Among the most important distribution systems in the hospitality industry water is the most important amongst all and generally, water provides a public utility similar to electrical energy. Hospitality industries are totally dependent on the supply of potable water and sanitary drainage network system. The primary sources of freshwater are lakes, rivers, and groundwater. Due to pollution affects rivers and lakes are not considered as source and finally the only source remains as groundwater. Again due to the scarcity of groundwater, there is also a need for recycling and conservation.
Water is classified as hard and soft depending upon its behavior towards soap solution.
Soft water: Water that readily forms lather with soap is called soft water. Rainwater, pond water, distilled water, etc. are examples of soft water. Soft water is slightly acidic.
Hard water: Water that does not easily form lather with soap is called hard water. Seawater and groundwater from tube wells are sources of hard water. Hard water is alkaline in nature.
Advantages of soft water
- Soft water consumes less soap for cleaning clothes.
- It is good for cooking, imparting good taste to cooked food.
- Soft water does not produce crust or deposit any scale in the pipe or other equipment that uses water.
Disadvantages of soft water
- Soft water is usually less palatable to drink due to a lack of minerals.
- Soft water does not provide vital minerals such as calcium and magnesium necessary for the body.
Advantages of hard water
- Hard water provides a good taste for drinking.
- It provides vital minerals necessary for the body.
Disadvantages of hard water
- The use of hard water causes wastage of soap and detergents. On average, hard water will destroy about 3 lb of soap per gallon of water. This also shortens the life of clothing and textile materials in the laundry.
- Scale is precipitated out of such water, which forms thick white crust (called scaling) inside pipes that carry them. This crust or scale a) gradually reduces the internal diameter and size of pipes, b) lowers the efficiency of the heating system by retarding the transmission of heat from the furnace or heating coil to the water inside the pipe, and c) interferes with the functioning of flow control valves in the pipeline.
- Hard water is not suitable for the paper, sugar, textile, and pharmaceutical industries
- Some people complain of dry skin after bathing in hard water.
Hardness of water
Total hardness is a test for overall water quality. There is no health concern associated with it. The degree of hardness is generally defined as calcium carbonate, equivalent of calcium and magnesium ions, present in water and is expressed in mg/L. In simple terms, hardness is a measure of how much calcium (and to a much lesser extent, magnesium) is in the water. Water hardness industry measures it in grains per litre, where 1 grain/litre = 64.72 mg/L.
pH value of water
The pH value of water is calculated as the logarithm of the reciprocal of hydrogen ion concentration (power of hydrogen and hence the term pH) present in water. It is, thus, an indicator of the acidity or the alkalinity of water. If pH of water is above 7, it will be alkaline and if it is less than 7, it will be acidic. The maximum acidity will be at zero value of pH and the maximum alkalinity will be at a value of pH equal to 14. Although pH value and hardness do not indicate the same property of water, the presence of carbonate ions in water (sometimes called ‘carbonate hardness’) pushes it towards alkalinity, and hence hard water is likely to have a high pH. A pH greater than 8.5 could indicate that the water is hard. Since measurement of pH is relatively simple, this could act as a reliable method to test the hardness of water.
The hardness of water is mainly due to the presence of dissolved bicarbonate (HCO3–), chloride (Cl–), and sulfate (SO42-), salts of calcium (Ca), magnesium (Mg), and iron (Fe). Sodium (Na) salts do not cause any hardness. All these salts that cause hardness to come from the rocks, get dissolved in the groundwater by way of rainwater percolating through the rock.
Ordinary soaps are mainly sodium and potassium salts of organic fatty acids such as stearic acid, palmitic acid, and oleic acid. When soap is added to hard water, calcium and magnesium salts dissolved in water react with the salts in the soap and form insoluble scum. The reaction occurs-
Na/K stearate/palmitate + Ca/Mg salt → Ca/Mg stearate/palmitate + Na salt
(soap salt) (hard water salt) (insoluble scum)
No soap in the mixture (mixture of hard water and soap) will form lather till all the salts present in the hard water are removed as scum. Thus soap is consumed without producing lather needed for cleaning clothes, resulting in a great wastage of costly soap. Synthetic detergents can overcome this problem as they form soluble salts of Ca and Mg and do not form a scum or soap curd.
Types of hardness
Depending upon the nature of the dissolved salts, hardness maybe
- Temporary or carbonate hardness
- Permanent or noncarbonate hardness
Temporary hardness- It is caused by the presence of dissolved bi-carbonates of calcium [Ca (HCO3)2].
Permanent hardness- It is caused by the presence of chloride and sulfate salts of calcium and magnesium like calcium chloride (CaCl2), calcium sulfate (CaSO4), magnesium chloride (MgCl2), and magnesium sulfate (MgSO4)
The reduction or removal of hardness from water is known as water softening. It is done mainly for the reduction in soap consumption, lowering the maintenance cost of plumbing fixtures, boiler tubes, and to improve the taste of food, etc., and saving energy.
The permissible hardness for public supplies normally ranges from 75 to 115 mg/L (14.25 mg/L is equivalent to one degree of hardness. Different methods for removal of hardness are shown below:-
The temporary hardness of water can be removed either by boiling or by adding lime to the water. The chemical reaction takes place (in boiling process) as
Ca(HCO3)2 + Heat → CaCO3 ↓ + CO2 ↓ + H2O
(Calcium bicarbonate) (Calcium carbonate, insoluble)
Mg(HCO3)2 + Heat → MgCO3 ↓ + CO2 ↓ + H2O
(Magnesium bicarbonate, insoluble)
The chemical reaction takes place (in addition of lime or Clarke’s process) as
Ca(HCO3)2 + Ca(OH)2 → 2CaCO3 ↓ + 2H2O
(Calcium bicarbonate) (Hydrated lime) (Calcium carbonate, insoluble)
Mg(HCO3)2 + 2Ca(OH)2 → Mg(OH)2 ↓ + 2CaCO3 ↓ + 2H2O
There are six methods for removing permanent hardness like,
- Washing soda process
- Base exchange process (or Zeolite process)
- Lime soda process
- Caustic soda process
- Ion-exchange process or demineralization(DM) process
- Calgon process
- The chemical formula of washing soda is Na2CO3. The reaction takes place when washing soda is added to hard water is
Na2CO3 + CaSO4 → CaCO3 ↓ + Na2SO4
Na2CO3 + MgCl2 → MgCO3 ↓ + 2NaCl
2. Hardness can be very effectively and economically removed by using a chemical called zeolite. A zeolite softener resembles a sand filter. The hard water enters the softener from top react with the zeolite and the softened water is collected through the strainer at the base. The reaction takes place as
Na2Z + Ca or Mg salt → Na2 salt + Ca or Mg zeolite
(Sodium zeolite/active zeolite) (Hard water salt) (Exchanged or used zeolite)
After a few days of operation, all the active sodium zeolite changes to used calcium and magnesium zeolite. These can be converted back to the active sodium zeolite by reacting it with a 10 percent solution of sodium chloride (common table salt solution). This process is known as regeneration. The reaction takes place as
CaZ / MgZ + 2NaCl → Na2Z + CaCl2 / MgCl2
(used zeolite) (sodium chloride (regenerated (dissolved salt removed by
Solution) zeolite) flushing water)
Advantages of zeolite process-
- Zero hardness can be obtained and have specific uses in textile industries, boilers, etc.
- The plants are compact, automatic, and easy to operate.
- The running, maintenance, and operation (RMO) cost is quite less.
- It also removes iron and manganese from water.
- There is no problem in treating water of varying quality.
3. In the lime soda process, in addition to washing soda lime is added to remove temporary hardness. Hydrated lime reacts with bicarbonates of Ca and Mg.
4. Caustic soda can be used to remove both carbonate (temporary) and non-carbonate (permanent) hardness. This process is very efficient for low alkalinity water. Calcium and magnesium hydrogen carbonates react with caustic soda to produce insoluble calcium carbonate and magnesium hydroxide. The reactions are-
2NaOH + MgSO4 → Mg (OH)2 ↓ + Na2SO4
2NaOH + CaCl2 → Ca (OH)2 ↓ + 2NaCl
4NaOH + Mg (HCO3)2 → Mg (OH)2 ↓ + 2Na2CO3 + 2H2O
2NaOH + Ca (HCO3)2 → CaCO3 ↓ + 2Na2CO3 + H2O
5. There are many types of equipment in the industry like water boiler, other process equipment, and scientific apparatus water boiler, and others to produce insoluble calcium carbonate and magnesium hydroxide which need water free of minerals. The process by which the minerals are removed is known as demineralization (DM) and the plant is known as the DM plant. It is very suitable for producing water of any desired hardness or even mineral-free water. The demineralized water is sometimes called deionized water and is as pure as distilled water.
The process consists of passing the water through cation exchange resins, which produce almost similar effects as are produced in the zeolite process, except that hydrogen (instead of sodium) is exchanged for the basic metallic ions. The cation exchange resins in fact are phenol aldehyde condensation products whose chemical formula is H2R (H represents hydrogen ion and R represents the organic part of the substance). The reaction takes place as below:
Ca (HCO3)2 + H2R → CaR + 2H2O + 2CO2 ↑
(fresh cation exchange resin) (exchanged or used resin)
Na2CO3 + H2R → Na2R + H2O + CO2 ↑
6. Calgon is the trade name of a complex salt, sodium hexametaphosphate (NaPO3)6. Calgon ionizes to give a complex anion, which subsequently combines with Ca and Mg ions in hard water.
(NaPO3)6 or Na2 (Na4P6O18) → 2Na+ + Na4P6O182
In addition of Calgon to hard water causes the calcium and magnesium ions of hard water to displace sodium ions from the anion of Calgon according to the following reaction:
CaSO4 + Na2 (Na4P6O18) → Na2SO4 + Ca (Na4P6O18)
This results in the removal of calcium and magnesium ions from hard water in the form of a complex compound with Calgon and thus the water softened. Sodium salts are released into the water without causing any hardness. It is being dosed into the water used for washing machines, dyeing work, etc.
Water distribution system
In cities and towns normally water is supplied by civic bodies through public water lines. It is required to have a storage reservoir on top of the building. The civic body charges the establishment for water consumption either lump-sum or through recording of consumption by water meters. However, many hotel units particularly in isolated areas find it economical and convenient to have their own bore well pumps within the premises that provide raw water which is further treated for consumption. But nowadays lifting of groundwater through the digging of wells needs permission from government departments. A hotel establishment needs a lot of water for various essential functions. An average figure will be 200 liters (about 50 gallons) per person per day.
Coldwater is used for diverse functions in a hotel like:-
- Cooking in the kitchen
- Kitchen, restaurant, and lavatory wash sinks and washbasins
- Lavatory flush
- Estate and floor cleaning purposes
- Fire-sprinkler system
- Cooling the diesel generating set, refrigeration plant, etc.
- Hot water and boiler make up water
- Gardening etc.
- In swimming pool and other water bodies, if any.
In India central-room heating is not required and hotels normally do not use such systems. Hot water is used for laundry purposes and kitchen, throughout the year and for the personal use of the guests, particularly during the winter season in hotels in plains and throughout the year for hill-station hotels.
Water quality requirements are different for different uses in the hotel industry. For example, water lines for drinking, kitchen, and washbasins/sink must be supplied with bacteria-free soft water, while laundry and other functions can work with plain soft water. In modern establishments, a laundry line is connected with the drinking water line. Lavatory washbasin and water closets (WCS) may be provided with only soft water. In many modern units, wastewater is collected, treated, and recycled. Rain-water harvesting has assumed great importance and in many establishments, this may supplement the main water supply system.
There are several water distribution systems used in hospitality and catering industries, like
- Upfeed system
- Upfeed system with circulating pumps
- Downfeed system (cold water only)
- Downfeed circulating system
- Combination system
- It is the most commonly used water distribution system where the pressure of water is sufficient to force water throughout a hotel building of six floors or less in height. The maximum number of floors that can be fed with this system depends on pressure, the resistance of pipe, and the height of the building.
- This system is used when the water pressure is inadequate and a circulating pump along with a return pipe is installed to increase water pressure and water to flow constantly throughout the system. This is frequently used on hot water lines to provide an adequate supply of hot water by making a provision of the water heater.
- Here water is forced or pumped to a storage tank (overhead) located on the top floor of the building. When water is required, it flows by gravity from the storage tank to the tap. This system is used in very tall buildings.
- It is very similar to the circulating puffed system. This technique is frequently used with hot water to ensure an adequate amount of hot water at each fixture.
- It is a combination of speed and down feed systems. The feed system is used for the lower building levels and the downfeed system for the upper building levels. This system is probably the most efficient distribution system for multiple-floor hotel buildings because main water supply pressure is utilized to the full extent and additional pressure is generated by pumps to reach water on the water storage tank located on the top floor of the building.
The normal hot-water temperature requirements in the hospitality industry are:-
- 110 degrees Fahrenheit or 43.3 degrees Celsius for domestic use.
- Normal personal washing: 140 degrees Fahrenheit or 60.0 degrees Celsius.
- Food production sinks 160 degrees Fahrenheit or 71.1degree Celsius.
- Dishwashing: 180 degrees Fahrenheit or 82.2 degrees Celsius.
- Pools and spas: 80-100 degrees Fahrenheit or 26.7 – 37.8 degrees Celsius.
- It is highly recommended to label fixtures supplied with water above 120 degrees Fahrenheit or 48.9 degrees Celsius with a warning that the water is hot and dangerous.
Swimming Pool Maintenance
Swimming pool design, construction and maintenance are controlled by local development authorities in coordination with public health department. The equipment and their utility connections are frequently tested by these departments.
The fundamental pool device is the filter. The filter removes impurities from water and keeps clear and sparkling. The true test of adequate filtering is to toss a small coin into the pool at its average depth and to be able to distinguish one side of the coin from the one it rests on at the bottom of the pool. The filter must cycle pool water every six to eight hours. Water turnover cycle consists of forcing all the pool water through the filter in a specified time period. In a normal operation, one water cycle is required each day. If swimming activity increases, more than one water turnover cycle may be required. Normally, pool water is used for cleaning the filter and filters are cleaned by back washing. The instructions given by the manufacturer of the filter should be followed, as there is no set schedule of cleaning of filters.
Swimming pool should be cleaned from time to time from debris, leaves, insects and soil by using various types of nets. The pH level of pool water should be between 7.2 and 7.6 or slightly alkaline. If pH exceeds 7.6 then there is a chance of developing water algae which may cause skin and mucous-membrane irritations to swimmers. If pH level falls below 6.8 metal equipment may corrode. Shock treatments are used to kill algae. Shock treatment means increasing the level of disinfectant from 1 part per
million of bromine to 5 parts per million (in case of chlorine it is 2 parts per million to 10 parts per million). In case of excessive growth of algae the pool must be cleaned after draining the water with acid chemicals known as acid washing.
Fittings in water distribution line
There are some important water line fittings such as valves, taps, cocks, tee, socket, nipple, bend and flushing cistern which are always present in any water-distribution line of a hotel. Valves and cocks are kept to a minimum in hot water line.
Valves, taps and cocks are fittings in water lines to regulate flow through the lines and are integral parts of any water-distribution system. The function of a valve is the same as a tap, i.e. to open and close or control flow of water through a line. The word tap is used when the valve is small in size and fitted just before any service utility such as basin, sink, shower etc. The flow of water in large pipelines is controlled by valves.
A tap is what we see at the draw-off end of water service line. They are normally screw-down type valves. Depending upon the directions of water entering the tap and coming out of tap they may be categorized as Bib tap, Pillar tap, Globe tap etc. Bib tap has a horizontal inlet and free outlet in the form of a bent tube called bib which prevents dust from entering into the free end and contaminating water when it comes out. Pillar tap has a vertical inlet and horizontal outlet through a bib. These are used in lavatory basins and baths. Globe tap has a horizontal inlet and vertical outlet, were used in baths and now replaced by pillar taps.
Cocks are normally plug-type valves and are quickly closed by a quarter turn of the knob as in a gas cock. This is used in a cold water system at the entry point of the civic water line into the premises and is called stopcock.
The term ‘valve’ is normally used to indicate controlling and most often for stopping or fully opening supply to a line and fitting. While stopcocks are plug type, valves may be screw-down type or sliding-plate type (like gate valve).
There are pipe fittings to facilitate layout of pipelines for branching (tee), joining of two pipes (sockets, nipples) and change of direction of pipelines (bends).
Flushing cisterns are normally of two types – Plunger and siphon type, Bell type. Both are supplied with cold water through ball tap and fitted with an overflow discharge outlet.