Phytoremediation is an emerging environmental-friendly technology that can be a promising solution to remediate oil-polluted soils. The impact of high amount of hydrocarbons on growth characteristics of burningbush and common flax was evaluated in this survey. The influence of organic fertilizers was also assessed on growth of plant species in oil-contaminated soil. Soil samples in which plants showed the best growth were analyzed for residual total petroleum hydrocarbons (TPHs) by GC-FID. Burningbush was employed for the first time in the history of phytoremediation of oil-polluted soils in this research. The two studied plant species demonstrated promising remediation efficiency in highly contaminated soil; however, petroleum hydrocarbon contamination depressed growth of surveyed plants significantly. Utilization of peat fertilizer improved plants’ growth parameters in highly oil-contaminated soil. Flax and burning bush reduced TPHs levels in contaminated soil by 87.63 and 65.29 percent, respectively, in comparison to initial concentration.

Microwave-Assisted Extraction (MAE) is a type of low-temperature thermal desorption process that its numerous advantages have caused a wide spread use of it. Microwave heating is a potentially attractive technique as it provides volumetric heating process to improve heating efficiencies as compared with conventional techniques. The ability to rapidly heat the sample solvent mixture is inherent to MAE and the main advantage of this technique. Presently MAE has been shown to be one of the best technologies for removing environmental pollutants specially PAHs, phenols and PCBs from soils and sediments. Five different mixtures and types of aggregation (Sand, Top soil, Kaolinite) besides three concentrations of crude oil as a contaminant (1000, 5000 and 10000 mg/L) were considered. The results indicated that regardless of aggregation, the presence of humus component in soil reduces the efficiency. Minimum and maximum efficiencies were for sandy soil (containing organic components) and kaolinite (without any organic content), respectively. According to the results of this research when some amount of humus and organic materials are available in the matrix, it causes the extraction efficiency to perform as a function of just humus materials but not aggregation. Increasing the concentration of crude oil reduced the efficiency with a sharp steep for higher concentration (5000-10000 mg/L) and less steeper for lower concentration (1000-5000 mg/L). The concentration of the contaminant, works just as an independent function with extraction time and aggregation factors. The extraction period of 10 min. can be suggested as an optimum extraction time in FMAE for PAHs contaminated soils.

To investigate the effect of total petroleum hydrocarbons (TPHs) contamination levels, organic fertilizers (poultry manure (PM) and poultry manure derived biochar (PMB)) and time of cultivation on growth characteristics of Oat (Avena sativa) and barley (Hordeum vulgare) in TPHs-contaminated soil, a pot experiment was conducted. The two studied plants had the potential for soil phytoremediation in highly TPHs contaminated soil,however, the plant growth decreased significantly with increasing the TPHs contamination. A high TPHs content had a toxicity effect on plant growth and degradation of TPHs. The results showed that the best degradation was achieved in the lowest TPHs level for soil cultivated with barley plant and the degradation of TPHs increased by adding fertilizer. According to the results in TPHs contaminated soil samples, the highest average of relative growth rate (RGR) of roots observed in barley plants as compared to the oat plants. Also, at each period of growth, barley plants showed an increased root/shoot ratio in TPHs contaminated soil compared to the oat plants (27. 6% after 10 weeks and 64. 17% after 20 weeks). Application of PMB improved mean shoot height, mean root, and shoot weight by about 17. 25, 52. 7, and 33. 88% for oat plants, and 4, 10. 23, and 46. 28% for barely plants compared to the un-amended treatments, respectively. The most degradation was achieved after 20 weeks for PMB treatment with barley plant at the lowest TPHs level (53. 41%) in which oat degraded more than 45% of TPHs from the soil. Generally, the results showed that phytoremediation of TPHs can be affected by different factors such as type of plant, type of fertilizer application, and period of remediation.

Bioflocculants are extracellular polymeric substances (EPS) synthesized and released by microorganisms including bacteria, algae and fungi with many applications for wastewater treatment. The current study aimed to produce bioflocculant compounds from bacteria and evaluate their efficiency in the treatment of polluted water with hydrocarbon. The bacteria were isolated from wastewater and oil-contaminated soils in Basrah city, Iraq. The bacteria used in the present study isolated and identified in a previous study, these isolates as Aeromonas simiae and Exiguobacterium profundum. Both Aeromonas simiae and Exiguobacterium profundum demonstrated high efficacy in the remediation of wastewater from the Najibiya plant achieving up to 88% turbidity reduction under optimal conditions. Aeromonas simiae showed varied performance in removing Total Dissolved Solids (TDS), Total Suspended Solids (TSS), and Total Petroleum Hydrocabons (TPHs), with the best results at 43%, 57%, and 86.04% respectively, under specific pH and dosage conditions. Similarly, Exiguobacterium profundum showed excellent results, particularly in removing TDS, TSS and TPHs, reaching up to 52%, 82% and 94.23% respectively. Exiguobacterium profundum was highly effective bacterium in removing TPHs from the wastewater of the AL- Najibiya plant reaching 94.23%. The effectiveness of both strains varied with pH levels and dosages, highlighting their potential in targeted wastewater remediation applications.