In wastewater treatment plants, energy consumption is often correlated with the magnitude and type of pollutant load, which can influence the treatment methods and technologies used in a plant. Wastewater treatment plants that have more influent biological oxygen demand (BOD) use more energy, on average, as shown by the slope of the orange trend line in the graph below. The bar graph below shows that plants that utilize trickle filtration have lower energy intensity on average, while plants that utilize nutrient removal in the treatment process have higher energy intensity on average. Nutrient removal is often necessary near sensitive waters.
How much energy does it take to treat wastewater?
chemicals. To remove these contaminants from wastewater before discharging it into natural environment, multiple processes are required, making the wastewater treatment energy-intensive. About 2 × 106joules electrical energy is consumed for treating
What is the secondary treatment of waste water?
Read this article to learn about the secondary treatment of waste water. The secondary treatment is also known as biological treatment. It is capable of abating biodegradable dissolved and/or suspended organic substances. By secondary treatment it is also possible to remove dissolved nitrogenous and phosphorous compounds from a waste water stream.
What type of electricity is used in wastewater treatment?
Wastewater aeration, pumping, and solids processing account for most of the electricity used in wastewater treatment. For both types of systems, greater amounts of energy are required for more advanced treatment
What is the potential energy in wastewater?
Considering the wastewater generation rate in the US estimated above, the total potential energy in wastewater is 1.2 × 1015J/day, 4.4 × 1017J/year. Current Technologies Currently, anaerobic wastewater treatment is the most widely used technology to recover energy from wastewater. The energy is harvested as methane production.
How much energy is used in wastewater treatment?
Wastewater treatment plants (WWTP) consume large amounts of energy, estimated at between 1% and 3% of global energy output. State-of-the-art facilities consume 20-45 kWh per population equivalent (PE) connected.
How much energy is required for water treatment?
Specific power consumption of state-of-the-art wastewater treatment plants should be between 20 and 45 kWh/(PE•a) [PE = Population Equivalent or unit per capita loading].
What is used in secondary treatment of wastewater?
Secondary wastewater treatment processes use microorganisms to biologically remove contaminants from wastewater. Secondary biological processes can be aerobic or anaerobic, each process utilizing a different type of bacterial community.
What happens in the secondary stage of wastewater treatment?
Secondary Treatment The secondary stage of treatment removes about 85 percent of the organic matter in sewage by making use of the bacteria in it. The principal secondary treatment techniques used in secondary treatment are the trickling filter and the activated sludge process.
Which of the following is low energy consuming system for waste water treatment *?
The correct answer is Both biogas and sludge.
What form of energy is obtained from sewer waste?
Wastewater facilities with an anaerobic digester can use biogas generated by the digester to produce heat, and in many cases electricity as well.
What is meant by secondary treatment?
Secondary treatment is the second step in most waste treatment systems during which bacteria consume the organic parts of the wastes. This is accomplished by bringing the sewage, bacteria and oxygen together in trickling filters or within an activated sludge process.
What is the main goal of secondary wastewater treatment?
The objective of secondary treatment is the further treatment of the effluent from primary treatment to remove the residual organics and suspended solids.
What is secondary waste?
Secondary waste is waste generated from different sources and of different nature, i.e. waste generated in a process that is known as a waste treatment operation; it includes residual materials originating from recovery and disposal operations, such as incineration and composting residues.
What are the steps involved in secondary treatment?
Secondary treatment removes the soluble organic matter that escapes primary treatment. It also removes more of the suspended solids. Removal is usually accomplished by biological processes in which microbes consume the organic impurities as food, converting them into carbon dioxide, water, and energy…
What is the purpose of secondary wastewater treatment quizlet?
The purpose of secondary treatment is to remove the suspended solids that did not settle out in the primary tanks and the dissolved BOD that is unaffected by physical treatment.
What is the difference between primary and secondary treatment of wastewater?
The initial and primary water treatment process removes large matter from wastewater while the secondary treatment will remove smaller particles already dissolved or suspended.
Secondary Treatment Definition
Secondary treatment of wastewater is a process that follows the primary treatment of sewage.
Objectives of Secondary Treatment
The objectives of secondary treatment are to remove the remaining suspended solids, BOD, and COD from the wastewater. It is done to reduce the primary clarifier load and improve the quality of the effluent discharged from the treatment plant.
What are the Stages of Wastewater Treatment?
The stages of wastewater treatment are collection, pre-treatment, primary treatment, secondary treatment, tertiary treatment, disposal, and reuse.
What is The Secondary Treatment of Wastewater?
This article will tell you about the second stage in the wastewater treatment process.
How Does Secondary Treatment Work
Secondary treatment is treating wastewater in a municipal water system that removes most contaminants from wastewater by reducing their levels to acceptably low levels.
What are The Alternative Types of Secondary Biological Processes?
There are a few different types of alternative secondary biological processes, and these include aerobic and anaerobic processes.
Conclusion
The secondary wastewater treatment process is more complicated than the primary wastewater treatment process. It is necessary to remove the remaining pollutants from the wastewater. The method includes various other activities that can remove the remaining impurities.
What is waste water treatment?
For waste water treatment almost always a microbial community having various species of organisms finds its way into a treatment unit. These organisms may enter a treatment unit from the surrounding environment as well as along with the waste water itself. Very often a portion of the biomass (microbes) produced during waste water treatment is recycled to the treatment unit. For abatement of a specified pollutant sometimes some specific organisms are added.
When to add nitrogen bearing compounds to wastewater treatment unit?
For synthesis of proteins and nucleic acids nitrogen bearing compounds are to be added to a wastewater treatment unit if those are not present as a constituent of the pollutants present.
What are the two stages of catabolic activity?
Generally catabolic activities are carried out in two stages. In the first stage the suspended organic matter present in waste water are solubilized and the larger dissolved organic molecules are hydrolyzed (spitted) into smaller molecules. Extra-cellular enzymes take part in these reactions. The relatively small amount of energy liberated during this step is not available to the cells (microbes) as the reactions occur outside the cells. .
When species present in an ecosystem do not use the same substrate (food) their environmental requirement is different?
When the species present in an ecosystem do not use the same substrate (food) their environmental requirement is different and they do not utilize the metabolic products and by-products of one another then there interaction is said to be neutral. In a community of micro-organisms in any ecosystem such an interaction is very rare.
Is suctoria anaerobic or aerobic?
These are unicellular, non-photosynthetic and motile. Some are parasitic and the other is phagotrophic. The majorities are aerobic and a few are anaerobic. The phagotrophic ones ingest smaller organism and organic matter. The group suctoria preys on the protozoa. They help in bio-flocculation.
What is the purpose of sewage treatment?
The purpose of the sewage treatment is to remove the solids present in the sewage. ROLE OF MICROORGANISMS. Microorganisms are unicellular microscopic living things. They multiply by binary division of cells within 10 to 20 minutes. They require oxygen for their respiration.
What are the two types of solids in sewage?
SOLIDS IN SEWAGE. The solids present in the sewage are of two types viz., Organic solids, and. Inorganic solids. Organic solids are the substances derived from living things like produces from plant and animal. Examples of organic solids are carbohydrate, protein, and fat.
What is activated sludge?
The activated sludge process (ASP) is an aerobic biological wastewater treatment process that uses microorganisms, including bacteria, fungi, and protozoa, to speed up decomposition of organic matter requiring oxygen for treatment.
What is the only thing to be provided for the respiration of aerobic organisms?
The organic solids present in the wastewater serve as food for the aerobic microorganisms. The only thing to be provided is the DO , which is essential for the respiration of the aerobic organisms.
What are the end products of anaerobic and aerobic processes?
Under aerobic conditions, if completely oxidized, organic matter is transformed into non-hazardous products. But an anaerobic process can produce methane (CH 4 ), which is explosive, and ammonia (NH 3) and hydrogen sulfide (H 2 S), which are toxic.
What are the two types of biological processes?
TYPES OF BIOLOGICAL PROCESSES. There are two types of biological treatment process; aerobic and anaerobic. Aerobic process means that oxygen is present for the microbes for respiration. Anaerobic process means that the process proceeds in the absence of DO.
What do aerobic bacteria use for respiration?
Aerobic bacteria use dissolved oxygen (DO) from the water bodies for their respiration. They oxidize organic matter under aerobic conditions. The end products of the decomposition are water, CO 2 and Cell tissues. Anaerobic bacteria use oxygen derived from chemical substances for their respiration.
Determining Energy Usage
Cutting Energy Usage and Costs
- Energy Management
Energy costs often make up 25 to 30 percent of a utility's total operation and maintenance (O&M) costs. They also represent the largest controllable cost of providing water and wastewater services. EPA works with utilities to manage and reduce costs, using the steps described in its E…
Renewable Energy Options
- Green power is electricity produced from renewable resources, such as solar, wind, geothermal, biomass, and low-impact hydroelectricity. Buying green power is one of the easiest and most effective ways to improve your organization's environmental performance.
Us Wastewater Generation
Energy in Wastewater
- The concentration of reducing matters in wastewater is usually expressed as the COD (chemical oxygen demand) value, which indicates how much oxygen is required for oxidizing the reducing matters. A typical wastewater has a COD value of ∼0.5 kg/m3. Based upon a theoretical 1.47 × 107 joules energy production per kg COD oxidized to CO2 and H2O, the energy density of waste…
Current Technologies
- Currently, anaerobic wastewater treatment is the most widely used technology to recover energy from wastewater. The energy is harvested as methane production. Taking off the energy lost due to the heat dissipation during energy transfer from various reducing matters to methane, the energy consumption for maintaining the microbial activity and, the ...
Conclusion
- Wastewater contains certain amount of energy that may be recovered. Extracting energy from wastewater cannot affect the overall energy consumption structure in the US, since it only contributes a very small portion of the total energy consumption in the US even with 100% energy recovery efficiency. However, it is possible to make the wastewater treatment plant self-sustain…
References
- P. L. McCarty, J. Bae and J. Kim, "Domestic Wastewater Treatment as a Net Energy Producer - Can This be Achieved?" Environ. Sci. Technol. 45, 7100 (2011). "Unified Facilities Criteria (UFC) - Domestic Wastewater Treatment," U.S. Department of Defense, UFC 3-240-09A, January 2004. H. Liu, R. Ramnarayanan and B. E. Logan, "Production of Electricity During Wastewater Treatment U…