Water Works Engineers (WWE) of California designed an upgrade to the Pukalani Wastewater Treatment Plant in Maui, Hawaii, which allows the plant to irrigate the Pukalani Country Club’s golf course while adhering to water reuse regulations, according to a case study on the Water & Wastes Digest website. The existing plant, which used an extended-aeration activated sludge process, was replaced by a new 0.2 mgd membrane bioreactor (MBR) plant.
The plant’s existing circular steel tank was in very poor condition, so WWE fast-tracked the design and construction of the MBR to ensure uninterrupted treatment. Space was also a concern. The 460,000-gallon-per-day MBR had to fit into the area allotted to a future 66-ft. diameter concentric circular package plant.
The plant was designed to exceed Hawaii’s R-1 water reuse limits. Although there are no nitrogen limits on the island, the MBR is designed to meet a total nitrogen effluent of less than 10 mg/L.
The MBR has improved the efficiency of the belt’s filter press, which produces 17 percent to 18 percent cake, and dropped polymer use by 50 percent.
Construction was completed in less than 10 months.
Stringent water discharge limits, especially in sensitive waterways, are driving a rebound in the global membrane bioreactor market, according to a report by Bluefield Research.