Water Resource Recovery Facility 3D Virtual Tour

Water Environment Federation

26 Sept 201210:01

Summary

TLDRThe video explains how wastewater is managed through various treatment processes in the United States. It covers the journey of wastewater from homes and businesses, through collection systems, to treatment plants. The process involves removing debris, separating solids, and using biological and chemical methods to purify the water. Advanced treatments like membrane filtration and disinfection make the water safe for reuse or release into natural bodies of water. Solids are processed into biosolids, which can be used as fertilizer. The video highlights the importance of wastewater management in maintaining a clean water environment.

Takeaways

💧 Water and waste from homes and businesses flow through a collection system of pipes, relying mostly on gravity to move, with lift stations used in deeper areas.
🏙️ Many older cities have combined sewers for both stormwater and sewage, which can overflow during heavy storms, increasing the volume of water processed.
🏭 Wastewater reaches over 16,000 publicly owned treatment plants in the US, which serve more than 190 million people.
🗑️ The first stage of treatment, called headworks, removes large debris like trash and grit to protect pipes and equipment.
🌿 Grit removal helps prevent damage to equipment and avoids buildup in later processes, separating heavy particles from organic matter.
🛢️ Primary treatment separates water from solids, removing 90-95% of settleable solids and 50-65% of suspended solids, including oil and grease.
🦠 Secondary treatment uses bacteria to break down nutrients like phosphorus and nitrogen, which can cause environmental issues if not removed.
🌱 Advanced treatment, including membrane filtration, can produce ultra-clean water suitable for reuse in industrial and agricultural settings.
⚡ Anaerobic digestion reduces pathogens and odors in sludge while producing methane, which can be used to generate energy for the treatment plant.
🚜 Biosolids from the final treatment process can be used as fertilizer after disinfection, turning waste into a valuable resource for agriculture.

Q & A

What happens to the water and waste that goes down the drain in homes and businesses?
-The water and waste flow through a network of pipes called a collection system, which leads to wastewater treatment plants. In the U.S., there are about 800,000 miles of collection systems.
How does wastewater typically move through the collection system?
-Wastewater usually moves through the pipes by gravity. When the pipes get too deep, pump or lift stations help move the wastewater to a new section, allowing it to flow downhill again.
What is the purpose of the headworks at a wastewater treatment plant?
-The headworks is the first stage of treatment, where large debris like trash, rags, and cans are filtered out to prevent clogging of pipes and pumps. It focuses on removing inorganic materials.
Why is grit removal important in the wastewater treatment process?
-Grit removal is crucial because grit consists of heavy particles like sand that can erode mechanical equipment and build up in later treatment stages, causing operational issues.
What is the main goal of the primary treatment process in wastewater treatment?
-The main goal of primary treatment is to separate water from organic solids through physical methods such as screening and sedimentation, allowing solids to settle at the bottom.
How does secondary treatment differ from primary treatment?
-While primary treatment uses physical separation, secondary treatment relies on biological processes. Bacteria in aeration basins break down solids and remove nutrients like phosphorus and nitrogen.
What role do bacteria play in the aeration basin during secondary treatment?
-Bacteria in the aeration basin consume organic solids and help reduce their volume. They also remove nutrients like phosphorus and nitrogen, preventing environmental issues like algae overgrowth.
What is the purpose of membrane filtration in advanced treatment?
-Membrane filtration in advanced treatment is used to produce ultra-clean water by forcing water through tiny pores that remove fine particles and microorganisms. This water can be reused for various purposes.
How is wastewater disinfected before being returned to the environment?
-Wastewater is disinfected to remove any remaining harmful microorganisms. Common disinfection methods include chlorine treatment, ultraviolet (UV) light, and ozonation.
What are biosolids, and how are they treated for reuse?
-Biosolids are treated sludge that meets certain criteria for reuse. The treatment process involves reducing pathogens and odors, and concentrating solids through methods like centrifuges and anaerobic digestion. These biosolids can then be used as fertilizer in agriculture.

Outlines

00:00

🚰 How Wastewater Moves Through the Sewer System

The first part explains how wastewater from homes, businesses, and industrial facilities flows into a sewer system through pipes. These pipes mostly use gravity to transport water, though pumps are needed when pipes are too deep. Older cities often have combined sewers that manage both stormwater and sewage, which can overflow during large storms. Wastewater is then sent to over 16,000 publicly owned water resource recovery facilities in the U.S., where the treatment process begins.

05:08

🗑️ Removing Debris and Grit from Wastewater

The wastewater treatment process starts at the 'headworks,' where large debris such as rags and trash are filtered out. This prevents clogs in the system. After removing inorganic waste, the wastewater enters the grit removal chamber, where heavier particles like sand settle out. This is essential because grit can erode equipment and cause buildup. Flow monitoring at this stage helps operators adjust treatment processes according to the volume and velocity of incoming water.

⚙️ Primary Treatment: Separating Solids from Water

During primary treatment, finer screens remove smaller debris from the water, and the main goal is to separate water from organic solids. Unlike the headworks, which focus on inorganic matter, this phase uses screening and sedimentation to remove organic materials. Primary clarification then allows heavier solids to settle at the bottom, where they are collected for further treatment. Around 90-95% of solid matter settles out, while oils and grease float to the top and are skimmed off.

🌱 Secondary Treatment: Removing Nutrients with Bacteria

In secondary treatment, the focus shifts to removing nutrients like phosphorus and nitrogen to prevent water pollution. These nutrients, if left untreated, can cause algae growth in rivers and lakes, leading to oxygen depletion, or 'dead zones.' The aeration basin plays a key role here, where blowers add oxygen to help bacteria break down organic solids. This process not only reduces the volume of solids but also removes harmful nutrients from the water.

🔄 Clarification and Advanced Treatment for Ultra Clean Water

After secondary treatment, the water undergoes secondary clarification to further separate solids, with some of the solids being reused to maintain healthy bacteria populations. Advanced treatment methods, such as membrane filtration, can be applied to produce ultra-pure water. This water is free from fine particles and microorganisms, making it suitable for reuse. Disinfection methods, such as chlorine or ultraviolet light, remove any remaining harmful bacteria before the water is returned to the environment or reused.

💩 Solids Treatment: Turning Waste into Biosolids and Energy

Solids collected from the clarification process undergo further treatment to become biosolids, which can be reused in agriculture. The solids are thickened and dewatered through methods like centrifuges. Anaerobic digestion is the next step, where bacteria break down organic matter in oxygen-free environments, producing biogas like methane. This biogas can power the treatment plant or even be sold as electricity. Finally, the solids are further dewatered and disinfected, often through composting, before being used as fertilizer.

👷 The Vital Role of Water and Wastewater Operators

Water and wastewater operators play a crucial role in managing the treatment process, ensuring that water and solids meet regulatory standards. Their work is essential for maintaining infrastructure and responding to challenges like urbanization and aging systems. The water sector also provides significant economic benefits, with investments in infrastructure creating thousands of jobs. Clean water is vital not only for today's society but also for future generations.

Mindmap

Keywords

💡Collection system

The collection system refers to the network of pipes that transport wastewater from homes, businesses, and industrial facilities to treatment plants. In the video, it's highlighted that there are about 800,000 miles of these systems in the U.S., with an additional 500,000 miles of private laterals connecting properties to the sewer system. This system is crucial for managing the flow of wastewater, often relying on gravity or pumps to move water to treatment plants.

💡Wastewater treatment plants

These facilities are responsible for treating and cleaning wastewater before it is released back into the environment. According to the video, there are about 16,000 publicly owned treatment plants in the U.S., serving over 190 million people. The plants carry out various stages of treatment to remove solids, nutrients, and microorganisms, ensuring the water is safe for reuse or release.

💡Headworks

The headworks is the first stage in the wastewater treatment process, where large debris like rags, trash, and sand are removed to prevent damage to pumps and pipes. The video describes this as essential for keeping equipment running smoothly, as it focuses on filtering out inorganic materials that could cause blockages or erosion later in the treatment process.

💡Grit removal

Grit removal is a step in the headworks where heavy particles like sand and gravel settle to the bottom of a tank and are removed by a rake. These materials are abrasive and can damage equipment if not removed early in the process. In the video, the importance of grit removal is emphasized as a way to prevent mechanical erosion and buildup in the system.

💡Primary treatment

Primary treatment is the second phase of wastewater treatment, where water is separated from organic solids through screening and sedimentation. The goal is to remove 90-95% of settleable solids and 50-65% of suspended solids. The video explains how this step differs from the headworks by focusing on organic matter instead of inorganic debris, preparing the water for further purification.

💡Clarifier

A clarifier is a tank used in both primary and secondary treatment to allow solids to settle at the bottom, while cleaner water flows out. The video describes how the clarifier removes a significant amount of solids and sends them to the solids treatment process, while water moves on for further purification. The rotating arm in the clarifier helps collect solids from the bottom for processing.

💡Aeration Basin

The aeration basin is a key part of secondary treatment, where oxygen is pumped into the water to encourage bacteria to feed on organic solids. In the video, the aeration process is crucial for reducing the volume of solids and removing nutrients like nitrogen and phosphorus, which, if left untreated, can lead to environmental problems like algae blooms in natural water bodies.

💡Activated sludge

Activated sludge is the name given to the mixture of water and bacteria used in the aeration process. Some of this sludge is recycled back into the aeration basin to maintain a healthy population of bacteria that breaks down organic solids. In the video, it is explained that this sludge helps reduce solids and keep the biological treatment process efficient.

💡Disinfection

Disinfection is the final stage of wastewater treatment, where any remaining microorganisms are eliminated to ensure the water is safe for release or reuse. The video discusses several methods of disinfection, including chlorine, ultraviolet light, and ozonation. This step ensures that harmful bacteria or pathogens are removed from the water before it is returned to the environment.

💡Biosolids

Biosolids refer to the treated organic solids from wastewater that can be reused, typically as fertilizer in agriculture. The video explains how solids go through thickening, dewatering, and anaerobic digestion to reduce pathogens and odors, transforming them into biosolids. These solids must meet specific standards for reuse, highlighting the resource recovery aspect of wastewater treatment.

Highlights

Water and waste from homes, businesses, and industrial facilities flow through a network of pipes called the collection system.

In the U.S., there are about 800,000 miles of collection systems along with 500,000 miles of private lateral pipes that connect properties to the sewer system.

Wastewater typically travels through pipes by gravity; when pipes get too deep, pumps or lift stations move the water into new sections to continue flowing downhill.

Many older cities have combined sewers that convey both stormwater and sewage, which can cause overflows during large storms.

There are 16,000 publicly owned wastewater treatment plants in the U.S. serving over 190 million residents.

The first treatment step, known as headworks, involves screens that filter out large debris to prevent clogs in the system.

Grit removal is the next step, where heavy particles like sand settle to the bottom, preventing damage to mechanical equipment later in the process.

Primary treatment separates water from solids using physical methods like screening and sedimentation.

Secondary treatment uses biological processes, like aeration, where bacteria feed on solids and remove nutrients such as phosphorus and nitrogen.

In secondary clarification, remaining solids are removed, and some are recycled as activated sludge to maintain beneficial bacteria populations.

Advanced treatment uses methods like membrane filtration to remove fine particles and microorganisms, resulting in ultra-clean water.

Disinfection, often using chlorine or ultraviolet light, removes any remaining harmful microorganisms before the water is returned to the environment.

Solids from the treatment process are converted into biosolids through methods like centrifugation and anaerobic digestion.

Anaerobic digestion reduces pathogens and produces biogas, which can be used to generate energy, potentially powering the entire treatment plant.

Once biosolids are treated and disinfected, they can be reused in agriculture as fertilizer, making the wastewater treatment process sustainable.