Petroleum waste is composed of some hazardous compounds, which may affect the terrestrial and aquatic ecosystem. These compounds are persistent in the terrestrial environment and may take several years prior to be degraded naturally. Therefore, some environmental friendly techniques are needed to be adopted to speed up the natural degradation process of such compounds. Biological technique is one of the most beneficent technique used to speed up the natural degradation of petroleum compounds across the world. Further improvement in biological technique using nano particles is also gaining scant attention to enhance the natural degradation process of petroleum waste. The proposed study aimed to develop an economic, rapid and environment-friendly remediation method for the oil companies to rehabilitate petroleum waste contaminated soil which could be achieved through developing microbial based technique. This study described further improvement in the bioremediation method, using mangrove roots powder with and without silver nitrate nanoparticles to accelerate the degradation of petroleum waste contaminated soils at various depths.) Objective 1. The present study was aimed to examine the difference in the soil physicochemical as well as geochemical characteristics between control and petroleum waste contaminated (with respect to distance and depth). For that purpose, three oil fields (Chanda, Nashpa and Mela) from Kohat Plateau and four oil fields (Kal, Chaknaurang, Messakaswal and Sadqal) from Potwar Plateau were selected. Soil samples were collected from surface 0-15cm (‘A’ horizon) and subsurface 15-30 cm (‘B’ horizon) and 30+cm (‘C’ horizon) for physicochemical and geochemical analysis (soil texture, pH, EC, organic matter, organic carbon, inorganic carbon, major elements: Al, Ca, K, Mg, Na, P, and trace elements such as Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn). Some sites had no ‘C’ horizon iv therefore information about such sites is restricted to only A and B horizons. The results of this study show that the soil of Kohat Plateau was sufficient in calcium and sodium. However, Phosphorus and potassium were found to be deficient in such soils. Whereas, Aluminum was found to be marginal in all soils. Petroleum waste contamination poses no effect on the lateral and horizontal distribution of all major elements in any of the soil profile of both the study areas. However, calcium was found to be decreases with increase in depth in a soil profile and distance from the contamination source. This suggests that petroleum waste may increase the concentration of Ca in the soil. Petroleum waste contamination poses no effect on major elements concentrations in all soils. Organic carbon content increases with the petroleum contamination except for a few exceptions. Total Cr, Zn and Pb concentration in all soils of both the study areas remained within the permissible limit. However, the total Cu, Mn, Ni and Cd concentration in all soils of both the study areas exceeds the permissible limit. Whereas, the concentration of Co in all soils of both the study areas was also above the permissible limit. Moreover, Copper and Nickel were found to be at elevated level in petroleum waste contaminated soil. The results of contamination factor show that Cd, Cr, Cu, Co, Mn, Ni, Pb and Zn depicts low to moderate contamination in the soil of Kohat and Potwar Plateau. However, enrichment factor show that Cr, Pb and Zn were in depleting range, whereas, Co, Cu and Ni were in normal range, However, Cd was significantly enriched and Mn was unusually enriched. Zinc and Nickel were in the category of deficient to minimal enriched, which indicated their occurrence in the soil was natural. Cadmium poses moderate risk to the ecological system whereas all the other trace elements (Cr, Cu, Co, Mn, Ni, Pb and Zn) may cause low ecological risk to the environment. Pearson correlation shows positive correlation of Ni with Cd, Cr, Co, and Pb except for Zn. Objective 2. To identify and isolate various genera of micro-organisms capable of degrading hydrocarbons at various depths of the soil profile in petroleum waste-contaminated sites, soil samples were collected from surface 0-15cm (‘A’ horizon) and subsurface 15-30 cm (‘B’ horizon) and 30+cm (‘C’ horizon). Around 18 bacterial strains were isolated from horizon A, B and C. Bacillus pumilus, Bacillus sp. Exiguobacterium aurantiacum, Bacillus megaterium, Lysinibacillus fusiformis,and Bacillus altitudinis) were isolated from surface soil. Whereas, Bacillus subtilis, Bacillus licheniformis, Lysinibacills fusiformis, Bacillus firmus, Bacillus sp., Bacillus oceanisediminis, Bacillus subtilis, Fictibacillus barbaricus, Bacillus sonorensis, Bacillus amyloliquefaciens, Lysinibacillus sphaericus were isolated from subsurface soil of petroleum waste contaminated soils. Objective 3. To prepare a microbe-based formulation for the remediation of petroleum waste-contamination, the uncontaminated/control soil was initially spiked with 50% petroleum waste. Then, the spiked soil was treated with fertilizer, consortium, mangrove root powder and silver nanoparticles alone or in combination (T1-T7). To evaluate the efficiency of the abovementioned treatments (at surface or subsurface soil) and to choose the best suitable treatment for the degradation of TPH, two lab experiments A (in aerobic conditions) and B (anaerobic conditions) were conducted for an incubation period of 240 days. The rate of degradation of TPH and total bacterial population was monitored regularly at various days of incubation (i.e., 0, 5, 20, 60 and 240). The results of the present study show that silver nanoparticles alone or in combination with consortium or/and fertilizer had no pronounce effect on the degradation of TPHs. Thus, cannot be considered suitable to be applied commercially to facilitate bioremediation. Whereas, consortium degraded a significant amount of TPH even in the beginning of incubation period. In addition, the efficiency of fertilizer in the degradation of TPHs was also observed at the end of incubation. Similarly, Total bacterial population was increased in the presence of fertilizer and consortium. Whereas, silver nanoparticles did not increase the total bacterial population. Thus, bioremediation is considered to be an effective technique to degrade TPHs than nano-bioremediation. Like silver nanoparticles, mangrove root powder (alone or in combination with consortium and/or fertilizer) did not show any positive or negative impact on the degradation of TPHs as well as on the total bacterial population. Thus, mangrove root powder is not suitable to enhance bioremediation of petroleum waste contaminated soils.