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Environmental Controls I/IG. Lecture 6 Overview Water Resources Water Supply Systems Planning Issues. Terminology. Potable Water: water fit for human consumption Gray Water: non-potable, used water containing no harmful wastes
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Environmental Controls I/IG Lecture 6 Overview Water Resources Water Supply Systems Planning Issues
Terminology Potable 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 Sewers Storm: contains rainwater and surface runoff Sanitary: contains human waste Combined: contains both
Acid Rain Rain combined with chemicals (SO2, COx, NOx,…) in the air to form a weak acid Water + Sulfur Dioxide = Sulfuric Acid H2O + 2SO2 H2SO4 + SOx Source: automobile emissions, coal fired electric generation, air pollution
Hardness Caused by calcium and magnesium salts Can be removed by “water softening” systems
Ph Scale Alkalinity: bicarbonates, carbonates, hydroxides (Ph>7) Acidity: hydrogen ions (Ph<7)
Water Table Naturally occurring depth to top of water in an aquifer S: p.896, F.21.2
Sources of Fresh Water Precipitation collection Surface water diversion Groundwater aquifers Desalinization
Hydrologic Cycle Water 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 Cycle Natural intercepts of water affect its purity and utility S: p. 859, F.20.4b
“We All Live Downstream” Human intercepts degrade quality S: p. 896 F.21.2
Toxins Around Us Arsenic: pressure treated lumber Cadmium: batteries Chromium: antifreeze Fluoride: rat poison, water treatment Lead: paints, piping, fuel Silver: photo-processing
Other Contaminants Chlorides (road salts) taste Copper (corroding pipe) taste Iron (corroding pipe) stains/taste Manganese (natural) taste/laxative/color Nitrates (fertilizer) health Pesticides health Sodium (road salt) taste
Groundwater Aquifer Artesian wells created from pressure due to elevation head 2.3’ of head = 1 psi
Upfeed System Supplied through pressurized street main or artesian well source S: p. 958. F.21.52
Cisterns Captured rainwater held in tanks to increase water availability and pressure May also be refilled manually San Francisco Plantation, Louisiana
Enhancing Water Pressure When natural pressure is insufficient then a pump or pressurized source must be used S: p. 913, F.21.13
Water Towers Used before electric pumping technology improved Hand pumps or manual labor Baltimore, MD Chicago, IL Scituate, MA
Water Towers Adapted for use on individual buildings S: p. 959, F.21.53
PumpingTechnology As technology improved, buildings could become taller (w/steel framing and elevators) Downfeed system S: p. 960, F21.54a
Pumping Technology Constant pressure up-feed system eliminates the house tank S: p. 965, F21.57
PumpingTechnology To prevent over- pressurization, intermediate house tanks are used S: p. 961, F.21.54b
Planning Issues Conservation strategies Facility requirements Waste disposal
Conservation Strategies Reduce use flow control fixtures Match grade to use culinary vs. irrigation Collection/Storage cisterns, retention basins, roof ponds, porous pavement Graskrete
Conservation Strategies Gray 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 Goals Reduce overall consumption Avoid surface runoff Allow percolation into soil to recharge groundwater table
Facility Requirements Check local codes for programming & ADA requirements S: p.864, T.20.3
Waste Disposal Verify 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 Reclamation Municipal programs that use treated wastewater for uses that do not require potable water Los Angeles County Water Reclamation Project