Frequently Asked Questions

Biosolids are the further processed and treated byproduct of domestic and commercial waste water treatment, which can be beneficially utilized as a soil amendment and fertilizer. The term “biosolid” was formally recognized by the Water Environment Federation (WEF) in 1991, which it defined as the “nutrient-rich, organic byproduct of the nation’s wastewater treatment process.” Biosolid fertilizers are regulated by the U S Environmental Protection Agency and are generally classified into two categories, Class B biosolids and Class A, or “exceptional quality,” biosolids. Biosolids that meet the Class B pathogen treatment and pollutant limitation criteria in accordance with Part 503 of Title 40 of the Code of Federal Regulations (40 CFR Part 503) can be land applied with formal site restrictions and strict record keeping, and biosolids that meet the Class A pathogen reduction requirements, vector attraction limitations and pollutant limitation criteria of 40 CFR Part 503 can be land applied without restriction by the EPA or mandated record keeping.

Top Choice Organic is a granular organic biosolid fertilizer that meets the Class A pathogen reduction requirements, vector attraction limitations and pollutant content limitations of 40 CFR Part 503. Top Choice Organic is manufactured to standards established by its exclusive marketer in the United States, Mannco Fertilizer Company. The manufacturing process for Top Choice Organic includes a series of processes to dry and dewater the biomass that is created as the byproduct of the treatment of domestic and commercial waste water, anaerobic digestion of the dried biomass by special anaerobic microorganisms, thermal drying of the anaerobically digested biomass for at least 40 minutes at temperatures of 840˚ to 1,200˚ F, screening to particle-size specifications, which includes dust removal and the recycling of oversized and undersized particles, and oiling with natural oils to improve particle size stability and reduce absorption of moisture from ambient air while in storage and transit. Top Choice Organic contains greater than 80% organic matter, has a moisture content of less than 10% and has a uniform granule size of 2 to 4 millimeters. Top Choice Organic contains nitrogen, phosphorous, calcium, iron, sulfur, zinc, copper, magnesium, manganese and other micronutrients.

Biosolid fertilizers have been in use in the United States since at least the early 1900s. In 1925, the City of Milwaukee began the active sale and marketing of microbes left over from its waste water treatment process to golf courses in the upper Midwest. This product was marketed under the name “Milorganite,” which was derived from MILwaukee ORGanic NITrogEn. By the mid-1930s, production and sale of this product hit 50,000 tons, and the City of Milwaukee could not keep up with demand.

Biosolid fertilizers enrich the soil with organic matter and essential nutrients. They contain a full range of essential plant nutrients that are released slowly and naturally, as plants need them during the growing season. The nutrients found in biosolid fertilizers, including nitrogen, phosphorous, calcium, iron, sulfur, zinc, copper, magnesium and manganese, are essential to good plant health, growth and fruiting. The high organic matter content of biosolid fertilizers acts as a sponge for water, air and nutrients, creating a natural environment where soil microorganisms can prosper and plant roots can multiply, grow and better develop. A larger root mass allows the plant to better survive draught and disease and more effectively and efficiently take up available water and nutrients. The organic matter in biosolid fertilizers increases the cation exchange capacity of the soil, which is a measure of soil fertility, by giving plant essential elements and minerals a natural surface to bind to, which reduces the leaching of primary and secondary nutrients contained in inorganic fertilizers and increases their uptake levels by crops. Most of the nitrogen contained in biosolid fertilizers, generally over 85%, is water insoluble, so that it does not leach, and it is naturally released to the plants by soil microbial activity when soil and climate conditions are favorable for plants to grow.

In a nutshell, the application of biosolid fertilizers to land enriches the soil with essential nutrients and organic matter and reduces the need for commercial inorganic fertilizers. The result is healthier, more fertile soil, resulting in improved plant health and higher crop production.


The nutrients in organic fertilizers, including Top Choice Organic, are stored in complex organic molecules and are generally water insoluble, so that they are not released for plant use until soil microorganisms break them down. This does not generally occur until soil and climate conditions are favorable for plant growth. Commercial “inorganic” fertilizers include chemically-based fertilizers, such as urea, and natural inorganic fertilizer, such as potash, which are generally soluble in water, must be watered in and are subject to leaching.

Top Choice Organic is a small granular fertilizer that can be blended with urea, phosphate, potash and other commercial inorganic fertilizers. Accordingly, it can be applied with and at the same time as the application of other fertilizers, or it can be applied separately. Because Top Choice Organic contains water insoluble nutrients, it can be applied in the fall after harvest and during fall field preparations and in the spring before planting. It can also be applied as a side dressed fertilizer after germination and during plant growth. Top Choice Organic is of a consistent size and mass, so that it can be applied by air flow, spinner truck, buggy, cart or airplane.

The National Academy of Sciences has reviewed current practices, public health concerns and regulatory standards for biosolid fertilizers and has concluded that "the use of these materials in the production of crops for human consumption, when practiced in accordance with existing federal guidelines and regulations, presents negligible risk to the consumer, to crop production and to the environment."

A biosolid fertilizer may have its own distinctive odor depending on the type of treatment it has been through. Some biosolid fertilizers may have only a slight musty, ammonia odor. Others have a stronger odor that may be offensive to some people. Compounds that contain sulfur and ammonia, which are both plant nutrients, cause most odors. Top Choice Organic has gone through an anaerobic digestion process for the purpose of reducing the intensity of its odor, but it does have a distinctive odor for several days after its application, which generally dissipates a few days after a rain or watering.

The U S Environmental Protection Agency regulates the land application of biosolid fertilizers pursuant to its regulations published as Part 503 of Title 40 of the Code of Federal Regulations. Biosolids that are to be applied to land must satisfy the strict quality standards set forth in the EPA’s regulations, and Class B biosolids are subject to application limitations and strict record keeping requirements. The Part 503 regulations set forth general and specific requirements for the use and disposal of sewage sludge that is surfaced disposed or incinerated and biosolids, including numerical limits for the amount of metals that these substances can contain, pathogen reduction standards, vector attraction reduction standards, mandated management practices relating to the process of producing biosolids, frequency of monitoring for metals and pathogens, and record keeping and reporting requirements for land applied Class B biosolids. The EPA’s regulations became effective in 1993 and were developed with input from university, EPA and USDA researchers from around the U. S. and involved an extensive review of the scientific literature and the largest risk assessment the EPA had conducted to that time. For more information on the EPA’s Part 503 regulations, see "A Plain English Guide to the EPA Part 503 Biosolids Rule."

Recycling biosolids as fertilizer is good for the environment. Manures and other natural organic matter have been recycled for centuries to improve soil fertility and productivity. When properly applied and managed, biosolid fertilizers will provide essential plant nutrients, improve soil structure and tilth, increase the organic content of soil, enhance a soil’s moisture and nutrient retention, enhance crops’ uptake of moisture and nutrients, and reduce soil erosion.

Biosolids recycling is regulated and encouraged by the United States Environmental Protection Agency and state and local authorities. Research and years of recycling experience have demonstrated that properly managed land application of biosolid fertilizers is environmentally safe.

There is information published in the common press that biosolid fertilizers will repel deer. However, Top Choice Organic is not registered with the U S EPA or any other agency as a deer repellent.

You can purchase Top Choice Organic in Arkansas and southeast Missouri from a retail farm supply dealer near you. A list of retail dealers of Top Choice Organic in this region can be found by clicking here.