• What are biosolids?
• Is it safe to use biosolids on my farm?
• Are there odors from the land application of biosolids? How are biosolids applied?
• What benefit is there to me, as the farmer in using biosolids?
• What can I expect if I allow biosolids to be applied to my farm?
• What about heavy metals?
• Who can I call with questions about using biosolids on my farm?

WHAT ARE BIOSOLIDS?

Sewage sludge or biosolids are the residue of material removed from sewage during the treatment process. Biosolids consist mainly of the bodies of dead bacteria, but there are also insoluble materials such as nutrients, sand and silt. Biosolids are not raw human wastes or the material filtered from untreated sewage!

IS IT SAFE TO USE BIOSOLIDS ON MY FARM?

Biosolids have been used as a substitute for commercial fertilizers in the United States for over 50 years. While you will get many opinions about the use of biosolids, most experts agree that the use of clean biosolids (low in heavy metals) at rates which meet the crop nitrogen need is a sound agricultural practice, and will not result in a risk to the farmer's health or a danger to his neighbors, nor will it lead to a degradation of the surrounding environment.

ARE THERE ODORS FROM THE LAND APPLICATION OF BIOSOLIDS?

All biosolids which are used on agricultural land in New Jersey must be stabilized. This process destroys the harmful bacteria and reduces the potential for odors from the sludge after application. Biosolids which are stabilized by aerobic or anaerobic digestion will have an earthy, musty odor. Biosolids stabilized by the use of lime will have an ammonia odor for several hours after being applied to the field. Most biosolids are applied in the liquid form, and are injected into the soil during application. This eliminates all but a very faint earthy odor, detectable at the edges of the field where material has been applied.

HOW ARE BIOSOLIDS APPLIED?

Many biosolids used as a fertilizer now being used on farms are in a liquid form, having a solids content of less than 6%. These biosolids are usually injected into the soil by specialized equipment, and little or no biosolids are visible on the ground surface after application. In most cases, biosolids are applied to fallow ground, but there are farms that inject biosolids into a perennial grass hay sod with excellent results. Liquid biosolids may also be applied to the surface of the ground as long as there is a growing crop, or the soil is disced or plowed within 24 hours of application. Some biosolids are applied in the dewatered form, similar to dairy manure. A manure spreader is used, and in this case the biosolids must be tilled into the soil within 24 hours of application.

WHAT BENEFIT IS THERE TO ME, AS THE FARMER, IN USING BIOSOLIDS?

The State regulations allow biosolids to be applied as a substitute for the nitrogen a farmer might normally use on his crops. This means that biosolids can be applied at a rate equal to the Extension Service recommendation for nitrogen for the particular crop being produced. A farmer using biosolids, therefore, saves on the cost of nitrogen and phosphorus fertilizers, as well as obtaining a portion of the potassium requirements of the crops.

A second benefit is the improvement in soil tilth, which comes from the addition or organic matter in the biosolids. Biosolids are 60 - 70% organic matter, and this will improve the water holding capacity of the soil.

Thirdly, the nitrogen in the biosolids is partially in the organic form. This means that this nitrogen is released slowly over the entire growing season, thereby reducing the potential of a rainstorm washing out all the seasons nitrogen before the crop has had a chance to use it. The organic portion the biosolids represents 30-60 lbs of the total N available over the growing season.

WHAT CAN I EXPECT IF I ALLOW BIOSOLIDS TO BE APPLIED TO MY FARM?

There are positive aspects to the use of biosolids on farmland, as well as some inconveniences. For many farmers, the positive aspects far outweigh these inconveniences. Because a permit is required from the State, the land application operation is subject to inspection by the regulatory agency. These inspections are very infrequent, and do not involve the farm operation outside those directly associated with the application or storage of biosolids.

There are slight odors sometimes associated with the application of biosolids, these odors being noticeable immediately adjacent to the field being used. Often neighbors or the township will object to the issuance of the permit. The permit application process requires notice to the township, and good practice suggests that the neighbors also be notified. These objections can often be alleviated by a visit to an operating site, where these people can see that there will not be any major odor or other environmental problems associated with the site. There may, however, be some degree of ongoing objection to the operation until the site has been operated for some time without the problems feared by those living near the site.

The actual application of the biosolids is perhaps the biggest inconvenience to the farmer. In most operations, only 8-10 acres per day can be completed due to the volumes of biosolids needed to meet most crop nitrogen needs. Biosolids cannot be applied during rainy days or on wet fields, so biosolids cannot be applied as quickly as commercial fertilizers. By having adequate equipment, however, the biosolids applier can work with the farmer to complete fields quickly as they become available for planting.

Overall, the experience of farmers using biosolids has been that the benefits far outweigh the minor inconveniences associated with using biosolids as your source of nitrogen.

WHAT ABOUT HEAVY METALS?

All biosolids and biosolids derived products, no matter what the source, contain some heavy metals. The biosolids used on farmland are tested at least monthly for heavy metal content, and the DEP approves each source of biosolids prior to allowing application to the farm. The state sets limits for the amount of each metal allowed in the biosolids, and these limits are among the most stringent in the nation.

When biosolids are applied to land with the proper soil pH (6.5 or greater), the metals are bound to the soil particles, and do not move into either the crop or the groundwater. The permit issued by the State requires that the soil pH be maintained at 6.5 or higher, thus insuring that the heavy metals do not contaminate the soil, crop or water. In addition, there are maximum amounts of metal which may be applied over the life of the site, with these limits being set by the Federal government. These limits further safeguard the farmer and the general public by insuring that no matter what the future use of the land, there will be no risk of a health or environmental hazard. Because of the high standard New Jersey sets for biosolids going onto farmland, it takes a minimum of 100 years to reach the load for the most restrictive metal, which in most cases is copper.

There is a wealth of evidence which shows that when biosolids meeting limits for metals is used in place of fertilizer, there is no danger to either the farmer, his neighbors or the general public.

WHO CAN I CALL WITH QUESTIONS ABOUT USING BIOSOLIDS ON MY FARM?