MWEA Process Seminar 2013 Happy Microbiology = Happy Operators Brian J. Ross, Genesee County Water & Waste Services November 6, 2013
The Activated Sludge Process
Microorganisms – How does an operator see them?
How do you use the Microscope? • Ocular Lens = 10x • Objective Lens = 10x, 40x, 100x • Light Source • Condenser • Adjustment Knob
How do you use the Microscope? 1) Prepare the Slide
2) Smear Preparation & Staining Simple Staining vs Differential Staining 1) Gram Positive 2) Gram Negative 3) Neisser Stain
Activated Sludge Microorganisms 5 Major Groups • Bacteria • Protozoa • Metazoa • Filamentous bacteria • Algae and fungi Bacteria are complex, even though each has only a single cell. Bacteria are among the most abundant organisms on Earth. Bacteria make up approximately 95% of all organisms in the Activated Sludge Process.
Bacteria – 3 Classifications • Aerobic • Anaerobic • Facultative The most important microorganisms in Activated Sludge are aerobic. Bacteria are frequently classified based on how they respond to oxygen.
Structure of Bacteria – 3 Shapes • Coccus (spherical or oval) • Bacillus (rectangular or rod-like) • Spirillum (spiral or corkscrew)
Structure of Bacteria • 1 ) Coccus (spherical or oval) occurring singly or in pairs – called diplococci attached in short chains – called streptococci in groups of four (4) – called tetrads in three dimensional cubes of eight – called sarcinae in grape-like clusters – called staphlyococci
Structure of Bacteria • 2) Bacillus (rectangular or rod-like) occurring in pairs – called diplobacilli in short chains – called streptobacilli occurring in short oval rods – called coccobacilli
Structure of Bacteria • 3) Spirillum (spiral or corkscrew) look like commas – called vibrios rigid body shaped like a corkscrew – called spirilla flexible body shaped like a corkscrew – called spirochetes
How is a Bacterium Built? • Slime layer excreted from the inside to the outside used for adsorption of larger particles ultimately used to form “floc” • Cell wall semi-rigid used to give it shape designed to protect internal parts • Cell membrane functions as an entrance and an exit to the cell secretes enzymes • Enzymes proteins that cause biochemical reactions they breakdown larger particles into smaller ones smaller units can transport across membrane process call absorption • Method of locomotion Single cell wiggle or squirm glide through medium propel with flagella
How do Bacteria Eat?
What do Bacteria need? • Organic compounds human wastes • Inorganic substances iron, sulfur, nitrogen • Essential elements carbon, nitrogen, phosphorous, sulfur, oxygen • Other nutrients carbohydrates, sugars, fats (used for energy) • Miscellaneous substances Ions: magnesium, calcium, potassium, iron, and chloride
How do Bacteria Multiply?
How do Bacteria Multiply?
Growth in Activated Sludge Bacteria - The Growth Curve Lag phase Accelerated growth phase Declining growth phase Stationary phase Death phase
How do Bacteria Multiply?
Process Control- What can we control? • It’s all about the operator maintaining favorable conditions for bacteria • Can we control? …. How?..... pH dissolved oxygen levels detention times sludge age (MCRT) food to microorganism (F/M) ratio temperature Industrial discharges
Protozoa – 3 Classifications • Amoebae • Flagellates • Ciliates Free-swimming ciliates Crawling (grazing) ciliates Stalked ciliates Protozoa play a critical role in the treatment process, digesting dispersed bacteria Protozoa make up approximately 3% of all organisms in Activated Sludge Protozoa are also single-celled microorganisms
Protozoa 1. Amoebae (“naked”, called Proteus ) Amoebae are the most primitive Protozoa. Amoebae feed on small organic particles, algae, bacteria, and other small protozoa. Amoebae contribute very little to the overall treatment of wastewater.
Protozoa 1. Amoebae (how it feeds on small organic particles - pseudopods )
Protozoa 1. Amoebae (“testate”, called Arcella )
Protozoa 2) Flagellates (called Flagellate Bodo ) – most common Flagellates are the most widespread of the Protozoa. Flagellates compete with bacteria for soluble nutrients. Flagellates also feed on bacteria and small algae.
Protozoa • Ciliates Free-swimming ciliates Crawling (grazing) ciliates Stalked ciliates Comes from the Latin word “eyelash” Ciliates feed on mostly bacteria, yeast, and algae They do not contribute to the overall treatment by actively removing organic matter They do contribute to the overall clarity of the wastewater by removing suspended bacteria Abundance of ciliates indicates that most organic material has been removed from the wastewater
Protozoa • Ciliates Free-swimming ciliates
Protozoa • Ciliates Free-swimming ciliates
Protozoa • Ciliates Free-swimming ciliates
Protozoa • Ciliates Crawling (grazing) ciliates Crawlers are not good swimmers. Common in Activated Sludge Process. Their dominance indicates good treatment Crawling ciliates gain their dominance after most soluble nutrients are removed At this stage, most of the dispersed bacteria have begun to clump together
Protozoa • Ciliates Stalked ciliates They have no cilia on their bodies The cilia around their mouth is used to gather food They rarely swim freely Found attached to almost anything Carchesium colony can contain hundreds of heads
Factors that affect Protozoa • Level of Organic Nutrients • Dissolved Oxygen • Competition influence • Temperature These factors influence the abundance and types of Protozoa present in the wastewater A lack of DO will severely limit the number and type of Protozoa in the system If there is a high level of organic nutrients the bacteria will out compete the Protozoa Protozoa grow best in ambient temperatures around 15-25 degrees C (+10C =2x)
Relative Numbers of Microorganisms vs Time in Activated Sludge
Metazoa – 3 Classifications • Rotifers • Nematodes (also bristle worms) • Tartigrades (water bear) Their presence indicates treatment system conditions Metazoa are multi-cellular organisms and include all animals except Protozoa. They are larger than Protozoa. Very little to do with removal of organic matter in the Activated Sludge process.
Metazoa • Rotifers • The word rotifer comes from the Greek word meaning “wheel bearing animal” • The “wheels” of the rotifer are called corona, which is covered in cilia • The corona provides locomotion and also brings food to the rotifer • The female is larger than the male. Lifespan of male is short. His purpose is to fertilize
Metazoa • Rotifers
Metazoa • Nematodes Nematode is simple structure, even though it is multi-cellular. Nematodes possess a digestive, reproductive, and nervous system. They feed on bacteria, fungi, small protozoa, and sometimes other nematodes Some have teeth like a spear they use to stick prey and then use it like a straw to suck out contents
Metazoa • Nematodes
Metazoa • Tartigrades (water bear) The word Taritigrade means “slow walker”. There movement is clumsy and slow. Water Bears have developed ways to survive extreme environmental swings. If they lack DO, they will swell up and float for days. If they lack water, they will shrivel like a raisin. Tartigrades are very sensitive to “toxic” conditions. They feed on algae and small protozoa. They feed like nematodes (pierce food – suck out parts)
Metazoa • Tartigrades (pregnant water bear)
The Food Web
Filamentous – 2 Classifications • Foaming filaments • Bulking filaments
Filamentous • Foaming filaments
Foaming filaments – caused by: • Excess greases, oils, & fats • Low F/M ratio • Temperature changes
Filamentous • Bulking filaments 1851 0041 The presence of some filamentous bacteria is helpful. They provide support structure for floc When they gain dominance they may cause settling problems Associated with changes in: temperature, DO, sludge age, nutrients, and grease.
Bulking filaments - caused by: • Low DO • Low F/M Ratios • Longer Sludge ages • Septic wastewater • Nutrient deficient incoming wastewater • Changes in pH • Excess greases, oils, and fats
Identifying types of filamentous • Filament shape and length • Cell shape and length • Cell septa • Sheath • Attached growth • Branching • Sulfur granules • Motility
Identifying types of filamentous • Filament shape and length
Identifying types of filamentous • Cell shape and length
Identifying types of filamentous • Cell septa
Identifying types of filamentous • Sheath
Identifying types of filamentous • Attached growth
Identifying types of filamentous • Branching
Identifying types of filamentous • Sulfur granules
Identifying types of filamentous • Motility
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