In a sewage or wastewater collection system, raw sewage travels underground through sloped pipelines (also called gravity pipelines). However, when the elevation of the source is not sufficient for gravity flow, digging for sewer pipes in excessive excavation depths is necessary. Installing a wastewater lift station at specific points in a gravity ...
Many rural communities across the United States rely on wastewater treatment processes that fall short of environmental and public health protection standards. The U.S. Environmental Protection Agency (EPA) and the U.S. Department of Agriculture (USDA) have introduced several funding mechanisms to improve water and wastewater infrastructure in smal...
Lagoon wastewater treatment systems are mostly found in small, rural and tribal communities in the U.S. and are used as the only method of treating community wastewater. Small communities of fewer than 3,000 residents usually prefer sewage lagoons because of their energy efficiency and low costs. However, recent wastewater treatment requirements, i...
To help public sector officials minimize fire and explosion hazards, the National Fire Protection Association (NFPA) publishes preventative requirements, fire codes and building standards. Used in alignment with state building codes, the NFPA 820 standard is specific to wastewater collection, transportation and treatment plants. Methane generated b...
Hindsight might be 20/20, but foresight is pretty essential when it comes to infrastructure planning. Too often, communities grow in a piecemeal type of way: A subdivision is built, so sewer lines are put in to serve the neighborhood. A strip mall goes up next door, tying into those same lines. The once quiet street above the sewer that was easy to...
Adding air directly to wastewater is considered a critical step in wastewater treatment because it facilitates the biodegradation of organic pollutants. However, this vital aeration process also consumes the most energy at wastewater treatment plants (WWTPs). Given that aerobic reactors in the secondary treatment activated sludge process account fo...
Aeration – or the addition of oxygen – is one of the most critical and energy-intensive processes in wastewater treatment, consuming up to 50 to 60% of the overall energy required by a wastewater treatment plant (WWTP). Aeration produces dissolved oxygen (DO) to facilitate the growth of microorganisms and is used across all stages of wastewater tre...
Long-term, comprehensive planning is key to successful wastewater treatment systems. Without a strong plan, a community's ability to facilitate development may be limited by its wastewater infrastructure – or worse, its rivers, lakes, streams and residents' basements may be at risk from failing wastewater infrastructure. A Master Plan will consider...
Under the auspices of the Safe Drinking Water Act, the U.S. Environmental Protection Agency applies the secondary treatment standards for wastewater as national minimum requirements for discharges from wastewater treatment plants to U.S. surface waters. Depending on receiving water conditions or specific state regulations demanding higher-quality e...
During the wastewater treatment process, the primary and secondary stages aim to remove the majority of suspended solids and organic contaminants before the effluent progresses to tertiary treatment. The primary treatment removes nearly 60% of settleable solids and the secondary treatment uses bacterial decomposition to remove nearly 85% of organic...
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 ...
