The town hired a consulting engineer who pilot-tested Geotube® dewatering containers. With proper chemical conditioning, this technology was shown to provide the most cost-effective volume reduction for alum sludge. Following the pilot’s success, the awarded contractor installed a laydown area using crushed stone and a textile underlayment mat, designed with drainage elevations of 1% leading to collection sumps. Geotube® containers were then installed with interconnecting pipe manifolds to distribute flow efficiently across multiple units.

Alum sludge and sediment were pumped using long-reach excavators modified with hydraulic pumps and a floating hydraulic dredge, which enabled access to hard-to-reach areas of the reservoir and former containment ponds.

Flow rates ranged from 800-2,500 gpm, with slurry solids content of 1-6% containing debris such as rocks, sticks, and leaves. The slurry was chemically treated using SmartFeed™ technology* to maintain optimal polymer dosing and ensure daily performance monitoring. The result was high water capture efficiency with discharge quality measuring just 24 NTUs. After several weeks of drainage, dewatered cake solids reached 38% dry solids, confirming the effectiveness of the alum sludge removal process.

* SmartFeed™ is a patent pending technology of Underwater Mineral Processing Services (UMPS).