MILITARY ENGINEERING FIELD MANUAL
CONTENTS 1 RELEVANT ASPECTS FOR OPTIMIZING THE AD PROCESS WHAT IS ANAEROBIC DIGESTION? THEORETICAL NOTIONS PRACTICAL IMPLICATIONS COMPLEXITY OF THE SYSTEM SEQUENTIAL PROCESS MULTIPARAMETRIC PROCESS TWO DEGRADATION PATHS OF THE ORGANIC MATTER IN?UENCE OF TEMPERATURE NEED OF A BALANCED DIET FOR THE MICROORGANISMS CRITERION FOR THE SELECTION OF FEEDSTOCK FOR AD TECHNICAL NOMENCLATURE DE?NITIONS PRACTICAL APPLICATIONS AND NUMERICAL EXAMPLES APPROXIMATE RATIO BETWEEN COD AND VS METHANE YIELD OF A SUBSTRATE WITH A KNOWN BMP COHERENT USE OF THE TS, VS, AND BMP VALUES CALCULATION OF THE HRT CHECKING THE OLR OPTIMIZING THE C/N RATIO OF A SUBSTRATES MIXTURE MANAGING THE PLANT “BY TABLES”: LIMITATIONS AND RISKS CONCLUSIONS ON THE USE OF TABLES THE DYNAMIC MANAGEMENT OF THE BIOGAS PLANT THE PH THE RELATIONSHIP BETWEEN PH AND ALKALINITY THE CHEMICAL COMPOSITION OF THE SUBSTRATE THE VFA PRO?LE MONITORING THE BIOGAS’ FLOW AND COMPOSITION MONITORING THE ORP MONITORING THE ELECTRIC CONDUCTIVITY THE OUTSOURCED BIOLOGICAL MANAGEMENT SERVICE: LIMITATIONS OF THE TRADITIONAL TECHNIQUES CONCLUSIONS THE AUTOMATIC TITRATOR: MYTHS AND LEGENDS BIBLIOGRAPHY 2 OVERVIEW OF THE LABORATORY METHODS FOR THE ANALYSIS OF FERMENTATIVE PROCESSES BASIC NOTIONS OF METROLOGY: ACCURATENESS AND PRECISION OR REPEATABILITY DE?NITIONS OF ACCURATENESS AND OF PRECISION OR REPEATABILITY ERROR PROPAGATION MEASURE METHODS EMPLOYED IN THE BIOGAS INDUSTRY CLASSICAL VOLUMETRIC AND BAROMETRIC METHODS VOLUMETRIC METHODS BAROMETRIC METHODS AUTOMATIC MEASURE SYSTEMS: AMPTS AND BRS REACTORS FOR BIOLOGICAL TESTS: WHICH ARE BETTER?—BIG OR SMALL ONES? THE MOST FREQUENT ERRORS IN THE MEASURE OF SMALL GAS FLOWS NORMALIZATION CORRECTION OF THE MOISTURE ELIMINATION OF CARBON DIOXIDE AUXILIARY PHYSICOCHEMICAL TESTS MEASURE OF THE PH AND THE ORP DETERMINATION OF THE DM AND VS OF BIOMASS DETERMINATION OF THE COD OF SLUDGE AND LIQUID SUBSTRATES THE IN SITU LABORATORY FOR THE REAL-TIME CONTROL OF THE BIOLOGICAL PROCESS 3 HOW TO PERFORM TESTS UNDER OPTIMUM CONDITIONS SCOPE MEASURING THE DM AND VS MEASURING THE DM WITH A MOISTURE ANALYZER CONFUSING THE “MOISTURE” AND THE “DM” SCALES WRONG SETTING OF THE DRYING TEMPERATURE WRONG INSTALLATION OF THE MOISTURE ANALYZER MEASURING THE DM OF SILAGE INTERPRETATION OF THE SCALE’S TECHNICAL SHEET MEASUREMENT OF THE DM WITH AN OVEN AND A SCALE MEASURING THE ASH CONTENT AND VS MEASURING THE COD AND TOTAL N HOW TO DESIGN A BIOLOGICAL EXPERIMENT THE PREPARATION OF BOTH INOCULUM AND SAMPLE THE INOCULUM/SUBSTRATE RATIO, I/S DE?NING THE MIX RATIO (INTENSITY OF STIRRING) THE BMP TEST: ONE GENERAL PROCEDURE, MULTIPLE APPLICATIONS GENERAL PROCEDURE FOR MEASURING THE BMP PROCESSING THE MEASURED DATA STEP-BY-STEP DATA PROCESSING FREQUENT CAUSES OF PROBLEMS DURING THE BMP TEST PROBLEMS CAUSED BY HUMAN ERRORS PROBLEMS CAUSED BY INSTRUMENTAL OR METHOD ERRORS 3 10 THE HYDROLYTIC AND METHANOGENIC ACTIVITY TESTS: CHECKING THE BACTERIA’S HEALTH 3 10 1 DEGRADATION OF POLYSACCHARIDES (GLUCOSE, STARCH, AND CELLULOSE) 3 10 2 CASEIN AND GELATIN IN POWDER 3 10 3 PROPIONIC AND BUTYRIC ACIDS 3 10 4 FATTY ACIDS (LIPIDS) 3 10 5 ACETIC ACID AND SODIUM ACETATE 3 10 5 1 STOICHIOMETRY OF ACETIC ACID AND SODIUM ACETATE 3 10 5 2 FIRST STEP: CHECKING THE METHANOGENIC CAPACITY OF ACETATE OR ACETIC ACID 3 10 5 3 SECOND STEP: THE SMA CALCULATION 3 11 ANALYSIS OF THE ERROR PROPAGATION IN THE BMP ASSAY AND ITS VARIANTS 3 12 A CONTROVERSIAL TECHNIQUE: CORRECTING THE PH, THE ALKALINITY, AND ADDING NUTRIENTS BEFORE STARTING THE BATCH TESTS 4 APPLICATION OF LABORATORY EXPERIMENTAL RESULTS TO THE MANAGEMENT OF THE BIOGAS PLANT PRACTICAL APPLICATIONS OF THE VS TEST MEASURING THE ORGANIC LOAD (OL) AND THE ORGANIC LOAD RATE (OLR) PRACTICAL APPLICATION MEASURING THE EF?CIENCY OF THE FEEDSTOCK’S CONVERSION INTO METHANE CORRECTIVE ACTIONS IN THE CASE ?DA < 45% PRACTICAL APPLICATIONS OF THE BMP TEST THE RIGHT PRICE FOR THE FEEDSTOCK OPTIMIZING THE BIOGAS PLANT’S DIET PREVENTING THE INHIBITION CAUSED BY “DIF?CULT” SUBSTRATES CHECKING THE DIGESTION EF?CIENCY OF THE BIOGAS PLANT DETERMINATION OF THE OPTIMUM SRT/HRT DETERMINING THE EF?CACY OF ADDITIVES AND PRETREATMENTS FREQUENT ERRORS IN PLANNING AND PERFORMING BIOLOGICAL TESTS USING REFERENCE SUBSTRATES TO CHECK THE HYDROLYTIC ACTIVITY: HOW TO FIND OUT IF SOMETHING IS GOING WRONG HYDROLYSIS TEST OF CELLULOSE HYDROLYSIS TEST OF SUGAR AND STARCH HYDROLYSIS OF PROTEINS LIPOLYTIC ACTIVITY TEST GENERAL SUBSTRATE INHIBITION TEST APPLICATIONS OF THE SMA TEST: PREVENTING THE BIOLOGICAL COLLAPSE AND SELECTING THE BEST INOCULUM TO START A BIOGAS PLANT PRACTICAL EXAMPLE ON HOW TO TEST AN INOCULUM SUSPECTED OF METHANOGENIC INHIBITION USING WINE VINEGAR PRACTICAL EXAMPLE OF THE SMA TEST FOR THE SELECTION OF THE INOCULUM NECESSARY FOR STARTING A NEW BIOGAS PLANT HOW TO DETERMINE THE DOSAGE OF TRACE ELEMENTS IF SMA < 10 USEFULNESS OF THE TEST WITH VINEGAR, ACETIC ACID, OR ACETATE AS REFERENCE SUBSTRATE REFERENCE SUBSTRATES 5 SOME SIMPLE TRICKS TO IMPROVE THE LABORATORY’S OPERATIVITY FOREWORD MEASURING THE PERCENTAGE OF METHANE IN THE BIOGAS WITH THE DOUBLE REACTOR SET AND WITH THE SYRINGE METHOD NECESSARY MATERIALS FOR THE SYRINGE TEST PERFORMING THE TEST WITH THE SYRINGE ERROR ANALYSIS OF THE SYRINGE METHOD SOLVING THE PROBLEM OF THE THERMOSTATIC BATH’S EVAPORATION SEAL THE GAP BETWEEN THE REACTORS AND THE PLEXYGLASS COVER BY MEANS OF O-RINGS OR RUBBER BANDS ADD SOME VERY SOLUBLE SALT TO THE WATER REPLACING THE WATER IN THE THERMOSTATIC BATH WITH ANY FLUID HAVING LOW VAPOR PRESSURE IMPROVED CONNECTION OF THE DC STIRRER MOTORS DESCRIPTION AND THEORETICAL ANALYSIS OF THE PROBLEM STEP-BY-STEP PROCEDURE TO CONNECT THE POWER SUPPLY AT THE CENTER OF THE LINE USING BRUSHLESS MOTORS CHECKING THE CALIBRATION (VOLUMETRIC METHODS) GRAVIMETRIC CALIBRATION METHOD VOLUMETRIC CALIBRATION METHOD FLUSHING THE HEAD VOLUME OF THE REACTOR WITH A GAS LIGHTER RECHARGE FINDING GAS LEAKS SOME SAFETY RULES FOR THE BIOLOGICAL LABORATORY IN THE BIOGAS PLANT 6 CRITICAL REVIEW OF THE SCIENTI?C LITERATURE FROM THE BIOGAS PLANT MANAGER’S PERSPECTIVE INTRODUCTION THREE METHODS TO FIND OUT ABSOLUTE TRUTHS: THE ARISTOTELIAN SYLLOGISM, THE CARTESIAN DOUBT PRINCIPLE, AND AVOIDING LOGIC FALLACIES THE CORRELATION BETWEEN BMP AND ELECTRICAL CONDUCTIVITY CONCLUSION ASSESSING THE VALIDITY OF THE VFA/TA (FOS/TAC) METHOD THE CAUSAL FALLACY INFORMATION FROM THE LITERATURE CHECKING THE LOGIC FLAWS CHECKING THE EF?CACY OF ENZYMES IN THE CORRECT WAY MISCONCEPTIONS OF THE SCIENTI?C LITERATURE AMPLI?ED BY THE MARKETING THE IMPORTANCE OF PH AND THE USE OF SODIUM BICARBONATE AS BUFFER AGENT IN ANAEROBIC PLANTS THE HYPED IMPORTANCE OF TRACE ELEMENTS THE USE OF “SPECIAL PRODUCTS” FOR DESULFURIZATION DATABASES AND MATHEMATICAL MODELS OF BMP THE CONSERVATION OF THE INOCULUM THE “EQUIVALENT CORN SILAGE UNIT” OLIVE MILL POMACE FATTY WASTE AND GLYCEROL MIXTURES OF SUBSTRATES SUBSTRATES WITH LOW CONCENTRATION OF DEGRADABLE ORGANIC MATTER ESTIMATING THE ACCURACY AND RELIABILITY OF DATA PUBLISHED IN THE LITERATURE NORMS ON THE BMP TEST PROCEDURE FOR INDUSTRIAL BIOGAS PLANTS AN OVERVIEW OF THE GERMAN VDI 4630/2014 IWA’S PROPOSAL OF STANDARDIZED BMP TEST THE DRAFT OF ITALIAN NORM E0209F670 UNI/TS CRITICAL ANALYSIS OF THE FLAWS IN THE EXISTING NORMS THE VDI 4630 THE IWA GUIDELINE FOR THE BMP ASSAY THE ITALIAN DRAFT OF STANDARD RELEVANT ASPECTS FOR OPTIMIZING THE AD PROCESS 1 1 WHAT IS ANAEROBIC DIGESTION? 1 1 1 THEORETICAL NOTIONS ANAEROBIC DIGESTION (AD) IS THE BIOLOGICAL PROCESS LEADING TO THE DECAY OF ORGANIC MATTER IN THE ABSENCE OF AIR BECAUSE AIR CONSISTS OF 21% OXYGEN, THE ANAEROBIC PROCESS IS SOMETIMES CALLED ANOXIC SEVERAL TYPES OF ANAEROBIC FERMENTATIVE PROCESSES EXIST IN NATURE: ALCOHOLIC FERMENTATION, E G , DURING THE PRODUCTION OF WINE OR BEER LACTIC FERMENTATION, E G , DURING THE PRODUCTION OF SAUERKRAUT (CHOU- CROUTE), CORN SILAGE, AND SOY SAUCE DARK FERMENTATION IT IS A PARTICULAR TYPE OF ANAEROBIC FERMENTATION THAT PRODUCES BIOHYDROGEN, AND REQUIRES ENERGY TO BE SUPPLIED AS HEAT PHOTOFERMENTATION CERTAIN BACTERIA AND CYANOBACTERIA PRODUCE BIO- HYDROGEN, BUT ONLY IF ENERGY IS SUPPLIED TO THEM AS LIGHT BUTYRIC FERMENTATION IT IS A PARTICULAR TYPE OF DARK FERMENTATION, LEADING TO SIMULTANEOUS PRODUCTION OF HYDROGEN, BUTANOL, AND ACETONE PROPIONIC FERMENTATION IT IS THE PRODUCTION OF PROPIONIC ACID BY MEANS OF PROPIONIBACTERIUM ACIDIPROPIONICI, GROWN UNDER STRICT ANAER- OBIC CONDITIONS USING LACTOSE AS THE CARBON SOURCE, AT PH 6 5 AND TEMPERATURE 30°C METHANOGENIC FERMENTATION THIS PROCESS IS DISCUSSED IN DETAIL IN THIS BOOK, ALTHOUGH SOME OF THE TECHNIQUES PRESENTED HERE CAN BE EMPLOYED TO OPTIMIZE DIFFERENT FERMENTATIVE PROCESSES THE ORGANISMS DIRECTLY INVOLVED IN PRODUCING METHANE ARE THE ARCHAEA, VERY SIMILAR TO THE BACTERIA, BUT BELONG TO ANOTHER KINGDOM, AND ARE PROBABLY THE BACTERIA’S ANCESTORS