1. 10-Grit chamber
    1. ● After screen sewage is then passed through a long narrow chamber called as grit chamber
    2. ● The chamber is about 10-20 meter and velocity of sewage flow is about | foot per second taking a detention period of 0.5-1 minute.
    3. Grit chambers are intended to remove the inorganic particles (such as sand, gravel, grit, egg shells, bones or other inert solid materials etc.)
  2. 11-A sedimentation tank
    1. A sedimentation tank allows suspended particles to settle out of wastewater as it flows slowly through the tank.
    2. A layer of accumulated solids, called sludge, forms at the bottom of the tank and is periodically removed.
  3. 12-Trickling filter bed
    1. ● Trickling filters are used to remove organic matter from waste-water. Trickling filters use aerobic processes for treatment.
    2. ● TFs enable organic material in the wastewater to be absorbed by a population of microorganisms attached to the medium as a slime layer
    3. ● As the wastewater flows over the medium the microorganisms present in the water gradually attach themselves to a rock or plastic surface and form a film. The organic material is degraded by the aerobic microorganisms.
  4. 13- Activated sludge process
    1. ● Subjected to aeration chamber for aeration for 6-8 hours.
    2. ● The aeration is accomplished by mechanically agitation or forcing compressed air continuously from the bottom of aeration tank.
    3. ● The organic matter of the sewage get oxidized into Co₂, nitrates and water with the help of aerobic bacteria.
  5. Chemical UNIT Process
    1. *Remove Conversion of Contaminants by s adding chemicals or by CHE RXD, che process
    2. [Precipitation-Adsorption - Dis infection -Chlorination -UV light- ozone
    3. APP
      1. CHE Precipitation Remove Phosphorous? and enhancement of suspended solids. removal in primary sedimentation
      2. Adsorption Removal of organics
      3. Disinfection disinfection of disease causing organisms.
  6. Physical unit process
    1. APPS
      1. screening- Remove coarse and Settleable solids by surface straining.
      2. Mixing mixing Chemicals and gases with waste. To maintain sold in suspension.
      3. Flocculation aggregarion of Smaller particles into larger one.
      4. Sedimentation Remove settlable Solids and thickening of sludge.
      5. floatation Remove finely suspended solid and particles.
  7. 16-Turbidity and temperature of wastewatr
    1. Turbidity
      1. •Sewage is highly turbid. •Turbidity of sewage is due to dissolved substances, colloidal matters, suspended solids and microbial cells.
      2. Units-NTU (Nephelometric Turbidity Units)
      3. Equipment using to measure - electronic turbidity meter or a turbidity tube
    2. Temperature
      1. • The temperature has an effect on the biological activity of bacteria present in the sewage and it also affects the solubility of gases in sewage. It also affects the viscosity of sewage (more is the temperature, lesser is the viscosity of sewage).
      2. The normal temperature, of sewage is slightly higher than he temperature of the water supply because of the additional heat due to utilization of water. Also when the wastewater flows in a closed pipes, its temperature future increases.
  8. 9- Color and odor of wastewater
    1. Colour
      1. -Fresh wastewater is usually a light brownish- gray color. -Travel time of the collection system increases anaerobic conditions develop and color changes for gray to dark gray, and to black. -This black color is due to the metallic sulfides which formed under the anaerobic conditions.
    2. ODOR
      1. Fresh domestic sewage is almost odorless. Septic or stale sewage is putrid in odor which is due to generation of H2S during anaerobic decomposition of organic matters. When industrial effluent is mixed, it give characteristics odor to sewage
  9. 8- Th OD theoretical oxygen
    1. ThOD INDICATE the amount of oxygen needed to oxidize the organic carbon to carbon dioxide and a other end products.
  10. 7- TOC
    1. measure of carbon in organic materials measure of total organic carbon indicates the level of contaminants or organic molecules present
    2. by injecting a sample of the WW in special device C is oxidized to CO2 then is measured and used to quantify the amount of organic matter in the WW. This method is only used for small concentration of organic matter.
  11. 6- COD
    1. is a test that measures the amount of oxygen required to chemically oxidize the organic material and inorganic nutrients, such as Ammonia or Nitrate, present in water. This test is much quicker than the BOD test, taking only about three hours to carry out.
    2. DONE BY boiling a sample of wastewater with a mixture of concentrated acids The amount of oxidizing agent remaining at the end of the test is measured.
  12. 5- BOD
    1. the amount of oxygen consumed by bacteria and other microorganisms while they decompose organic matter under aerobic
    2. BOD tests are carried out in a laboratory and, usually over a period of five days, as the organic matter in the wastewater breaks down.
    3. The result is the amount of oxygen used in degrading the organic matter in (mg/L).
  13. 4- Effect of temperature on sewage.
    1. • The temperature has an effect on the biological activity of bacteria present in the sewage and it also affects the solubility of gases in sewage. It also affects the viscosity of sewage (more is the temperature, lesser is the viscosity of sewage).
    2. The normal temperature, of sewage is slightly higher than he temperature of the water supply because of the additional heat due to utilization of water. Also when the wastewater flows in a closed pipes, its temperature future increases.
  14. 3- Environmental problems due to Stormwater runoff.
    1. environmental problems: Fast-moving stormwater runoff can erode stream banks. Stormwater runoff can push excess nutrients from fertilizers and other sources into rivers and streams
  15. 2- Types of wastewater
    1. ❖ Domestic: wastewater by residential, shop, offices, schools, etc. and normally generated from toilets and bathroom
    2. ❖ Industrial: wastewater generated by industries. Quantity and quality depend on the type of industry
    3. ❖ Storm water: rainwater may contain pollutants
  16. 1-Sources of industrial wastewater.
    1. Industrial waste include
      1. organic pollutants and toxic chemical i.e. heavy metals -- Acid and alkalis -- Oils, lubricants ,petroleum and grease
    2. Industrial waste enters from :-
      1. a-Iron and steel industry b-Food industry c-Organic chemical industry which includes paints ,dyes......