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CE301 Environmental Engineering 09 October 2006

CE301 Environmental Engineering 09 October 2006 - C.W Cook...

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Unformatted text preview: C.W. Cook Professor in Environmental Engineering P.E. Registered Professional Engineer in Texas DEE Diplomate American Academy of Environmental Engineers Joseph F. Malina, Jr., Ph.D., P.E., DEE Environmental Engineering Joseph F. Malina, Jr., Ph.D., P.E., DEE C.W. Cook Professor in Environmental Engineering Education Manhattan College, Riverdale, NY B.C.E. (1957) Civil Engineering (Sanitary Engineering) University of Wisconsin at Madison M.S. (1959) Civil Engineering, (Sanitary Engineering) Ph.D. (1961) Civil Engineering, (Sanitary Engineering) Experience The University of Texas at Austin Civil Engineering Department 1961-present 1976-1988 Chairman of the Department JFM 09 October 2006 Environmental Engineering Protect the health, safety and welfare of the public Minimize the impact of human activities on the quality of the environment Environmental Engineering is at the Intersection of Natural, Built, & Information Environments Environmental Engineers Renaissance People of the 21st Century Educated in the Fundamentals of Civil Engineering Understanding of Environmental Ecology, Economics, & Sociology (to some extent) Quality of Life Providing the engineering infrastructure 1 Environmental Engineering Infrastructure includes: Water Supply Abundant, safe & potable Collection & Treatment of Storm Water Wastewater (residential, commercial & industrial) may be the limiting resource controlling growth in Water Collection & Disposal of solid wastes residuals (sludge& biosolids) Texas Indoor & outdoor air pollution control Water Supply and Demand Texas Water Resources In Texas in the year 2030 Water shortages could reach 5.4 x 10 6 acre-feet per year acre(1.76 x 10 12 gal per year) [5 x 10 9 gal/d], if projected growth is realized in Municipal Use of Water about 200 gal/cap-d Water Use 2 protect public health provide potable (clear and clean) drinking water WATER TREATMENT Water Treatment Chemistry Hydraulics Water Treatment Chemistry Chemical addition: Chlorine (Cl2)for disinfection (killing pathogens) Cl2 + H2O= HOCl + H+ + Cl Ammonia (NH4(OH) to reduce chlorine demand by minimizing the formation of undesirable chlorinated organic compounds (TRIHALOMETHANES) Lime [CaO or Ca(OH)2] for softening precipitation of [CaO soluble Ca++ and Mg++ as insoluble solids [CaCO3 and Mg(OH)2] Ferric Sulfate [Fe2 SO4)3] for coagulation of colloidal solids into large suspended solids that settle Water Treatment (continued) Other chemical that are added in Austin: Fluoride - strengthens tooth enamel Activated Carbon removes tastes and odors Carbon dioxide to remove excess lime Sodium hexametaphosphate [CalgonTM] to "Stabilize" water and reduce scaling Stabilize" Water Treatment Processes Hydraulics Screening - Removes large solids Rapid Mix - For thorough mixing of Flocculation - Slow and gentle stirring to Sedimentation - Separation of solids by Filtration - Removal of solids that do not settle out gravity form larger, heavier solids (flocs) chemicals in the water Aerial View of Davis Water Treatment Plant 3 Flocculation Basin Flocculation and Sedimentation Basins Reactor Clarifier includes Flocculation and Sedimentation 4 Municipal Wastewater Approximately 50 to 70% of wastewater Water Supply after Filtration the water used for municipal and purposes is returned as Municipal Wastewater flow rates Average flow = 100 gal/cap-day gal/cap Design flow = 150 gal/cap-day gal/cap= 300 gal/cap-day Peak flow gal/capUntreated Municipal Wastewater Concentration Constituent Solids, total (TS) Suspended solids (SS) Biochemical Oxygen Demand, Total organic carbon (TOC) Nitrogen (total as N) Phosphorus (total as P) Oil & Grease Total coliform No./100 mL Unit mg/L mg/L mg/L mg/L mg/L mg/L mg/L Weak 350 100 110 80 20 4 50 107 Medium 720 220 220 160 40 8 100 108 Strong 1200 350 400 290 85 15 150 109 Municipal wastewater is ~99.9% water and ~0.1% impurities Water Content % 99.92 99.82 99.75 5 Wastewater Treatment Objectives Protection of human health Protection of the aquatic environment Wastewater Treatment Removal of suspended solids Removal of soluble organic substances Removal of Nitrogen & Phosphorus (algae blooms) Elimination of pathogens Wastewater Treatment Processes Screening to remove large objects Grit removal ( sand and grit) Sedimentation removal settleable solids Biological treatment to convert soluble organic material to biosolids Sedimentation to remove biosolids Cholrination (Chlorine) to eliminate pathogens Chlorine) Dechlorination (Sulfur Dioxide) to remove Dioxide) residual chlorine and protect biota in receiving stream South Austin Regional Plant Aeration Basin Sedimentation Basin 6 Effluent Characteristics Austin, TX Concentration Austin Effluent Constituent Unit mg/L mg/L mg/L Permit Limits 2005 Monthly Annual Average Average Average 2 2 0.2 15 10 2 5 5 2 Secondary Clarifier Suspended solids (SS) Biochemical Oxygen Demand, Ammonia Nitrogen Treated Wastewater Effluent Residuals Engineering & Management Sludge Biosolids Solid Wastes Hazardous Materials Composting Municipal Wastewater Sludge & Biosolids Windrow Composting Biosolids - Dilodirt 7 Scarab Mixing Windrow Scarab used to Turn and Reshape Windrows Windrow Composting Temperature of Biosolids Increases to >160OF Finished Compost Aging of Composted Biosolids Zilker Gardens Solid Wastes (Refuse) Production Rate 3.5 pounds per person - day 8 Municipal Solid Waste Characteristics Constituent Typical Composition % by weight Food Waste Paper Cardboard Plastics Textiles Rubber Leather Yard Waste Wood Glass Steel Cans Aluminum Cans Other Metals Dirt, ash, etc. Total 12 30 6 11 4 1 2 12 6 5 5 1 2 3 100 30 2 3 1 6 10 4 4 Amount Separated 30-lb basis Solid waste Disposal options - Separation of recyclable materials (MRF) - Sanitary Landfills - Incineration - Composting City of Austin Recycles Paper Containers (aluminum, steel, glass, & plastic) Yard wastes Mixed Wastes Sanitary Landfill Spread, compact, & cover daily Landfill Liner Installation Landfill Gas Collection Wells 9 Generators converting Landfill Gas to Electricity Environmental Engineering Undergraduate Courses CE 341 Intro to Env. Engr. Env. Engr. CE 342 Water & Wastewater Treatment Engr. Engr. CE 346 Solid Waste Engr. Engr. CE 364 Design of Wastewater and Water Treatment Facilities CE 369L Air Pollution Control Engr. Engr. CE 370K Environmental Sampling & Analysis Definition: Sustainable Development Development that meets the needs of the present without compromising the ability of future generations to meet their own needs Brundtland Commission, 1986 World Commission on Environment and Development the Environmental Challenges Protect the health, safety and welfare of the public Minimize the impact on the quality of the environment Environmental Engineering at the Intersection of Natural, Built, & Information Environments 10 ...
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