Suchergebnisse

AbstractApplications of advanced oxidation processes (AOPs) in water and wastewater treatment have been the subject of growing interest throughout the last decade. Although UV/hydrogen peroxide (UV‐H2O2) is the most established technology among the UV‐AOPs, UV‐chlorine (UV‐Cl) is emerging as a reliable and potentially more cost‐effective alternative. Recent studies have indicated that UV‐Cl processes may be more efficient and economically favourable for the degradation of some chemicals of emerging concern from contaminated water. Moreover, in terms of the formation of disinfection by‐products (DBPs), UV‐H2O2 seems to have no superiority over UV‐Cl. This said, more investigation in the assessment of genotoxicity and cytotoxicity of DBPs is required. Additionally, more pilot‐scale and full‐scale studies are required to establish UV‐Cl as a reliable alternative to UV‐ H2O2. This paper compares UV‐Cl and UV‐H2O2 AOPs for the degradation of intractable chemicals from water and wastewater based on the practical considerations of efficiency, cost, DBP formation, kinetics and sensitivity to water matrix variability. Finally, various modelling approaches to UV‐Cl have been reviewed. This review showed that UV‐Cl is superior to UV‐H2O2 in terms of degradation efficiency and cost effectiveness and can be a robust alternative in many UV‐AOPs applications.

AbstractThirty‐five utilities across the United States (54%), Australia (26%), and Canada (20%) were surveyed to identify their experiences with early warning monitoring and source control of cyanobacteria. All utilities experience pelagic blooms, but only 20% monitor for benthic cyanobacteria. Most utilities (86%) have early warning monitoring programs. However, monitoring frequencies and long analytical turnaround times negatively impacted the effective use of monitoring data for rapid bloom detection and prompt implementation of reactive measures to control blooms/bloom‐related issues. Thus, a tiered monitoring approach is recommended: Tier 1–event detection, Tier 2–cyanobacteria confirmation, and Tier 3–metabolite confirmation. Most utilities (68%) implement source control strategies for cyanobacteria, with algaecides and aeration being the most frequently used (36%). Utilities relied on manufacturer recommendations to design source control strategies, although site‐specific optimization is needed based on water quality/bloom conditions. Control strategies were restricted by source geometry, limited optimization, metabolite generation, and environmental impacts. Successful source control of cyanobacteria was further negatively impacted by external nutrient loading. Therefore, source control strategies should be implemented jointly with external nutrient control initiatives.