Environmental Controls I/IG
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Transcript of Environmental Controls I/IG
Environmental Controls I/IGEnvironmental Controls I/IGLecture 6 Overview
Water ResourcesWater Supply Systems
Planning Issues
TerminologyTerminologyPotable Water: water fit for human consumption
Gray Water: non-potable, used water containing no harmful wastes
Black Water: non-potable, used water that contains harmful or human waste
Drains and SewersDrains and SewersStorm: contains rainwater and surface
runoff
Sanitary: contains human waste
Combined: contains both
Acid RainAcid RainRain combined with chemicals (SO2, COx, NOx,…) in the air to form a weak acid
Water + Sulfur Dioxide = Sulfuric AcidH2O + 2SO2 H2SO4 + SOx
Source: automobile emissions, coal fired electric generation, air pollution
HardnessHardnessCaused by calcium and magnesium salts
Can be removed by “water softening” systems
Ph ScalePh ScaleAlkalinity: bicarbonates, carbonates, hydroxides (Ph>7)
Acidity: hydrogen ions (Ph<7)
Water TableWater TableNaturally occurring depth to top of water in an aquifer
S: p.896, F.21.2
Water ResourcesWater Resources
Sources of Fresh WaterSources of Fresh Water
Precipitation collection Surface water diversion Groundwater aquifersDesalinization
Hydrologic CycleHydrologic CycleWater exists in three phases—vapor, liquid, solid
Water storage takes several forms– clouds, groundwater, snow/ice, lakes/river/oceans
S: p. 859, F.20.4a
Hydrologic CycleHydrologic CycleNatural intercepts of water affect its purity and utility
S: p. 859, F.20.4b
““We All Live Downstream”We All Live Downstream”Human intercepts degrade quality
S: p. 896 F.21.2
Toxins Around UsToxins Around UsArsenic: pressure treated lumberCadmium: batteriesChromium: antifreezeFluoride: rat poison, water treatmentLead: paints, piping, fuelSilver: photo-processing
Other ContaminantsOther ContaminantsChlorides (road salts) tasteCopper (corroding pipe) tasteIron (corroding pipe) stains/tasteManganese (natural) taste/laxative/colorNitrates (fertilizer) healthPesticides healthSodium (road salt) taste
Water Supply SystemsWater Supply Systems
Groundwater AquiferGroundwater AquiferArtesian wells created from pressure due to elevation head
2.3’ of head = 1 psi
Upfeed SystemUpfeed SystemSupplied through pressurized street main or artesian well source
S: p. 958. F.21.52
CisternsCisternsCaptured rainwater held in tanks to increase water availability and pressure
May also be refilled manually
San Francisco Plantation, Louisiana
Enhancing Water PressureEnhancing Water PressureWhen natural pressure is insufficient then a pump or pressurized source must be used
S: p. 913, F.21.13
Water TowersWater TowersUsed before electric pumping technology improved
Hand pumps or manual labor
Chicago, IL
Baltimore, MD
Scituate, MA
Water TowersWater TowersAdapted for use on individual buildings
S: p. 959, F.21.53
PumpingPumpingTechnologyTechnology
As technology improved, buildings could become taller (w/steel framing and elevators)
Downfeed system
S: p. 960, F21.54a
Pumping TechnologyPumping TechnologyConstant pressure up-feed system eliminates the house tank
S: p. 965, F21.57
PumpingPumpingTechnologyTechnology
To prevent over- pressurization, intermediate house tanks are used
S: p. 961, F.21.54b
Planning IssuesPlanning Issues
Planning IssuesPlanning IssuesConservation strategiesFacility requirementsWaste disposal
Conservation StrategiesConservation StrategiesReduce use flow control fixtures
Match grade to use culinary vs. irrigation
Collection/Storage cisterns, retention basins, roof ponds, porous pavement
Graskrete
Conservation StrategiesConservation StrategiesGray Water Systems: captures drainage from non-black water waste fixtures and reuses it for lesser quality needs …irrigation, car washing…
Recently legalized in Utah. Opposition was due to contamination concerns and inappro-priate soil composition
Conservation GoalsConservation GoalsReduce overall consumption
Avoid surface runoff
Allow percolation into soil to recharge groundwater table
Facility RequirementsFacility RequirementsCheck local codes for programming & ADA requirements
S: p.864, T.20.3
Waste DisposalWaste DisposalVerify local sewer system availability/capacity Municipal sewer Septic system on site
Soil percolation Drain field/septic tank location Drain field proximity to other water sources
Water ReclamationWater ReclamationMunicipal programs that use treated wastewater for uses that do not require potable water
Los Angeles County Water Reclamation Project