Challenge: To construct injection wells in an area with no centralized wastewater treatment plants, limited space, and a low permeability volcanic environment.
Solution: Because a centralized wastewater treatment plant was unavailable and there was inadequate space to construct a leach field, the Kalama Beach Corporation, one of the Sullivan Family of Companies (Foodland and other stores), determined that injection wells were the best option for managing wastewater at a new supermarket in Kīlauea, Kauaʻi. The site is located makai (inland) of the Underground Injection Control (UIC) line, and therefore is in an exempted aquifer as defined by the Hawaii Department of Health (DOH) in HAR §11-23. The site overlies the Kōloa Volcanics, which are composed of ponded lava flows, pyroclastic deposits, sediment, and other weathered material that generally have relatively low permeability.
INTERA’s first task was to prepare a preliminary injection well investigation and report to inform the well designs. The Hawaiʻi Department of Health, Safe Drinking Water Branch strictly enforces rules on maximum depth, vertical separation from potential drinking water aquifers, and artesian pressure. We provided oversight for the drilling of a test borehole, and the design, permitting, and construction of two injection wells. After drilling a test borehole to 195 feet below ground surface, we identified potential disposal zones in the subsurface. An injection test was performed, and a final well design was prepared based on the information collected from the borehole.
INTERA also provided services during well construction. We monitored drilling and provided and approved design changes. Well drilling proved to be challenging due to the dense, low permeability lavas and difficulties associated with drilling fluid disposal. INTERA also prepared the well completion reports in compliance with DOH regulations. These reports are required to complete the UIC permit and give the owner permission to inject wastewater.
Results: INTERA, working in collaboration with the drilling company, successfully constructed and tested two injection wells that are meeting the flow requirements for the on-site wastewater treatment plant. These wells are playing a critical role in supporting the ongoing operation of the supermarket.