Aruba experienced a tourism boom in the mid-1990s that has continued to this day. With this came the challenge of treating the ever-increasing volume of wastewater generated by the increased population and the dozens of new world-class hotels along Aruba’s pristine beaches.
The first wastewater treatment plant on the island was built in the 1960s near a neighborhood of hotels on the western side of the island in the town of Bubali. It was not until the mid-1990s that this plant had to be expanded. It was soon overloaded once again.
Witteveen + Bos drew up a wastewater master plan in 1997 that estimated the amount of wastewater the country would need to treat each year up to 2015. The island was exceeding its capacity much sooner than anticipated.
“It appeared that the amount of concentrated wastewater collected from septic tanks and cesspools by means of vacuum trucks was considerably larger than expected,” said project manager Ab Reterink. Complaints were beginning to surface on account of the over-utilized wastewater treatment plant.
The Aruba government, led by Department of Public Works Aruba Project Manager of Planning & Designing Giovanni Tromp, responded quickly by initiating plans to expand the Bubali plant and add two new treatment plants in an effort to divert septic truck waste and sludge dewatering away from Bubali hotel district and provide the town of St. Nicolas with a gravity-fed treatment plant to ensure 100% of the island’s wastewater was fully treated.
An international tender was issued in 2005. After a long deliberation, Florida Aquastore and local contractors Albo Aruba and Croon were awarded the contract.
The Bubali and San Nicolas wastewater treatment works take in domestic wastewater from gravity sewer lines. The Parkietenbos plant processes wastewater from septic tanks brought to the plant by vacuum trucks. Central sludge processing is carried out at Parkietenbos. The advanced treatment plants utilize tertiary filtration (disc filter) and UV disinfection, which allows a large portion of the wastewater to be reused for internal plant use and irrigation.
Sequencing batch reactor (SBR) technology is used to treat the Parkietenbos and San Nicolas wastewater. The SBR is relatively insensitive to variations in the biodegradable components and can accommodate the intermittent flow delivered by vacuum trucks. This helps to diminish the odor (in conjunction with biofilters) and mosquito nuisance to the nearby hotel district.
“No untreated wastewater is disposed directly into the sea,” Reterink said.
Corrosion resistance of the tank system and equipment was imperative due to the extremely aggressive coastal environment and corrosive gases found in the treatment plants. As a result, the treatment tank specifications called for Aquastore glass-fused-to-steel tank or concrete tank with T-Lock liner and special cement ash from Europe.
“It feels good when the work you do benefits a population on multiple levels, or, in this case, an entire nation,” said Matt Whelchel of Flordia Aquastore. “Our treatment plants featuring the Aquastore tanks addressed a real economic and environmental threat to the island, and we can’t really ask for a better result than that.”
Source: Engineered Storage Products
