###### Abstract  
Municipal solid waste and sewage sludge are produced in large quantities that are often managed through industrial composting treatment. Because of their origin, composition, and complexity, ensuring adequate stabilization of the organic matter, and sanitation of fecal contaminants during composting is of the utmost significance, and difficult to achieve on an industrial scale. In this study, the operations of six industrial composting facilities that process municipal solid waste and sewage sludge were evaluated from the point of view of the sanitation achieved and the quality of the compost produced. In addition, the results were compared using the model of industrial compost from green waste. Differences between the plants were ascribable to operations other than composting systems. High phytotoxicity and fecal contamination above legislation thresholds were found in compost produced from municipal solid waste. In contrast, compost from sewage sludge were more stable and mature than those produced from green waste, and also had an adequate level of sanitation. The raw material and operational factors are of great relevance to obtain a stable, mature, and pathogen-free compost. f 2  
on the activities of enzymes involved in the carbon, nitrogen and phosphorus cycles [13] and provides a high amount of organic matter [14]. Therefore, it is useful as an agricultural soil conditioner and fertilizer [15]. In this sense, the other main waste material of urban origin, sewage sludge, has management alternatives that include even thermochemical decomposition [16]. Regarding the composting of SS, some key aspects must be taken into account. SS possess certain characteristics that are common to MSW, which makes it also suitable for composting. However, due to its low C/N ratio, requires co-composing with, e.g., lignocellulosic waste [17]. Among the most negative aspects of MSW and SS are the content of heavy metals and the presence of recalcitrant xenobiotic substances, which are capable of migrating and distributing through environments [18; 19]. Besides, research is increasingly focused on the study of techniques to improve the quality of the final product obtained, without forgetting the conservation of natural resources [20] and the reduction in environmental impact [21]. For the compost to be suitable for agriculture, maturity and stability should be ensured. The stability is often evaluated using seed germination tests [7]. However, respiratory is one of the best tools to monitor the stability of the material during the composting process [22]. The maturity identifies the grade of organic matter transformation during the process and the validation of the elimination of phytotoxicity in the compost generated is preferred [23]. On the other hand, a correctly prepared compost must not contain pathogens that pose risks to health and the environment. Fecal contamination indicators are used to determine that the compost is safe [24] and to verify that the sanitation conditions were reached during the process. This is especially important for large pile sizes used at industrial scale composting in which it is difficult to establish that the desired conditions are reached in the whole mass. Due to the above considerations, it is important to conduct a study to evaluate whether the urban waste bio-materials and the conditions of the composting process influence the quality of the compost obtained. In this study, a comparative analysis is carried out of the compost produced from industrial composting facilities that process municipal solid waste (MSW) and sewage sludge (SS) and compare them with those produced from green waste (VR).