1、Designation:D418907(Reapproved 2014)Standard Test Method forSilt Density Index(SDI)of Water1This standard is issued under the fixed designation D4189;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number
2、in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the siltdensity index(SDI)of water.This test method can be used toindicate the quantity of particulat
3、e matter in water and isapplicable to relatively low(276 kPa(40 psi).7.3 Measure the temperature of the water.7.4 Open the membrane filter holder and place a 0.45-mmembrane filter(47 mm in diameter)on the support plate ofthe holder.Some filter holders include a foam support pad,which should be used.
4、Place the filter grid side up.Handle themembrane filter only with dull tweezers to avoid puncturing.Avoid touching the membrane filter with the fingers.NOTE1Other membrane filter sizes,that is,25 mm or 90 mmdiameter,can be used.NOTE2Record the manufacturer of the membrane filter and themanufacturers
5、 identification for the membrane filter.7.5 Make sure the O-ring is in good condition and properlyplaced.Replace the top half of the filter holder and closeloosely.7.6 Bleed out trapped air by cracking the ball valve.Closethe valve and tighten the filter holder.7.7 Open the ball valve.Simultaneously
6、,using a stopwatch,begin measuring the time required for the flow of 500 mL.Record the time(ti).Leave the valve open for continued flow.NOTE3Time(ti)to collect 500 mL should be within 610%of thetime to collect 500 mL using nonplugging reference water at the samewater temperature.The nonplugging refe
7、rence water can be obtained byfiltering distilled water through a 0.2-m pore size membrane filter.NOTE4If tiis less than 90%of the nonplugging time,the filter maybe cracked and a new filter should be used.If tiis more than 110%of thenonplugging time,then a smaller sample size,that is,250 mL or 100 m
8、Lshould be used.NOTE5The 500-mL sample size is based on a 47-mm diameter filter.If a different filter size is used,adjust the sample size in direct proportionto the filter area.7.8 Measure and record the times to collect additional500-mL(Note 6)volumes of sample,starting the collection at5,10,and 15
9、 min of total elapsed flow time.Measure the watertemperature and check the pressure as each sample is collected(Note 7 and Note 8).NOTE6If the initial size was not 500 mL,use the same sample sizeas used in 7.7.NOTE7The pressure must remain at 207 6 7 kPa(30 6 1 psi)throughout the test.NOTE8The water
10、 temperature must remain constant(61C)through-out the test.This is necessary because flow rate changes by about 3%C.7.9 After completion of the test,the membrane filter may beretained for future reference.8.Calculation8.1 Calculate the silt density index(SDIT)as follows:SDIT5%P30T5F1 2titfG100Twhere
11、:%P30=percent at 207 kPa(30 psi)feed pressure,T=total elapsed flow time,min(usually 15 min,seeNote 9),ti=initial time required to collect 500 mL of sample,s,andtf=time required to collect 500 mL of sample after testtime T(usually 15 min,see Note 9),s.NOTE9For this test method,%P30 should not exceed
12、75%.If%P30exceeds this value,use a shorter time for T;that is,5 or 10-minmeasurements in 7.8.If%P30exceeds 75%after 5 min,other testmethods should be used to analyze for particulate matter.9.Report9.1 Report the following information:9.1.1 The SDI,with a subscript indicating the total elapsedflow ti
13、me(T)in minutes,9.1.2 The water temperature before and after the test,and9.1.3 The manufacturer of the 0.45-m membrane filterused for the test,as well as the manufacturers identification forthe membrane filter.10.Precision and Bias310.1 The interlaboratory test was performed by nine opera-tors from
14、five laboratories using test waters of their choice,whose SDI values varied from 0.4 to 15.Waters used included3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D19-1151.ContactASTM CustomerService at serviceastm.org.FIG.1 Apparat
15、us for Measuring the Silt Density IndexD4189 07(2014)2 RO permeate,deionized water,tap water,and undefinedprocess water.The pooled single operator precision is 0.43.10.2 Only pooled single operator precision was determinedfor this test method.The test method is very sensitive to bothquantity and siz
16、e of suspended particles,which contribute tothe plugging of the membrane filter.Maintenance of theintegrity of the samples cannot be guaranteed through prepa-ration of the bulk mix,subsampling for testing,shipping,andholding.Moreover,approximately 5 gal of sample are requiredfor each SDI test run.Thus,if large stock solutions exhibitingdifferent SDI values could be prepared and if representative 30to 55-gal subsamples could be drawn,shipping two or three ofthese samples to each of six or more la