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')h SE'PlAC LANK SYSII^I I'.FI•F.C•IS ON ( ROUND WAILK Q('AI.I Il <br />GROUNI) <br />Tablc 23 summarizes the bacteriological character of household septic <br />Soil Absorption System 1 <br />tank effluent (Siegrist, 1977; and University of Wisconsin, 1978). The <br />quantities of indicator bacteria such as fecal coliform are high, and <br />Viraraghavan and 1 <br />pathogenic bacteria such as Pseudomonas aeruginosa, have commonly been <br />the primary objective ( <br />isolated. In addition, results of analyses for Staphylococcus aureus and <br />(drainfield tile) systern <br />salmonellae have indicated their presence in septic tank effluents, FuTonly <br />concentration of various <br />infrequently and in rT lower concentrations (10 homes, 6 of 63 samples <br />the septic tank effluent <br />positive at 10-1000/1(,� ml and 11 homes, 2 of 55 samples positive at 3.4- <br />the soil at which soi. v <br />2201100 ml, respectively) (Siegrist, i977). Viruses in septic tank effluents <br />effects of air and soil t <br />are high only if infections have occurred. Salmonellae have been detected <br />efficiency of the septic 1 <br />in 59 percent of 17 different septic tank pumpout sludges, which shows <br />site of the study was ne <br />clearly that septic effluents need to be purified before release to eithor <br />conditions in this reg <br />ground water or surface water (Bouma, 1979). <br />temperatures, usually wi <br />Table 23: Summary of Bacteriological Character of Household Septic <br />spring when ground watt <br />the �jil ampies taken fr( <br />Tank Effluents <br />was sandy clay for the i <br />less sand at depths of 2 1 <br />septic tank effluent app <br />Number 95. Confidence <br />results of the field stud' <br />of Mean Interval <br />indicated the followinf, fr <br />Reference Organism Samples (NO./100 ml) (No./100 ml) <br />-------_--___-- _—_-- <br />1. The soil t-ad <br />percent) Ui 1 <br />1 Total <br />present in the <br />bacteria 88 3.4xlUb 2.5 to 4.8x1U8 <br />2. Reductions o• <br />l Total <br />range, much <br />coliform 91 3.4x1O6 2.6 to 4..'4x1U6 <br />has special si <br />substantial an <br />t Fecal <br />be added to la <br />coliform 94 /" 4.2x1O5 2.9 to 6.Tx1U5 <br />(\ L 2t' C <br />� t7 <br />3. High ammonia <br />Fecal <br />coliform 151-S:(nt106 �.5x106 to 1.Ox107 <br />an increase i <br />nitrification <br />oc-C),cre'D <br />nitrate build - <br />1 Fecal <br />possible hea1C <br />streptococci 97 3.k:_ 2.0 to 7.2x103 <br />4. Efficiency wi <br />2 Fecal <br />greater effit <br />streptococci 155 4.Ox1O4 8.Ox1U3 to 2.Ox105 <br />parameters d <br />fromSeptemt <br />1 Pseueomonas <br />was greater. <br />' <br />Aeruginosa 33 8.6x103 3.8 to 19.0x103 <br />to 75 percen; <br />_ <br />percent for ar <br />water levels e <br />Reference 1 Siegrist (1977), data from 5 tanks. <br />a declining to <br />Reference 2 University of Wisconsin (1978), data from 7 tanks. <br />Soil Absorption System E, <br />Based on the ab <br />reductions relative to t <br />