Water Meta-cycle model and indicators for industrial processes- the pulp & paper case in China

Abstract

To address the increasingly grim water environmental crisis and achieve the sustainable development goal in 2030, a fresh water Meta-cycle model and corresponding indicators are proposed to optimize the water resources utilization within a local industrial area. The out-of-date single-track and linear water utilization mode is improved in the Meta-cycle model in which it possesses the characteristics of closed-loop, multiple order and high efficiency. The efficient and ecological utilization, conservation, regeneration as well as recycling of water resources are highly emphasized in the model. The water Meta-cycle model comprises 5 levels: the natural metabolic level (Level 0), the ecological treatment level (Level 1), the wastewater treatment in industrial park level (Level 2), the wastewater pretreatment within enterprise level (Level 3), and the production related water within enterprise level (Level 4). Based on this conceptual model, a series of indicators is presented in the paper, including recycling rate and recycle time, water source diversity index, greenhouse gas (GHG) emission, direct water footprint of the model and adaptive evaluation of water treatment. A case of a typical pulp and papermaking enterprise is used to illustrate the proposed model. The results demonstrate the key role of ecological regeneration cycle. It is expected that the Meta-cycle model will be an effective mode for the safe and sustainable management of regional water resources.