Small and medium scale industries in Nigeria play a major role in polluting water bodies, and key among these pollutants are suspended solids, biological oxygen demand and heavy metals contamination. Conventional methods of treatment, such as chemical precipitation, do not provide sustainable solutions as the pollutants are merely transferred from the waste water to a sludge residue which is disposed of by land-filling. The pollutants eventually find their way to freshwater supplies thereby contaminating it.Water hyacinth is a noxious weed that has a rapid growth rate and easily congests the water ways in Lagos, a coastal city in Nigeria, thereby creating serious problems in navigation, and irrigation. This can be harvested, and in line with the golden rules of sustainable development, used for the sustainable treatment of some industrial wastewaters.This work investigates the effectiveness of water hyacinth in wastewater treatment. After a 5-week simple experiment, in which water hyacinths were planted in wastewater samples obtained from three different industries, the average removal of pollutants were found to be 53.03%, 64.41%, 65.4%, 47.22%, 94.67% and 30.30% for Total Suspended Solids (TSS), Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO), nitrate-nitrogen, cadmium and iron respectively. Average Biocentration Factors (BCF) obtained for cadmium, copper and iron were 583.83, 734.41 and 2982.95 respectively.

The possibility of microbial degradation of plastic waste was investigated by isolating microorganisms present in dumpsite containing low-density polyethylene (LDP). Aspergillus niger (fungi) and Pseudomonas sp. (bacteria) were identified and subsequently used to biodegrade plastic waste. The medium was made up of 0.2 g of MgSO 4 , 1.0 g of KH 2 PO 4 , 1.0 g of K 2 HPO 4 , 1.0 g of NH 4 NO 3 , 0.02 g of CaCl 2 , 0.05 g of FeCl 3 in 1000 ml water. 10 ml of the medium containing the bacteria and/or fungi was poured into test tubes and 0.1 g of the plastic sample (Pure water sachet) pre-treated with ethanol was introduced into the tubes. The pH of the medium was adjusted to 7.2, 5.4 and 6.0 for Pseudomonas sp., Aspergillus niger and the mixed culture respectively. Each experiment was carried out aerobically at room temperature and incubated on a rotary shaker at 120 rpm. The weight loss in each experiment was monitored at 10 days interval for 60 days. The total weight loss after 60 days was 7.2%, 12.4%, 15% for degradation with Pseudomonas sp., Aspergillus niger and the mixed culture respectively. From this study it can be inferred that Pseudomonas sp. and Aspergillus niger have the ability to degrade plastics. It can also be inferred that Aspergillus niger degraded plastics better than Pseudomonas sp. and there was synergy between the two microorganisms since the mixed culture gave a higher degradation.

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The microbial activities and the biodegradation-abilities of undefined consortium in contaminated soils in the Niger Delta of Nigeria were studied. The Respirametry technique was adopted to evaluate the microbial activities while the soils were incubated with 2% () ν ν crude oil in mineral salt medium at 37˚C in three stages of two weeks each in a shake flask. At the end of the last phase, components of the crude oil degraded by the undefined consortium in the soils were identified with the gas chromatographic techniques. The consortia of the different samples studied showed different degree of capacities on the crude oil, removing a large number of components of the crude oil, making the areas potentially suitable for in-situ bioremediation.

The biodegradation of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, 2-methylnaphthalene and anthracene was investigated using pure and mixed culture of Paenbacillus alvei (bacteria) and Penicillum restricum (fungi) (isolated from crude oil contaminated sites in Rivers state of Nigeria). The abilities of these organisms to biodegrade the PAHs were studied by growing the isolates in a mineral salt medium (MSM) with the PAHs in shake flasks placed in a shaking water bath rotating at 150 rpm at room temperature for 21 days. The samples were withdrawn every three days for analysis of the residual PAHs using SRI 8610C Gas Chromatograph (GC), while the growth of the organisms was determined by using the dry biomass method. The results showed that the concentrations of PAHs decreased with an increase in the exposure time throughout a 21-day period, thus confirming the abilities of the organisms to feed on the PAHs. The results showed that the bacteria had more affinity for naphthalene, while the fungi had more affinity for anthracene. It was, however, observed that the samples from the flask which contained mixed PAHs and mixed culture of Paenbacillus alvei and Penicillum restricum had the highest and most significant biomass growth thus suggesting a synergy between the two organisms.