Remediation of Polluted Wastewater Effluents: Hydrocarbon Removal

The onset of the industrial revolution has led to a surge in the quantity of hazardous compounds that are released into the environment. These hazardous pollutants consist of a variety of hydrocarbons and other organic compounds that pose serious risks to humans, animals and the environment. The presence of hydrocarbons in wastewater effluents is due to a variety of sources, which include oil spillage, pesticides, urban storm water discharges and automobile oil. The removal of hydrocarbons from wastewater before discharge into receiving water bodies from wastewater effluents entails a variety of processes, with the most common processes being phytoremediation, bioremediation and chemical remediation. Phytoremediation is a cost effective method of reducing risk to human and ecosystem health posed by contaminated water. It entails the use of plants for the removal of contaminants and could involve mechanisms such as phytodegradation, rhizodegradation, rhizofiltration, phyto extraction, phytovolatilization, hydraulic control and phytostabilization. On the other hand, bioremediation is the use of microorganisms to breakdown or degrade pollutants in a contaminated site. The technology is low cost and has a generally high public acceptance. It consists of biostimulation (addition of nutrients to indigenous microorganisms) and bioaugmentation (addition of hydrocarbon degrading microorganisms). In the case of chemical remediation, it involves the use of chemicals for the treatment of contaminated sites. Substances, such as dispersants and solidifiers are used in chemical remediation. This study was aimed at reviewing the sources, impacts and remediation processes for hydrocarbon polluted wastewater effluents. This review was able to describe the sources and impacts of hydrocarbon polluted wastewater effluents and the various methods of treatment

Survival of Botryodiplodia theobromae in yam tissues

Meeting: International Society for Tropical Root Crops. Africa Branch, Triennial Symposium, 2d, 14-19 Aug. 1983, Douala, CMIn IDL-737

Survie de Botryodiplodia theobromae dans les tissus de l'igname

Réunion: International Society for Tropical Root Crops. Africa Branch, Triennial Symposium, 2d, 14-19 Aug. 1983, Douala, CMDans IDL-638

Investigation of the Effect of Initial Biomass on Nitrate and Phosphate Removal from Synthetic Wastewater by Selected Bacteria Isolates

Although nitrogen and phosphorus are important nutrients to the existence of living organisms, their presence in excessive amounts in wastewater could have detrimental effects to humans and other living organisms. The present investigation was aimed at ascertaining the effect of initial biomass concentration on the nutrient removal efficiency of four bacterial species in synthetic wastewater under shaking flasks conditions. Four different initial biomasses [2.91 x 108 cfu/mL, 5.82 x 108 cfu/mL, 8.73 x 108 cfu/mL and 1.16 x 109 cfu/mL (Klebsiella sp.); 6.31 x 108 cfu/mL, 1.26 x 109 cfu/mL, 1.89 x 109 cfu/mL and 2.52 x 109 cfu/mL (Pseudomonas sp.); 1.75 x 108 cfu/mL, 3.49 x 108 cfu/mL, 5.24 x 108 cfu/mL and 6.98 x 108 cfu/mL (Lysinibacillus sp.), and 7.1 x 108 cfu/mL, 1.42 x 109 cfu/mL, 2.13 x 109 cfu/mL and 2.84 x 109 cfu/mL (Staphylococcus sp.)] were used for the study. For nutrient removal studies, the respective initial biomasses of the test isolates were inoculated into flasks containing the wastewater media. Aliquot samples were taken at the beginning of the study and every 24 h for 96 h for the estimation of growth rate, pH, phosphate and nitrate concentrations in the wastewater, using standard methods. The results revealed only slight phosphate decreases in the wastewater after the expiration of incubation. All the test isolates showed significant nitrate removal ability except the Lysinibacillus sp. After 96 h incubation 68.36 to 90.67 %, 91.80 to 95.29 %, 3.20 to 11.48 % and 86.77 to 94.33 % of nitrate was removed in the presence of the Klebsiella sp., Pseudomonas sp., Lysinibacillus sp. and Staphylococcus sp., respectively. The study was able to reveal the phosphate and nitrate removal ability of the isolates at the different initial biomasses used for the investigation

Investigation of the Role of Selected Fungal Strains in the Removal of Phosphate and Nitrate in Synthetic Wastewater

Aims: This study investigate the role of four fungi species in the removal of phosphate and nitrate in a low nutrient synthetic wastewater. Also investigated was the effect of initial inoculum size on the nutrient removal ability of the strains. Materials and Methods: The fungal strains used for the study were Aspergillus niger, Aspergillus flavus, Absidia spp and Fusarium spp Four different initial inoculum sizes of each of the respective isolates were used for the nutrient removal studies. After inoculation with the test strains, aliquot samples were taken from the media at time zero and every 24h, for the estimation of total phosphate, nitrate and pH in the medium, using standard methods. Results: All the strains showed nitrate removal ability, irrespective of the initial inoculum size used for inoculation. After 96 h, the percent nitrate removed ranged from 25.25% to 77.52%, 26.12% to 39.80%, 8.88% to 44.23% and 29.50% to 87.34%, in the presence of Aspergillus niger, Aspergillus flavus, Absidia spp and Fusarium spp, respectively. None of the fungi exhibited phosphate removal ability, except Aspergillus niger which showed very slight potential for phosphate removal. Despite the observed differences in nitrate concentration removed by the different strains, these differences were not observed to differ significantly between the initial inoculum sizes used for investigation (p≤ 0.05). Similarly, the phosphate concentrations in the presence of the test strains did not differ significantly between the different initial inoculum sizes (p≤ 0.05). The pH values of the wastewater inoculated with the fungal strains increased with time of incubation. This trend was also observed irrespective of the initial inoculum size used. Conclusion: The study was able to provide an insight into the phosphate and nitrate removal efficiency of the test strains under the experimental conditions. Keywords: Phosphate; nitrate; fungi; nutrient removal; wastewater

Microbial Roles and Dynamics in Wastewater Treatment Systems: An Overview

ABSTRACT The quality of wastewater effluents is responsible for the degradation of receiving water bodies, such as lakes, rivers, streams. The two main processes for the removal of impurities from wastewater influents are chemical and biological treatment but due to some drawbacks of the chemical treatment, biological treatment is now employed. Microorganisms are of major importance in industrial wastewater treatment, agricultural and aquaculture. They reside in the sediment and other substrates, and in the water of aquaculture facilities. Microorganisms may have positive or negative effects on the outcome of aquaculture operations. Positive microbial activities include elimination of toxic materials such as ammonia, nitrite, and hydrogen sulfide, degradation of uneaten feed, and nutrition of aquatic animals such as shrimp, fishes. These and other functions make microorganisms the key players in the health and sustainability of aquaculture. The role of the different microbial groups present in the waste water treatment systems with particular importance of bacteria and protozoa in the removal process of nitrogen and phosphorus indicate that the biological treatment system is very effective in the wastewater treatment systems

Aliphatic Hydrocarbon Profile of Crude-oil Degraded by Bacteria Isolates from Bitumen-polluted Surface Water from Agbabu, Ondo State

The use of microorganisms for the remediation of petroleum hydrocarbons contaminated environments has been shown to be more suitable and convenient alternative to other approaches. In this study, degradation of aliphatic fractions of Bonny light crude oil by five bacteria: Bacillus cereus ATCC 14579, Campylobacter hominis ATCC BAA-381, Dyadobacter koreensis NBRC 101116, Micrococcus luteus Sn1-1 and Pseudomonas aeruginosa aab51a04 isolated from bitumen-contaminated surface water in Agbabu, Ondo State (E040 48-491 and N060 34-361 ) was investigated. The residual aliphatic hydrocarbons after degradation were estimated by Gas chromatography/Mass Spectroscopy analysis. The GC-MS analyses revealed that D. koreensis had the best degrading ability; it reduced 57% of the total detectable aliphatic compounds in the crude oil while Campylobacter hominis had the least percentage reduction (28%). P. aeruginosa, B. cereus and Micrococcus luteus had 42%, 38% and 35% percentage reduction respectively. However, crude oil treated with the combination of the five bacteria resulted in 70% reduction of the total detectable aliphatics thus revealing better degradative performance than individual species

POLLUTANTS IN WASTEWATER EFFLUENTS: IMPACTS AND REMEDIATION PROCESSES

Due to extensive industrialization and increase in population density and urbanized societies, the world is faced with problems related to the management of wastewater. On a daily basis, the effluents generated from domestic and industrial activities constitute a main cause of pollution of receiving water bodies, which is a great burden on water quality management. Some of these pollutants are pathogenic microorganisms, phosphorus and nitrogen, hydrocarbons, heavy metals, endocrine disruptors and organic matter. The majority of water related infections, such as cholera, typhoid fever, diarrheoa and others are caused by the presence of pathogenic microorganisms in water. The diseases caused by bacteria, viruses and protozoa are the most common health hazards associated with untreated waters. The main sources of these microbial contaminants in wastewater are human and animal wastes Also, the presence of these phosphorus and nitrogen in excess amounts could lead to the eutrophication of water sources, which may also create environmental conditions that favour the growth of toxin-producing cyanobacteria. Chronic exposure to some of such toxins produced by these organisms can cause a host of other diseases. In addition, the danger of nonbiodegradable and recalcitrant pollutants in water is their ability to persist in natural ecosystems for an extended period and have their ability to accumulate in successive levels of the biological food chain. As a result of these negative effects, a number of processes are in place for the treatment of wastewater effluents before discharge into receiving water bodies. This review was therefore aimed at providing an insight into the major pollutants in wastewater effluents and the various treatment processes