This study investigated snail shell as a carrier to immobilize Pseudomonas putida and Bacillus subtilis isolated from refinery effluent for the degradation of naphthalene in synthetic wastewater at various process conditions such as initial naphthalene concentration, pH, adsorbent dosage and ambient temperature of 30 o C in batch mode. The results showed that the adsorption and the biodegradation capacity increased with increase in naphthalene concentration, where 73.11%, 74.46% and 65.20% of the optimum concentration (50 mg/L) were removed by immobilized Pseudomonas putida, Bacillus subtilis, and snail shell respectively after 72 hours incubation. The optimal degradation occurred at the adsorbent dosage of 2 g at pH 9 and pH 7 for the adsorption and biodegradation respectively. The results were well fitted to both Langmuir and Freundlich models. Therefore, snail shell can be employed as a low-cost adsorbent and solid support matrix for immobilizing microorganisms in remediating hydrocarbon contaminants.

Five microorganisms were isolated from aged sulphide conventional method. The same was inoculated into similar wastewater collected after the production of upper leathers from Sokoto red goatskins, Nigeria. The effects of anaerobic treatment of the tannery effluent resulted and TSS and reducing sludge formation expected from sulphide was observed as being proportional to electrical conductivity increase with respect to time, temperature and McF standard. At day 9 with 1.0 McF, isolate T 51.09 % at 25°C and 64.03 % at 27 80.12 % at 37°C as the highest percentage recorded. Isolate T conductivity by 5.9 % at 25°C with 0.5 McF, 45.5 % at 27 the same period of treatment. At day 7 with increase temperatures, the same isolate had 108.22% increase in electrical conductivity conductivity of the treated wastewater is expected, this abrupt increase is abnormal, and may be due to complex nature of tannery wastewater The maximum percentage reduction of sulphide was 25.35 % and 20.42 % by day 5 with 1.0 McF at 25 most probable because the anaerobes that induced the oxidation of carbon content of the wastewater while abstracting energy for their respiration. This causes S sulphide bringing about an increase of the parameter at the beginning of the treatment later decline, while depleting the carbon substances in the wastewater.

Tannery sulphide-lime unhairing and liming wastewater is known to be highly polluted with very high values of COD and BOD and many other pollutants that poses serious threat to land and aquatic systems when discharge without treatment. gram positive, they were inoculated into the sulphide room temperature, 27°C and 37°C for 5,7 and 9 days with different McFarland standards of 0.5 and 1.0 McF. The results obtained shows various percentage reduction o the effectiveness of individual isolates, it was observed that at day 9, the highest percentage reduction of BOD 5 was recorded by isolate T temperatures, 27°C and 37°C respectively with 0.5 McF, implying that the isolates are likely to be mesophilic (35°C-37°C). Further reduction of COD was recorded when treatment temperature and time was increase to 37°C such that after day 9, isolate T 79.29 %, at 27°C and 37°C respectively. The maximum reduction of COD with 1.0 McF at 37 day 9 treatment period was 69.91 % by isolate T which induced oxidation of carbon content of the wastewat process. The process also caused the reduction of Sulphur present in the wastewater leading to the generation of hydrogen sulphide gas which suggest the source of smell of the gas in any tannery lime yard.