In wastewater treatment, the clarification process removes suspended solids using gravity. The secondary function of a wastewater clarifier is to remove accumulated scum or floating matter on the surface. This blog post discusses the primary and secondary clarification processes, the types of wastewater clarifiers and how an experienced wastewater ...
Even after the primary physical treatment, wastewater contains large quantities of dissolved and colloidal organic material. Though primary treatment can reduce biochemical oxygen demand by as much as 30%, the treated effluent still requires a secondary treatment that uses complex biological processes to remove organic contaminants. The goal ...
With more than 2,800 contaminated sites in 50 states, public concern about per- and polyfluoroalkyl substances (PFAS) contamination has grown, yet a great deal about these so-called "forever chemicals" remains unknown. Faced with such uncertainty, the U.S. Environmental Protection Agency (EPA) has set no formal limits on a moving target like PFAS d...
Conventional wastewater treatment involves several physical, chemical and biological processes to remove solids, organic matter and nutrients from wastewater. Primary treatment removes coarse solids and other large materials from wastewater. At this stage, municipal wastewater treatment technologies eliminate organic and inorganic solids and floata...
The total phosphorus amount indicates how much phosphorus — as dissolved or particulate states — exists in a given wastewater sample. As an essential nutrient for plants and animals comprising aquatic ecosystems, the amount of phosphorus functions as a critical parameter to determine the health of waterways across the U.S. The slightest increase in...
E. coli, one of the most common pathogens found in domestic wastewater, can cause gastroenteritis. This bacteria, which often lives in the digestive system, are one of many pathogens that can contaminate drinking and surface water. However, most pathogens are difficult to measure directly. Instead, a pathogen indicator can help detect fecal contami...
When building a wastewater treatment plant (WWTP), municipal leaders are often baffled by their options and associated costs. To get started, they can estimate wastewater treatment plant construction costs at three increasingly granular levels. First-order costs: All construction costs for complete treatment plants. Second-order costs: Costs for sp...
Preventative maintenance helps maintain or extend the life of a product by proactively performing inspections and maintenance in a timely manner. This concept might seem simple. For example, if you purchase a new car, it initially has little maintenance. If you keep up with scheduled oil changes and have recommended parts inspected periodically, it...
To protect receiving bodies of water and avoid eutrophication, the U.S. Environmental Protection Agency (EPA) has encouraged states to adopt Total Nitrogen and Total Phosphorus Numeric Water Quality Standards. These numeric criteria help identify and list impaired waters, develop Total Maximum Daily Loads (TMDLs) and write National Pollutant Discha...
Municipal wastewater treatment systems across the U.S. are facing pressure to improve their performance without increasing costs. However, the average wastewater treatment plant life expectancy is 40 to 50 years, and treatment equipment typically lasts 15 to 20 years. As a result, a majority of Publicly Owned Treatment Works (POTWs) established in ...
The U.S. Environmental Protection Agency (EPA) has established effluent guidelines for wastewater discharged to surface waters. The effluent limits are enforceable parameters that dictate the amount and type of pollutants present in water facilities' discharge, including Publicly Owned Treatment Works (POTWs). Below, we discuss the types of effluen...
Operation and Maintenance (O&M) at a Publicly Owned Treatment Work (POTW) is a constant battle against the forces of time and nature. The contaminants being treated can deteriorate reinforced concrete while turbulent flows and suspended solids can erode steel structures. This highlights the need for a regular wastewater treatment plant maintena...
The United States Environmental Protection Agency (EPA) shared information on the Drinking Water and Wastewater Infrastructure Act, which comprises the water and wastewater provisions of the Infrastructure Investment and Jobs Act. The Senate approved the Act in August 2021, and the House passed it Nov. 5. We eagerly wait to see the difference addit...
In the 1970s and 1980s, federal grants paid a majority of the costs to build or expand wastewater treatment plants. Many Publicly Owned Treatment Works (POTWs) constructed then had a lifespan of 40 to 50 years and have now reached the end of their service lives. Such wastewater treatment facilities face numerous challenges, including design inadequ...
Energy represents a significant expense across all stages of the wastewater treatment process — from raw sewage collection to effluent discharge. Wastewater treatment plants throughout the U.S. consume more than 30 terawatt hours per year of electricity, amounting to $2 billion in annual electric costs. Estimates suggest that electricity costs cons...
Iowa wastewater facilities design standards were adopted in the late 1970s and early 1980s. Today, the Iowa Department of Natural Resources (DNR) supplements these specifications with the 10 States Standards to help municipalities design or upgrade Publicly-Owned Treatment Works (POTWs) in the state. However, the detailed design standards for POTWs...
Contaminant type and quantity, coupled with local effluent regulations, constitute key factors that influence a municipality's approach to wastewater treatment. Large amounts of oxygen-demanding substances, nutrients and synthetic organic chemicals in effluents today pose challenges far more complex than what most Publicly Owned Treatment Works (PO...
The Clean Water Act (CWA) of 1972 paved the way for the mass-scale construction of wastewater treatment plants across the United States. The significant improvement in the quality of effluent water at the time could be credited to these treatment plants, or Publicly Owned Treatment Works (POTWs). However, most treatment plants at the time offered a...
Understanding and meeting municipal wastewater effluent standards will improve the quality and sustainability of your community, and it is not a challenge you have to meet on your own. Municipalities representing a wide range of sizes, densities and resources have met these standards. With the right partner to guide you through the process - a...
South Beloit and Integrated Fixed-Film Activated Sludge Treatment (IFAS) To prepare for nitrogen and phosphorus removal requirements, the City of South Beloit, Illinois, turned to Fehr Graham to plan and design its Wastewater Treatment Plant to remove unwanted nutrients. The improvements, designed by Fehr Graham in 2018, are under construction. The...
