Biomedical subjects

Ajit P Annachhatre

Publications and source records attributed to Ajit P Annachhatre.

4 recordsLinked to original sources

PubMed2006

Lead removal through biological sulfate reduction process.

The feasibility of lead removal through biological sulfate reduction process with ethanol as electron donor was investigated. Sulfide-rich effluent from biological process was used to remove lead as lead sulfide precipitate. The experiments were divided into two stages; Stage I startup and operation of sulfidogenic process in a UASB reactor and Stage II lead sulfide precipitation. In Stage I, the COD:S ratio was gradually reduced from 15:1 to 2:1. At the COD:S ratio of 2:1, sulfidogenic condition was achieved as identified by 80-85% of electron flow by sulfate reducing bacteria (SRB). COD and sulfate removal efficiency were approximately 78% and 50%, respectively. In Stage II, the effluent from UASB reactor containing sulfide in the range of 30-50 mg/L and lead-containing solution of 45-50 mg/L were fed continuously into the precipitation chamber in which the optimum pH for lead sulfide precipitation of 7.5-8.5 was maintained. It was found that lead removal of 85-95% was attained.

Chemical Precipitation↗

PubMed2004

Novel microbial nitrogen removal processes.

The present-day wastewater treatment practices can be significantly improved through the introduction of new microbial treatment technologies. Recently, several new processes for nitrogen removal have been developed. These new nitrogen removal technologies provide practicable options for treating nitrogen-laden wastewaters. The new processes are based on partial nitrification of ammonium to nitrite combined with anaerobic ammonium oxidation. These processes include the single reactor system for high ammonia removal over nitrite (SHARON) process, which involves part conversion of ammonium to nitrite; the anaerobic ammonium oxidation (ANAMMOX) process, which involves anaerobic ammonium oxidation; and the completely autographic nitrogen removal over nitrite (CANON) process, which involves nitrogen removal within one reactor under oxygen-limited conditions. These new processes target the removal of nitrogen from wastewaters containing significant quantities of ammonium.

Industrial Waste↗

PubMedDate not supplied

Nitrification modelling in biofilms under inhibitory conditions.

A biofilm model has been developed for simulating nitrification in biofilms under inhibitory conditions. Nitrification inhibition has been modelled using uncompetitive inhibition kinetics. Inhibition kinetic experiments were performed by varying the bulk concentrations of inhibitory compound, aniline. Two sets of results were obtained with a nitrifying biofilm that was unacclimated to aniline and another which was acclimated to aniline. Fitting of the nitrification inhibition biofilm model to the experimental results yielded the nitrification inhibition constant, Ki, for aniline. Both the experiments yielded a value of about 3mg/L for Ki, which was similar to that obtained during nitrification inhibition experiments with suspended growth process carried out in an earlier study. The nitrification inhibition biofilm model is general and can be applied to nitrification inhibition with other toxic compounds.

Aniline Compounds↗

PubMedDate not supplied

Modeling of nitrification inhibition with aniline in suspended-growth processes.

Nitrification inhibition due to aniline was investigated in completely mixed suspended-growth, batch, and continuous processes. Synthetic wastewater was used with aniline as the carbon source. The experiments were conducted at aniline concentrations inhibitory to nitrifier organisms. In the batch tests, degradation took place rapidly (within 4 to 6 hours) for initial aniline concentrations below 100 mg/L, with nitrification picking up as soon as the aniline concentration decreased to less than 3 to 4 mg/L. For initial aniline concentrations of 250 mg/L and higher, complete nitrification did not take place even though the aniline concentration decreased to less than 3 to 4 mg/L. This observation indicated nitrifier inhibition due to aniline. In the continuous experiments, a hydraulic residence time of 8 to 24 hours and a solids retention time of 8 to 24 days were maintained. Complete nitrification took place at bulk aniline concentrations less than 0.5 mg/L, while at higher aniline concentrations, nitrification inhibition took place. The inhibitory effect of aniline on the nitrification process was modeled using uncompetitive inhibition kinetics. Modeling of batch processes yielded the value for the inhibition constant for aniline, Ki, as 3.3 mg/L. Modeling of continuous processes yielded criteria for stable process operation for nitrification under inhibitory conditions, which were also confirmed through experimental results.

Aniline Compounds↗