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ERT 417/4 WASTE TREATMENT IN BIOPROCESS INDUSTRY SEM 1 (2011/2012)

ERT 417/4 WASTE TREATMENT IN BIOPROCESS INDUSTRY SEM 1 (2011/2012). Characteristics of Industrial Waste. CHARACTERISTICS OF INDUSTRIAL WASTE. Physical Characteristics. Chemical Characteristics. Biological Characteristics. Toxicity. Organic Matter. Inorganic Matter.

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ERT 417/4 WASTE TREATMENT IN BIOPROCESS INDUSTRY SEM 1 (2011/2012)

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  1. ERT 417/4WASTE TREATMENT IN BIOPROCESS INDUSTRY SEM 1 (2011/2012) Characteristics of Industrial Waste

  2. CHARACTERISTICS OF INDUSTRIAL WASTE Physical Characteristics Chemical Characteristics Biological Characteristics Toxicity Organic Matter Inorganic Matter Measurement of Organic Compound

  3. Total Solids Odors PHYSICAL CHARACTERISTICS Turbidity Temperature Color

  4. Sludge is solids removed from WW during treatment. TS content Floating matter Solids that are treated further are term biosolids Settleable matter Total Solids (TS) Colloidal matter Matter in solution Solid classification Total Solids (TS) • Mass remaining after a WW sample has been evaporated at 103–105 C Total Suspended Solids (TSS) • Mass remaining on Whatman GF/C after drying at 105 C • After WW sample has been filtered, the preweighted filter paper is • placed in an aluminium dish for drying before weighing. Total Dissolved Solids (TDS) • Solid that pass through the filter, & are then evaporated at specific temp. • Contains a high fraction of colloidal solids. Volatile Suspended Solids (VSS) • Solid that can be volatilized & burned off when the TSS are ignited at • 500 50C. Ref: (Metcalf and Eddy, 2003)

  5. Analysis of solids data The following test results were obtained for a WW sample at the headwork to a WW-treatment plant. All of the tests were performed using a sample size of 50 mL. Determine the concentration of total solids(TS), total suspended solids (TSS), volatile suspended solids (VSS), and total dissolved solids (TDS). The samples used in the solid analysis were all either evaporated, dried or ignited to constant weight. Tare mass of evaporating dish = 53.5433 g Mass of evaporating dish + residue after evaporation at 105oC = 53.5794 g Mass of evaporating dish + residue after ignition at 550oC = 53.5625 g Tare mass of Whatman GF/C filter after drying at 105oC = 1.5433 g Mass of Whatman GF/C filter + residue after drying at 105oC = 1.5554 g Mass of Whatman GF/C filter + residue after ignition at 550oC = 1.5476 g Ref: (Metcalf and Eddy, 2003)

  6. SOLUTION • Determine TS • Determine TSS

  7. SOLUTION • Determine VSS • Determine TDS

  8. turbidity A measure of the light-transmitting properties of water due to the presence of colloidal & residual suspended matter Measurement based on comparison of the intensity of light scattered by a sample to the light scattered by a reference suspension under the same conditions. Turbidity Unit Nephelometric Turbidity Unit (NTU) Colloidal matter will scatter or absorb light and this prevent its tranmission. Ref: (Metcalf and Eddy, 2003)

  9. color Refer to degree of absorption of light energy in visible spectrumm (400 – 700 nm) light Fresh WW color light brownish-gray Color Then changes to gray, dark gray & black color due to the formation of metallic sulfide (sulfide produced under anaerobic conditions When the color of the WW is black, the WW is often described as septic Ref: (Metcalf and Eddy, 2003) (Davis & Cornwell, 2008)

  10. temperature Temp. of WW >>Temp. of local water supply due to the addition of warm water from households and industrial activities. light Very important because of its effect on chemical reaction & reaction rates, aquatic life & suitability of the water for the beneficial uses Temperature At high temp. O2 is less soluble in warm water Foster the growth of undesirable water plants & WW fungus High mortality rate of aquatic life Increase in rate of biochemicla reactions, thus decrease the quantity of oxygen present in surface waters. Ref: (Metcalf and Eddy, 2003)

  11. odors Caused by gases produced by the decomposition of organic matter or by substance added to the WW. of organic matter or by substance added to the WW. Odors light Industrial WW may contain odorous compounds or compounds that produce odors during the process of WW treatment. Effect of odors Vomitting Caused poor appetite for food H2S toxic at elevated concentration Lowered water consumption High mortality rate of aquatic life Can create psychological stress on human being at low concentration Ref: (Metcalf and Eddy, 2003)

  12. Chemical characteristics Chemical Characteristics Organic matter Inorganic matter Measurement of organic compound

  13. Chemical characteristics -inorganic matter- Most of water contain light Amount presence cause by Leaching of chloride-containing rocks and soil with which the water comes in contact Chlorides Pollution from sea water/ agricultural/ industrial/ domestic WW Chloride conc. > 250 mg/L noticeable taste Domestic water should contain < 100 mg/L chloride Ref: (Metcalf and Eddy, 2003) (Davis & Cornwell, 2008)

  14. Chemical characteristics -inorganic matter- Essential to the growth of microorganisms, plants & animals (known as nutrients) light Because of N2 is an essential building block in the synthesis of protein, N2 data will be required to evaluate the treatability of WW by biological processes. Nitrogen Insufficient N2 can necessitate the addition of N2 to make the waste treatable. Where control of algal growths in the receiving water is necessary, removal or reduction of N2 in WW prior to discharge may be desirable. Total N2 is comprised of organic N2, ammonia, nitrite & nitrate Ref: (Metcalf and Eddy, 2003)

  15. Chemical characteristics -inorganic matter- Phosphorus is also essential to the growth of algae and other biological organisms. light Phosphorus Poly phosphate Forms of Phosphorus Orthophosphate Organic Phosphate light Is required in the synthesis of protein Sulfate is reduced biologically under anaerobic conditions to sulfide, which in turn can combine with hydrogen to form hydrogen sulfide (H2S). Sulfur The accumulated H2S can then be oxidized biologically to sulfuric acid, which is corrosive to steel pipes and equipment. Ref: (Metcalf and Eddy, 2003)

  16. Chemical characteristics -inorganic matter- Formed by anaerobic decomposition of organic matter containing sulfur or from reduction of mineral sulfites and sulfates light H2S Is toxic The principal byproduct from the anaerobic decomposition for the organic matter in WW light Methane Is a colorless, odorless & combustible in hydrocarbon of high fuel value light Ref: (Metcalf and Eddy, 2003)

  17. Chemical characteristics -inorganic matter- The trace quantities of many metals such as cadmium (Cd), cronium (Cr), Copper (Cu), Iron (Fe), lead (Pb), mercury (Hg), manganese (Mn), nickel (Ni) & zinc (Zn) are important constituents of most waters. Many of these metals are classified as priority pollutants Metals Most of these metals are necessary for growth of biological life (absence of sufficient quantities of them could limit growth of algae Are toxic in excessive quantities. Ref: (Metcalf and Eddy, 2003)

  18. MEASUREMENT OF ORGANIC SUBSTANCES • The analysis used to measure aggregate organic materialmay be divided into 2; • To measure gross conc. of organic substance greater than 1.0 mg/L • To measure trace conc. in the range of 10-12 to 100 mg/L • Laboratory methods commonly used today to measure gross amounts of organic • matter (typically greater than 1mg/L) in wastewater include; • Biochemical oxygen demand (BOD) • Chemical oxygen demand (COD) • Total organic carbon (TOC) • Complementing of these laboratory tests is the theoretical oxygen demand (ThOD), • which is determined from the chemical formula of the organic matter. (Metcalf and Eddy, 2003)

  19. Biochemical Oxygen Demand(BOD) • The most widely used parameter of organic pollution • 5-day BOD – involved the measurement of the dissolved oxygen used by • microorganisms in the biochemical oxidation of organic matter. • BOD test results are used to; • Determine the appropriate quantity of oxygen that will be required to • biologically stabilize the organic matter present. • Measure the efficiency of some treatment process • Determine the size of waste treatment facilities. • Determine compliance with wastewater discharge permits. • BOD at 20oC for 5 days is used as standard test (measure after 5 days in incubation at 20oC). • Use bacteria to oxidize biodegradable organic in wastewater sample after incubation. • BOD can be calculates by measuring DO before & after incubation. (Metcalf and Eddy, 2003)

  20. Calculation of bod • when the dilution water is not seeded (e.g. untreated WW); • BOD (mg/L) = D1 – D2 • P • when the dilution water is seeded; • BOD (mg/L) = (D1-D2)- (B1 – B2) f • P • where, • D1 = dissolved oxygen of diluted sample immediately after preparation (mg/L) • D2 =dissolved oxygen of diluted sample after 5days incubation at 20oC (mg/L) • B1 = dissolved oxygen of seed control before incubation (mg/L) • B2 = dissolved oxygen of seed control after incubation (mg/L) • f = fraction of seeded dilution water volume in sample to seeded dilution • water volume in control • P = fraction of WW sample volume used to total combined volume

  21. Exercise : Calculation of BOD The following information is available for a seeded 5-day BOD test conducted on a wastewater sample. 15mL of the waste sample was added directly into 300mL incubation bottle. The initial DO of the diluted sample was 8.8mg/L and the final DO after 5 days was 1.9mg/L. The corresponding initial and final DO of the seeded dilution water was 9.1 and 7.9 respectively. What is the 5-day BOD (BOD5) of the wastewater sample? Ans : 115.2 mg/L

  22. modeling of bod reaction is assumed to obey first-order kinetics Integrating between the limits of UBOD & BODt and t=0 and t=t, Where, BODr = amount of waste remaining at time t (days) expressed in oxygen equivalents (mg/L) k1= first-order reaction rate constant (1/d) UBOD = total @ ultimate carbonaceous BOD (mg/L) t = time (d)

  23. modeling of bod reaction, cont’ Typical value of k1 for untreated WW = 0.23d-1 To determine the reaction constant , k at Temp. other than 20oC, (T = 20 to 30oC) (T = 4 to 20oC) (T ≠ <20oC) often quoted in the literature

  24. Example : Calculation of BOD Determine the 1-day BOD and ultimate first-stage BOD for a wastewater whose 5-day 20oC BOD is 200 mg/L. The reaction constant k (base e)=0.23d-1. What would have been the 5-day BOD if the test had been conducted at 25oC? Ans : UBOD = 293 mg/L, BOD1=60.1 mg/L BOD5=224 mg/L SOLUTION : Determine the UBOD Determine the 1-day BOD Determine the 5-d BOD at 25 C

  25. Limitations in the bod test • A high concentration of active, acclimated seed • bacteria is required. • Pretreatment is needed when dealing with toxic • wastes, and the effects of nitrifying organisms must • be reduced. • Only the biodegradable organics are measured. • The test does not have stoichiometric validity after • the soluble organic matter present in solution has • been used. • Long period of time is required to obtain results.

  26. COD of organic matter or by substance added to the WW. To measure the oxygen equivalent of the organic material in WW that can be oxidized chemically using strong chemical agent (dichromate in an acid solution) COD Many organic substances can be oxidized chemically compared to oxidized biologically (Example: lignin) Higher than BOD because Inorganic substances that are oxidized by the dichromate increase the apparent organic content of sample Certain organic substances may be toxic to the microorganisms used in the BOD test ADV: COD test can be completed in 2.5 h The dichromate can react with the inorganic substance Ref: (Metcalf and Eddy, 2003)

  27. Differences between bod & cod

  28. Total organic carbon (TOC) To determine total organic carbon in an aqueous sample. The test methods for TOC utilize heat & oxygen, ultraviolet radiation, chemical oxidants, or some combination of these methods to convert organic carbon to carbon dioxide which is measured with an infrared analyzer or by other means. TOC TOC can be used as a measure of its pollution characteristics and in some cases, it has been possible to relate TOC to BOD and COD values. TOC test can be completed in 5-10 min.

  29. Theoretical oxygen demand (T Od) h ThOD is the stoichiometric amountof O2 required to oxidize completely a given compounds ThOD It can only be evaluate when complete chemical analysis of WW is available.

  30. Example : Calculation of ThOD Determine the ThOD for glycine (CH2(NH2)COOH) using the following assumption; If the 1st step, the organic carbon & nitrogen are converted to carbon dioxide (CO2) and ammonia (NH3), respectively In the 2nd and 3rd steps, the ammonia is oxidized sequentially to nitrite and nitrate. The ThOD is the sum of the oxygen required for all three steps. Ans : ThOD= 112 g O2/mol glycine.

  31. solution : Calculation of ThOD Write a balanced reaction for the carbonaceous oxygen demand. Write balanced reaction for the nitrogeneous oxygen demand: i) nitrite (HNO2) ii) nitrate (HNO3) c) Determine the ThOD = Sum of the oxygen required for all three steps. Ans : ThOD= 112 g O2/mol glycine.

  32. Example : Page 97 (Textbook) DETERMINATION OF BOD/COD, BOD/TOC & TOC/COD RATIOS Determine the theoretical BOD/COD, BOD/TOC, and TOC/COD ratios for The following compound C5H7NO2 (MW=113). Assume the value of the BOD first-order. Reaction rate constant is 0.23/d Ans : BOD/COD = 0.68 BOD/TOC = 1.82 TOC/COD = 0.37 SOLUTION : • Determine the COD • Write a balanced reaction for Carbonaceous oxygen demand • b) Determine the BOD of the compound • Determine the TOC of the compound • Determine the ratios required.

  33. Chemical characteristics -organic matter- Carbohydrates (25 – 50 %) Protein (40 – 60 %) Fats & oil (8 – 12 %%) Principle group Small amount Organic compounds Surfactants Volatile organic compounds Pesticides

  34. OIL & grease Origin in WW from butter, margarine, vegetables fats & oil. They also obtained nuts, cereals & some fruits. Oil & grease They float & interfere with biological treatment process & also cause maintenance problem. Small amouNtof organic matter in ww Surfactants or surface-active agents are large organic molecules, slightly soluble in WW & cause foaming in WW treatment plants Surfactants Priority pollutants were selected on the basis of their known or suspected carcinogenicity, mutagenicity, or high acute toxicity. Priority Pollutants Many of the organic priority pollutants are classified as volatile compounds (VOCs)

  35. Small amouNtof organic matter in ww Organic compounds that have a boiling point ≤ 100 C and/or a vapor pressure > 1mm Hg at 25C are generally considered to be VOCs (e.g. vinyl chloride) VOCs Are great concern because: Once such compounds are in the vapor state are much more mobile, therefore more likely to be released to the environment. The presence of some of these compound in atmosphere may pose a significant public health risk They contribute to a general increase in reactive hydrocarbons in the atmosphere, which can lead to the formation of photochemically oxidants. Are toxic to many organism and can be significant contaminants of surface waters. Pesticides

  36. Biological characteristics General classification of microorganisms found in surface water & WW

  37. Pathogenic organisms found in WW may be excreted by human beings & animals who are infected with disease or who are carries a particular infectious disease. Pathogenic organisms Bacteria Protozoa Helminths Viruses

  38. toxicity light Toxicity is the degree to which a substance is able to damage an exposed organism. toxicity Can refer to the effect on a whole organism,such as Animal Bacterium Plant

  39. Toxicity test • Toxicity test are used to; • Assess the suitability of environmental conditions for aquatic life • Establish acceptable receiving water concentrations for conventional • parameter such as DO, pH, temp. or turbidity. • Study the effects of water quality parameters on wastewater toxicity. • Determine the effectiveness of wastewater-treatment method. • Assess the degree of wastewater treatment needed to meet water • pollution control requirement. • Determines compliance with federal & state water quality standard • and water quality criteria. • Establish permissible effluent discharge rate

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