Characterization of a hybrid sequencing batch reactor system for treatment of wastewater using suspended microbial aggregates and biofilms

A moving bed biofilm reactor was studied for its capability of carbon oxidation and nitrification. The hybrid system made use of suspended biomass in the forms of microbial aggregates and attached biomass in the form of biofilms on suspended carriers. The carriers used for biofilm support were made of polyethylene and have a wagon wheel shape. The carrier fill ratio, which is defined as the volume ratio of carrier to the whole reactor was a key characteristic parameter of the reactor. The experimental runs used different carrier filling ratios from 25 to 50% to determine the optimal operating value for this type of hybrid reactor. Also the nutrient conditions were modified to test the capacity of the system to adapt to various changes in phosphorus loading in the influent wastewater. The results showed that for an influent chemical oxygen demand (COD) of 600 mg/L, ammonia of about 24 mg/L and hydraulic reaction time of 6 hours there was no difference in the performance of the system under the different carrier filling rations.

Characterization of a hybrid sequencing batch reactor system for treatment of wastewater using suspended microbial aggregates and biofilms

A moving bed biofilm reactor was studied for its capability of carbon oxidation and nitrification. The hybrid system made use of suspended biomass in the forms of microbial aggregates and attached biomass in the form of biofilms on suspended carriers. The carriers used for biofilm support were made of polyethylene and have a wagon wheel shape. The carrier fill ratio, which is defined as the volume ratio of carrier to the whole reactor was a key characteristic parameter of the reactor. The experimental runs used different carrier filling ratios from 25 to 50% to determine the optimal operating value for this type of hybrid reactor. Also the nutrient conditions were modified to test the capacity of the system to adapt to various changes in phosphorus loading in the influent wastewater. The results showed that for an influent chemical oxygen demand (COD) of 600 mg/L, ammonia of about 24 mg/L and hydraulic reaction time of 6 hours there was no difference in the performance of the system under the different carrier filling rations.

Fragment of a Wagon Wheel Hub: Restoration and Conservation

In order to stop the corrosion process which damaged the wagon wheel hub, it was necessary toperform a thorough and laborious restoration process on it [1]. [...]

Desain dan Analisis Geometri Propellant Grain Configuration pada Roket Padat

This article examine mathematical model of propellant grain configuration to obtain the appropriate burning area in sonda rocket. Sonda roket is experimental rocket that created by Pustekroket LAPAN to support research on space sector with altitude as the target of assessment. Burning area for hollow grain, wagon wheel grain, star grain are analysed analytically through mathematical modelling. Than the results are compared by manual calculation using SolidWork. The results show that burning area of three types of grain did not show a significant difference between these two methods.

Mild Displacements of Boulders during the 2019 Ridgecrest Earthquakes

ABSTRACT Strong seismic waves from the July 2019 Ridgecrest, California, earthquakes displaced rocks in proximity to the M 7.1 mainshock fault trace at several locations. In this report, we document large boulders that were displaced at the Wagon Wheel Staging Area (WWSA), approximately 4.5 km southeast of the southern terminus of the large M 6.4 foreshock rupture (hereafter “the large foreshock”) and 9 km southwest of the nearest approach of the M 7.1 mainshock surface rupture. Some boulders appear to have slid along essentially flat surfaces, which suggest that dynamic stresses overcame the coefficient of friction. Other boulders appear to have rocked within their sockets. In both cases, we use simple mechanical models to estimate total peak dynamic accelerations between 0.5 and 1g, commensurate with modified Mercalli intensity 9. It is unclear if the strongest shaking at this location occurred during the large foreshock or the M 7.1 mainshock. The inferred accelerations are higher than predicted mainshock ground motions at WWSA, although local high accelerations could have been generated by path, site, or source effects. Gaps between boulders and their sockets are easily visible in the immediate aftermath of earthquakes and provide a quick indication of strong shaking. More importantly, the gaps quickly fill with surficial organic debris, including seeds and leaves of the year, that quickly become entombed. Boulders may thus potentially be extracted to examine gap fillings associated with past earthquakes, providing a new datable paleoseismic method.