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Environmental engineering


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Environmental engineering

  1. 1. SUBTOPICS: 1. Wastewater 2. Pollution of Receiving Water 3. Wastewater CollectionReporter: Salinas
  2. 2. SUBTOPICS: 1. Principles of Wastewater Treatment 2. Land-Based TreatmentReporter: Japin
  3. 3. SUBTOPICS: 1. Wastewater Treatment PlantsReporter: Orlanes
  4. 4. SUBTOPICS: 1. On-Site Treatment Facilities 2. Government / Public Role in Pollution ControlReporter: Real
  5. 5. 12.2 WASTEWATER Wastewater can be formed by a variety ofactivities, including washing, bathing, and usingthe toilet. Rainwater runoff is also consideredwastewater. No matter where it comes from, thiswater is full of bacteria, chemicals, and othercontaminants.What is Wastewater Treatment? Wastewater treatment is the process of takingwastewater and making it suitable for dischargeback into the environment. Wastewater treatmentreduces the contaminants to acceptable levels so asto be safe for discharge into the environment.
  6. 6. 12.2.1 CONSTITUENTS1. Microorganism2. Solids - Total Solids - Inorganic Constituents - Organic MatterInorganic constituents of wastewater includes:1. Chlorides & Sulfates2. Nitrogen & Phosphorus3. Carbonates & Bicarbonates4. Toxic Substances
  7. 7. Organic Matter includes:1. Protein2. Carbohydrates The sources of these biodegradablecontaminants include excreta and urinefrom humans: food wastes from sinks:soil and dirt from bathing, washing,laundering: plus various soaps,detergents, and other cleaningproducts.
  8. 8. 12.2.2 BOD MEASUREMENT The amount of organic matter in wateror wastewater can be measured directly(as TOC),but this doesn’t tell uswhether the organics are biodegradableor not. TOC is determined by measuringthe amount of CO2 produced when theproduced when the organic carbon in thesample is oxidized by a strong oxidizerand comparing it with the amount in astandard of known TOC.
  9. 9. Figure 12-1Total OrganicCarbon Analyzer Currentmodel of anautomaticanalyzer in w/cchemicaloxidation is usedto determine theTOC in water andwastewater.
  10. 10. 12.2.2 BOD MEASUREMENT kt kt L L0 (10 ) and L 0 L L (1 10 0 )Where:L = carbonaceous BOD remaining at time t = t (O2 neededto oxidize carbonaceous organic matter remaining).L0 = ultimate carbonaceous oxygen demand (i.e. ultimateBOD; O2 needed to oxidize carbonaceous organic matterinitially present).L0 – L = carbonaceous oxygen demand (i.e. BODsatisfied; O2 used to oxidize carbonaceous organicmatter at time t = t.t = time (days)k = rate constant (base 10) (day -1)
  11. 11. 12.2.3 Municipal Wastewater The excreted waste from humansis called sanitary sewage.Wastewater form residential areas,referred to as domestic sewage,includes kitchen, bath, laundry, andfloor drain wastes. These, togetherwith the liquid wastes fromcommercial and industrialestablishments, are termed municipalwastewater.
  12. 12. 12.2.3 Industrial Wastewater Wastewater from industries includeemployees’ sanitary wastes, process wastesfrom manufacturing, wash waters, andrelatively uncontaminated water fromheating and cooling operations.12.2.3 Stormwater The runoff from rainfall, snowmelt,and street washing. It is lesscontaminated than municipal wastewater.
  13. 13. 12.3 POLLUTION OF RECEIVING WATERS 12.3.1 Effects of Pollutants Water pollution occurs when thedischarge of wastes impairs water qualityor disturbs the natural ecologicalbalance.The contaminants that cause problems includes:1. Pathogens2. Organic Matter3. Solids4. Nutrients5. Toxic & Hazardous Substances6. Other Pollutants (color, foam, heat, & radioactive materials.
  14. 14. 12.4 WASTEWATER COLLECTION 1. Early Systems 2. Present SystemsPresent Systems Sewage collection systems todaynormally consist of separate stormand sanitary sewers in the newerareas and combined sewers in theolder sections of cities.
  15. 15. 3 Types of Sewers1. Sanitary Sewers Sanitary sewers carry domestic sewage, liquid commercial and industrial wastes, and undesirable contributions from infiltration and storm water.2. Storm Sewers Storm sewers receive storm water runoff from roads, roofs, lawns, & other surfaces.3. Combined Sewers Combined sewers perform the functions of sanitary and storm sewers and are common in the older section of most municipalities because these sewers carry sanitary wastes and are connected to basement floor drains, any surcharging could cause a backup of untreated sanitary sewage into basements.
  16. 16. There are two types of wastewatertreatment systems:1.Biological treatment plant , &2.Physical/Chemical treatment plant
  17. 17. Commonly used chemical processes forindustrial wastewater treatment:1.Oxidation2.Reduction3.Precipitation4.NeutralizationCommonly used chemical processes formunicipal wastewater treatment:1.Disinfection2.Precipitation
  18. 18. Physical processes of wastewater treatment:1.Removing grit2.Clarifyinhg raw sewage & concentrating the settled solids4.Clarifying biological suspensions & concentrating the settled floc5.Gravity thickening of primary or secondary sludges
  19. 19. Impounded System:1.Wetlands2.Aerated Lagoons3.Anaerobic Lagoons4.Aerated Ponds5.Facultative PondsAdvantages of Land based TreatmentMethods Over Wastewater Treatment Plants:1.Characterized Simplicity2.Lower Operating Cost3.Lower Capital Cost
  20. 20. Regarded as Practical Cutlets forthe Disposal of Treated orUntreated Wastewater:1.Streams2.Lakes3.Rivers4.Oceans
  21. 21. Factors that Influence the Decision inChoosing a Suitable WastewaterTreatment Method:1.Local Preference2.Experience of the consultant based onengineering methods3.Wastewater process/track record ofthe processOptions in Dealing with the Organic &Inorganic Contaminants:1.Removed physically2.Converted biologically3.Changed chemically
  22. 22. Objective of Land Application System The objective of the land basedtreatment was to reduce wastedischarged to surface waters whileutilizing the nutrient content forcrops and encourage the used ofeffluent for irrigation and groundwater recharge.
  23. 23. Permeable Soil – a type soil havingpores or openings that permitsliquids or gases to pass through.Impervious soil – an impenetrablesoil.Sludge – the substances that areremoved during water treatment.
  24. 24. Permeable Soil – a type soil havingpores or openings that permitsliquids or gases to pass through.Impervious soil – an impenetrablesoil.Sludge – the substances that areremoved during water treatment.