## 1 Introduction  
Globally, different anthropogenic activities have resulted in increasing environmental pollution, and its consequences has injured almost all components of the ecosystem [1; 2; 3]. Soil, as a vital component of the terrestrial ecosystem, is prone to pollution from different sources, including industrial and agricultural activities [4; 5; 6; 7]. Wide verities of pollutants entering the soil posing a huge threat and risk to human health and natural ecosystem [8; 9; 10; 11; 12]. Polycyclic aromatic hydrocarbons (PAHs), petroleum, and related derivatives represent the main sources of soil contamination [13; 14; 15; 16; 17]. Indeed, these organic pollutant groups are listed as priorities and receive considerable attention, owing to their toxic, genotoxic, mutagenic, and potentially cancer-causing properties [18; 19].  
To deal with this problem, several treatment technologies are used, including chemical, physical, and biological, as well as thermal for remediation of these contaminated soils. Among the best approaches is the bioremediation technology, which is categorized as a promising approach that continues to gain more attention due to its efficiency, cost-effectiveness, and environmental-friendly byproducts [20; 21; 22]. The process mainly relies on the activity of a wide spectrum of microorganisms to degrade the target contaminants to lower toxic levels. Bioremediation of PAH-contaminated soil has been performed utilizing distinctive approaches [7]. In any case, composting as a remediation approach has been considered a reasonable strategy in this field, because it provides nutrients for indigenous microorganisms to degrade the target contaminants; simultaneously, applying this approach is a great opportunity for feasible and sustainable reuse of the natural biodegradable fraction of wastes. Additionally, the process is cost-effective compared with other approaches--for instance, compostingcosts between $50-$140 per ton, while applying slurry or biopiling treatments cost $170 per ton and $130-$260 per cubic meter, respectively [23; 24; 25; 26; 27]. Bioremediation of PAH-contaminated soil through composting could be implemented through incorporating PAH-contaminated soils to the composting process, or by adding compost to contaminated soils. Also, bioaugmentation or surfactant application might be included to achieve the final set objectives [16; 25; 28; 29; 30; 31; 32; 33; 34]. Biodegradation of PAHs intrinsically depends on microbial activity, where bacteria and fungi are considered the foremost vital variables governing the bioremediation process [35; 36; 37]. However, the functionality of these microorganisms is affected by different factors within the composting mixture, including biotic and abiotic factors. In this context, the environmental condition (pH, temperature, moisture,), nutrient availability, oxygen presence, and bioavailability of the contaminants are essential parameters for process control and performance [38].  
This review focuses on the application of composting and compost addition for the bioremediation of soils contaminated with PAHs. In this regard, the impact of different controlling factors like temperature, PAH structure and concentration, co-substrate stability, co-substrate mixing ration, and bioaugmentation are discussed. Moreover, other issues, such as bioavailability, surfactant application, and the degradation pathways of PAHs are illustrated, in order to provide an insight into the process that is necessary for new development.