Utilization of biochar for resource recovery from water: A review

Over the past few decades, the shortage of water resource has prompted a shift in human concept about waste water: from waste to valuable resource. Utilizing wastewater can not only mitigate water scarcity, but also provide an opportunity for nutrient and energy recovery, further offsetting part of the exploitation of valuable resources. When establishing resource recovery systems of wastewater, the implemented technology and materials should be preferentially considered in order to achieve economically feasible and environmentally responsible solutions. The advantages of biochar in cost, nutrient retention and pollutant adsorption efficiency endow its possibility for resource recovery. Thus, understanding the relationship between biochar and resource recovery is essential to develop the applications of biochar in environment remediation and wastewater utilization. However, to this date there is no comprehensive review that establish the relevance between biochar and recycled substance. In this review, we aim to evaluate the roles of biochar in resource recovery from wastewater. Recyclable substances with the presence of biochar mainly include components, water resource and energy. Viable and effective methods for different recovered targets are classified. In particular, through revealing the interrelationship between biochar production methods and recovered substances, we try to provide the guideline for biochar selection. The re-application and value of recovered substances are also summarized comprehensively. Moreover, the current problems, existing limitations, and promising industrial application value of biochar in resource recovery from water are also put forward. This review can create awareness about the possibility of various options for resources recovery from water with biochar and contribute to further development and demonstration in wastewater treatment.