TABLE 1

Monensin concentrations in the influents and the effluents of the anaerobic digesters

PeriodDaysLow ALow BaFastbSlow
ManurecMonensin concn (mg · liter−1)dManurecMonensin concn (mg · liter−1)dManurecMonensin concn (mg · liter−1)dManurecMonensin concn (mg · liter−1)d
InfluenteEffluent (day)InfluenteEffluent (day)InfluenteEffluent (day)InfluenteEffluent (day)
Startup1–114M00NAfM00NAM00NAM00NA
P1115–202M00NDg (201)M00ND (201)M00ND (201)M00ND (201)
P2203–216M2000.09NAM2000.09NAM0+0.09NAM00NA
217–230M3000.12NAM3000.12NAM0+0.12NAM00NA
231–244M4000.15ND (231)M4000.15ND (231)M0+0.15ND (231)M00ND (231)
245–264M5000.19NAM4000.15NAM0+0.19NAM00NA
P3265–280M5000.190.12 (267)M5000.19ND (267)M0++10.11 (267)M00ND (267)
281–306M5000.190.14 (301)M5000.190.12 (301)M0++52.29 (301)M00ND (301)
M5000.19NAM5000.19NAM0++52.73 (306)M00NA
P4307–320M5000.19NAM5000.19NAStoppedM0++1NA
321–338M5000.190.11 (331)M5000.190.11 (331)StoppedM0++20.81 (331)
339–352M5000.19NAM5000.19NAStoppedM0++3NA
353–366M5000.190.13 (365)M5000.190.13 (355)StoppedM0++41.80 (365)
367–383M5000.190.14 (383)StoppedStoppedM0++52.55 (383)
  • a M500 manure batch was started on day 267 and discontinued on day 355 of the operating period.

  • b Discontinued on day 306 of the operating period.

  • c M200, M300, M400, and M500 refer to the four batches of manure from monensin feed-dosed cows (corresponding to the 194, 320, 432, and 546 mg · d−1 monensin dosing rates, respectively). M0+ or M0++ indicates that monensin was added directly to control cow (M0) manure.

  • d Detection limit was 0.10 mg · liter−1.

  • e Values are based on dilution (manure was diluted before feeding).

  • f NA, measurement not available.

  • g ND, monensin not detected.