Effect of temperature on microbial population and performance of an aerobic thermophilic reactor treating cattle slurry and waste food

Abstract

This study was carried out to quantify and identify the presence of somatic coliphages, RNA coliphages, sulphite-reducing clostridia, Clostridium tyrobutyricum or its related clostridia, faecal coliforms, enterococci and heterotrophs in a mixture of cattle slurry and waste food (whey and jam) that had undergone aerobic thermophilic treatment (ATT). We also investigated the influence of different factors, including pH, COD, temperature, odour removal, addition of waste food (whey and jam) and nitrogen losses, on the long-term ATT process. The processes were conducted semi-continuously with retention time of five days and with the waste food and slurry mixture (1:4) being added daily into the reactor. The experiments lasted seven days for each thermophilic temperature (50, 60 and 70 degrees C). Our work showed that, at the higher temperature of the ATT operation, the number of microorganisms declined much more rapidly than at the lower temperature and the final product was hygienically safe. The use of waste food (whey and jam) was beneficial because it buffered pH.

Drop in dry mass and organic substance content in the process of autothermal thermophilic aerobic digestion

“…In the first stage, the temperature is maintained in the lower range of thermophilic decomposition (40÷50°C). The disinfection maximum is reached in the last stage due to a temperature of 50÷60°C (Augustin et al 2007; Mohaibes et al 2011;Skowron et al 2011). Neutralized sludge is dumped daily only from the last stage.…”

Wind tunnel study of ammonia transfer from a manure pit fitted with a dairy cattle slatted floor

“…[15,21,22] The latter are of crucial importance in triggering the NH 3 release process, [17] because they allow for the convective transport of freshly volatilized molecules upwards the manure pit and the barn, a mechanism that repeats itself for as long as the conditions are favourable. [23][24][25][26] Ye et al [27] and Ye et al [28] reported laboratory studies carried out to evaluate the effect of air velocity (u), turbulence intensity (TI ), pH, slats opening size and headspace height (HH ) on NH 3 emissions from a scale pig house model with an aqueous solution mimicking the manure.…”