Operations, Maintenance and Replacement of Passive Treatment Systems
For AMD discharges where passive treatment methods are sufficient, the passive systems require much less continuous maintenance than active treatment. Still, even passive systems require a plan for ongoing operation, maintenance, and replacement (OMR). Such OMR concerns should be analyzed even before the system is constructed, based on water quality information and flow measurements.
Provisions must be made for even the most basic maintenance activities, including mowing grass around a system and removing leaves that may clog conduits. Some systems are surrounded by fences to prevent vandalism. Also, animals may damage a system, especially muskrats, whose tunnels must be blocked with dirt and rocks.
Different types of passive treatment systems require specific OMR activities. The list below includes some of these requirements and the types of systems to which they apply. Follow the links for descriptions of each system, including more detailed OMR information.
Clean & remove accumulated metals
- Aerobic wetlands
- Settling ponds
- SAPS & Vertical flow ponds (via flushing)
- Anoxic limestone drains (at effluent only)
Replenish limestone
Replace compost
- SAPS & Vertical flow ponds (via flushing)
- Sulfate-reducing bioreactors
Final Recommendations of the Long Term Operation, Maintenance, and Replacement Workgroup PA Department of Environmental Protection
Operation and Maintenance Manual for Passive Treatment Systems developed by Damariscotta
Why do some passive treatment systems fail? by James J. Gusek, P.E.
Operation & Maintenance Technical Assistance for Passive Treatment Systems, a service provided by Stream Restoration, Inc.