Water Production and Recycling at the Radisson Blu Resort & Spa, Golden Sands
"Throughout our lives, we exist mostly as water. This connection to water applies to everyone, all over the world. So how can people live happy and healthy lives? The answer is to purify the water that makes up your body. Water in a river remains pure because it is moving. When water becomes trapped, it dies. Therefore, water must constantly be circulated. The water - or blood - in the bodies of the sick is usually stagnant. When blood stops flowing, the body starts to decay, and if the blood in your brain stops, it can be life threatening. We all have an important mission: To make water clear again, and to create a world that is easy and healthy to live in. In order to accomplish our mission, we must first make sure that our hearts are clear and unpolluted. If all the people of the world can have love and gratitude, the pristine beauty of the earth will once again return."
by Masuru Emoto - The Hidden Messages in Water
The tourism industry is an industry which makes use of high volumes of water. Without stretching ones imagination, one immediately visualises large swimming pools and frequent showers; but one can also mention large industrial kitchen equipment such as dish washers, irrigation of landscaped areas and last but not least water cistern flushings as areas where a large volume of water is used. Unfortunately in Malta water is a very scarce natural resource (average annual rainfall of about 600mm) and the artificial production of water is costly, not only in terms of money but also due to the fact that this process requires considerable amounts of energy which translates to burning of oil, CO2, air pollution, a contribution to the enlargement of the Ozone layer, the consequent changes in climate and evidently the adverse effects on the environment.
Way back in the years 2002/03 when the Radisson SAS Golden Sands Resort & Spa was still on the drawing board, these factors, together with others that were equally important, were being considered. As a result of these considerations, thousands of Euros were invested in order to reduce water wastage and in order to reuse as much water as possible. As a first step, the building was designed so that any potential water catchment areas that could be used to collect rain water were utilised for this purpose. No less that 5 large water reservoirs with a total capacity of 4300 cubic meters were constructed to be used as water storage space. This ensured the maximisation of the use of the little rain water that falls in the area. Three separate water pipelines run throughout the property. These are the first class water system, the hot water system and the second class water system. The first class water and the hot water pipelines distribute very high quality water to baths, showers, saunas, steam baths, Jacuzzis, wash hand basins and kitchen sinks. The three swimming pools and 7 water features on the resort, which together have a total capacity of over 1200m3 are also supplied from the first class water system. First class water and hot water are both supplied from the same source. This water is produced by two Sea Water Reverse Osmosis (SWRO) plants. Each SWRO Plant is capable of producing 180m3 per day and this is normally sufficient to meet the first class and hot water requirements of the resort. Sea water is pumped from any of three lined boreholes which are over 150m deep. The sea water is first coarse screened in a relatively small reservoir after which it passes through a sand filter and finally through a 10 micron cartridge type filter. Before the pressure is raised to 70 bar, its Ph is adjusted to 6.4. This ensures that the life span of the membranes is maximised. The post treatment of the product water includes chlorination and readjusting the Ph value to about 8.5. Each RO train incorporates a pressure recovery unit and a reciprocating swash plate high pressure pump. These render the equipment even more efficient and require only 3.6 KWhr of electricity to produce 1 m3 of water. Since the water is being produced on site, there are savings also in the transportation of this water. The average annual production of water by these two SWRO plants has been 50,000 m3. A number of parameters of both the feed water and the product water are monitored and controlled on a daily basis. For example the conductivity (purity) of the water produced varied between 200 and 300 micro siemens which is well below the threshold set by local and international regulators in this regard. The water produced is stored in a 1200 m3 reservoir at 19OC. The water temperature is also an important parameter that is monitored regularly as this could be a determining factor on the water quality delivered. Accredited third parties are also brought in to regularly sample and check on the water quality.
Second class water is used for flushing water cisterns and for irrigation of the surrounding landscapes. This water is mainly supplied from the Sewage Treatment Plant STP. This is capable of handling 380 m3 of waste water per day, although the maximum amount that was treated in 24 hours in peak season was 270 m3. In the three years that this plant has been in operation, it has treated an average of 30,000 m3 of waste per year. The weekly quantity of second class water produced by this plant is often more than the demand of the resort and more than 25% of this water is pumped into a nearby reservoir so that the Parks Department can make use of it. Essentially the Resort is passing on good quality irrigation water to the authorities for use in national forestation projects.
The STP consists of 4 cess pits serviced by two macerating sewage pumps each. The waste is pumped intermittently through a screen into a number of settling tanks. The heart of the plant consists of two Rotary Biological Contactor RBCs. These include a large number of closely placed PVC discs that are partially submerged and that are mounted axially on a slowly rotating shaft. Enzymes (biological growth) are cultured on these rotating discs and they are repeatedly cycled into the waste (in the lower sector) and in the air to breathe (in the upper sector). The flow is closely controlled so that as waste passes through this maze, the bacteria / enzymes eat away waste products and leave relatively clean water (Suspended solids 5mg/L, 5 day Biochemical Oxy Demand BOD 5mg/l). The water thus produced is then filtered and disinfected and finally stored in any one of three second class water reservoirs. Again the quality of this water is monitored and controlled on a daily basis and third parties are brought in regularly to ensure that this water is of the right quality. In this case the most important parameters to monitor are free chlorine level, BOD and turbidity. This plant does not need any compressed air and leaves very little residual solid waste. The settling tanks need desludging about once every two years, although this frequency is dependent on the quality of the influent.
These two systems, that is, the Sea Water Reverse Osmosis Plant and the Sewage Treatment Plant and their auxiliaries, render the Resort self sufficient for its water supplies and sewage disposal needs. Moreover their efficiencies means that this property is less taxing on the National Electrical grid, is not detrimental to the water table, and causes less pollution to the air, land and surrounding seas.
Anyone interested in obtaining more information about these systems or other ecological and engineering systems adopted at
SAS Radisson Golden Sands Resort and Spa may contact
Ing. Ray Vassallo
e-mail rvassallo@radisson.com.mt
