Biological wastewater treatment Markevich R Belarusian State Technological

Biological wastewater treatment Markevich R. М. Belarusian State Technological University Minsk, Sverdlov Str. 13 a Contacts (+375296933379; marami@tut. by)

Learning targets § Understanding of the conversion process of different pollutant in bacterial cell § Understanding the degradation process of organic compounds, nitrogen and phosphorous § Understanding the mechanism of anaerobic technology § Grasp the principle of UASB Replace the title also in the footer line in the master slide 2

Content - Introduction - Mechanism of contaminants removal by microorganism - Bacterial species in activated sludge treatment process - Anaerobic treatment technology: pros and cons - Commonly used anaerobic treatment technology - Innovative technologies of biological wastewater treatment Replace the title also in the footer line in the master slide 3

1. Introduction § Why biological treatment • • • Reduce BOD Reduce SS Oxidize ammonia, remove nitrogen and phosphorous Oxidize sulphide Remove possibly harmful organics Substances which have negative impact on water quality have to be converted by simple biological processes into harmless substances. § What is biological treatment • Treatment of the wastewater with adapted biomass Replace the title also in the footer line in the master slide 4

Biodegradability § BOD/COD ratio: • 0. 4 -0. 7: readily biodegradable • Below 0. 4: slowly biodegradable • -zero: not biodegradable § Most organic compounds are biodegradable, but: • Several compounds needs special adapted biomass • Some compounds are toxic above certain levels Replace the title also in the footer line in the master slide 5

Main objective of biological wastewater treatment § Substances which have negative impact on water quality have to be converted by simple biological processes into harmless substances: • Gases • Soluble substances: • Solids Replace the title also in the footer line in the master slide N 2, CO 2, CH 4 H 2 O, NO 3 -, HCO 3 Biomass, flocs 6

Microorganismn aerobic degradation § Protozoa • Ciliates unicellular organism free swimming organism robust, grazing of flocs • Vorticella convalaria good oxygen supply • Mastigophorans flagellates for locomotion • Rotifer multicellular organism high generation time and sludge age Replace the title also in the footer line in the master slide 7

Characteristics of activated sludge Compact flocs of activated sludge Activated sludge in conditions of filamentous swelling Replace the title also in the footer line in the master slide Activated sludge in conditions of gel swelling 8

Step-by-step change of populations during biocenosis development of activated sludge Dispersed bacteria Filamentous forms of bacteria Zoogloeas accumulations Colorless flagellates Free floating ciliates Hypotrichida ciliates Rotifer Nematode Fastened ciliates Small naked amoebae Small testate amoebae Large testate amoebae Replace the title also in the footer line in the master slide Oligochaeta and gastrotrich worms Suctoria ciliates and another hunters (water bears, rotifers, fungi) 9

Flagellates Small Bicoeca petiolata Anisonema acinus Replace the title also in the footer line in the master slide Large Peranema pleururum Peranema trichophorum 10

Naked amoeba Astromoeba radiosa Amoeba papillata Amoeba proteus Replace the title also in the footer line in the master slide Thecamoeba sp. 11

Testate amoebae Trinema enchelys Arcella gibbosa Centropyxis aculeata Arcella vulgaris Centropyxis sp. Replace the title also in the footer line in the master slide Euglypha sp. 12

Free-floating ciliates Uronema nigricans Chilodonella unsinata Dexiotricha sp. Lagynophria acuminata Litonotus lamella Prorodon ovum Trachelophyllum pusillum Coleps sp. Replace the title also in the footer line in the master slide 13

Hypotrichida ciliates Aspidisca costata Euplotes patella Replace the title also in the footer line in the master slide Drepanomonas revoluta Aspidisca turrita 14

Rotifers Lepadella rhomboides Keratella cochlearis Rotaria tardigrada Lecane pusilla Lecane bulla Lecane flexilis Replace the title also in the footer line in the master slide Dipleuchlanis propatula 15

Peritricha ciliates Carchesium batorligetiense Epistylis plicatilis Vorticella convallaria Epistylis longicaudatum Replace the title also in the footer line in the master slide Opercularia phryganeae Thuricola similis 16

Suctoria ciliates Staurophria elegans Rhabdophrya sp. Tokophrya quadripartita Replace the title also in the footer line in the master slide Acineta foetida Acineta sp. 17

Worms Gastrotrichs Tobrilus helveticus Chaetonotus sp. Replace the title also in the footer line in the master slide 18

Water bears Water mites Replace the title also in the footer line in the master slide 19

Examples of organisms distribution of activated sludge by main indication groups Free-floating ciliates Peritricha 0, 49% ciliates 15, 14% Rotifers 1% Rotifers 0, 05% Free-floating ciliates 4% Testate amoebae 39% Hypotrichida ciliates 5, 70% Small flagellates 13, 76% Testate amoebae 45, 21% Naked amoebae 19, 66% Replace the title also in the footer line in the master slide Peritricha ciliates 55% Hypotrichida ciliates 1% 20

Examples of organisms distribution of activated sludge by main indication groups Hypotrichid a ciliates 1% Small flagellates 1% Large flagellates 0% Peritricha ciliates 1% Freefloating ciliates 1% Rotifers 1% Worms 0% Testate amoebae 95% Free-floating ciliates 4% Suctoria ciliates 0, 9% Peritricha ciliates 3% Rotifers 1, 3% Testate amoebae 42, 1% Hypotrichida ciliates 4% Small flagellates 44, 2% Replace the title also in the footer line in the master slide 21

Examples of organisms distribution of activated sludge by main indication groups Suctoria Free-floating ciliates Peritricha ciliates 0, 02% Rotifers ciliates 0, 05% 8% 1% Hypotrichid a ciliates 17% Testate amoebae 35, 14% Small flagellates 1, 44% Naked amoebae 37, 05% Replace the title also in the footer line in the master slide Suctoria ciliates 2% Free-floating ciliates 21% Rotifers 1% Worms Testate 1% amoebae 37% Naked amoebae 0% Peritricha ciliates 8% Small flagellates Hypotrichida 2% ciliates 26% Large flagellate 2% 22

The stages of removal of contaminants from sewage Diffusion of contaminations from the liquid phase and sorption them on the surface of activated sludge flakes Delivery of substances into the cells (diffusion, active transport, phagocytosis, the splitting of macromolecules by exoenzymes, sorption of solid particles) Catabolism (splitting) of pollutants to simple connections

Catabolism of carbohydrates Monosaccharides Most of microorganisms Starch Fungus and bacteria, having amylase Cellulose and hemicellulose Pectin substances Replace the title also in the footer line in the master slide Bacteria: Cytophaga, Sporocytophaga, Sorangium, Cellulomonas, myxobacteria and others. Fungus: fungus Trichoderma viride, Aspergillus niger, Fusarium spp. Bacillus polymyxa, Clostridium felsineum and other. 24

Catabolism of Triglyceride Hydrolysis of Triglyceride Glycerol Fatty acid Oxidation to pyruvic acids β-oxidation Pseudomonas fluorescens, Bacillus fluorescens, Pseudomonas liguefaciens, Achromobacter lipolyticum, other bacteria and fungi

Catabolism of hydrocarbons Methane Ethane, propane, etc. Aromatic hydrocarbons Lignin Replace the title also in the footer line in the master slide Methylomonas, Methylobacter, Methylococcus Pseudomonas, Acinetobacter, Arthrobacter, Mycobacterium, Micrococcus, yeast of the genus Candida Pseudomonas, Mycobacterium, Bacillus, Flavobacterium, Nocardia, Aspergillus, Penicillium and other. Consortium of microorganisms 26

Conversation of Nitrogen compounds Replace the title also in the footer line in the master slide 27

Putrefaction Proteins Proteases (Proteus vulgaris, Pseudomonas, Bacillus, Clostridium) Nucleic acids Nucleases (Mycobacterium, Corynebacterium, Nocardia) Uric acid, urea Ureases Micrococcus urea, Sarcina urea NH 4+, CO 2, H 2 O Replace the title also in the footer line in the master slide 28

Consumption of reduced nitrogen compounds Assimilation process Dissimilation process (nitrification) NH 3, NH 4+ Nitrosomonas Nitrosospira Nitrosococcus Nitrosolobus Most of microorganisms Amino groups amino acids Nitrogen-containing cell connections Replace the title also in the footer line in the master slide NО 2 Nitrobacter Nitrospina Nitrococcus NО 329

Influencing factor § 1. temperature § 5℃ ~ 15 ℃ ~ 30 ℃ ~ 35 ℃ § almost stop slow optimal § 2. DO § DO > 2 mg/L § 3. Alkalinity § p. H: 8. 0 ~ 8. 4 § 4. sludge age § SRT>10 d Replace the title also in the footer line in the master slide 30

Nitrate reduction Dissimilation process (denitrification) Assimilation process NО 3 - NО 2 -, NО 3 Many bacteria some mushrooms seaweed NH 4+ NО 2 - NО Pseudomonas Bacillus Spirillum Alcaligenes Paracoccus Thiobacillus N 2 О Amino acids N 2 Replace the title also in the footer line in the master slide 31

Denitrification § • Heterotrophic bacterial • Electron acceptor: NO 3 • low DO condition Overall reaction: 2. 86 g 1 g Replace the title also in the footer line in the master slide 3. 57 g 32

Biological phosphorous removal § Principle § phosphorus accumulating organisms (PAO) • • • Heterotrophic Anaerobic: PAO will release P Aerobic: PAO will intake P Remove P by discharging sludge P releasing consume carbon source: BOD/P>17: 1 Replace the title also in the footer line in the master slide 33

Scheme of transformations of phosphorus compounds • Anaerobic conditions • Aerobic conditions phosphate-accumulating organisms Gl Gl PSHA PPh acetate, propionate РО 4 PPh 3 - СО 2 РО 43 - PSHA– polymeric saturated hydroxy acids; Gl –glycogen; PPh -- polyphosphates

Flow chart of biological treatment of municipal wastewater 1 – pumping station; 2 – receiving chamber; 3 – lattice; 4 – sand trap; 5 – primary clarifier; 6 – bioreactor; 7 – secondary settler. Replace the title also in the footer line in the master slide 35

Scheme of bio-sorber 1 – bio-sorber; 2 – aeration column; 3 – fluidised bed of coal; 4 – cone; 5 – catchment; 6 – coal filtering bed; 7 – industrial water drainage tray; 8 – tray for purified water; 9 –water distributor; 10 – circulation pump; 11 – ejection chamber. Replace the title also in the footer line in the master slide 36

Variants of biological wastewater treatment with a deep removal of nitrogen and phosphorus compounds Flow chart of А/О Process® Flow chart of А 2/О Process® Replace the title also in the footer line in the master slide 37

Variants of biological wastewater treatment with a deep removal of nitrogen and phosphorus compounds Flow chart of Bardenfo Flow chart of UCT Replace the title also in the footer line in the master slide 38

Variants of biological wastewater treatment with a deep removal of nitrogen and phosphorus compounds Flow chart of MUCT Flow chart of JHB Replace the title also in the footer line in the master slide 39

Variants of biological wastewater treatment with a deep removal of nitrogen and phosphorus compounds Flow chart of ISAN Replace the title also in the footer line in the master slide 40

Anaerobic treatment technology § Mechanism - Four key stages • Hydrolysis - Complex organic molecules are broken down into simple sugars, amino acids and fatty acids • Acidogenesis - Remaining components are further broken down into VFAs, ammonia, carbon dioxide, and hydrogen sulfide • Acetogenesis - simple molecules created through the acidogenesis phase are further digested by acetogens to produce largely acetic acid, as well as carbon dioxide and hydrogen. • Methanogenesis - methanogens use the intermediate products of the preceding stages and convert them into methane, carbon dioxide, and water. Replace the title also in the footer line in the master slide 41

Anaerobic treatment technology § Advantages of anaerobic treatment • Appropriate for high COD-concentrations • High volumetric load => small volumes required • Low sludge production (3 -10 lower than with aerobic treatment) • Low energy demand, no aeration necessary • Yield of biogas • Lower cost than for aerobic treatment • Degradation of substances which are non-biodegradable under aerobic conditions • Suitable for hot climate conditions Replace the title also in the footer line in the master slide 42

Anaerobic treatment technology § Disdvantages of anaerobic treatment • Efficiency of degradation of organic substances only up to 70 -80% => aerobic post-treatment required • Balance of volatile fatty acids • Long adaption phases necessary • Sensitivity towards oszillating temperature, p. H-value, changing concentrations and loads • Detailed monitoring systems required • Sometimes p. H-control required Replace the title also in the footer line in the master slide 43

General scheme of the transformation of organic substances under anaerobic conditions Process Substrate Bacteria Organic substances (polymers) Proteins Carbohydrates Lipids Lipolytic, proteolytic and cellulolytic bacteria H y d r o l y s i s Amino acids, sugars Fermentation bacteria A c i d o g e n e s i s Volatile fatty acids and alcohols A c e t o g e n e s i s Acetate/hydrogen Syntrophic hydrogen-forming bacteria Methanogenic bacteria M e t h a n o g e n e s i s Methane/СО 2 Replace the title also in the footer line in the master slide 44

Гидролиз Hydrolysis Cellulose Hemicellulose Starch Pectin Clostridium, Bacteroides, Acetivibrio, Eubacterium, Bacillus, Lactobacillus, etc. Proteins Clostridium, Peptococcus, Bifidobacterium, Eubacterium, Termobacteroides Replace the title also in the footer line in the master slide Lipids Clostridium, Micrococcus 45

Кислото Acidogenesis Fermentation bacteria Strict anaerobes Clostridium, Bacteroides, Eubacterium, etc. Facultative anaerobes Streptococcus Sulfate-reducing bacteria Denitrifying bacteria Replace the title also in the footer line in the master slide 46

Ацетогенез Кислото Acetogenesis Syntrophic hydrogen-forming bacteria Syntrophomonas, Syntrophobacter Hydrogen-using bacteria (methane bacteria and sulfate-reducing bacteria) Replace the title also in the footer line in the master slide 47

Кислото Methanogenesis 4 CH 3 COOH + 4 H 2 → 5 CH 4 + 2 H 2 O + 3 CO 2 4 H 2 + СО 2 → CH 4 + 2 H 2 O Methanogenic bacteria Methanobacter, Methanococcus, Methanogenum, Methanosarcina, Methanothrix, etc. The strictest anaerobiosis р. Н 6 -8 Co, Mo, Ni Replace the title also in the footer line in the master slide Only 8 substrates are used: СО 2 + Н 2, formate, oxocarbon, methanol, acetate, mono-, di- and triethanolamines) 48

Effect of p. H of waste water ALKALIZATION Consumption VFAs Formation of ions NH 4 ACIDIFICATION Formation VFAs р. Н > 9 Overloading the reactor by pollution р. Н ≤ 5 р. Н 6− 8 long-term destabilization work of the bioreactor buffer capacity of fermentation medium (carbonic acid, VFAs, ammonium ions) Replace the title also in the footer line in the master slide inhibition of methanogenesis р. Н 6− 8 resumption of the process 49

Effect of process temperature Thermophilic regime 50 -55 С Mesophilic regime 30 -40 С + A sufficiently high rate of destruction of pollution Low energy consumption for stabilizing the temperature regime + Higher velocity Higher productivity of bioreactor − Higher costs of maintaining the temperature A lower species diversity of methanogenic biocenosis

The presence in the waste water of biogenic elements, inhibitors and toxic substances BOD : N : P = 100 : 1 : 0, 2 С : N from 20 : 1 to 100 : 1 Inhibitors and toxic substances Dissolved ammonia 50 mg/l VFAs 2000 mg/l Hydrogen 0. 2 -0. 5% in the gas phase Dissolved Hydrogen sulphide 200 mg/l Heavy metals, antibiotics, etc.

The rate of biomethanogenesis Process temperature Chemical composition of raw materials (Thermophilic process 40 -55 С) Acidic stage (р. Н 6, 0 -6, 5) Replace the title also in the footer line in the master slide Density of bacterial association The degree of homogenization of the medium Mesophilic process 20 -40 С Methane Stage (р. Н 6, 5 -8, 0) 52

Biogas output Выход биогаза 1 t of fermented dry organic matter 1 t of carbohydrates 1 t of fat Replace the title also in the footer line in the master slide 300– 600 nm 3 of biogas 420– 470 nm 3 of biogas to 1000 nm 3 of biogas 53

Commonly used anaerobic treatment technology § Anaerobic biofilter 1 − distribution system; 2 − supporting grid; 3 − layer of loading material; А − initial wastewater; Б − biogas; В − treated wastewater Replace the title also in the footer line in the master slide 54

§ Bioreactor with a downward flow of sewage 1 − supporting grid; 2 − layer of vertically oriented initial material; А − initial wastewater; Б − biogas; В − treated wastewater Replace the title also in the footer line in the master slide 55

§ UASB-reactor (Upflow anaerobic sludge blanket reactor) § Advantages • High reduction of BOD • Can withstand high organic and hydraulic loading rates • Low sludge production (and, thus, infrequent desludging required) • Biogas can be used for energy (but usually first requires scrubbing) 1 − distribution system; 2 − treating zone; 3 − deflector; 4 − crevice (entrance to the settling zone); 5 − gas control baffle; 6 − catchment tray; 7 − gas collecting box; 8 − settling zone; А − initial wastewater; Б − biogas; В − treated wastewater Replace the title also in the footer line in the master slide 56

§ UASB-reactor (Upflow anaerobic sludge blanket reactor) § Disadvantages • Treatment may be unstable with variable hydraulic and organic loads • Requires operation and maintenance by skilled personnel; difficult to maintain proper hydraulic conditions (upflow and settling rates must be balanced) • Long start-up time to work at full capacity • A constant source of electricity is required • Not all parts and materials may be locally available • Requires expert design and construction • Effluent and sludge require further treatment and/or appropriate discharge Replace the title also in the footer line in the master slide 57

§ Hybrid bioreactor 1 − distribution system; 2 − supporting grid; 3 − layer of loading material; А − initial wastewater; Б − biogas; В − treated wastewater Replace the title also in the footer line in the master slide 58

§ Bioreactor with fluidized layer of carrier particles 1 − distribution system; 2 − carrier particle layer; 3 − pump; А − initial wastewater; Б − biogas; В − treated wastewater; Г − wastewater recycling Replace the title also in the footer line in the master slide 59

Innovative Technologies Of Biological Wastewater Treatment § Autotrophic anamox process • Partial nitrification, during which part of the ammonium nitrogen is oxidized to nitrite by bacteria of the first group: 2 NH 4+ + 3 O 2 → 2 NO 2− + 4 H+ + 2 H 2 O. • The autotrophic anoxidic oxidation of the remaining ammonium nitrogen by nitrite to molecular nitrogen, carried out by a second group of bacteria: NH 4+ + NO 2− → N 2 + 2 H 2 O. • Currently, two technologies are used in the world: • Technology DEMON® (Austria); • Technology of Paques ANAMMOX® (Nederland). Replace the title also in the footer line in the master slide 60

Sewage NH 4+ Ammonification Assimilation Anamox process Nitrification 1 stage Organic compounds of nitrogen in the composition of contaminants Assimilation NО 2 Organic nitrogen compounds in the cells Nitrification 2 stage NО 3 - Denitrification N 2 Molecular nitrogen in the atmosphere Advantages of autotrophic anoxidation: - high efficiency (up to 90% of nitrogen is removed); - economy (per unit of removed nitrogen is spent 60% less oxygen); - less excess biomass is formed; - readily oxidizable organic substances are not required. The cost of nitrogen removal is reduced by 2 -3 times. Replace the title also in the footer line in the master slide 61

Application of aerobic granulated activated sludge Aerobic granules of activated sludge are stratified: • in the outer layers - aerobic heterotrophs and nitrifiers; • inside the granules are denitrifying agents and phosphateaccumulating denitrifying bacteria. Basic conditions for obtaining • • changing of substrate saturation and starvation conditions; the process of cyclic (periodic) action; rising flow of sewage; limited time for sedimentation. Replace the title also in the footer line in the master slide 62

Membrane methods http: //www. saveplanet. su/tehno_590. html Replace the title also in the footer line in the master slide 63

Wastewater treatment by using the SBRreactor (Sequencing Batch Reactor) Aeration Filling in Reaeration Sludge removal Cycle Drainage of treated water Sludge sedimentation http: //www. saveplanet. su/tehno_582. html Replace the title also in the footer line in the master slide 64

Questions § Which process can reduce contaminants, assimilation or dissimilation? § How can you judge if certain wastewater can be treated with biological process? § Describe the four stages of anaerobic digestion § What is the pros and cons of anaerobic treatment technology? Replace the title also in the footer line in the master slide 65