Hotel Soaltee Oberoi – Kathmandu Nepal
Hotel Soaltee Oberoi now Hotel Soaltee; is a leading hotel in Kathmandu Nepal. Its water requirements are met by a number of deep bore wells in the hotel premises and through the municipal water supply. While the municipal water is clear, the bore well water posed two problems. First, the bore well water had a fishy odour. Secondly, though this water was clear on withdrawal it turned turbid on contact with air.
The water also had pale yellow colour, which caused staining problems at use points in the hotel. Common customer complaint was stains on the bathtubs. The hotel tried several methods of filtration but all these proved unsuccessful for removing colour from the bore well water.
Ion Exchange investigated the problem and conducted various troubleshooting activities.
Water Analysis: The bore well water drawn from about 300 meter deep wells when analyzed & microbiological tests undertaken showed a plate count of coliform bacteria of 10 colonies per 100ml. Infrared spectra of the concentrated sample showed the existence of methylene groups. Fish oil, humic acids, fulvic acids, proteins and other organic substances of terpene origin were the suspects.
Treatment Methods: Various conventional treatment methods were tried to remove the organics and colour from the well water at the hotel. These include Coagulation, Chlorination, Activated Carbon treatment and Potassium Permanganate Treatment. However, all the above methods failed to improve the colour of the well water. Hence, Organic Removal Ionexchangers were tried out for treatment.
Assuming that the organics to be mainly hydrocarbons, anion resins made by Ion Exchange were tried. Initial screening of the isoporous and macroporous ionexchangers was done. Based on the performance, strong base type I ionexchanger (trade name Indion 830) was selected and after laboratory tests to check consistency in performance and effective elution, the ionexchanger was tried out at the site. Colour removal of greater than 90% was obtained and after successful trials, the hotel went for a full-scale plant using the ionexchanger.
Plant Design: The organic removal ion exchanger was incorporated immediately after the activated carbon filter in the following equipment already installed by the hotel- Extended aeration by sprinklers, Alum dosing system, Pressure sand filter and Activated carbon filter. Alkali dosing was considered before aeration to remove ammonia from the water. Chlorination was done prior to filtration. The plant was designed to treat 900cubic meters of water per day.
The ionexchanger effectively removed organics and the colour from well water. Purified water was sparkling clear. The average chlorides in the drinking water were well below the 200ppm Cl level as specified by WHO.
Understanding of client’s problems, systematic evaluation of alternative treatment methods, scaling up to the full scale plant and monitoring of plant performance have all shown to be useful in solving Hotel Soaltee’s problem of water treatment. Client has been satisfied with the performance of the plant and resins. The hotel ordered another unit to supplement the first one. In addition, two more hotels in Kathmandu installed similar organic removal units using the ionexchanger.
The organic removal ionexchanger shows great prospects in solving problem of treatment of such difficult waters.