Estimation of degree of mixing in baseline and modified design of anaerobic digester using radiotracers technique

The Anaerobic digestion (AD) is a biological means for decomposition of manure in an oxygen-free environment. The implementation of the AD at a large scale is associated with high failure rates. The performance of anaerobic digesters is affected by mixing regime of substrates in the reactors. Therefore, the optimal modifications in the design of digesters are to be done to attain optimal degree of mixing in the AD. In the present study, the degree of mixing of the two different designs of the AD was done by measuring residence distribution time (RTD) using radiotracer. To compare the design parameters of the AD, two scales down (1:20) version of AD were fabricated viz., baseline (R1) and modified design (R2). About 200 μCi of ^99mTc (t_1/2 = 6.02 h, γ: 140 keV) as sodium per technetate used as a radiotracer in each measurement