Hotel Engineering & Maintenance- Unit 3 Notes with Different Resources

UNIT-3 NOTES

HOTEL ENGINEERING & MAINTENANCE

WATER MANAGEMENT SYSTEM

MAJOR SOURCES OF WATER

 Rivers
 Lakes
 The Sea
 Rainwater
 Wells
 Artificial Lakes
 Recycling Water

SOURCES OF WATER-CATEGORY
 There are two sources of water
 Surface sources, e.g. rivers, lakes, ponds, etc.
 Ground water taken out by water pumps, tube wells etc.
 Recycled water e.g. treated wastewater used in hotels for washing and other uses than drinking or cooking.
 Generally, surface water are found to be more potable than ground water if the bore-well is not been drilled until the water table beneath the earth.
 As the primary source of fresh water are rivers, lakes, and ground water. If rivers and lakes become polluted, our water resources become seriously restricted because more water must be extracted from the ground. This presents a potential problem, which could limit growth of hotel in some areas.
 The water table in many areas is falling public works department to drill deeper wells to obtain increasing amounts of water. In effect, we are using ground water faster than nature can replenish it.
 Water may have to be treated to make it potable (Drinkable), that is, safe for human consumption.
 The treatment process depends on the number and types of water impurities and the rate at which potable water is desired. These can costly process. The distribution network supplies water to where it is needed.
 The drainage network collects unwanted or waste water and delivers it to a treatment plant, where it can be treated, thus preparing it for recycling.

Water Hardness
 Water Hardness is a measure of the amount of calcium and magnesium salts in water. The more calcium and magnesium in water, then it means harder the water. Water hardness is usually expressed in milligrams per litre (mg/l) of dissolved calcium and magnesium carbonate.

WATER HARDNESS TABLE

Soft Water	0-17 mg/l of minerals
Slightly Hard Water	17-60 mg/l of minerals
Moderately Hard Water	61-120 mg/l of minerals
Hard Water	121-180 mg/l of minerals
Very Hard Water	More than 180 mg/l of minerals

HOW TO REMOVE WATER HARDNESS

Chemical Process of Boiling Hard Water
 Boil water to remove temporary hardness.
 Temporary Hardness in water can be easily removed by boiling.
 After Boiling Calcium/Magnesium, bicarbonate decomposes to give calcium/magnesium carbonate, which is insoluble in water. That's why it comes out.
Addition of Lime (Clarke’s Process)
 The calculated amount of lime (CaO) or, more generally, hydrated lime is added to the water. The calcium carbonates and magnesium can be removed in sedimentation tank.
 Calcium hydroxide is Clark’s reagent (mixture). It removes the hardness of water by converting bicarbonates into carbonate.
WASHING SODA PROCESS
 Hardness of water means presence of salts of calcium and magnesium. This salt decreases the efficiency of cleansing action of soap.
 To remove the hardness we used to add washing soda which result that calcium or magnesium ion react with Na2CO3 to form insoluble compound (Ca or Mg) which precipitates (Solution to solid) out.
BASE EXHCANGE PROCESS- ZEOLITE PROCESS
 Zeolite (A Green Salt/Green Sand) is a naturally available salt, which reacts with salts in hard water and forms insoluble salts of Ca and Mg.
LIME SODA PROCESS
 In this process, in addition to washing soda, lime is added to remove temporary hardness.
CAUSTIC SODA PROCESS
 Caustic soda can be used to remove both hardness:
   Carbonate (Temporary)
 Non-Carbonate (Permanent)
   Calcium and magnesium hydrogen carbonates react with caustic soda to produce insoluble calcium carbonate and magnesium hydroxide.
Ion Exchange by Resin/Demineralization
 The process by which the minerals are removed is known as demineralization (DM) and the plant is known as DM plant.
Calgon Process
 The addition of Calgon to hard water causes the calcium and magnesium ions of hard water to displace sodium ions from the anion (Negative Charge) of calgon.
 In this method, the hardness in water is removed by the adsorption of Ca++ and Mg++ ions.
Some of the most common signs of hard water include
 Linens and clothes look dull and feel rough.
 Ugly stains on white porcelain and scale build-up on faucets
 Low water pressure from showers due to clogged pipes.
 Chalky, white residue or spots appear on dishes.
 Strains appearing in the shower.

WATER SUPPLY
From Main:
 This is the water supply from the public works department, either from the water reservoirs or from deep wells.
 A water main is buried underground just outside the building water supply line.
 The main pipe of the building water pipe line is fixed to the water main, with a gate valve and water meter attached to it.
 The amount of water you pull from the main will pass through the water meter.
 The water meter works on the principle of pressure and time period the water passes through it, for the reading.
From Wells:
 If the facility of mains supply is not there, water may be pumped from a deep well, drilled on your on land use area. The pump when pulls the water from underground, mechanical energy is converted to water pressure.

WATER DISTRIBUTION SYSTEM
Up feed system
 When the water supply pressure is adequate to force water throughout a building with floors.
 The maximum number of floors that can be serviced with this system depends on the water pressure at the main, fixture pressure requirements, piping resistance, and the height of the building.
 When water pressure is inadequate either in main or deep well pump, circulating pump is installed in the supply line to raise the water pressure, to overcome piping resistance or building height.
This system is frequently used on hot-water lines to provide an almost zero wait time for hot-water supply.

Down feed system
 Water is forced or pumped to a storage tank locate above the highest fixture level. When water is required, it flows by gravity from storage tank to the fixture. For hot water supply in tall buildings, down feed system are fitted with circulating pumps in the line to ensure adequate amounts of hot water at each fixture.

Combination systems
 The up feed system is used for lower building levels and the down feed system for upper building levels. This system is effective distribution system for multiple-floor buildings because water main supply pressure is utilized to the fullest extent and pumps and an upper water storage tank provide additional pressure for the upper levels.

Swimming Pool

 It’s of paramount importance for operators to ensure their pool is clean and safe.

 In order to fight off harmful bacteria, pools need to maintain adequate pH levels. This measures the acidity of the water. Ideally, the swimming pool should have a pH level of 7.4, which helps with chlorine disinfection.
 If pH levels aren’t maintained, it could lead to harmful bacteria breeding within the water. This would obviously cause a huge safety concern for users of the pool.
Swimming Pool Parts
 Water Inlets—Plumbing jets where filtered water enters the pool. Inlet jets direct the water in a counter clockwise motion around the pool.
 Skimmers—Water-level basket holders with plumbing leading water out of the pool into the internal piping system leading back to the filters. Fill water must be regulated to keep the pool water at the optimum level; otherwise, a low water level will cause air to be drawn into the closed liquid loop and the circulating system will cease to operate.
 Skimmer Baskets—These are catch baskets (4 are shown) designed to fit into skimmers where surface debris can be caught and removed from water. The counter clockwise circulation of the surface water will cause most debris to pass into one or more of the skimmer baskets. Baskets holding the debris can be lifted out and emptied periodically.
 Main Drain—Located at the bottom of the deepest point in the pool, drains debris off the bottom of the pool, or can be used to drain the pool entirely, if necessary.
 Drain Manifold—Collects water from all drain lines returning water from the pool to the filter. Manifold has a regulating valve on each line for controlling the volume of flow from each returning line. Valves are usually adjusted to regulate an even flow through each skimmer with a partial flow through the main drain. Main Trap—May be opened and the trap basket emptied of any debris that was missed by the skimmer baskets (small rocks, etc.), before water enters the pump.
 Pump—Creates the positive pressure that forces water through the filter and back through return lines to the pool. The pump also creates the negative (vacuum) pressure on the circulation system that brings water through the skimmers and drain from the pool.
 Pool Heater— To make water warm
 Pool Vacuum - A vacuum foot with two connections—s— one for a pole that gives the user access to the bottom of the pool in deep water, and the other that connects to a length of hose that can reach the surface of the water and fit into one of the skimmers. By adjusting the valves at the manifold, all vacuum pressure may be directed to only one skimmer to which the vacuum hose is connected. This provides a total vacuum capability to the location where the vacuum foot is directed at the bottom or side of the pool. This procedure should be done when needed or at least once a week.
 CAUTION: When attaching a vacuum hose to the skimmer inlet, the pump should be turned off. If the pump is running, the force of the vacuum in the skimmer is strong enough to capture and break fingers.

Sizes of Swimming Pool
 Swimming pools can be found in all sizes and shape. A very good size could be 35 ft X 70 ft X 12 ft deep. It will hold about 30,000 gallons of water and will have a plumbing system.

SWIMMING POOL MANAGEMENT SYSTEM
 To keep the pool water transparent, sparkling and free from dirt, filtered water must be used.
 After a specified period of time, usually as recommended by a local public health authority, entire water content should be cycled through the filter.
 To ensure proper functioning, the filtration equipment must be cleaned periodically according to o a maintenance schedule.
 The process of cleaning the filters is known as backwashing.
 Different types of nets are used to remove floating objects and also large objects that are settled at the bottom of the pool.
 In some pools, the pool water is continuously kept in motion where it passes through the filter and all unwanted floating objects are trapped in the filter.
 Chemicals are added to the pool water to maintain the proper hygienic conditions.
 Disinfectants are added to make the water bacteria-free.
 The dosing can be done manually or may be automated.
 To maintain the correct pH level appropriate chemicals are added.
 The pH is normally maintained between 7.2 to 7.6.
 Algae, which are water plants that grow in water, are also very difficult to eliminate. If their growth is not hampered by disinfectants, they are to be manually removed.
 Water is supplied to the pool by the water treatment plant in the hotel.

Calculation of Water Requirements

 The total water requirement is calculated from the previous energy database available of your own property and other existing hotels in the area.

GALLON: 3.785 LITERS 

 By the available database, the assumption as per the following parameters is done:
 Water consumption per occupied guest room night. (Gallons of water per occupied room)
 Water consumption per guest room per year. (Gallons of water per room per year)
 Water consumption per square foot per year. (Gallons of water per square foot)
 Water consumption per Cover in the food service outlets and room service. (Gallons of water per cover)
 The estimates for a hotel are done per guestroom in the property.
 Variables for these requirements will be, laundering requirements, sewage requirements, ground irrigation, swimming pools, and direct consumption that is assumed not returned to sewage lines, e.g. drinking water, water for cooking, etc.
 Further, the water requirements is calculated based on ratio of water consumption between sewage and rest all other consumption.