Water & waste water systems

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Hospitality facilities require relatively large amounts of water and create large amounts of waste water as well. Water is used by hotels in guestroom areas for bathing and sanitary purposes. F&B operations use water for food preparation, cooking, and a variety of cleaning purposes. Laundry operations are also substantial consumers of water. Grounds and landscaping can consume significant amounts of water as well. Swimming pools require a substantial amount of water when filled and ongoing amounts to replace water lost to evaporation and other losses. Finally, operations with cooling towers can evaporate large amounts of water in their operation.

Usage of water in hotels can range from 40,000 gallons per room per year for economy properties to 80,000 gallons for upscale and as much as 150,000 gallons for resort operations. The variation is primarily due to the items dis cussed in the paragraph above (e.g. does the property have F&B, etc.)

Water costs are typically composed of a charge for water supply and a charge for waste water removal & treatment. In the US, total water costs typically range from $3 to $8 per 1000 gallons about 50% being supply charges. Water can be produced by the property itself from a well or other water source rather inexpensively. Water can also be produced by operation of a desalinization plant a very expensive but sometimes unavoidable option. In addition to the water cost itself, the cost of hot water is increased by the cost of the fuel. The result is that hot water can cost an additional $8 20 per 1000 gallons.

Water systems require water at a proper pressure and in adequate quantity. Pumps may operate on the water system within the building to provide pressure and quantity as needed. The hot water system also needs water supplied at an appropriate temperature. Many hotel operations in the US attempt to supply hot water at approx. 120 °F at the supply point with a target of approx. 115 °F at the actual point of use. Water for sanitizing purposes in F&B is generally produced at 140 °F with supplemental heating done at the point of use as needed.

Each usage of water within the building has requirements regarding the quality of the water. Water quality refers to the bacteriological, physical (taste, clarity and odor), radiological, and chemical characteristics of water relative to its safety for human consumption. Standards specify maximum contaminant levels that may occur in potable (drinkable) water. Quality water standards governing potable water in the United States (US) are set forth in the Safe Drinking Water Act of 1974; it was amended in 1986 and again in 1996. The law is enforced by the US Environmental Protection Agency. If the facility’s water comes from a source other than a public water utility, maintaining water quality becomes the responsibility of the hospitality manager.

If the water supplied by the water utility is potable, the operation does not need to do further treatment. However, sometimes this is not the case for the utility water or the property is supplying water from its own source. In this instance, the water treatment is needed. This treatment involves the removal of any suspended solids as well as some sort of treatment to kill bacteria. Bacteria are often killed using chlorine although in some locations this is done via ultra violet radiation or ozone. Sometimes there is a need for additional treatment as well to remove some other contaminants.

A common water treatment is softening. This is done to remove calcium or magnesium from the water. Removal of these minerals allows the water to more easily create a soap lather when bathing. It also reduces the chances of a mineral buildup on plumbing fixtures and of spotting on surfaces. There are also advantages of softening for water used in other equipment as is noted below.

Additional water treatment will be necessary for water supplied to boilers and cooling towers (CT), pools and laundry equipment in a facility. These additional specifications concern maxi mum allowable limits on hardness (calcium and magnesium), alkalinity, dissolved solids, suspended solids, dissolved oxygen, carbon dioxide, iron, manganese, silica, and micro organisms. If the equipment water quality is not controlled properly it can cause formation of inorganic deposits and corrosion in boiler tubes and CT, soap curd (scum) and fabric damage. Untreated or stagnant water in CT, air conditioning (a/c) drip pans, fountains, hot tubs, showerheads and faucets, etc. encourages algae formation that can foul pumps and equipment and foster bacterial growth that can lead to Legionnaires disease. Managers are responsible for ensuring that preventative maintenance is done on all a/c coils and that a/c pans are clean and treated. They are also responsible for insuring that proper chemical levels are maintained at all times in pans, hot tubs, indoor fountains and cooling towers. Showerheads and aerators should be cleaned or replaced on a schedule.

Waste water is the used water and solids from the facility flowing into a septic system or treatment plant. Storm water, surface water, and ground water are included in the definition of waste water and depending on location, they may also enter a waste water treatment plant. Waste water standards define maximum contaminant allowances rather than ‘‘quality’’ specifications. Of particular concern for discharged waste water is the water temperature, biological oxygen demand, and the amount of fat, oil and grease, total suspended solids, and micro organisms present.

In facilities there are essentially two waste water systems the sanitary sewer system and the storm sewer system. Additional subsystems may feed into these two systems. Bathroom, restroom and other waste water discharges flow into the sanitary sewer system, which are treated by the local or regional sewage treatment facilities. Kitchen discharges also flow into this system, but must first pass through a grease trap (grease separator) for grease removal. Circulating boiler and cooling tower water discharges ‘‘bleed streams’’ and laundry water discharges should also enter the sanitary sewer system. Chemical content of these two subsystems may have to be monitored to avoid surpassing waste water contaminant allowances.

‘‘Gray water’’ or ‘‘run off ’’ water from roof drains, parking lots, and other outdoor areas of the property enter the storm sewer system. This waste water may be diverted into holding ponds to be used for landscape or other outdoor watering systems. However, this water will also have contaminants that may have to be monitored.

Back flow prevention devices are installed in the main water line to a building just after the water meter. The devices are used to prevent a hotels water system from over pressurizing and forcing the water back into the municipality’s system. This can happen if a domestic booster pump has higher pressure than the municipality’s water pressure or if the municipal system were to lose pressure.

Backflow prevention devices are becoming a standard requirement in a majority of cities. Typically, annual or bi annual testing of the device is required by the municipalities or fines can be incurred, including having the water turned off at the meter.

References

Harrison, J. F., & McGowan, W. (1997). WQA Glossary of Terms. Lisle: Water Quality Association.

Kemmer, F. N. (Ed.). (1988). Nalco water handbook. New York, St. Louis: McGraw Hill.

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