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