SEWAGE SLUDGE UTILIZATION IN MARYLAND

from the Maryland Department of the Environment website, page:
http://www.mde.state.md.us/reference/sewagesludge.html

WHAT IS SEWAGE SLUDGE?
Sewage sludge is not sewage. It is one of the final products of the treatment of sewage at a sewage (wastewater) treatment plant. After threatment to break down the organic matter and kill disease organisms, the remaining fine particles ultimately become sludge. Although much o the water has been removed, sludge for application to farm land is still mostly water and looks just like mud.

HOW MUCH SLUDGE IS PRODUCED IN MARYLAND?
Each year over a million wet tons of sewage sludge are generated in Maryland. As we continue to restore the Chesapeake Bay, the nutrients released to surface waters from sewage treatment plants decreases, and the amount of sludge generated continues to increase.

HOW IS SLUDGE USED?
There are five major ways that sludge is used in Maryland. The most common usage is application to agricultural land which uses about two thirds of the sludge produced in the state. The next largest is land reclamation. After that, about 10% is composted or pelletized and made into a commercial soil supplement. Burial in landfills and incineration account for the rest.

WHY APPLY SLUDGE ON FARM LAND?
Sludge application recycles nutrients that would otherwise be lost. A material formerly thought to be a waste is now recycled as a new resource. If farmers could not use sludge, they would have to pay for nitrogen and phosphorus. Other plant nutrients such as magnesium, zinc, copper, iron, calcium, and sulfur are found in sludge. Using sludge as an agricultural nutrient and soil supplement saves landfill space and is cheaper than other methods of sludge disposal or utilization. Using sludge helps in the Chesapeake Bay restoration effort.

WHAT IS THE ROLE OF STATE GOVERNMENT?
The Maryland Department of the Environment (MDE) is the primary agency regulating sludge operations. A sludge contractor files an application for a permit with MDE which consists of soil and sludge tests and other information MDE uses to assure that all regulatory requirements are met. The site is also inspected to be sure that the application materials are correct. If everything is satisfactory, the contractor is permitted to apply the sludge. MDE inspects the farm during and after sludge application. To support the administration of the sludge program, sewage treatment plants are charged fees based on the amount of sludge they produce and how it is used.

WHAT IS THE ROLE OF LOCAL GOVERNMENTS?
County governments receive copies of every permit application. County governments can review and comment on each application, request a public informational meeting, participate in site assessment visits, inspect and monitor each site in their county, and have the right to enforce the permit requirements.

SLUDGE STATISTICS
MDE has issued more than 3,500 sludge permits since 1974. No cases of health effects or water pollution have occurred from the use of sludge on farms in Maryland. About 80,000 acres on more than 600 farms throughout Maryland are currently permitted to receive sewage sludge. In Maryland, sewage sludge is recycled more than any other material, both in terms of quantity (over 600,000 tons per year) and rate (about 82%).

HOW CAN YOU BE SURE SLUDGE APPLICATION IS SAFE?
The Maryland Department of the Environment has set up requirements to assure that use on land is safe for both humans and the environment.

Pathogen Control
Regulations require that sewage sludge be treated to reduce disease causing organisms to safe levels.

Heavy metals
Regulations set maximum concentrations in the sludge and maximum amounts that can be applied to land.

Pretreatment
Industrial waste is treated to remove contaminants before being released to the sewer system.

Buffer Zones
Buffer zones from 10 to 400 feet may be required to protect health and the environment.

Slope Requirements
Sludge may not be applied on slopes greater than 15%.

Application Rates
Application rates are calculated to ensure that all sludge nitrogen is used by the crops, without excess runoff or leaching to the groundwater.

Frozen Ground Restrictions
Slopes must be less than 6%, buffers are increased, soils must have good drainage, and vegetative cover must be present.

Nutrient Management Plans
These plans show the amount and kind of nutrients needed on each field of a farm and set a nutrient budget to ensure no excess nutrients are applied. This protects water quality by minimizing runoff.

Time Restrictions
No grazing by animals for 30 days, controlled public access for 12 months, no crops to be eaten raw by people for 3 years.

Monitoring Records
Sludge analyses are submitted to MDE from treatment plants, a recent sludge analysis is required for each permit application, and records from applicators, site inspections, and treatment plants are reviewed.

Site Inspection
Site inspections are held during permit review by MDE and County Health staff, during the sludge operation, and after completion. MDE conducts about 1,500 sludge site inspections each year.


Q: Who benefits from agricultural use of sludge?

A: We all do.

Sewage customers get an economical disposal plan.
Farmers get a free source of nutrients.
Maryland gets a cleaner environment.


FOR MORE INFORMATION:

Sewage Sludge Utilization Section: (410) 631-3375