Introduction to Environmental Engineering Lecture 14 Water Quality Continued Chapter 8

Solids The separation of solids is one of the primary objectives of wastewater treatment Solid Anything other than a liquid or gas Anything remaining after evaporation at 103  C

Solids Total Solids TS = total solids, mg/L W ds = weight of dish plus the dry solids, mg W d = weight of clean dish, mg V = volume of sample, L

Solids Total Solids = dissolved solids + suspended solids Volatile Solids = solids burned 550 – 600  C FS = Fixed Solids = remaining ash from 550 – 600  C

Nitrogen Remember, building blocks of life Carbohydrates, Protein, Fatty Acids, Nucleic Acids Nitrogen is a major component of Amino Acids, which are the building blocks of protein NH 3 is an intermediate in biological metabolism Organic nitrogen and NH 3 indicate recent pollution – Kjeldahl Nitrogen test Nitrite and Nitrate indicate pollution some time ago Both are measured colorimetrically

Bacteriological Measurements Microbiology – study of organisms that can not be seen with the naked eye Recall, before the late 1800’s no one knew that they existed. Louis Pasteur Range in size from 1 mm to mm From an environmental standpoint they are important in every compartment, Air, Water and Soil Most of the organic carbon available for life is in the form of microbes

Bacteriological Measurements It is really their world, from a population standpoint 1 gram of rich soil contains: 2.5 billion bacteria 0.5 million fungi 50,000 algae 30,000 protozoa

Bacteriological Measurements An Environmental Engineer needs to have a knowledge of microbes to remove them in water treatment (filtration and chlorination) to support them in wastewater treatment (carbon, nitrogen and phosphorus removal from waste)

Bacteriological Measurements Only a small fraction cause disease Pathogens Typhoid and cholera killed millions around the turn of the century These two waterborne diseases drove technology advancement Today, Salmonella, Shigella, Hepatitis, Entamoeba, Giardia, Cryptosporidium are the main U.S. concerns

Bacteriological Measurements Epidemiology The connection between pathogens in water and human disease was made by Dr. John Snow Father of Epidemiology Determined that a Cholera outbreak was from water downstream of London Removed the water pump, ending the outbreak

Bacteriological Measurements Indicator Organisms Coliforms – group of microbes used to show contamination of a source Qualities of a good indicator organism 1. Inhabits the digestive tracts of warm-blooded animals 2. Plentiful 3. Easily detected 4. Harmless 5. Survive longer than most pathogens

Bacteriological Measurements Principal Methods of Measurement Filter Count Coliforms captured on a filter Filter placed in agar Colonies grown and counted MPN Test Diluted samples placed in broth Gas production indicates fermentation Count the positive reactions, statistics

Assessing Water Quality Standard Methods for the Examination of Water Quality (Standard Methods) Quantitative Measurement Techniques of everything that may be in water Drinking Water Standards EPA – Primary and Secondary Standards MCL – Maximum Contaminant Level Wastewater Effluent Standards NPDES Permit – National Pollution Discharge Elimination System Surface Water Quality Standards A  E levels