The ‘Digestate Treatment’ module consists of a multi-stage system that treats and recycles the liquid by-products from anaerobic digestion. This process produces water suitable for discharge, an organic solid fertiliser rich in nitrogen and phosphorus, and a liquid inorganic fertiliser rich in nitrogen and potassium. In the module, the digestate passes through several stages of a separation cascade in succession. Coarse and fine solids are removed in the first two stages by mechanical separation. In the subsequent steps, membrane processes are then used to target finer impurities and dissolved compounds. During the process, all relevant process parameters are recorded to monitor the separation processes and establish mass and energy balances.

The chosen approach ensures efficient resource recovery, reduces waste generation and helps to meet environmental standards. A key feature of this module is its flexibility, which enables it to adapt to different feedstocks or system objectives. The module enables the recovery of nutrients and water – both key aspects of a functioning circular economy.  By converting waste streams into useful products, the module demonstrates a sustainable approach to waste management and resolves potential issues associated with the direct application of raw digestate.