What is the definition of sewage according to the provided text?

Sewage, also referred to as domestic sewage, domestic wastewater, or municipal wastewater, is a type of wastewater generated by a community of people. It is typically transported through a sewer system.

What are the two primary sub-types of sewage mentioned in the text?

The text identifies two main sub-types of sewage: greywater, which comes from sinks, bathtubs, showers, dishwashers, and clothes washers, and blackwater, which is the water used to flush toilets along with the human waste it carries away. Greywater is generally considered safer and easier to treat due to lower pathogen content.

Besides water and human waste, what other materials can be found in sewage?

Sewage can also contain soaps and detergents, food waste from dishwashing (potentially increased by garbage disposal units), toilet paper (where bidets are not used), macro-pollutants, micro-pollutants, some municipal solid waste, and pollutants from industrial wastewater.

How is sewage typically transported from a building to a treatment facility or disposal site?

Sewage usually travels from a building's plumbing either into a sewer system, which carries it to a treatment plant or disposal site, or into an onsite sewage facility. Collection from multiple households typically occurs in sanitary sewers or combined sewers.

What factors can influence the amount of sewage flow per person in a community?

Several factors influence water consumption and, consequently, sewage flow rates per person. These include water availability, water supply options, climate (warmer climates may increase consumption), community size, economic level, industrialization, water metering, water cost, and water pressure.

What are the main parameters measured to assess the strength or quality of sewage?

The primary parameters measured to assess sewage strength or quality, as well as to determine appropriate treatment options, include solids, indicators of organic matter, nitrogen, phosphorus, and indicators of fecal contamination.

What types of pathogens are commonly found in sewage?

Sewage contains pathogens that originate from fecal matter. The four main types identified are pathogenic bacteria, viruses, protozoa (in the form of cysts or oocysts), and helminths (in the form of eggs).

How is the organic matter content in sewage typically quantified?

The organic matter content in sewage is commonly quantified using indirect methods that measure oxygen consumption. The primary methods used are Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD).

What are the general options for sewage disposal mentioned in the text?

General sewage disposal options include dilution, which utilizes the self-purification capacity of water bodies, discharge through marine outfalls, land disposal, and the use of sewage farms. All these methods carry a risk of water pollution.

What is the definition of blackwater in a sanitation context?

In a sanitation context, blackwater refers to wastewater from toilets that likely contains pathogens transmissible via the fecal-oral route. It typically consists of feces, urine, water, and toilet paper from flush toilets.

How does greywater differ from blackwater, and what are its potential uses?

Greywater is wastewater from sinks, baths, washing machines, and dishwashers that does not contain fecal contamination. Because it has fewer pathogens than blackwater, greywater is generally safer to handle and easier to treat and reuse onsite for purposes like toilet flushing or irrigation.

What is the typical temperature characteristic of sewage compared to the ambient environment?

The temperature of sewage tends to be slightly higher than that of drinking water but is generally more stable than the ambient temperature.

How does the odor of fresh sewage differ from that of older, septic sewage?

Fresh sewage typically has an "oily" and relatively unpleasant odor. Older or septic sewage, however, develops a foul odor due to the presence of hydrogen sulfide gas and other decomposition by-products.

What is the usual pH range for sewage?

The pH value of sewage is typically near neutral, generally falling within the range of 6.7 to 8.0.

What is the approximate composition of sewage in terms of water and solids?

Sewage is primarily composed of water, with solids making up less than one part per thousand. This means sewage is roughly 99.9% pure water, with the remaining 0.1% consisting of dissolved or suspended solids.

How is the organic matter in sewage classified?

The organic matter in sewage is classified in two ways: by its form and size (suspended/particulate or dissolved/soluble) and by its biodegradability (inert or biodegradable).

What are the main components of the organic matter found in sewage?

The organic matter in sewage primarily consists of protein compounds (around 40%), carbohydrates (about 25-50%), oils and grease (about 10%), and smaller quantities of urea, surfactants, phenols, and pesticides.

What is the environmental impact of discharging organic matter from sewage into water bodies?

When organic matter from sewage is discharged into water bodies, it serves as food for microorganisms. The resulting population growth consumes oxygen, which can negatively affect aquatic life by depleting dissolved oxygen levels.

What are the major nutrients found in sewage that can cause environmental problems?

The major nutrients of concern in sewage are nitrogen and phosphorus. If discharged untreated, these nutrients can lead to eutrophication in lakes and reservoirs, causing excessive algal growth and harming aquatic ecosystems.

What are the two forms in which nitrogen is found in raw sewage?

In raw sewage, nitrogen is present in two forms: organic nitrogen and ammonia. The ammonia originates from the urea found in urine, which rapidly hydrolyzes.

What are the sources of phosphates in sewage?

Phosphates, which are the primary form of phosphorus in sewage, come from two sources: inorganic phosphates, mainly from detergents and other household chemical products, and organic phosphorus, which is bound to organic compounds.

What is used as an indicator for fecal contamination in sewage, and why?

Fecal coliforms, particularly Escherichia coli, are commonly used as indicators of fecal contamination in sewage. This is because E. coli are intestinal bacteria excreted by warm-blooded animals, including humans, and are present in high concentrations, making their detection a reliable sign of fecal presence.

What types of items might people be tempted to flush down toilets, potentially causing blockages or other issues?

People may be tempted to dispose of items like toilet paper, wet wipes, diapers, sanitary napkins, tampons and their applicators, condoms, and expired medications down toilets. Additionally, items like children's toys, toothbrushes, or even clothing might end up in the sewage system.

What are micro-pollutants found in sewage, and where do they originate?

Micro-pollutants in sewage can include environmental persistent pharmaceutical pollutants and microplastics. Microplastics, such as polyethylene and polypropylene beads or polyester and polyamide fragments, often come from synthetic clothing and bedding abraded during wear and laundering, or from disintegrated plastic packaging.

What factors determine the composition of sewage?

The composition of sewage is influenced by various factors, including climate, the social and economic situation of the community, and the habits of the population regarding water use and waste disposal.

How does water consumption in a region affect the "strength" of its sewage?

In regions where water use is low, the sewage tends to be more concentrated and therefore "stronger" (higher pollutant concentrations) compared to regions with high per capita water use, such as the United States.

What are typical concentrations and loads for BOD in raw sewage in developing countries?

Typical values for BOD in raw sewage in developing countries are around 50 grams per person per day, which translates to a concentration of approximately 300 mg/L.

What is the population equivalent (PE) and how is it used in wastewater management?

The population equivalent (PE) is a measure used to express the strength of wastewater, often comparing industrial wastewater to domestic sewage. For instance, a "population equivalent" of 60 grams of BOD per person per day is a common benchmark for high-income countries.

What are the estimated per capita loads for total suspended solids and BOD in US households, considering the use of kitchen waste disposals?

For US households, estimates suggest per capita loads of 95 g/person/day for total suspended solids and 85 g/person/day for BOD. These figures are higher if homes utilize kitchen waste-food grinders.

What is the average daily urine generation rate per person?

Based on a global literature review, the median urine generation rate per person per day is approximately 1.42 liters.

What factors influence the volume of domestic sewage produced per person?

The volume of domestic sewage produced per person, or per capita, is directly related to the water consumption in that specific locality.

What are the two daily peak flow rates of sewage typically observed at a treatment plant?

The two main peak flow rates of sewage usually observed at a treatment plant occur in the morning, at the beginning of the day, and in the evening, at the beginning of the night.

What is considered a "world average" water consumption figure per person, according to a 1992 publication?

According to a 1992 publication, a design figure considered a "world average" for water consumption is between 35 to 90 liters per person per day.

What is a common estimate for sewage flowrate per person per day in high-income countries, often used for design purposes?

A flowrate estimate of 200 liters of sewage per person per day is frequently used in high-income countries, for example, in the design of sewage treatment plants.

What are wastewater quality indicators used for?

Wastewater quality indicators are laboratory testing methodologies used to assess the suitability of wastewater for disposal, treatment, or reuse, providing insights into its physical, chemical, and biological characteristics.

What are the main parameters measured to assess sewage strength and quality?

The main parameters measured to assess sewage strength and quality include solids, indicators of organic matter (like BOD and COD), nitrogen, phosphorus, and indicators of fecal contamination.

What are the traditional techniques used to monitor organisms in sewage?

Traditional techniques for monitoring organisms in sewage involve filtering, staining, and examining samples under a microscope.

What is metagenomics in the context of analyzing environmental samples like sewage?

Metagenomics refers to the process of sequencing DNA directly from an environmental sample, allowing for the study of the entire community of organisms present in the sewage, including potentially new or rare species.

How is sewage commonly collected and transported?

Sewage is typically collected and transported through gravity sewers, either in a sanitary sewer system (which excludes stormwater) or a combined sewer system (which also carries stormwater).

What is the primary difference in function between a sanitary sewer and a combined sewer?

A sanitary sewer is specifically designed to transport only sewage from buildings, excluding stormwater. In contrast, a combined sewer system is designed to carry both sewage and stormwater runoff together.

What is infiltration in the context of sewer systems?

Infiltration is the process by which groundwater enters sewer pipes through defects such as cracked pipes, faulty connections, or poorly sealed manholes. This can dilute the sewage and potentially introduce additional pollutants.

What can happen if sewer systems exfiltrate sewage into the groundwater?

When sewer systems exfiltrate sewage into the groundwater, it can lead to groundwater pollution, potentially contaminating water sources.

What is industrial wastewater, and how does it differ from typical sewage?

Industrial wastewater is generated by industrial processes and may be discharged into public sewerage systems. It can differ significantly from typical sewage by containing a wider range of pollutants at much higher concentrations, some of which may be toxic or non-biodegradable.

What is the purpose of discharging treated or untreated wastewater through submarine outfalls?

Submarine outfalls are pipelines used to discharge wastewater to the sea, often with the intention of utilizing the sea's natural assimilative capacity for further treatment of the effluent. Natural factors like sunlight and salinity in seawater can aid in disinfection.

What was the historical practice for sewage discharge in Europe before the 20th century?

Before the 20th century, sewers in Europe typically discharged directly into bodies of water like rivers, lakes, or oceans without any prior treatment, relying solely on the ecosystem's capacity to break down the waste.

What is the estimated global percentage of wastewater that is treated?

While figures vary, a 2021 study estimated that globally, about 52% of sewage is treated, though treatment rates are highly unequal across different countries, with developing nations treating significantly less than high-income nations.

What are the benefits of treating sewage?

Treating sewage is beneficial because it helps to reduce environmental pollution. Processes like primary treatment remove floating and settleable matter, while secondary treatment further reduces organic waste, making the water safer for discharge or reuse.

What is an alternative to discharging sewage into the environment?

An alternative to discharging sewage into the environment is to reuse it in a productive way, such as for agricultural, urban, or industrial applications, provided it complies with local regulations and safety requirements.

What resources can be recovered from sewage to support sustainable agriculture?

Resources that can be recovered from sewage to support sustainable agriculture include carbon, nitrogen, phosphorus, water, and energy, contributing to a circular economy approach and reducing reliance on synthetic fertilizers.

What is a sewage farm, and how does it function?

A sewage farm utilizes sewage for irrigation and fertilizing agricultural land. Microbes and bacteria in the soil convert suspended solids into humus, providing essential nutrients like nitrogen and phosphorus for crop growth, which is particularly valuable in arid climates.

What are the primary factors that influence the assimilative capacity of receiving water bodies for sewage discharge?

The assimilative capacity of receiving water bodies depends on several factors, including their ability to sustain dissolved oxygen levels necessary for organisms that break down organic waste, and the existing water quality before the discharge. The dilution factor also plays a role.

Sewage Wiki: The Unseen Flow: A Scientific Examination of Municipal Wastewater

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Terminology

Sewage vs. Wastewater

Sewage, often termed domestic wastewater or municipal wastewater, refers to the wastewater generated by a community. It is typically conveyed via a sewer system. While often used interchangeably, wastewater is a broader term encompassing any water after use, including industrial or agricultural wastewater, whereas sewage specifically relates to domestic and municipal sources.

Blackwater and Greywater

Sewage is broadly categorized into two streams:

Blackwater: Wastewater from toilets, containing human excreta, water, and toilet paper. It poses significant pathogen risks.
Greywater: Wastewater from sinks, bathtubs, showers, dishwashers, and washing machines, typically without fecal contamination. It is generally safer and easier to treat for reuse.

Composition

Overall Appearance

Fresh sewage is typically slightly grey with a relatively mild, oily odor. As it ages and undergoes decomposition, it turns darker grey to black and develops a foul odor due to gases like hydrogen sulfide. Sewage often exhibits high turbidity due to suspended solids. Its temperature is usually slightly elevated compared to drinking water but more stable than ambient temperatures. The pH is generally near neutral (6.7–8.0).

Pollutants

Sewage is primarily water (around 99.9%), with the remaining 0.1% comprising various solids, both dissolved and suspended. These solids include organic and inorganic matter, microorganisms, nutrients, and potentially micro-pollutants. The exact composition varies significantly based on factors like water consumption, diet, and industrial inputs.

Organic Matter: Constitutes about 40% protein, 25-50% carbohydrates, 10% oils/grease, and smaller amounts of urea, surfactants, phenols, and pesticides. Measured by BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand).
Nutrients: Primarily nitrogen (as organic nitrogen or ammonia) and phosphorus (as phosphates). Excessive levels can lead to eutrophication in receiving waters.
Pathogens: Includes bacteria (e.g., Salmonella, E. coli), viruses (e.g., Hepatitis A, Rotavirus), protozoa (e.g., Giardia), and helminths (e.g., Ascaris eggs). Assessed indirectly via fecal coliform counts.
Solid Waste: Includes settleable and suspended matter, toilet paper, wet wipes, and other discarded items. Larger debris is removed via screening.
Micro-pollutants: Can include pharmaceuticals, endocrine disruptors, hormones, microplastics, and residual disinfection byproducts like trihalomethanes.

Flow Rates & Characteristics

Factors Influencing Flow

Per capita sewage flow rates are directly linked to water consumption, which is influenced by numerous factors: water availability, climate, community size, economic status, industrialization levels, water metering practices, water cost, and water pressure. For instance, warmer climates often correlate with higher water usage.

Concentrations and Loads

Sewage composition varies globally. Developing countries often produce more concentrated sewage (higher pollutant load per volume) due to lower water consumption, while high-income countries typically have higher water consumption and thus lower concentrations but potentially higher loads per person. Typical per capita BOD loads can range from 40-60 grams per day.

Developing Countries (Approximate):

Total Solids: 180 g/person/day (1100 mg/L)
BOD: 50 g/person/day (300 mg/L)
Total Nitrogen: 8 g/person/day (45 mg/L)
Total Phosphorus: 1.0 g/person/day (7 mg/L)

High-Income Countries (Approximate):

BOD Load: ~60 g/person/day
US Residential Flow: 189-365 L/person/day

Collection Systems

Sanitary Sewers

These systems are specifically designed to transport domestic and commercial wastewater (sewage) away from buildings. They are engineered to exclude stormwater and surface runoff, ensuring a more consistent flow and concentration of pollutants, which is advantageous for treatment processes.

Combined Sewers

A combined sewer system collects both sewage and stormwater runoff in a single pipe. While simplifying infrastructure, this design leads to significant dilution of sewage during rainfall events, increasing flow rates at treatment plants and potentially causing overflows of untreated or partially treated sewage into receiving waters.

Dilution Factors

Infiltration

Groundwater can enter sewer pipes through leaks in pipes, joints, or manholes. This infiltration increases the volume of flow and can introduce additional pollutants if the groundwater is contaminated or saline. Factors like sewer age, construction quality, and proximity to the water table influence infiltration rates.

Stormwater & Industrial Input

Beyond combined sewers, direct connections for stormwater runoff and discharges from industrial facilities can also dilute sewage. Industrial wastewater, in particular, may contain unique or toxic pollutants that require pre-treatment before entering the municipal system to prevent adverse effects on treatment processes and infrastructure.

Disposal & Assimilation

Land Application

Applying sewage to land serves as a disposal and treatment method, particularly beneficial in arid climates where water is scarce. The organic matter can be converted to humus, providing nutrients for crops. However, careful management is required to prevent soil deterioration and groundwater contamination.

Water Body Discharge

Discharging treated or partially treated sewage into rivers, lakes, or oceans relies on the water body's natural assimilative capacity. This capacity refers to the ecosystem's ability to break down pollutants. The effectiveness depends on the volume of discharge relative to the receiving water body's flow and its existing condition. Marine outfalls are pipelines that discharge wastewater into the sea, often below the surface.

Sewage Treatment

Treatment Stages

Sewage treatment aims to reduce environmental pollution and health risks. Key stages include:

Preliminary Treatment: Removal of large debris using bar screens and grit chambers.
Primary Treatment: Settling of settleable and floating materials in large tanks.
Secondary Treatment: Biological processes to reduce dissolved organic matter (BOD) using microorganisms.
Disinfection: Killing remaining pathogens before discharge.

Effective treatment is crucial for protecting water quality and public health.

Reuse & Reclamation

Resource Recovery

An alternative to environmental discharge is the productive reuse of treated sewage. This includes applications in agriculture, urban landscaping, and industrial processes. Recovering resources like water, nutrients (nitrogen, phosphorus), carbon, and energy from sewage contributes to sustainable resource management and circular economy principles.

Sewage Farms

Sewage farms utilize sewage for irrigation and fertilization of agricultural land. This practice is historically significant and remains a low-cost option in water-scarce regions. The organic solids are converted into humus, supplying essential plant nutrients. Modern sewage treatment plants often replace traditional sewage farms due to better control over vectors and odors.

Regulations

Legal Frameworks

Sewage management is governed by regulations that mandate specific treatment levels before discharge into the environment or for reuse applications. These regulations are often integrated into broader national sanitation policies, which may also cover human excreta management, solid waste, and stormwater. Compliance with water quality standards is legally required in most jurisdictions to protect ecosystems and public health.

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References

A full list of references for this article are available at the Sewage Wikipedia page

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Important Notice

This page was generated by an Artificial Intelligence and is intended for informational and educational purposes only. The content is based on a snapshot of publicly available data from Wikipedia and may not be entirely accurate, complete, or up-to-date.

This is not professional advice. The information provided on this website is not a substitute for professional environmental engineering, public health, or scientific consultation. Always refer to official documentation and consult with qualified professionals for specific applications or concerns related to sewage and wastewater management.

The creators of this page are not responsible for any errors or omissions, or for any actions taken based on the information provided herein.

The Unseen Flow

💡 Dive in with Flashcard Learning! 💡

Terminology 📚

💧 Sewage vs. Wastewater

🚽 Blackwater and Greywater

Composition 🧪

👀 Overall Appearance

☣️ Pollutants

Flow Rates & Characteristics 📊

📈 Factors Influencing Flow

⚖️ Concentrations and Loads

Collection Systems 🚇

🏠 Sanitary Sewers

🌧️ Combined Sewers

Dilution Factors 🌊

💧 Infiltration

🏭 Stormwater & Industrial Input

Disposal & Assimilation ➡️

🌿 Land Application

🌊 Water Body Discharge

Sewage Treatment ⚙️

🛠️ Treatment Stages

Reuse & Reclamation ♻️

🌱 Resource Recovery

🏞️ Sewage Farms

Regulations 📜

⚖️ Legal Frameworks

Teacher's Corner 🧑‍🏫

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References

📜 References

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Disclaimer ⚠️

📜 Important Notice

Dive in with Flashcard Learning!

Terminology

Sewage vs. Wastewater

Blackwater and Greywater

Composition

Overall Appearance

Pollutants

Flow Rates & Characteristics

Factors Influencing Flow

Concentrations and Loads

Collection Systems

Sanitary Sewers

Combined Sewers

Dilution Factors

Infiltration

Stormwater & Industrial Input

Disposal & Assimilation

Land Application

Water Body Discharge

Sewage Treatment

Treatment Stages

Reuse & Reclamation

Resource Recovery

Sewage Farms

Regulations

Legal Frameworks

Teacher's Corner

True or False?

Test Your Knowledge!

Gamer's Corner

Discover other topics to study!

References

Feedback & Support

Disclaimer

Important Notice