What is a biological process in a sewage treatment plant?

Biological treatments rely on bacteria, nematodes, or other small organisms to break down organic wastes using normal cellular processes. Wastewater typically contains a buffet of organic matter, such as garbage, wastes, and partially digested foods. It also may contain pathogenic organisms, heavy metals, and toxins.

Which treatment is a biological treatment in sewage treatment?

The presented biological wastewater treatment processes include: (1) bioremediation of wastewater that includes aerobic treatment (oxidation ponds, aeration lagoons, aerobic bioreactors, activated sludge, percolating or trickling filters, biological filters, rotating biological contactors, biological removal of …

What is the purpose of biological treatment?

Explanation: Biological treatment of water, also called a secondary treatment of water, is the removal of organic waste from water using microbes. The extent of impurity in water is measured by its Biological Oxygen Demand(BOD).

What is the purpose of biological treatment of waste water?

Discharge of domestic sewage into a river will result in rise of BOD because decomposer organisms consume a lot of oxygen. Thus biological treatment of waste-water or sewage treatment is very necessary in order to decompose sewage thereby increasing the dissolved oxygen in water and decreasing the BOD.

What are the advantages of biological treatment?

Compared to other treatment methods, biological methods have certain advantages such as (1) treatment technology is traditional and well understood; (2) enhanced efficiency in terms of organic content removal; (3) cost-effective; and (4) environment friendly and safe.

How do you treat BOD in water?

You can reduce COD and BOD by adding hydrogen peroxide to the wastewater solution. The hydrogen peroxide will chemically attack the organics in the wastewater, degrading them and reducing the measured COD and BOD.

What are the 3 types of sewage treatment?

Wastewater is treated in 3 phases: primary (solid removal), secondary (bacterial decomposition), and tertiary (extra filtration).

What is biological processing of waste?

In microbiological terms, biological waste-treatment processes are effectively large man-made microbial culture systems designed to transform large amounts of carbonaceous material into inoffensive products (including relatively innocuous microbial biomass).

How many types of STP plants are there?

4 Types of Sewage Treatment Plants.

What causes high BOD?

High biochemical oxygen demand can be caused by: high levels of organic pollution, caused usually by poorly treated wastewater; high nitrate levels, which trigger high plant growth.

What is the principle of sewage treatment?

The basic principle of the working of a biological treatment plant is decomposition of the raw sewage. This process is done by aerating the sewage chamber with fresh air. The aerobic bacteria survive on this fresh air and decompose the raw sewage which can be disposed of in the sea.

What are the disadvantages of biological waste?

Cons of Aerobic Digestion Inappropriate release of the nutrient-rich sludge into rivers or ponds can cause algae overgrowth, or eutrophication, which kills fish and other aquatic life. Energy consumption and excess sludge production can be reduced by treating wastewater first with anaerobic microbes.

Which of the following is biological treatment process?

There are two types of biological treatment process; aerobic and anaerobic. Biological wastewater treatment is an extremely cost effective and energy efficient system for the removal of BOD (Biological Oxygen Demand), since only micro-organisms are used.

What is BOD value?

Biochemical oxygen demand (BOD) represents the amount of oxygen consumed by bacteria and other microorganisms while they decompose organic matter under aerobic (oxygen is present) conditions at a specified temperature.

Why is BOD important in water quality?

The BOD is an important parameter for assessing water quality. It deals with the amount of oxygen consumption (mg O2 L− 1) by aerobic biological organisms to oxidize organic compounds. Sewage with high BOD can cause a decrease in oxygen of receiving waters, which in turn can cause the death of some organism.

What is the BOD value of pure water?

UPLOAD PHOTO AND GET THE ANSWER NOW! Solution : A pure water would have about 1 ppm value. A water supply with BOD level of 3.5 ppm is moderately clean, and water with a BOD level of 6.9 ppm is considered as polluted water.

What are the 2 types of sewage treatment plant?

Generally, they can be classified into the following types of system: Activated sludge plant (ASP) Rotating disc system. Submerged aerated filter (SAF)

What are the 4 stages of sewage treatment?

  • Step 1: Screening and Pumping.
  • Step 2: Grit Removal.
  • Step 3: Primary Settling.
  • Step 4: Aeration / Activated Sludge.
  • Step 5: Secondary Settling.
  • Step 8: Oxygen Uptake.
  • Sludge Treatment.

What are the two main methods of sewage treatment?

Wastewater treatment is usually broken down into two sections: primary treatment, which removes grease, dirt, gravel, and floatable waste, and secondary treatment, which removes even more suspended solids and pollutants by using biological processes.

What are the biological characteristics of wastewater?

  • Bacteria.
  • Protozoa.
  • Fungi.
  • Viruses.
  • Algae.
  • Rotifers.
  • Nematodes.

What is the BOD and COD?

Biochemical oxygen demand (BOD) is the amount of oxygen required by the microorganisms to break down the organic materials, whereas chemical oxygen demand (COD) is the amount of oxygen required to break down the organic material via oxidation.

How do you calculate capacity at STP?

  1. Total domestic (raw) water demand = TWD.
  2. Estimated Sewage X = 90 % of TWD.
  3. Estimate Sewerage X = 90/100 * TWD For Eg If TWD = 1500 KLD.
  4. Capacity of S.T.P = 90 / 100 * 1500 KLD = 1350 KLD.

Why is BOD measured for 5 days?

BOD occurs in 2 general stages. While calculating the oxygen demand, the carbonaceous stage is taken into account. This stage is almost completed in 5 days, which means that most of the organic content of the sewage is oxidized under aerobic conditions in 5 days. Hence ,BOD for 5 days is calculated.

How do you reduce BOD in wastewater?

  1. Focus on removing TSS from wastewater first.
  2. Get a properly sized EQ tank.
  3. Control the pH of the waste stream.
  4. Install a modern plate pack DAF made of stainless steel or plastic.
  5. Use a regenerative turbine air dissolution pump.

What happens if BOD is high?

The greater the BOD, the more rapidly oxygen is depleted in the stream. This means less oxygen is available to higher forms of aquatic life. The consequences of high BOD are the same as those for low dissolved oxygen: aquatic organisms become stressed, suffocate, and die.

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