-DUWEESH 48 Only Countries of Energy (who have money) have the extra Energy to Reclaim/Reuse Water à Wastewater Treatment While, other countries still struggle to have a partial of energy/water supply. FARAH M. AL-DUWEESH 49 Farah M. Al Duweesh Assistant Professor of Chemical Engineering [email protected] FARAH M. AL-DUWEESH 50