Water Flashcards
(12 cards)
Elaborate on drinking water with reference to the ADWG
Drinking water is supplied by the tap and is treated and is for human consumption. Drinking water is used for cleaning clothes, food preparation, and human consumption, showering, bathing. However, it must go a considerable treatment. Regarding ADWG. The guidelines show what it is for suitable drinking water.
What is the deal with water
Water is an essential recourse for extracted from environment to support households, industry, drainage, sewage and mining.
Describe how water treatment changes on the intended use and source
Water is treated depending on its intended purpose. The method to disinfection and information for safe and healthy drinking water. For hard saline water it undergoes desalination. For fresh soft water it is conventional.
Outline the brief steps of conventional water treatment
Conventional water treatment involves coagulation. The silicate particle charges are neutralised so they can form larger particles and settle or be filtered. Flocculation involves the agitation so larger particles can form large masses which settle or filtered from a solution. Sedimentation involves allowing the sediments to settle, it is allowed for numerous hours for it to occur. The solution can then be transferred to filtration tank, sediments are treated before disposal. Filtration water transfers through several filters to remove impurities. Disinfection. Water is treated using chemical agents or uv radiation. Storage, water is transferred to storage tanks to allow for suitable storage so it can be used for high use during rural or domestic period consumption.
Water filtration is depending on its intended use and origin. Suspended matter is removed from fluctuation, sedimentation then filtration. The surface of fine silicate and aluminium silicate in clays is negatively charged and can made to larger particles with addition positive highly charged cat ions such as aluminon ion and polymers
What is the deal with flocculation and coagulation
Dissolved and suspended particles are present in untreated water. The particles are from land erosion. The silicate clay minerals, decaying organic matter and sand enter the water through wind and water flow causing soil erosion. The silicate clay particles are negatively charged causing water repel and they go to suspend in the water. Coagulation and filtration remove suspended clay in the water. Coagulation involves coagulants with high charge cation or cationic polymer to remove the charge where they can insoluble mass called floc which are insoluble and can be removed through sedimentation and filtration. Coagulants include iron (iii) chloride aluminium sulphate and polyDADMAC. Raw water becomes more transparent.
What is the deal with using chlorine for water treatment
Hypochlorous acid, chlorine and hypochlorite’s are oxidisers used in water treatment. Raw water contains microorganisms that may cause infectious diseases. Thus, after sedimentation, fluctuation and coagulation, and filtration the water is treated to kill microorganisms (disinfectants). Chlorine atoms are used as they are strong oxidisers, which can inhibit microbial growth by reacting with important biological molecules (proteins, coenzymes, nucleic acid, antioxidant and lipids) Chlorine is added and it reacts with water to form hypochlorous acid then ionises to hypochlorite ion with water, conjugate base of hypochlorous acid. Effected by equilibrium decrease increases it. Water soluble hypochlorite salts may also be added (sodium hypochlorite and calcium hypochlorite) through adding it then they form hypochlorite, then it forms hypochlorite ions when in water. Hypochlorite ions react with water to form hypochlorous acid.
How does magnesium decrease the effectiveness of soap
Magnesium and calcium reduce the effectiveness of soap. Hard water contains exceeding concentrations of calcium ions, magnesium ions and other ions. Magnesium and calcium leach to the lakes, rivers and reservoirs from water flow over the aquifer or acidic rain to dissolve carbonate and leach carbon to lake, river, ground water. Caused from minerals such as limestone, gypsum, dolomite and calcite. Decreases ability of soap. Which is an emulsifier. Grease and water are combined by emulsifier soap anion. Non-polar interacts with oil polar and polar interacts with water. Does not combine because negative charge of surface repels each other. Causes build-up of precipitation.
What is the deal with zeolites
Natural and modified zeolites can be used in purification of hard water softening it with through the exchange of cations.
Ions in hard water effectively reacts with the carboxylate for the micelles to neutralise it. Thus, their ability to form micelles is reduced. React with the soap an ion. Create the anions. Moreover, the neutralised carboxylate creates soap scum. The water becomes softer through removing ions in hard water. Zeolites and ion-exchange resins can be used to remove ions. Zeolite minerals are aluminosilicate compounds that are highly porous with a high surface area. The sodium is adsorbed to them the water is passed through and the sodium is exchanged with the ion in the hard water. Water flows over zeolite or ion-exchange. Weakly adsorbed sodium. Neutralisation of charge prevents formation of micelles. To recharge the ion-exchange or zeolite concentrated sodium chloride is passed through it and the sodium ions exchange the calcium and magnesium ions bound to the surface.
Outline how thermal distillation works
Water containing high amounts of minerals is called saline. It is commonly not safe for human consumption and agriculture use. It dehydrates animals. There are two methods of water desalination. Thermal distillation and reverse osmosis which involves water to be forced to pass through a semi-permeable membrane. Salt water is 97% of the water. Salt water is saline containing high amounts of minerals. Thermal distillation involves heating saline water to a boil then the steam can then be condensed to pure water recovering. Increasing agriculture use, population and increased climate change.
Outline the steps of reverse osmosis
Reverse osmosis
Water undergoes a process of desalination through going water desalination through osmosis. The process of osmosis involves the travel of water from a low solute level to a high solute concentration. The semi-permeable allows diffusion of certain molecules, whilst preventing entrance of other molecules such as dissolved ions. The process of desalination involves forcing water from a region of high solute concentration to a low solute concentration through the semi-permeable membrane. The process removes dissolved salts, heavy metal ions, microorganisms, organic compounds. Fresh water product has a 99 to 100% purity. Impurities are collected and removed when forced through semi-permeable membrane.
Society benefits of desalination
The desalination plants there are over 18 000, they provide water in water scarce areas. They are providing potable water for over 300 million people. The water plant has benefits but also flaws including. Including.
Disadvantages of reverse osmosis
Expenses:
The development, construction operation, maintenance of desalination plants.
Energy use:
Desalination plants use large amounts of electrical energy (for force in reverse osmosis) and thermal energy (thermal distillation) which is currently derived from non-renewable energy. Energy consumption increases greenhouse gas emissions contributes to global warming
Membrane fouling and scaling
The membrane pores become clogged with impurities including salts, silica and microorganisms and must be cleaned with hazardous chemicals or replaced.
Chemicals used in pre and post treatment: The input (saline) and output (fresh) water is treated using a range of chemicals to remove organic compounds, minerals, and microorganisms before and after desalination. The chemicals used in treatment are hazardous
Discharge of brine:
The concentrated solution (brine) from desalination is a waste material that is disposed of by discharging the material into the ocean. This discharge may affect marine plants and animals.
Toxic chemicals in the waste material.
The waste material is discharged may contain trace amounts of toxic material that may be harmful to marine life in the ecosystem where the waste is discharged.
Death of marine animals and important microorganisms.
Fish and other marine organisms are killed during the inflow of saline water from the ocean. Smaller organisms including plankton and fish eggs are killed during treatment of saline water inside the plant.
