Colorado Department of Public Health and Environment, Water Quality Control Division and U.S. Environmental Protection i Agency, Region VIII Biosolids Recycling Is Safe Biosolids Recycling Is Good For The Environment Biosolids Recycling Is Good For The Economy ------- Households generate wastewater. When we run clothes washers, take showers, and flush toilets, we turn clean water into wastewater. Our® businesses and industries also generate wastewater. Most wastewate* a combination of soap suds, toilet paper, and other matter, travels througj^an ^ extensive plumbing and sewer system until it reaches the domestic wastewater treatment plant. At the plant, we treat the wastewater prior to discharge into a river, lake or stream. The by-product of the wastewater treatment process is a natural organic material formerly known as sewage sludge. We treat these wastewater solids to produce a natural fertilizer and soil conditioner called BIOSOLIDS. Since the 1920s, biosolids have been used by farmers, horticulturists, land use specialists, and the public, not only in Colorado but throughout the United States and the world. The Colorado Department of Public Health and Environment and the U.S. Environmental Protection Agency regulate and encourage recycling of biosolids because their valuable nutrients and organic matter can improve plant growth and soil structure. WHAT ARE BIOSOLIDS? Biosolids are treated solid, semi-solid, or liquid residues removed from wastewater when it is cleaned. In fact, the cleaner our wastewater gets during treatment, the more solids a treatment plant will generate. When solids are initially separated from wastewater they are about 99 percent water. Biosolids do not include animal manures, untreated septage, municipal solid wastes, hazardous wastes, industrial sludges such as those generated from oil and gas refineries, or grit and screenings removed during preliminary wastewater treatment. "The use of biosolids in agriculture is the wave of the future, and it is an environmentally and economically responsible way to deal with this by- product." (Dwayne Westfall, Ph.D., Department of Agronomy, Colorado State University, Ft. Collins, CO) ------- ix In the United States, we have used biosolids in a number of ways. These include land application where crops such as corn, soybeans, grains, hay, and pasture are grown; land application to non-agricultural land areas such as forests, parks, cemeteries, golf courses, and land-reclamation sites; and land application to lawns and gardens. Disposal methods include using landfill space, disposal in monofills (wastewater solids only), and incineration. Eighty-five percent of the biosolids generated in Colorado are recycled; we apply 60 percent to pasture and rangeland and to agricultural land producing corn and dryland wheat; we apply 20 percent to land reclamation sites, and we sell 5 percent to nurseries and other users. Only 15 percent of Colorado's wastewater solids are disposed of in landfills. Colorado's 85 percent biosolids recycling rate compares to a U.S. - wide biosolids recycling rate of about 50 percent. U.S. EPA Region 8 Library 80C-L 999 18th St., Suite 500 Denver, CO 80202-2466 5% Marketed 20% Land Reclamation Colorado Biosolids 15% Landfill ------- WHY IS IT IMPORTANT TO RECYCIE BlOSOLIDS? The Colorado Department of Public Health and Environment and the U.S. Environmental Protection Agency strongly support the recycling of biosolids. Biosolids are a valuable resource rich in nutrients and organic matter. This makes the material useful as a fertilizer and a soil conditioner. Benefits associated with recycling biosolids include: improving soil structure and water-holding capacity to prevent erosion, increasing crop yields, diverting a recyclable material from landfills, and providing an inexpensive alternative to chemical fertilizers. Typical Colorado biosolids have a nutrient value of 6 percent nitrogen, 2 percent phosphorus and 0.02 percent potassium; in addition to micronutrients and valuable organic material. Biosolids can decrease the pre- harvest operating cost for dryland wheat and irrigated corn by approximately 15 percent1 while maintaining similar crop yields. During an eight-year study researchers from Colorado State University tested biosolids on dryland winter wheat at four sites near Bennett, CO, in Adams County. The estimated annual income using biosolids consistently exceeds income using chemical fertilizers.2 Estimated Average Annual Income For Dryland Winter Wheat SITE 1 SITE 2 SITE 3 SITE 4 Chemical Fertilizer at Agronomic Rate 50 lb N/ac-Sites 1 & 2; 60 lb N/ac-Sites 3 & 4 Biosolids at Agronomic Rate 3 Ions biosolids/ac or-45-50 lb N/ac 1 Department of Agricultural and Resource Economics Information Report IR: 92-1, Colorado State University Cooperative Extension Service, July, 1992. Assumes a cost of $3.00/Acre for METROGRO™ Biosolids product. 2 Eight Years of Application of Sewage Sludge to Dryland Winter Wheat, Technical Bulletin, TB 92-1, Colorado State University, January, 1992. ------- 4LS Completing the cycle is an urban-rural cooperative effort that has existed in Colorado since the early 1980s. Many of the nutrients contained in biosolids come from agricultural products ^ consumed by Colorado citizens. Recycling these nutrients back to their original source, soil, is an environmentally sound way to manage biosolids. Mi In Colorado there are usually two types of biosolids: liquid biosolids j and dewatered biosolids. Liquid biosolids are often injected under the surface layer of the soil to minimize odors. Dewatered biosolids are applied with equipment typically used for spreading animal manures, and can be incorporated into the soil by plowing or disking. B iosolids will have some odor when land / applied. The treatment process stabilizes biosolids and minimizes odors. Treated biosolids smei! something like mulch, which has an earthy odor; they do not smell like raw sewage. Incorporating biosolids into the soil further reduces odors. The odors are not harmful. They are noticeable to some people. They are present for a short time. ------- e treat biosolids to eliminate harmful microorganisms (pathogens) that reside in wastewater. As required by both federal law and the Colorado Department of Public Health and Environment, domestic wastewater treatment plants must treat biosolids to reduce pathogens and to reduce the attraction to insects and animals before the material can be used. In Colorado, aerobic (with air) digestion and anaerobic (without air) digestion are the most common methods for treating biosolids. Digestion creates an environment that kills pathogens through heat and reduction of the microbial food source. Treating biosolids thus stabilizes the material and also minimizes odors. "The Rocky Mountain Water Pollution Control Association strongly supports the recycling of biosolids to enhance the productivity of natural soils thereby conserving and recycling our limited natural resources." The Colorado Department of Public Health and Environment takes extensive measures to ensure correct and safe use of biosolids by requiring compliance with the State's biosolids regulations. Regulatory compliance includes monitoring, record keeping, reporting, permitting, and laboratory analyses by all wastewater treatment plants involved with generating and applying biosolids. The Colorado Department of Public Health and Environment has the authority to investigate any biosolids project to determine compliance with State standards. Projects violating the regulations may lose the right to use this valuable resource and violators can be penalized. Any citizen can report problems about biosolids use and safety by calling (303) 692-3500. ------- Decades of scientific research have shown that we can use biosolids safely. Scientists at reputable institutions such as Colorado State University, University of Colorado at Boulder and Denver, and other national institutions have conducted research on biosolids. Extensive data collected since the 1920s indicate that the use of biosolids, when in compliance with State regulations, poses no threat to human health or the environment. There has never been a substantiated case of illness or environmental harm caused by proper biosolids use. However, mismanagement of a site or misapplication of biosolids may lead to problems. Research in this area is ongoing to ensure that the public health and safety and the environment are protected from any harmful effects associated with biosolids recycling. "I haven't had any troubles with it (biosolids) and I would recommend it to anybody who would like to get out of the chemicals and who would like to get into some natural fertilizing." (Sr. Maria Michael Newe, O.S.B., Abby of Saint Walburga, Boulder, CO) "Since we started using it (biosolids), we've doubled our yield on a lot of the drylands. Some of the sandy fields where we could hardly get any production (10-15 bushels), we're up to 40; and the irrigated (lands), we have a good crop every year now since we've been using it. We've used it on milo, wheat, corn, and it helps the production on all of it." (Lloyd Land, Brighton, CO) ------- Colorado biosolids do contain trace amounts of metals — many are the same micronutrients typically found in vitamins and many are required for plant growth. We cannot recycle biosolids exceeding metals criteria (shown below). We recycle biosolids only when metal concentration levels are suitable for application to farm lands, reclamation sites, or lawns and gardens. Colorado Department of Public Health and Environment Maximum Metals Concentration, mg/kg (Dry Weight Basis) Average Metals Concentration of Colorado Maximum Colorado Limit For Land Metal Biosolids1 Application of Biosolids Arsenic 7 75 Cadmium 7 85 Chromium 57 3000 Copper 636 4300 Lead 106 840 Mercury 6 57 Molybdenum 18 75 Nickel 42 420 Selenium 10 100 Zinc 750 7500 1 Average values of samples taken from 7 years of Colorado wastewater treatment plant data. Data provided by the Colorado Department of Public Health and Environment, Water Quality Control Division. ------- B efore we can land apply biosolids, we study each site. We base biosolids application rates upon the agronomic rate for the crop or vegetation to be grown, soil type, and site characteristics. The agronomic rate is limited to the amount of nitrogen which is taken up and used for plant growth. Using the agronomic rate ensures optimum uptake of nitrogen and prevents nitrogen migration into ground waters. Nitrogen is a valuable nutrient found in biosolids. Scientific research indicates that when biosolids are applied to crops such as corn, the nitrogen release rate may better match the plants' needs compared to chemical fertilizers. Biosolids vs Chemical Nitrogen Fertilizer Availability and Uptake By Plants Planting Harvest NITROGEN RELEASE RATE C NITROGEN UPTAKE RATE ------- WHAT noif DOES COIORADO DERKRTMEin DF PlIBIIC HEALTH AND EMNMEKT PlAY IN EKSII1G THE QUALITY AND SAEETY The chemical makeup and biological components of biosolids depend upon the composition of wastewater. Household chemicals, oil and grease, microorganisms, pesticides, and solvents are a few of the pollutants that could be found in wastewater. As a result, the quality and recyclability of the biosolids can be affected . The best way to ensure that pollutants remain at safe levels is to prevent their discharge into the sewer system. The Colorado [Department of Public Health and Environment administers and enforces The National Pretreatment Program that the Clean Water Act mandates. The pretreatment program establishes strict standards that can result in large dollar fines for industries that discharge excess pollutants such as copper, zinc or other metals to a treatment plant. Compliance by industry and strict enforcement of the pretreatment program by state and local authorities ensures that the wastewater treatment processes are working effectively, thus improving the quality and safety of biosolids. The Colorado Department of Public Health and Environment also regulates the quality and use of biosolids through its Biosolids Management Program. k— ------- Hi As we treat our wastewater more thoroughly and as Colorado's population continues to grow, biosolids generation will continue to increase. Finding alternatives for biosolids use depends greatly on the acceptance of this valuable product by Colorado citizens. The Colorado Department of Public Health and Environment, the U.S. Environmental Protection Agency and others working with biosolids recycling invite you to take an active role in learning more about the wastewater treatment process and the generation and recycling of biosolids in your community. For further information about biosolids please contact: Bob Brobst, USEPA VIII, 99918th St., Suite 500, Denver, CO 80202, (303) 293-1627, or Phil Hegeman, Colorado Department of Public Health and Environment, 4300 Cherry Creek Drive South, Denver, CO 80222-1530, (303) 692-3598. This document was made possible through a grant provided by the U.S. Environmental Protection Agency, Region VIII. Written by Laura A. Langner. Reviewed by Ken Barbarick and Dwayne Westfall, Colorado State University, Department of Agronomy. Art and Printing by State of Colorado, The Design Center. ------- "Our soils are extremely sandy. We believe the organic material and slow nitrogen release in the METROGRO™* products are critical to our crop production. They (biosolids) have given us a fine crop, good bushel weights, and excellent yields. On a cost savings basis - if we had to replace what we are doing on that 1,000 acres with commercial - probably around $50,000 a year in cost savings." (John Moser, Hudson, CO) xr§4 ¦ m '¦ - * U.S. EPA Region 8 Library ; 80C-L. 999 18th Si., Suite 500 Denver, CO 80?02-2466 * METROGRO™ is the trade name of biosolids distributed by the Metro Wastewater Reclamation District, Denver, CO. ------- 908F96002 R8 0037 Biosolids Recycling Is Safe Biosolids Recycling Is Good For The Environment Biosolids Recycling Is Good For The Economy c i Colorado Department of Public Health and Environment, Water Quality Control Division and U.S. Environmental Protection Agency, Region VIII ------- |