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Treatment of Waste H2O


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wastewater in NZ, sewage treatment in NZ, process of wastewater in NZ, process of sewage treatment in NZ, primary secondary tertiary treatment of waste water, screening of wastewater, grit removal tanks, sedimentation, process of separation, anaerobic digestors, activated sludge, trickling filters, oxidation ponds, polishing ponds, disinfection of waste water, wetlands, irrigation, UV lamp disinfection of wastewater, chlorine disinfection of wastewater, ozone disinfection of wastewater

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Treatment of Waste H2O

  1. 1. Treatment of Waste H2O b.stev
  2. 2. the USED H 2 O of a COMMUNITY ie: kitchen sink/ tub/ toilet shower/ laundry/ industry <ul><li>CORRECT treatment is necessary to health </li></ul><ul><li>SAVES exposure to infectious organisms </li></ul><ul><li>THEN the H 2 O is returned to waterway s </li></ul>
  3. 3. PRIMARY: infiltration/ screening/ grit removal/ sedimentation SECONDARY : anaerobic digestors (organic waste) activated sludge/ trickling filters/ oxidation ponds (H2O) TERTIARY: disinfection/ wetlands/ irrigation
  4. 4. WASTEWATER system starts as a complex network of pipes & junctions that feed the material and fluid to the treatment plant PIPES last 20-50yrs:dependent upon material used <ul><li>THE SYSTEM EXPERIENCES LOAD INCREASE FROM: </li></ul><ul><li>tree roots </li></ul><ul><li>cracks </li></ul><ul><li>poor design </li></ul><ul><li>installation </li></ul><ul><li>deterioration </li></ul><ul><li>flood </li></ul>
  5. 5. PRIMARY TREATMENT This load increase is known as,”INFILTRATION,”. Maintenance is constant to : <ul><li>- mend ruptures </li></ul><ul><li>- install new seals </li></ul><ul><li>- check apparatus </li></ul><ul><li>- upgrade areas </li></ul>PREVENTS SEWER overflow and seeping into the soil/ drains and the environment
  6. 6. SCREENING FINE SCREENS intercept : <ul><li>solids plastics </li></ul><ul><li>paper </li></ul><ul><li>leaves </li></ul><ul><li>wood </li></ul>DRUM SHAPE revolves: 3 mm screens of stainless steel that catches the debris DEBRIS is transported offsite to a landfill Arrival at the treatment plant :
  7. 7. PUMPED AIR in the FLUID generates motion This reduces density & allows grit to settle in HOPPERS GRIT REMOVAL TANKS This: GRIT, is removed offsite ORGANIC SOLIDS remain suspended (Water Care Services Ltd, 2008)
  8. 8. AUTOMATIC scrapers collect this from a sloped floor removed offsite SEDIMENTATION FLUID & ORGANIC SOLIDS slowly flow within big tanks, this settles the “organic solids”
  9. 9. SEDIMENTATION ANAEROBIC DIGESTORS ACTIVATED SLUDGE Process of Separation [organic waste] [wastewater]
  10. 10. 37.5C & acid forming bacteria breakdown organic materials organic acids ANAEROBIC DIGESTORS BIOGAS: collected to generate POWER, contributes to the electricity demand in the plant THE GAS is collected – called,” BIOGAS ,” (Water Care Services Ltd, 2008) NEXT: methane forming bacteria utilise acids produce methane & CO 2 gas
  11. 12. Activated sludge Trickling filters Oxidation ponds Polishing ponds DISINFECTION Irrigation Wetlands Outlet THE PROCESS
  12. 13. bacteria strip out, organic pollutants This DECREASES the concentration of pollutants in the ,” WASTEWATER ,”. ACTIVATED SLUDGE wastewater after the,”sedimentation,” : aerated with O 2 & saprotrophic bacteria (Water Care Services Ltd, 2008)
  13. 14. An example of an activated sludge tank:
  15. 16. ALGAE & BACTERIA mature the H 2 O and an anaerobic sludge layer settles OXIDATION PONDS MOST COMMON SYSTEM used in NZ 4 – 6 week stage of treatment Large pond/s where the H 2 O is,”settled out.” (Water Care Services Ltd, 2008)
  16. 17. Most effective method is to utilise, SERIES of cells, in the process ALSO: remaining time it takes for the human intestinal bacteria to die off POLISHING PONDS 5 -10 day process: settles the algal solids left in the H 2 O after having ,” settled out .”
  17. 18. UV gives high quality product the harbour first : the H 2 O passes through sand filters that extract particles to: DISINFECTION 15 microns 254nm quartz tube lamp of 300W is used Mangere Site has 7776 UV LAMPS (Water Care Services Ltd, 2008)
  18. 19. CHLORINE <ul><li>destroys many microbes </li></ul><ul><li>O 2 & electricity are used = O 3 </li></ul><ul><li>removes colour from the H 2 O </li></ul><ul><li>NOT used in NZ </li></ul><ul><li>easy & effective </li></ul><ul><li>in disuse over UV - due to </li></ul><ul><li>the environmental impacts </li></ul>OZONE (American Chemistry Council, 2005) ALSO:
  19. 20. USED FOR: septic tank & oxidation pond effluent &, secondary/tertiary stages of treatment WETLANDS 5 – 10 day flow through a ,”wetland,” - plants rooted in soil of a shallow pond BACTERIA settle to plant stems and aeration of H 2 O transfers the process
  20. 21. IRRIGATION H 2 O from the treatment plant can be used for IRRIGATION purposes THOUGH much care is needed to ensure the soil & vegetation is not suscepted to microbial contamination from this. VERY dependent: toxcity hazard involved with the use of land & timing of the crops to be grown
  21. 22. Bibliography Disinfection of wastewater. (n.d). Retrieved September 18, 2008, from http//: disinfectionb.htm - 5k American Chemistry Council.Inc. (2007). Chlorine chemistry division- wastewater disinfection . Retrieved September 18, 2008, from http//: chlorine/sec content.asp?CID=1198& DID=4534&CTYPEID=107 Science Learning Hub. (2008). Disinfection of wastewater.sciencelearn.hub . Retrieved September 18, 2008, from http// /contents/you_me_and_uv/nz_research/ disinfecting_wastewater- 25k Ministry of Environment. (2005). Client . Retrieved September 18, 2008, from http// %20Ponds%202005%20Final…-
  22. 23. Global Water Instrumentation.Inc. (2007). Inflow and infiltration of sanitary sewer systems . Retrieved September 18, 2008, from http//:www. – 33k Natural Resource Management and Environmental Department. (2007). Retrieved September 18, 2008, from http// 551e07.htm – 129k