Frequently Asked Questions
What is Bloom®?
Bloom is a fertilizer and soil conditioner made from EPA approved Exceptional Quality Class A biosolids. Bloom provides essential plant nutrients, including slow-release nitrogen, and organic matter, which is key to building healthy soil. Slow-release fertilizers like Bloom slowly add nutrients to the soil by naturally breaking down and decomposing into a plant-available form. Research has shown Bloom provides improved drought resistance and water holding capacity among other benefits. Bloom is great for improving and establishing lawns, remediating poor soils, planting trees and shrubs, and establishing flower and vegetable gardens, among other applications.
DC Water produces Bloom at its Blue Plains Advanced Wastewater Treatment Plant using an advanced process that uses high heat, high pressure and biology to produce a soil amendment similar to compost. Bloom meets all U.S. Environmental Protection Agency (EPA) standards for use in homes and gardens. Learn more.
Are there environmental benefits to using Bloom?
There are multiple benefits for using Bloom. Applying biosolids to the land helps capture carbon and prevents it from being released to the atmosphere. Using Bloom also reduces demand for commercial petroleum-based fertilizers and the energy used to manufacture it. Using biosolids locally reduces emissions and the carbon footprint created by hauling this valuable product far from its source. Learn more with this factsheet.
Oversight from EPA means that biosolids-based soil amendments are more regulated and studied than other fertilizer and soil amendment alternatives. Bloom goes beyond these standards to produce EPA-certified Exceptional Quality biosolids, the EPA’s highest rating.
I’ve been hearing about PFAS. What are they and are they found in Bloom?
PFAS are a group of more than 3,000 manmade chemicals that are fire, oil, grease, water and stain resistant, and are found in a wide array of consumer and industrial products, including non-stick cookware, food packaging, dental floss, cleaning products, and cosmetics. Exposure to humans can occur through a number of pathways, including ingestion and inhalation. At high concentrations, PFAS compounds have been linked to negative health consequences. We share the growing public concern over the presence of these chemicals in our society, and strongly believe that source control is the long-term solution.
While there is no EPA approved methodology yet for testing biosolids for these compounds nor any standards set for their concentration levels, DC Water is participating in efforts to help determine the concentration of these compounds in our Bloom product and the associated risks. Our preliminary sampling results show extremely low concentrations of these compounds in Bloom (on the level of parts per billion) – several orders of magnitude below levels found in household dust, which presents a much higher exposure risk. We are coordinating with researchers and utilities across the nation, including a joint study with the DC Chapter of the Sierra Club, to study the risks posed by these small concentrations.
Recent measurements of Bloom have shown concentrations of PFOS and PFOA to be many thousands of times lower than in food packaging materials, hundreds of times lower than in products like ketchup, organic tomato sauce, and cosmetics, and ten times lower than the levels measured in dust. Learn more about PFAS and biosolids in this factsheet.
What does Bloom® smell like?
Bloom’s products are low in odor and often described as earthy or musty. After it is applied and mixed with soil, odors are even further reduced. It can take up to a week to 10 days for any odor of Bloom to completely disappear, however. For large-scale orders, we can provide free samples of material for you to get a better sense of the texture, odor and other properties.
How is Bloom made?
DC Water has the largest advanced wastewater treatment plant in the world. Our wastewater goes through a very sophisticated, tightly controlled process to transform our waste into a precious resource. DC Water has invested in advanced processing called thermal hydrolysis that treats materials at extremely high heat and pressure to kill pathogens and then takes it through anaerobic digesters, which convert some of the solids into renewable natural gas. The final product, Bloom, is sold in bulk to commercial farmers and construction companies, and is also blended on site into our Sandy and Woody Blends. A portion of Bloom is also dried and bagged offsite by one of DC Water’s partners.
Which product should I use for my project, how much do I need and how should I apply it?
The short answer is it depends on what you’re looking to accomplish, how you are applying the product (topdressing versus incorporation), the quality of your soil, and many other factors. This page provides a table of usage by product and includes a calculator where you can calculate how much material you need. Our team is available to help you figure out what product and quantity is best; email us for a consultation at firstname.lastname@example.org.
Where can I purchase Bloom?
Bloom’s blends can be purchased in bulk directly from Blue Plains for orders as small as a few cubic yards or from a host of retailers in Maryland, DC and Virginia. Cured Bloom is available only through retailers (though we welcome inquiries from retailers interested in purchase of pallets). This page has a dynamic map where you can enter your zip code to sort by the nearest retailer to you. Fresh Bloom is available only directly from Blue Plains, for commercial use such as farming and construction.
Do other cities use biosolids soil amendments?
Yes. Cities like Milwaukee, Seattle, Tacoma, Austin, Houston, Boston, and Baltimore use and sell their high quality biosolids soil amendment products. Milorganite, for example, has been produced for a century and can be found in most home and garden centers nationwide. Click here for a comprehensive list.
Where can I learn more about the science and research behind the product?
Bloom regularly partners with independent researchers at area universities and institutions on research projects to test the efficacy of different applications. Click here for a page summarizing some of the recent research. Bloom also undergoes regular testing by independent labs; sample analyses for each of our products can be found on this page.
What about other toxins like trace metals and pharmaceuticals?
Toxins are something we monitor both as prescribed by EPA and beyond mere regulatory compliance to ensure that we are not harming the environment or putting public health at risk. There are minute trace amounts of pharmaceuticals and other compounds but in concentrations many orders of magnitude below what is found in products on our shelves and in therapeutic doses of the pharmaceuticals.
Trace metals are present in Bloom at a level that is detectable but not deemed by the EPA to be a risk to human health and are in most cases an order of magnitude below the EPA’s Class A Exceptional Quality standards. Many of the metals found in biosolids are also present at higher concentrations in popular multi-vitamins and consumer products that we use every day. In addition, heavy metals typically enter the water system from industrial sources (only around 3% of total flow to Blue Plains). DC Water has an aggressive pre-treatment program that requires these users to remove these compounds before they reach Blue Plains. To put it in context, it’s estimated that a healthy adult would have to eat 38 cups of biosolids per year to reach the FDA’s recommended daily value of copper.
Another family of compounds are antibacterials like triclosan, which are used in antimicrobial soaps and hand sanitizers. DC Water monitors and has invested in research related to these compounds. However, triclosan can be found at much higher levels in products we use every day. There are 4,000 parts per million of triclosan present in a single use of common toothpaste. DC Water’s biosolids contain only 15-20 parts per million of triclosan.
This summary of a report conducted by King County Washington provides more detail on the relative risk of pharmaceuticals and other compounds. It looks at four potential pathways to human exposure, including a child eating a spoonful of soil amended with biosolids every day. The calculations show that it takes many years of this level of exposure (sometimes thousands of years) to consume enough soil to get a single therapeutic dose of the compound.