The City of Roswell, New Mexico, has developed an innovative and award-winning system for managing biosolids, achieving significant cost savings and environmental benefits. The system, implemented in 1985, has garnered recognition for its outstanding performance in sludge composting, earning accolades like the Rocky Mountain Environment Association’s Merit Award and the New Mexico Water & Wastewater Association’s Outstanding Achievement Award. At its heart is the utilization of paved sludge drying beds and a highly efficient Brown Bear tractor, which together have streamlined operations and minimized environmental impact.
Cost-Effectiveness through Paved Drying Beds:
- Paved drying beds, covering a total of 50,050 square feet, were chosen over traditional sand-based beds, resulting in substantial capital savings.
- Construction costs for the paved beds were significantly lower, totaling $340,000 compared to an estimated $786,600 for sand beds.
- The paved beds also required less land, just two acres compared to six acres for sand beds, further reducing expenses.
Efficiency and Labor Savings:
- The Brown Bear tractor, with its versatile attachments, plays a crucial role in the efficiency of the system.
- It handles sludge mixing, aerating, turning, truck loading, and stockpiling, minimizing the need for manual labor.
- This automated approach has reduced annual labor costs to $2,403, compared to $5,522 for a hypothetical sand bed operation with manual labor.
- The paved beds facilitate quicker drying times, with sludge reaching the desired dryness in 4-6 weeks compared to up to 24 weeks for sand beds.
Environmental Benefits:
- The system effectively minimizes odor and insect problems, a common concern with traditional sludge management methods.
- The Brown Bear’s regular turning and mixing of the compost pile helps release ammonia and prevent septic conditions, further reducing odors.
- The final composted product is fine, homogenous, and rich in nutrients, making it a valuable soil additive for agriculture and gardening.
- The composting process meets stringent environmental regulations, including the EPA’s 40 CFR 503 standards, ensuring the safety and quality of the final product.
The Roswell Wastewater Plant’s success story highlights the effectiveness of innovative and environmentally sound approaches to biosolids management. By prioritizing efficiency, cost-effectiveness, and environmental protection, the city has created a model system that benefits both the community and the environment.
