Integrated urban water management by coupling iron salt production and application with biogas upgrading

Abstract

Integrated urban water management is a well-accepted concept for managing urban water. It requires efficient and integrated technological solutions that enable system-wide gains via a whole-of-system approach. Here, we create a solid link between the manufacturing of an iron salt, its application in an urban water system, and high-quality bioenergy recovery from wastewater. An iron-oxidising electrochemical cell is used to remove CO2 (also H2S and NH3) from biogas, thus achieving biogas upgrading, and simultaneously producing FeCO3. The subsequent dose of the electrochemically produced FeCO3 to wastewater and sludge removes sulfide and phosphate, and enhances sludge settleability and dewaterability, with comparable or superior performance compared to the imported and hazardous iron salts it substitutes (FeCl2, and FeCl3). The process enables water utilities to establish a self-reliant and more secure supply chain to meet its demand for iron salts, at lower economic and environmental costs, and simultaneously achieve recovery of high-quality bioenergy.

Iron Recycle-Driven Organic Capture and Sidestream Anaerobic Membrane Bioreactor for Revolutionizing Bioenergy Generation in Municipal Wastewater Treatment

“…Of these, CEPT is regarded as a simple and effective method for capturing organic matter and phosphorus by adding coagulants into extant primary sedimentation facilities. , However, the addition of coagulant in CEPT represents 55% of the total operation cost of a novel WWTP (at 0.03 €/m 3 of wastewater) . It is thus necessary to address two urgent issues: the high chemical costs and huge amount of inorganic sludge produced at high coagulant dosages. − Aluminum or iron coagulants can be recycled through the direct chemical acidification of CEPT sludge. , Aluminum-containing acidic sludge, however, is unsuitable for subsequent use in the AD process . In contrast, iron-enhanced primary sludge (Fe-PS) has superior anaerobic degradability, and it facilitates methane production and in situ biogas desulfurization .…”