Biological treatment of effluents with microalgae can be a sustainable and effective technology. It is mainly useful for the meat industry which produces large volumes of effluents from the animal slaughter, meat processing and the cleaning of their facilities. The objective of this paper was to determine the optimal operating conditions of the Scenedesmus obliquus culture for the removal of contaminants from poultry effluent and recovering valuable nutrients for biomass production. Experiments were performed at laboratory scale using poultry effluent from anaerobic digestion without dilution and the microalga Scenedesmus obliquus. The evaluation was based on four dilution rates from 0.20 to 0.35 1/day on semi-continuous growth bioreactor. Results demonstrated that the highest biomass productivity of 0.57 gbiomass/L day was achieved at 0.30 1/day. However, the highest nutrients removal efficiency was obtained at 0.20 1/day. In these conditions, the removal efficiency exceeded 80% for nitrogen and phosphorus and 99% for E. coli, at all dilution rates tested and was above 90% for COD. Also, using a dilution rate of 0.20 1/day, a quantum yield of up to 0.24 g/E and nutrient coefficient yields of up to 41 mgN/gbiomass and 32.32 mgP/gbiomass were achieved. In conclusion, cultivation of Scenedesmus obliquus in poultry effluents can be adjusted based on the objective. That is to say, a dilution rate of 0.30 1/day is recommended for biomass production and 0.20 1/day is suggested for tertiary treatment. The production of microalgae coupled with biological treatment allows recovery of nutrients, generating biomass and treating the industry effluents before their final disposal. ______________________________________________________________
Understanding the components of pharmaceutical wastewaters and their potential risk as sources of pollution when discharged into the environment is imminent for environmental and public health significance. This study was aimed at evaluating untreated wastewaters from pharmaceutical industries in Nigeria. Results obtained showed that the colors of the wastewaters were mostly turbid, few in brown and only one colorless sample; revealed high turbidity (16 - 999 NTU). The pH ranged from 2.9 to 9.2, whereas phosphate and nitrate levels were between the ranges of 0.0122-15.66 mg/L and 0.18-87.02 mg/L respectively. Heavy metal analysis showed high levels of iron at 53.53 mg/L and 25.6 mg/L, with chromium at 7.190 mg/L. The BOD and COD were high for most of the wastewaters. Bacteria isolates were detected in all samples with population ranging from 3.0 x 104 cfu/mL to 2.7 x 1012 cfu/mL, while fungi was averaged at 7.0 x 105 cfu/mL and total coliform was between 2.6 x 102 to 2.7 x 107 cfu/mL. Although total susceptibility to gentamicin and sulphamethozazole/trimethoprin was observed in isolates from two industries, there was an obviously high (20 - 100%) drug resistance among the bacteria tested. The most frequently resisted drugs were ampicillin, sulphamethozazole/trimethoprin, cefuroxime, augumentin and clindamycin at values of 90.6%, 89.3%, 85,9%, 85.9% and 83.9% respectively; while nitrofurantoin (36.9%) and chloramphenicol (32.2%) were the least resisted drugs. The discharge of wastewaters without adequate treatment into aquatic environments could result in severe pollution, hence the need for proper treatment to protect the ecosystem and public health is necessary. ______________________________________________________________