Ethanol fermentation requires oxygen to maintain high biomass and cell viability, especially under very-high-gravity (VHG) condition. In this work, fermentation redox potential (ORP) was applied to drive the aeration process at low dissolved oxygen (DO) levels, which is infeasible to be regulated by a DO sensor. The performance and characteristics of flocculating yeast grown under 300 and 260 g...

The aims of these experiments were treating tapioca processing waste water to produce polyhydroxyalkanoates (PHAs) and removal of chemical oxygen demand (COD). The experiments were conducted in a sequencing batch reactor with a volume of 6 L. The entire experimental condition was anaerobic-aerobic-anaerobic. Experiment 1, 2 and 3 had the first 2 h for feeding time while Experiment 4 had 3 h. Th...

(a) The treatment efficiency in MBR was observed under different aeration rates. It was found that the optimal rate of aeration for removal efficiency was 3m/h.Increasing aeration rate resulted in shear stress, which caused elevated rates of sludge floc breakage, and consequently, supernatant COD. Excessive aeration rate could consequently also affected nitrogen removal by destructing anoxic co...

labyrinth spillway is an appropriate option to pass pmf discharge. the most advantages of this type of spillway are higher discharge capacity, easy aeration as well as low fluctuations of flow surface. it is essential to find the optimum geometry considering the maximum passing discharge under specific hydraulic conditions with minimum construction cost. in this study, fuzzy inference system (f...

Biowaste composting at several plants in Scandinavia has been troubled by low pH in the collected waste as well as after the composting process. Our hypothesis was that increased aeration would give a higher and faster rise in pH during the composting process, and that this would give a higher decomposition rate. The objective was to test this hypothesis by experiments in full scale, with an em...

The aim of this work was to study the production of the bioinsecticide using the aerobic cultivation. Two-stage cultivation process was used: aerobic vegetative growth and end-phase of sporulation (with aeration and without aeration). The cuts of working volume evaluated were 20, 40, 60 and 80 %. The highest value of spore concentration (2.17x10 CFU/mL) and spore productivity (7.2x10 CFU/mL.h) ...

A hierarchical controller for tracking the dissolved oxygen (DO) reference trajectory in activated sludge processes is proposed and investigated. The removal of nitrogen and phosphorous from wastewater is considered. Typically, an aeration system itself is a complicated hybrid nonlinear dynamical system with faster dynamics compared to the internal dynamics of the DO in a biological reactor. It...