The U.S. Army Construction Engineering Research Laboratories (USACERL) has been developing and adopting improved sludge dewatering systems for U.S. Army wastewater treatment plants. USACERL selected reed beds as the best alternative for future Army sludge dewatering systems based on the system's economical and technical feasibility and on a demonstration of the technology at Fort Campbell, KY, USA.
This paper compares the Army's options for upgrading Fort Campbell's sand-drying beds, analyzes costs, discusses sludge hydraulic and solids loading rate data from existing reed bed operations in the United States, and presents 5 years' operational data from Fort Campbell. Options considered for comparison included: land application of sludge at training fields, wedgewater beds, vacuum-assisted beds, wedgewater beds and composting, mechanical dewatering systems, and a “no change” option in which sand-drying beds would have been retained.
In conclusion, this paper summarizes advantages and limitations of reed bed sludge dewatering. Advantages of reed beds may include: low investment especially when sand-drying beds are converted to reed beds, savings of sludge removal costs, and the benefits inherent to using a simple and economical technology. Limitations may include: large land requirements and little scientific understanding of this empirical technology. The challenge will be to further develop appropriate disposal technologies to meet new U.S. sludge regulations.