Evidenced by its extensive use in desserts or as a standalone snack, the macadamia nut is favored by many as a high-quality nut. One of the world’s leading producers of these nuts produces more than 15 million lb per year out of its Hawaii processing plant.
The Problem
Producing the nuts is a rather meticulous process that involves multiple steps, including collection, high-strength cracking, cleaning and dehydration. The nut-cleaning process generated an average 8,500 gpd and up to a maximum 10,000 gpd of high-strength wastewater. It contained shell residuals in concentrations of 2,500 mg/L BOD and 1,000 mg/L TSS. Newer permit guidelines required effluent quality improvements, while limited facility space necessitated the purchase of equipment with minimal footprints. The nut processor overhauled its treatment processes, which include upstream fine screening, a dissolved air flotation treatment plant and advanced biological treatment.
The Solution
Designers gravitated towards membrane bioreactor technology for advanced treatment, and after consideration of a variety of different systems, they selected the Smith & Loveless TITAN MBR. This system was selected because of its high-quality effluent, minimal footprint and pre-engineered design.
The MBR’s membranes are fully submerged in the aeration zone, offering a reduced footprint. The nut processor’s pre-engineered system was constructed of 31-by-12-in. tankage that was factory-built and prepared for simple installation upon delivery.
The MBR offers many additional benefits, including eliminating the need for downstream clarifiers and providing water reuse capabilities for a number of functions. The system can be customized to include a variety of integral zones depending on the user’s needs, including nutrient removal, sludge holding and post-aeration.
A Resolution
The nut processor’s TITAN MBR was installed utilizing existing facilities and occupies a minimal footprint. After a few years of operation, the MBR delivers high-quality effluent that exceeds all permit requirements.
The system operates with minimal operation requirements of the client. A seasonal chemical cleaning process requires only a few hours of labor, while the plant remains fully operational. This enables plant resources to remain more focused on the goal at hand: producing high-quality macadamia nuts.
