Wastewater Valorization: Practice around the World at Pilot- and Full-Scale

Abstract

Over the last few years, wastewater treatment plants (WWTPs) have been rebranded as water resource recovery facilities (WRRFs), which recognize the resource recovery potential that exists in wastewater streams. WRRFs contribute to a circular economy by not only producing clean water but by recovering valuable resources such as nutrients, energy, and other bio-based materials. To this aim, huge efforts in technological progress have been made to valorize sewage and sewage sludge, transforming them into valuable resources. This review summarizes some of the widely used and effective strategies applied at pilot- and full-scale settings in order to valorize the wastewater treatment process. An overview of the different technologies applied in the water and sludge line is presented, covering a broad range of resources, i.e., water, biomass, energy, nutrients, volatile fatty acids (VFA), polyhydroxyalkanoates (PHA), and exopolymeric substances (EPS). Moreover, guidelines and regulations around the world related to water reuse and resource valorization are reviewed.

Valorization of Brewery Waste through Polyhydroxyalkanoates Production Supported by a Metabolic Specialized Microbiome

“…During the last few years, population growth has led to an increase in industrialization in order to ensure population needs, causing an increase in the quantity and variety of waste generated, as well as an increase in the production and utilization of petrochemical products, namely plastics [1][2][3]. Consequently, the interest in renewable resources has been increasing due to the rising awareness regarding the use of more environmentally friendly products, such as polyhydroxyalkanoates (PHAs), which are biodegradable, biocompatible polyesters that present properties that are similar to conventional plastics [4]. These bioplastics, which can be produced from wastes, have numerous potential applications, thus contributing to a circular economy and to the Sustainable Development Goals [3,[5][6][7].…”

Dairy and Wine Industry Effluents as Alternative Media for the Production of Bacillus-Based Biocontrol Agents

“…Lowering the content of carbon sources, as the main contaminants of waste-based media, is significant from the point of view of ecological efficiency of the created bioprocess solution, considering the positive impact on reduction in environmental burden. In addition to the sustainability aspect, it is important to emphasize economic savings as a consequence of lowering the demands for water utilization in the medium preparation phase [ 55 ]. In the particular cases, for CW-based medium, 100% water consumption reduction was achieved as the pure whey was used as the cultivation medium, while the WFW had to be diluted to avoid substrate inhibition due to very high initial sugar concentrations; thus, the savings in this case in terms of water consumption were 25%.…”

Recovery of structural extracellular polymeric substances (sEPS) from aerobic granular sludge: Insights on biopolymers characterization and hydrogel properties for potential applications

“…Currently, the extraction of sEPS from waste AGS is considered as a virtuous pathway in the logic of water resource recovery facilities (WRRFs) (Duque et al, 2021;Kehrein et al, 2020;Kisser et al, 2020;ROYAL HASKONINGDHV, 2020). The first direct effect of sEPS recovery from waste AGS is represented by a significant reduction of excess sludge disposal whose costs represent one of the greatest incidence of OPEX costs for a wastewater treatment company (Wei et al, 2003).…”