NMRWA 2019 Instructor of the Year Award Presented to Probiotic Solutions® Project Engineer, Heather Jennings

Ms. Jennings

Heather Jennings, Probiotic Solutions® Project Engineer

Bio Huma Netics, Inc. congratulates Heather Jennings, Project Engineer for Probiotic Solutions®, who was awarded Instructor of the Year at the New Mexico Rural Water Association (NMRWA) Conference on April 10. Ms. Jennings, who has been training and presenting for five and a half years, teaches basic and advanced wastewater math for certification, a course on microbes, and a nitrification/denitrification course.

NMRWA is a non-profit organization with over 480 water and wastewater system members, representing over 1,297,000 New Mexicans. NMRWA strives to provide the highest quality training and technical assistance and to represent the legislative and regulatory interests of its members.

Ms. Jennings truly enjoys working with NMRWA. “They have a great sense of community. They help each other––there’s no competition. It’s a very good community––a great group of people––that strives to better the water quality in New Mexico.”

Ms. Jennings has been with BHN since 2015. She has a BS in Chemical Engineering from Brigham Young University and has 16 years of engineering experience.

Probiotic Solutions® is the BHN soil and wastewater bioremediation division that assists industries such as food processing, municipal wastewater, pulp and paper, chemical refineries, and others who use water in their processes to treat and return safe, clean water to the environment.

Bio Energizer® Cuts Sludge Hauling Costs for Potato Wastewater Treatment Plant

Potato Wastewater TreatmentA wastewater treatment plant in Pennsylvania was experiencing process control problems when new potato waste stream flows increased by 26%. The additional load was causing filamentous issues in the sequencing batch reactor (SBR), settlability problems, and increased sludge hauling costs.

The engineer was unable to maintain the 8-foot decant level in the sequencing batch reactor (SBR). He couldn’t decant more than 2–3 feet under the excess load.

Probiotic Solutions® BIO ENERGIZER® was batch fed into 2 SBRs daily. Within 1 week, operators were able to decant 8 feet of supernatant from each SBR. The dosage rate was increased when the factory use of stored potatoes increased starches and residual BOD in the wastewater.

BIO ENERGIZER® applied over a period of 2 months to the wastewater treatment plant resulted in increased microbial activity, reduced filament and foam, improved decanting, reduced accumulated sludge and sludge hauling costs.

Probiotic Solutions® BIO ENERGIZER® is a formulation of nutrients, organic acids, natural biological stimulants, and energy systems that balance the natural microbial ecosystem to increase bio-oxidation capacity in lagoon systems. BIO ENERGIZER® is a broad-spectrum bio-activator containing over 30 essential microbial growth-promoting ingredients. Wastewater facility operators have been using BIO ENERGIZER® for many years to cut their sludge-hauling costs. For more information, go to www.probiotic.com.

Read the Case Study here. 

Bio Energizer® Reduces Cost and Turbidity in Paperboard Lagoons

BOD & COD Discharges in Paperboard Lagoon

A paper mill wastewater facility was treating 940 tons of paper bags, recycled linerboard, and corrugating medium, daily. The mill was interested in improving wastewater operating efficiency and lowering operating expenses over their standard polymer usage. The plant was experiencing filamentous bacteria, solids, and bulking issues in the final clarifier. It was discharging 4,000 pounds of fiber per day into the Ohio river.

The combined effluent from two anaerobic ponds filled an aerobic pond before clarification. After clarification, effluent was discharged to the river and the biosolids were processed by a belt press for thickening before landfill application.

A 9-month test was developed in which Probiotic Solutions® BIO ENERGIZER® was administered to make nutrients more available to wastewater microorganisms, thereby stimulating natural bio-oxidation processes and enhancing sludge reduction. BIO ENERGIZER® applied over a period of 9 months resulted in reduced filamentous bacteria, bulking issues, and total suspended solids (TSS.) Turbidity in the effluent dramatically improved with $50,000 in polymer savings in the final clarifier. Additionally, fiber discharge was reduced, as were the BOD and COD levels in the effluent.

Probiotic Solutions® BIO ENERGIZER® is a formulation of nutrients, organic acids, natural biological stimulants, and energy systems that balance the natural microbial ecosystem to increase bio- oxidation capacity in lagoon systems. Wastewater facility operators have been using BIO ENERGIZER® for many years to cut their sludge-hauling costs. For more information, go to www.probiotic.com.

See the Case Study here.

Do Constructed Wetlands Improve Water Quality?

wetlands at sunset

Constructed wetlands, which mimic natural wetlands, treat municipal and industrial wastewater, mine drainage, small business and household greywater, animal wastes, and agricultural and stormwater runoff. They are recommended by regulatory agencies as a best management practice to control urban runoff.

Shallow Water Ecosystems

Constructed wetlands are shallow-water ecosystems that mimic natural wetlands. The wetland ecosystem—water, plants, microorganisms, sunlight, substrate, and air—filters and treats wastewater. Water quality is improved through physical, biological, and chemical processes, and the risk of pollution from runoff is reduced.1

Surface or subsurface water is present in both constructed and natural wetlands. Constructed wetlands are also called artificial wetlands, engineered wetlands, man-made wetlands, greywater wetlands, reed beds, soil infiltration beds, or treatment wetlands.

Pollutants and Pathogens Are Removed

Treatment through constructed wetlands removes pollutants, organic matter, metals, hydrocarbons, nitrogen, phosphorus. A variety of pathogens is also removed, although wetlands are not specifically designed to do so. In addition, high organic loads, as found in agricultural wastewater, can be reduced from wetland treated wastewater.2

Some wastewaters are treated exclusively by constructed wetlands. Generally, however, wastewater influent enters the wetland after primary treatment that separates solids from liquids. As such, wetlands serve as a secondary or tertiary treatment, sanitizing effluent prior to water reclamation.

cattails in wetlandWetland Construction

Wetlands are constructed inside a basin that is lined with plastic, concrete, or clay. The filter is a substrate of sand and gravel.  The shallow depth, slow flow, and saturated substrates in wetlands encourages settling.2,3

Vegetation—such as bulrushes, reeds, cattails, and duckweed—is vital to the removal of metals and other pollutants. Heavy metal uptake varies among plants. Plant roots and rhizomes loosen substrate medium, increasing water movement through the rhizosphere. Water is channeled through holes in the substrate caused by decaying plant roots.2,4

The Treatment Process

Treatment occurs as wastewater flows through the substrate and the rhizosphere. The slow flow allows longer periods of contact between wastewater and wetland surfaces. A diverse community of aerobic and anaerobic microorganisms is attracted to the organic/inorganic materials and the opportunities for gas/water interchanges. Microorganisms attach to roots and rhizomes, forming a biofilm that breaks down pollutants and organic matter. Nutrients–carbon, nitrogen, and phosphorus–provided by plant litter and decomposing plants feed the microbial process. 2,4

In the substrate, suspended solids are filtered out of the wastewater and pathogens are removed by filtration and adsorption. The saturated substrate creates an oxygen-deprived environment in which oxygen is consumed more rapidly than it is replaced. This low-oxygen environment prevents the growth of plants unfit for a wetland environment.4

The low-oxygen environment is also essential to the elimination of pollutants. Nitrogen is broken down and nitrogen gas is released harmlessly into the atmosphere. Phosphorus is collected and stored within a wetland system by binding phosphorus in organic matter or by coprecipitation with iron, aluminum, and calcium. Likewise, heavy metals are sequestered in the substrate or absorbed by plants.2,4

Surface Flow and Subsurface Flow

The two types of constructed wetlands are surface flow or floating treatment wetlands, and subsurface flow or reedbed systems. Vegetation floats on the water in floating or surface flow wetlands. Surface flows are horizontally flowing, meaning wastewater flows parallel to the substrate.2,5

In subsurface wetlands, plants grow in gravel. Water may flow horizontally or vertically—in which case, wastewater moves down through plants and substrate. Whether vertical or horizontal, in a subsurface wetland, wastewater flows between plant roots and never surfaces.4,6

Water Reclamation

Discharged water is controlled by an outlet structure that allows seasonal and maintenance adjustments in water depth. Wetland-treated water may be stored for reclamation or land-application. Water may also be discharged to the water supply where allowed by regulations.7

Benefits and Disadvantages

Besides improving the quality of wastewater effluent, constructed wetlands cost less to build and power than conventional treatment. Furthermore, they are cheaper to operate and require fewer man-hours and less operational expertise. Ancillary benefits include providing wildlife habitats, recreational sites, and educational and research opportunities. Wetland construction also appeals to engineers, wastewater treatment operators, biologists, and environmentalists

heron in wetlandsSome advantages of wetland construction include:

  • Improved water quality
  • Water conservation and reuse
  • Flood storage
  • Attracting wildlife
  • Habitats for fish and wildlife
  • Low construction costs
  • Low energy requirements
  • Low operating costs
  • Minimal operational attention and expertise
  • Education and research
  • Recreational opportunities for photographers, bird watchers, and hunters1,3

Some of the disadvantages include:

  • Some complex pollutants cannot be successfully filtered
  • Require more land
  • Subsurface flows can clog
  • Surface flows attract mosquitos,
  • Surface flows are also susceptible to odor and algae2

The benefits far outweigh the disadvantages. In fact, many issues can be avoided by proper planning and operation. Fish and wildlife can reduce mosquitoes, and a canopy of wetland vegetation can prevent algae. Odor can be alleviated with primary treatment. Odor can also be prevented by maintaining a layer of gravel above the aquifer, controlling water levels, and thinning wetland plants to encourage water flow.6

Issues caused by clogged subsurface flows can be averted by avoiding the use of fine mediums in the substrate. Reducing organic overload, and practicing good wastewater pre-treatment also helps prevent clogs. Because there is no standing water in subsurface flow wetlands, they are odorless, don’t attract mosquitos, and are less susceptible to cold temperatures. Additionally, subsurface flow wetlands also occupy less area than surface flow wetlands and are better at the removal of pathogens.7

A Growing Trend

Constructed wetlands are used throughout the world to treat wastewater and runoff, improving water quality. They may also be used residentially, following primary septic tank treatment. Using constructed wetlands to treat greywater is a growing trend in water conservation. Finally, reclamation and reuse of wetland-treated water is a proactive step to solving the global water crisis.

For more information about wetland construction and regulations, see the EPA Constructed Wetlands page.


  1. J Gelt (1997). Constructed Wetlands: Using Human Ingenuity, Natural Processes to Treat Water, Build Habitat, University of Arizona Water Resources Research Center,
  2. Constructed Wetland, Wikipedia,
  3. Constructed Wetlands Factsheet, National Small Flows Clearinghouse,
  4. A Handbook of Constructed Wetlands, EPA,
  5. (2000). Wastewater Technology Fact Sheet: Free Water Surface Wetlands, EPA,
  6. (2000). Wastewater Technology Fact Sheet: Wetlands: Subsurface Flow, EPA,
  7. (2008). Constructed Wetland, NRCS,

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Unique Water Towers That You Should See

Al Khobar water tower

Al Khobar, Saudi Arabia

From globes to lighthouses, historical and refurbished water towers around the world are eye-catching landmarks.

Countless Unique Water Towers

watermelon water tower

Luling, TX

Water towers have been painted with flags, globes, and smiley faces. There are baseball towers, golf ball towers, and even an eight-ball tower (Tipton, Missouri).  A Groucho Marx water tower is located in Limestone, Maine. A depiction of Kermit the Frog has been painted on the water tower in Kermit, Texas. The Rosemont water tower in Chicago resembles a rose. In Niles, Illinois, the water tower is a representation of the Leaning Tower of Pisa. The Earthoid water tank in Germantown, Maryland, is an artistic rendering of the planet’s oceans, complete with typhoons.

Water Towers that Look Like Food

There’s an apple water tower in Jackson, Ohio; a peach in Gaffney, South Carolina; a strawberry in Poteet, Texas; a pumpkin in Circleville, Ohio. Luling, Texas, recognizes the watermelon industry with its watermelon water tower and annual Watermelon Thump celebration. In Rochester, Minnesota, a corn cob water tower––painted to show the correct number of kernels per row–– has been upgraded with nightlights. A water tower in Lakeland, Florida, looks like a birthday cake, complete with candles.

Ketchup Water Tower

Collinsville, IL

The largest bottles of ketchup and of bourbon are in Collinsville, Illinois, and Louisville, Kentucky, respectively. Westminster, Colorado, features a water tank decorated with the Savery Savory Mushrooms label. There is a can of Sprite in Cincinnati, Ohio; a Campbell’s soup can in Camden, New Jersey; and a can of Libby’s fruit salad in Sunnyvale, California. The Dixie cup water tower is in Lexington, Kentucky. In honor of actress Virginia Christine, Stanton, Iowa, erected two water towers––one that looks like a teacup and the other, a coffee pot. Representing its sister city, Tingsryd, Sweden, the town of Lindström, Minnesota, features a teapot water tower.

Lindstrom water tower, MN

Water Towers Across the Sea

house water tower

Thorpeness, Suffolk

Similarly, a Swedish coffee pot water tower represents Kingsburg, Sweden. House in the Clouds is a water tower disguised to look like the local buildings in Thorpeness, Suffolk. It once included a home and is now a bed and breakfast. An historic water tower in Berlin looks like a black lighthouse. In Saudi Arabia, the Al Khobar water tower that sits on an island lights up purple and green at night. It is a tourist attraction that houses a restaurant and a viewing balcony as well as the city water supply. The striped Riyadh water tower in Saudi Arabia also features a restaurant and an observation deck. Groups of blue striped “mushroom towers” in Kuwait are similar in appearance to the Riyadh tower. The spherical Kuwait towers, which were built by the same Swedish engineering company, feature a coffee house and ballroom. The pyramid-shaped Svanke water tower on the island of Bornholm, Denmark, was inspired by old navigational symbols. In Kizu, Japan, the spiral Kizumanami water tower, which closely resembles the Al Mulwiya mosque of Samarra, was inspired by the regional bamboo.

spherical water towers

Kuwait Towers

A Tribute to Water Towers

The non-functional, stained-glass Water Tower that sits on a rooftop in Brooklyn, New York, is a tribute to the rooftop water towers in New York City. Sculptured from salvaged plexiglass and steel, it is lit by sunlight during the day and features light shows at night. It’s a stunning reminder of the importance of clean, sustainable water.

What does your water tower look like? Does it have an interesting history? Let us know what unique water towers you’ve seen during your travels.


yellow striped water tower

Riyadh, Saudi Arabia

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Bio Energizer® Improves SVI by 50% at Citrus Plant Wastewater Treatment

citrus production

A citrus plant struggled with poor settling in the clarifier of its wastewater treatment, which caused the sludge blanket to remain high. Even at a low flow rate of 1.2 million gallons per day (MGD), the high sludge blanked allowed less than 18” of free board. The slightest flow increase caused solids to carry over the weir with the effluent. Since the citrus plant frequently produced wastewater flows 1.5 to 2.5 MGD, the wastewater treatment plant continued to suffer from solids washout and clarifier effluent total suspended solids (TSS) excursions. The citrus plant wastewater treatment was a 6 million gallon per day (MGD) traditional aeration system with secondary clarification.

The Wastewater Manager’s overall objective was to obtain better settling in the secondary clarifier by improving the quality of the biological sludge. High sludge blankets and solids washouts were occurring frequently. A sludge volume index (SVI) of 200 indicated a poor quality sludge with bulking problems. All attempts to cure the bulking, including return sludge chlorination, provided little relief.

To activate the biological processes in the treatment system, Probiotics Solutions® BIO ENERGIZER® was fed directly into the influent flume at the aeration basin. Return activated sludge (RAS) chlorination was continued.

Sludge settling rates began to improve after about 30 days of treatment with BIO ENERGIZER®. A 50% improvement in SVI reduced the sludge blanket and put a stop to TSS excursions into the effluent, improving operation efficiency of the citrus plant wastewater treatment.

Probiotic Solutions® BIO ENERGIZER® is a formulation of nutrients, organic acids, natural biological stimulants, and energy systems that balance the natural microbial ecosystem to increase bio-oxidation capacity in lagoon systems.

Read the Case Study here.

Industrial Wastewater Treatment for Corn Processing Plant

Bio Energizer Treatment for Corn Processing Plant

Within a few months of operation, a lagoon and spray field system at a corn processing plant in Indiana began giving off offensive odors. Chemical oxygen demand (COD) levels in the anaerobic and aerobic lagoons climbed to 8,000 mg/L and 4,000 mg/L respectively. The pH in the anaerobic lagoon was dropping dangerously low for methane production. Attempts to resolve the issues with bacteria, odor masking products and lime were unsuccessful and short-term at best. Lime settled to the bottom of the lagoons, temporarily raising pH and reducing odors. The odor soon became unmanageable and an annoyance to neighbors.

In March, Probiotic Solutions® BIO ENERGIZER® was administered to the anaerobic lagoon at the rate of 1 gpd. Within 4 weeks of initial application, pH began rising and the odors were dramatically reduced.

BIO ENERGIZER® applied over a period of 30 days to the anaerobic lagoon system of the corn processing wastewater treatment plant resulted in biochemical oxygen demand (BOD) and COD reduction, odor reduction, and improved pH levels. COD levels in surplus effluent that was pumped to the city dropped from 8,000 mg/L to 200 mg/L, saving the plant $22,000 per month in excess COD charges.

Product Information

Probiotic Solutions® BIO ENERGIZER® is a formulation of nutrients, organic acids, natural biological stimulants, and energy systems that balance the natural microbial ecosystem to increase bio-oxidation capacity in lagoon systems. BIO ENERGIZER® is a broad-spectrum bio-activator containing over 30 essential microbial growth-promoting ingredients. 

See Case Study here.

Bio Energizer, Micatrol & Bio Feed Reduce COD and Stabilize Wastewater Treatment for Plastic Producer

chartA plastic manufacturer in Taiwan needed a new process to efficiently treat elevated incoming chemical oxygen demand (COD) to comply with stringent EPA regulations for effluent discharge. The plant is an activated sludge treatment system with an influent of approximately 2,000 cubic meters per day (CMD) which is equivalent to approximately 530,000 gallons per day (GPD). The plant was unable to bring the plant into compliance using alternative technologies. 

A 60-day test was developed in which liquid probiotics were introduced into the wastewater stream. BIO ENERGIZER®, Bio Feed, and MICATROL® were administered to make nutrients more available to wastewater microorganisms, thereby stimulating natural bio-oxidation processes and enhancing COD reduction. The test involved an initial  dose of 7 ppm for 30 days. After the initial treatment period, the dose was reduced to 3 ppm and watched carefully. Samples were frequently collected at the influent as well as the effluent to test for COD. 

Probiotic Solutions® BIO ENERGIZER®, Bio Feed, and MICATROL® were able to keep the biome and effluent COD stable under normal operating conditions and during times of system overload. The probiotics applied to the plastic manufacturer’s wastewater treatment system not only improved COD reduction, but also reduced odors, improved sludge settleability, decreased the volume of chemicals required to control pH, and improved turbidity.

Probiotic Solutions® BIO ENERGIZER® is a formulation of nutrients, organic acids, natural biological stimulants, and energy systems that balance the natural microbial ecosystem to increase bio-oxidation capacity in lagoon systems. BIO ENERGIZER® is a broad-spectrum bio-activator containing over 30 essential microbial growth-promoting ingredients. 

See the Case Study here.

Recycled Sewage: What Are We Putting on Our Farmland?

farm fields

Sewage sludge is a controversial input for farmers to use. Considering the toxins in today’s wastewater, are our treatments and regulations effective in eliminating micropollutants from sludge?

Sewage sludge––otherwise known as biosolids––is given away to farmers as a fertilizer. This government-sanctioned program is considered an environmentally-friendly solution to wastewater pollution.

Organic Means Derived from Living Organisms

Biosolids are approximately 70 percent organic matter and provide two of the three principal nutrients required by crops: nitrogen and phosphorus.1In this case, “organic” is defined as “of, relating to, or derived from living organisms.”2

Sludge Is Not Free of Toxins

It is important to note that the term “organic matter,” as it relates to biosolids, does not mean free of chemicals, pesticides, or toxins. Sludge is not only processed manure; wastewater comes from a combination of household and industrial waste. It contains micropollutants.

Sludge Contains Micropollutants

Micropollutants are various substances that have adverse environmental effects. This includes polymers, pharmaceuticals, flame-retardants, household cleaning supplies, heavy metals, street drugs, toxicity from industry, and biological waste. Additional toxic compounds can be created through the processing of micropollutants.

Industrial Wastewater Increases Toxicity

The level of micropollutants in sludge varies depending on the influent. Many municipalities receive influent from numerous industrial companies, multiplying the contaminants in the sludge. The Minnesota Twin Cities’ Metro Plant, for example, receives influent from over 600 industries.4

Wastewater Treatment Plants Do Not Eliminate Micropollutants

Wastewater treatment plants (WWTPs) remove solid organic matter and pathogens. Some toxins may degrade during the process. However, many treatment plants are outdated, and even current plants weren’t designed to treat micropollutants.5

Wastewater Treatment Is Improving

Luckily, wastewater treatment is improving with plant upgrades. Disinfection, for example, can be done with UV light, without the use of chlorine. Ozonation degrades micropollutants through oxidation. The use of activated carbon removes micropollutants through adsorption.

Sludge reduction is a non-toxic step to protect the environment that older treatment facilities can take now. Sludge can be reduced with Bio Dredge®for WWTPs or Septicure®for septic systems, which naturally enhance biological degradation.


In addition to updated treatments, metals and pathogens are regulated in the use of land-applied biosolids. Federal and state regulations and quality standards governing the use of sewage sludge are set forth in the EPA guide, Land Application of Sewage Sludge, also known as 503 regulations:

  • Heavy metal contamination limitations
  • Pathogens limitations
  • Vector attraction reduction
  • Site restrictions
  • Crop harvest restrictions
  • Record keeping
  • Reporting1

It is important to note that, although the terms “sludge” and “biosolids” are interchangeable, sludge that doesn’t meet regulations is not used as for biosolids. Sludge and biosolids are frequently tested both to check the effectiveness of treatment and to confirm regulatory compliance. Additionally, controls have been established to ensure regulations are met before, during, and after land application.6

Prior to land application, biosolids must meet all pollutant, pathogen reduction, and vector attraction reduction requirements. Nitrogen, phosphorus, and potassium content of biosolids is analyzed. Application rate is calculated for the crop based on current content and past applications.6

During land application, the target application rate is checked against the actual application rate. Records must be kept of application sites, weather, all involved parties, as well as any neighbor observations. Finally, records must be filed, regulatory reports must be submitted, and relevant information must be provided to the farmer.6

Says Jared Alder, Executive Senior Director of Probiotic Solutions®:

As long as the proper steps are undertaken, placing biosolids on farm land is acceptable. It’s like placing fertilizer on your grass each winter. We need to ensure that proper procedures are followed when applying any type of biosolids onto crops that are used for food consumption. 

Checks-and-Balances Make Biosolids a Safe Agricultural Input

Although we now have a multitude of toxins coming from today’s industrial waste, upgrades in treatments, regulations and strict quality control can prevent biosolids from being a risky agricultural input.

Read part one of this two-part series: Land-Applied Sewage: Do Farmers Benefit from Recycled Sewage?


  1. R Cowell (2010). Sludge, a free fertilizer for farmers, can pose health and environmental risks, Indy Week, https://indyweek.com/news/sludge-free-fertilizer-farmers-can-pose-health-environmental-risks/
  2. (2016) Merriam-Webster, https://www.merriam-webster.com/dictionary/organic#other-words
  3. B Ellison (2015). Removing toxic micropollutants from wastewater: an interview with Dr. Michael Cimbritz, AZoCleantech, https://www.azocleantech.com/article.aspx?ArticleID=579
  4. B Bienkowski, (2014). Drugs, chemicals seep deep into soil from sewage sludge, Scientific American, https://www.scientificamerican.com/article/drugs-chemicals-seep-deep-into-soil-from-sewage-sludge/
  5. M McFarland (2001). Chapter 4: Control of biosolids quality, Biosolids Engineering, https://www.globalspec.com/reference/54377/203279/chapter-4-control-of-biosolids-quality
  6. National Biosolids Partnership (2011). National Manual of Good Practice for Biosolids, https://www.wef.org/globalassets/assets-wef/3—resources/topics/a-n/biosolids/national-biosolids-partnership/manual-of-good-practice-for-biosolids-v2011.pdf

Please note that this information does not reflect the views of Bio Huma Netics, Inc., the developer of Probiotic Solutions. This article is provided for informational purposes only.

Land-Applied Sewage: Do Farmers Benefit from Recycled Sewage?

seedlings in soil

Recycled sewage is a valued resource to farmers. Disposing of treated sewage by land-application is not only government-sanctioned, it’s considered environmentally responsible. 

Clean Water Raises Sludge Problems

The U.S. Clean Water Act of 1972 that required municipalities to remove 85 percent or more of contaminants from treated wastewater significantly reduced water pollution. Because it opened a door to recycled water use, the act also created a sludge disposal issue. Sludge is a byproduct of residential, commercial, and industrial wastewater treatment, produced when solid waste is separated from liquid waste through settling.

Solving the Growing Sludge Crisis

Wastewater treatment plants (WWTPs) in the U.S. create billions of tons of sewage sludge every year. This poses a growing sludge disposal concern. However, according to the Water Environment Federation (WEF) and the EPA, sludge becomes a valued resource if it is land-applied to farm-fields. This approach to sludge disposal was government-sanctioned in the United States in the late 1970s.1

Marketing Sludge

In the 1990s, the National Federation of Wastewater Treatment Plant Operators held a contest for a more marketable term for sewage sludge. “Biosolids” was chosen from 250 suggestions. The term biosolids is used to describe sludge in Australia and the U.K., as well as in the U.S.2

What Farmers Always Knew About Sludge

While controversial among activists and consumers, land application of septic and sewage sludge is not a new practice. It’s no secret that manure––whether from cows, pigs or chickens––is beneficial to crops and soil. It’s no secret among farmers that manure from humans is also beneficial. Farmers have been land-applying raw sewage––at one time called “Night Soil”––to fields and crops for centuries.3

Beneficial Properties of Sludge

The organic matter in sludge conditions and improves soil structure. It is also known to improve water-holding capacity and increase beneficial soil microorganisms. Biosolids have high nutrient value. Nitrogen and phosphorus act as fertilizer. The phosphorus in sludge is valuable to farmers, as phosphorus is a necessary and costly fertilizer.2

How Sludge Is Made

WWTPs receive incoming residential and commercial wastewater, as well as pre-treated industrial wastewater.

  • Incoming wastewater (influent) goes through a screening process.
  • Non-biodegradable solids are removed to a landfill.
  • Sludge is thickened to decrease its volume.
  • Sludge is treated and decomposed by beneficial bacteria (microorganisms or microbes) and dewatered to a semi-solid state.
  • Sludge is composted by blending with a carbon source––such as sawdust or straw––and oxygen. Beneficial bacteria digest the compost. Heat produced by composting kills parasites and pathogens.
  • Lime may be blended into the sludge to bring the pH above 12, which kills the pathogens.4

Forms of Recycled Sludge

Sewage sludge takes many forms, including:

  • slurry,
  • dry powder,
  • humus-like organic matter,
  • granular,
  • pellet,
  • cake,
  • lime-amended biosolids, and
  • composted.4

How Sludge Is Applied

Farmers may till or plow dry biosolids into the ground. Alternately, they may spray a slurry onto the soil, or inject it directly into the soil. The leading application of biosolids is agricultural land application. Other uses include composting, incineration, use in land rehabilitation, forestry, and landfill.

Restrictions for Using Recycled Sewage

Biosolids are broken down into two classes: Class A, which is considered sterile, and Class B, which is for non-consumable use. Class B biosolids, which are permitted to contain pathogens, may not be used on food or feed crops. In addition, Class B biosolids are not for use on turf, for grazing animals, areas with public exposure, or for use on lawns and gardens.3

Because they are considered sterile, restrictions don’t apply to Class A biosolids. In fact, Class A biosolids are sold as compost to home gardeners under a variety of brands: EarthBlends, Earthlife, EKO Compost, Granulite, Growers’ Blend by Earthwise Organics, Miracle-Gro Organic Choice Garden Soil, Nitrohumus, Nu-Earth, Nutri-Green, Oceangro, OrganaGrow, and ORGRO. (Note: this list is not all-inclusive.)5

Do you put recycled sludge on your garden or farmland? How do you know if it’s safe? Tune in next week to read part two of this two-part series: Recycled Sewage: What Are We Putting on Our Farmland?


  1. (1994) EPA Land Application of Sewage Sludge: A Guide for Land Appliers on the Requirements of the Federal Standards for the Use or Disposal of Sewage Sludge, 40 CFR Part 503, EPA, https://www.epa.gov/sites/production/files/2018-11/documents/land-application-sewage-sludge.pdf
  2. R Cowell (2010). Sludge, a free fertilizer for farmers, can pose health and environmental risks, Indy Week, https://indyweek.com/news/sludge-free-fertilizer-farmers-can-pose-health-environmental-risks/
  3. (2011) Class B  biosolids, Sourcewatch, https://www.sourcewatch.org/index.php/Class_B_Biosolids
  4. (1997) Sludge Treatment and Disposal: Management Approaches and Experiences, European Environment Agencyhttps://www.eea.europa.eu/publications/GH-10-97-106-EN-C/file
  5. About sewage sludge: branded products containing sewage sludge, Sludge News, http://www.sludgenews.org/about/sludgenews.aspx?id=5

Please note that this article does not reflect the views of Bio Huma Netics, Inc., the developer of Probiotic Solutions. This information is intended to be informational.

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