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The differences between the times of appearance of inflexions and minimum concentration of contaminants are related to the sampling frequencies. Physicochemical composition of the raw tannery wastewater. Additionally, the small volume of the reactor and the use of a fine bubble diffuser helped to keep DO at high concentrations.
The pre-treated wastewater was used as feed to the SBR. Furthermore, some researchers aimed to evaluate the effects of coagulants obtained from natural sources and agro-industrial byproducts such as Ryu et al.
During the remainder oficiql the first anoxic phase, further decrease in the concentration of N-NO x – or any other inflexion in the DO or ORP profile was not observed. They could be implemented as a real-time control for optimization of the SBR operation, because length of each phase in the reactor could be adjusted to the time when inflexions in the profiles occur.
This alteration in ORP profile corresponded to the sudden increase in the concentration of nitrogen in the tannery wastewater Figure 4and it was due to changes in the production process at the industry. These can be used to identify specific control points during the SBR cycle. Anoxic condition was achieved during the first phase in the SBR cycle with average DO concentration of 0. Raw wastewater The industrial influent was collected from a tannery located in the faceta of Barquisimeto, Venezuela.
During the investigation, a mix of reagents was used: Monitoring the biological nutrient removal from wastewaters has been considered difficult due to the lack of available control parameters. Please click button to get gaceta oficial book now. The reactor had three openings: Characteristics of coagulant and adjuvant as color Cturbidity Bcalcium Ca-Bmagnesium C and Mg-B and chloride Cl – -D were measured following the procedures of Standard Methods Cycles evaluated in the SBR showed the efficiency of the biological system for nitrification, but showed its inefficiency to perform the ammonification of the organic nitrogen present in tannery wastewater.
Finally, profiles of ORP, DO and pH could be related with gqceta and denitrification processes, then these profiles were efficient ways to monitor gsceta evolution of biological nutrient removal, and real-time control can be implemented for optimization of the SBR operation. The pond acted as a pre-treatment of the wastewater for the amendment of total solids and precipitation of chromium due low solubility of the metal at pH of the effluent.
The average physicochemical composition of tannery wastewater is shown in Table 1. The integrated 50211 for the treatment of tannery wastewater operated continuously for 90 days. The purpose of this combination was to generate an effluent which meets the discharge limits established in the Venezuelan environmental regulations.
Additional anoxic phase was included to improve nitrogen removal; no external carbon source was needed. Raw wastewater The industrial influent was collected from a tannery located in the city of Barquisimeto, Venezuela.
The coagulation-flocculation process is one of the most frequently used treatments for tannery wastewater, but it is usually applied as pretreatment 14 17 The SBR system operated according to anoxic-aerobic-anoxic principles.
However, Dosta et al.
Microbiological analysis The results of on-line and physicochemical measurements were supplemented by basic microbiological analysis, which determined the bacterial density of nitrifying and denitrifying microorganisms present in the mixed liquor Figure 7.
During the remainder of the first anoxic phase, further decrease in gacetta concentration of N-NO x – or any other inflexion in the DO or ORP profile was not observed. Good correspondence was found between the end of nitrification and the inflexions in the pH and ORP profiles for all the cycles evaluated during the SBR performance. Figure 2 COD behavior during the biological treatment of tannery wastewater.
It was determined that nitrifying microorganism density gacfta larger than denitrifiying bacteria density; therefore, the efficiency of nitrification was higher than that of the denitrification process during the biological treatment of tannery wastewater. Tannery wastewater has some contaminants, like sulfurs, that could suffer oxidation and produce additional inflexions in the ORP profile. The reactor had three openings: The evaluation of the tertiary treatment showed that the effluent generated from the coagulation-flocculation treatment had gacdta Average COD concentration at the end of the biological treatment was These results confirmed that the predenitrification strategy with a short filling period was a good selection for the tannery wastewater treatment due to the fact that the readily biodegradable COD present in raw wastewater was not consumed during the filling time.
Good correspondence was found between the end of nitrification and the inflexions in the pH and ORP profiles for all the cycles evaluated during the SBR performance. Tannery wastewater; biological treatment; physicochemical treatment; nutrient removal; online monitoring; bacterial density. The results of on-line and physicochemical measurements were supplemented by basic microbiological analysis, which determined the bacterial density of nitrifying and denitrifying microorganisms present in the mixed liquor Figure 7.
It is characterized by being rich in magnesium sulfate and potassium chloride, which are important agents during coagulation-flocculation process. SBR worked by predenitrification strategy since many researchers have shown its effectiveness to remove nitrogen from tannery and slaughterhouse wastewaters 3 4 21 Finally, density of nitrifying bacteria was greater than density of denitrifying bacteria during biological treatment.
This profile was a complement for ORP and pH profiles during the process control in the aerobic phase. The most widely used coagulant agents for tannery wastewaters are aluminum and iron salts. At that time, it was considered that the denitrification process was over. Gacetq also provides the advantage that nitrogen removal can be carried out in a single reactor by maintaining anoxic and aerobic stages sequentially 5 6. Thus, the low rate of ammonification was considered one of the main reasons that impeded a higher total nitrogen removal from the tannery effluent in the SBR.
It was demonstrated that the limiting step to remove nitrogen during biological treatment was ammonification, but the remained organic nitrogen was removed during the ulterior physicochemical gaceeta.
The system was able to produce an effluent which met the COD and total nitrogen limits established in the venezuelan legal regulations for discharge into water bodies. It was demonstrated that the limiting step to remove nitrogen during biological treatment was ammonification, but the remained organic nitrogen was removed during the ulterior physicochemical treatment.
Average COD concentration at the end of the biological treatment was In addition, densities of nitrifying and denitrifying microorganisms in the mixed liquor were evaluated during the biological treatment. Avenida Guajira con calle