1、Designation: E 1798 96 (Reapproved 2001)Standard Test Method forAssessing Treatability or Biodegradability, or Both, ofOrganic Chemicals in Porous Pots1This standard is issued under the fixed designation E 1798; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers simulating the activated sludgesewage treatment proc
3、ess and therefore gives a measure of theextent of biodegradation or removal likely to occur duringsewage treatment.1.2 Assessment of treatability or biodegradability, or both,of water soluble organic compounds in the porous pot testrequires dissolved organic carbon (DOC) measurements orspecific chem
4、ical analysis.1.2.1 Dissolved organic carbon (DOC) measurements, rela-tive to the controls, can be used to calculate the removal of thetest chemical or water soluble residues by the porous pottreatment (see 12.3). The DOC measurements do not identifywater soluble chemicals. Specific chemical analysi
5、s, on theother hand, can be used to identify and quantify the parent testchemical or (if standards are available) any water solubleresidues formed by the porous pot treatment. A specificchemical analytical method must have a limit of detection(LOD) #0.1 mg/L in water or #0.1 mg/Kg in solids.1.3 The
6、feature that distinguishes this test from otheractivated sludge simulation tests is the retention of the acti-vated sludge in a porous liner, that eliminates the need for asecondary clarifier and facilitates control of the critical param-eter, the sludge retention time (SRT).1.4 Porous pots can be c
7、ompletely sealed and testsusing14C-labeled test compounds are then possible. Carbondioxide in the exhaust gas and bicarbonate in the effluent canbe used together to assess the extent of mineralization, andlevels of radiolabel in the sludge and in the aqueous phase mayalso be determined.1.5 By simult
8、aneously measuring the efficiency of the potsin removing DOC, it is also possible to determine whether thetest compound has any adverse effect on normal sewagetreatment processes.1.6 The SI units given in parentheses are for informationonly.1.7 This standard does not purport to address all of thesaf
9、ety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements see Section 6.2. Referenced Documents2.1 AS
10、TM Standards:2E 178 Practice for Dealing with Outlying Observations3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 aeration chamberthe interior volume of the porousliner or candle that holds the activated sludge.3.1.2 activated sludge (mixed liquor)a heterogeneousmixture, susp
11、ended in sewage influent, consisting of a varietyof microorganisms (primarily bacteria) formed into flocculentparticles, that is cultured for the purpose of removing organicsubstrates and certain inorganic constituents from wastewatersby metabolic uptake and growth on these substrates. Normaloperati
12、ng concentrations of activated sludge in aeration unitsrange from 2000 to 5000 mg/L (1).33.1.3 biochemical oxygen demand (BOD)the biochemicaloxygen demand, measured as the amount of oxygen used forrespiration during the aerobic metabolism of an energy sourceby acclimated microorganisms. Carbonaceous
13、 BOD is a mea-sure of the amount of oxygen used during the metabolism of anorganic substrate and represents the amount of COD that hasbeen oxidized biologically at any time. Nitrogenous BOD is ameasure of the amount of oxygen required for the biologicaloxidation of inorganic nitrogen compounds (nitr
14、ification).BOD5is the biochemical oxygen demand after five days ofincubation (1).1This test method is under the jurisdiction of ASTM Committee E47 onBiological Effects and Environmental and is the direct responsibility of Subcom-mittee E47.04 on Environmental Fate of Chemical Substances.Current edit
15、ion approved March 10, 1996. Published May 1996.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The boldface
16、 numbers given in parentheses refer to a list of references at theend of the text.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.4 biodegradationdestruction of chemical compoundsby the biological action of living organisms (2).3
17、.1.5 chemical oxygen demand (COD)the amount ofoxygen required to oxidize the organic matter in a givensample under the best possible analytical conditions for maxi-mum oxidation of the organic matter to carbon dioxide andwater. The theoretical COD (CODth) is the COD that can becalculated from a bala
18、nced equation for total oxidation of theorganic matter to carbon dioxide and water; for this, theempirical formula for the organic matter must be known (1).3.1.6 effluentas used in this standard, treated and clarifiedwastewater leaving an activated sludge treatment system.3.1.7 hydraulic retention t
19、ime (HRT)as used in this stan-dard, average liquid through-put time. Mathematically equal toreactor volume/liquid flow rate.3.1.8 mineralizationconversion of organic compounds ina wastewater to CO2,H2O and simple salts by microbiologicaloxidation (1).3.1.9 mixed liquor volatile suspended solids (MLV
20、SS)asused in this standard, that portion of the activated sludge whichis lost by ignition at 550C for 15 min. It corresponds to thebiological and organic fraction of the solids.3.1.10 OECDOrganization for Economic Cooperationand Development (3).3.1.11 primary biodegradationoxidation or alteration of
21、 amolecule by bacterial action to such an extent that character-istic properties of the chemical are no longer evident or whenit no longer responds to analytical procedures specific fordetecting the original compound (2).3.1.12 primary treatmentthe removal of separable mate-rials from wastewaters by
22、 sedimentation (1).3.1.13 secondary clarifiera settling tank used to separatethe solids from the liquids in activated sludge mixed liquor (1).3.1.14 secondary treatmentthe removal of colloidal andsoluble organic material from wastewaters. Settleable materialis usually removed prior to secondary trea
23、tment. Secondarytreatment processes are usually biological in nature, for ex-ample, activated sludge or trickling filtration, but may bechemical and physical in nature. The term secondary treatmentis sometimes used to indicate a certain level of removal ofbiochemical oxygen-demanding materials (1).3
24、.1.15 settled domestic sewageas used in this standard,raw domestic sewage which has been allowed to settle for atleast 2 h.3.1.16 sludge retention time (SRT)as used in this stan-dard, average time (usually measured in days) that activatedsludge is retained in the aeration or treatment chamber.Mathem
25、atically equal to the total solids in the system/solidswasted per day.3.1.17 treatabilityremoval of a compound from wastewa-ter by a particular sewage treatment process whether bybiodegradation or by some other means (2).3.1.18 ultimate biodegradationcomplete conversion of amolecule to carbon dioxid
26、e, water, inorganic salts and productsassociated with the normal metabolic processes of bacteria (2).4. Summary of Test Method4.1 This test method is designed to simulate the activatedsludge sewage treatment process and is performed using aporous pot-type laboratory-scale activated sludge apparatus,
27、based on an original design developed by the United KingdomWater Research Centre (4,5). The original design was modified(see Fig. 1) (6) and has been utilized in determining the effectsof temperature and growth media components, for example,phosphate, on the growth of activated sludge and the toxici
28、ty oftreated effluents (7,8). It has also been used in the environmen-tal safety evaluation of a new product (9). The modified testfacilitates control of the SRT, and the effect of this fundamentalparameter on the efficiency of removal of surfactants in porouspots has been described (10).4.2 The tes
29、t and control pots are filled with mixed liquorfrom an activated sludge plant treating predominately domesticsewage and then operated as continuous-flow systems withprimary effluent or settled domestic sewage as backgroundfeed.4.3 A solution or suspension of the test compound is dosedinto the test p
30、ot by means of a suitable micro-metering pump.The concentration of the test compound in the influent sewageis 10 to 20 mg C/L since the practical lower detection limit ofthe DOC analyzer is 1 to 3 mg C/L. A lower concentration ofthe test compound may be used if a highly sensitive analyticalmethod is
31、 available or if radiolabeled compound is used. Thetotal flow to the pot (sewage + test compound dosing solution)is controlled to give the required hydraulic retention time.4.3.1 A similar flow of sewage and a dosing solution of asuitable reference compound such as sodium benzoate areadded to the co
32、ntrol pots. Benzoate biodegrades easily andcompletely in this test system, and is added at such aconcentration as to ensure that the total organic carbon loadand the total sewage flow are the same in both control and testpots. Reference compounds may also have other uses (see11.5).4.4 Air is supplie
33、d to the pots through a diffuser stone toensure adequate oxygen transfer to the mixed liquor, and anadditional flow througha5mmopen tube is provided to ensurecomplete mixing of the system. The air flow should besufficient to maintain and thoroughly mix the solids in suspen-sion and keep the concentr
34、ation of dissolved oxygen above 2mg/L at all times. In order to maintain an adequate dissolvedoxygen (DO) concentration it will be necessary to maintain anair to wastewater flow ratio of 5 to 10/1 on a volume to volumebasis.4.5 Sludge is wasted directly from the aeration chamberthrough the base of t
35、he pot by means of a suitable peristalticpump. To avoid problems caused by the low flow ratesrequired, the pump is fitted with a timer and operated intermit-tently.4.6 The levels of biodegradable materials remaining in theunit effluents are dependent on the SRT and the growth kineticsof those organi
36、sms that are involved in the metabolism of thecompound under consideration. The test is therefore, in effect,a kinetic study and consequently should be conducted at aconstant temperature. Further, by making measurements at twoor more temperatures, the biodegradability of the test com-pound under sum
37、mer and winter operating conditions may beestablished.E 1798 96 (2001)2FIG. 1 Porous Pot UnitE 1798 96 (2001)3FIG. 1 (continued)E 1798 96 (2001)4FIG. 1 (continued)E 1798 96 (2001)54.7 The removal of test compounds is determined by analy-sis of effluents and comparison of the results obtained frompot
38、s containing test compound to those from control potstreating only settled sewage and benzoate. Primary biodegra-dation is assessed by specific analysis of the test compounds ineffluents after correction for volatilization and adsorption of theparent compounds onto activated sludge. Further, analysi
39、s ofDOC in effluents provides a measure of ultimate biodegrada-tion after corrections have been applied for volatilization andadsorption of parent compounds and biodegradation interme-diates onto sludge.4.7.1 For materials that are insoluble or are absorbed orprecipitated onto the activated sludge,
40、additional informationwill be required to distinguish between biodegradation andremoval by these other processes. The additional informationmay be obtained by analysis of the sewage sludge or byusing14C-labeled test compounds.4.8 The capabilities of the porous pots to efficiently removesoluble organ
41、ic carbon and ammoniacal nitrogen from sewagefeed is done by measuring the loss of DOC and ammoniacalnitrogen during porous pot treatment. However, the loss ofammonia can only be used when the SRT is sufficiently longfor viable populations of nitrifying bacteria to become estab-lished in the sludge.
42、5. Significance and Use5.1 Secondary wastewater treatment using activated sludgeis one of the most important biological treatment processes inuse today. The porous pot simulates the activated sludgesewage treatment process in the laboratory and provides datathat can be used to predict the fate of or
43、ganic compounds in fullscale plants.5.2 A good correlation between the laboratory test and fullscale plants is achieved by the use of primary effluent or settleddomestic sewage and controlling key parameters in rangestypical of such treatment process. These parameters includetemperature, pH, DO conc
44、entration, hydraulic residence time(HRT) and sludge retention time (SRT).6. Apparatus6.1 Porous Pot Aeration Vessel (Engineering Drawing ofURPSL Design (see Fig. 1)The porous pot vessel liner isconstructed from porous high density polyethylene sheets. Thethickness ranges from 3.2 to 13.6 mm and pore
45、 sizes are from65 to 90 m. The retention of the liner is about 20 m and allparticles above this size are retained in the system. The outervessel can be constructed of glass or an impermeable plasticsuch as acrylonitrile butadiene syrene copolymer (ABS).6.2 Oil-Free Compressor, for supplying compress
46、ed air tothe aeration vessel.6.3 Suitable pumps are required to dose porous pots withtest substance solutions and sewage at the required rates (0 to1.0 mL/min for test substance solutions, 5 to 20 mL/min forsewage). If the URPSL apparatus is used, an additional pumpis required to waste sludge from t
47、he pot.6.3.1 Low rates of sludge wastage are attained using a pumpset at a high flow rate but operating intermittently. The actualflow is calculated as follows: pump throw (mL/min) bypumping time (s)/timer cycle (s); for example, when the pumpin operating for 10 s each minute and the pump throw is 3
48、mL/min, the wastage rate would be 0.5 mL/min.6.4 Sample Bottles, 1 L, to hold test substance dosingsolutions.6.5 Silicone Rubber Tubing, bore, 0.5 mm inside diameter(ID).6.6 Polypropylene Transmission Tubing.6.7 Tube Connectors.6.8 Diffuser Stones.6.9 Measuring Cylinders, 25-mL.6.10 Graduated Pipett
49、es, 1-mL.6.11 Stopwatch.6.12 Sample Bottles, 40-mL, for collection of samples forwaste sludge and mixed liquor suspended solids determina-tions.6.13 Thermometer, 0 to 50C.6.14 Measuring Cylinders 1 and 2 L, for each pot to collectwaste sludge.6.15 Timer, for sludge wastage pump allowing intermittentoperation.6.16 Right-Angled Plastic Tube, to fit on one end of the airline to ensure complete mixing of activated sludge.7. Reagents and Materials7.1 Activated Sludge Mixed Liquor, collected from aerationbasin or oxidation ditch of domestic wastewater treatmentp
