The estimated potential for long‐term energy‐efficiency improvement of water/wastewater utilities (WWUs) ranges from 10 to 30%. Energy efficiency measures generally have short payback periods and are more economical than adding renewable energy generation. This article presents experience gained from working with German WWUs on energy efficiency since 2013, focusing on six case studies: (1) making full use of available energy use data, (2) reducing costs by avoiding demand spikes and optimizing electricity contracts, (3) improving the efficiency of over‐dimensioned booster station pumps, (4) reducing energy use for space heating at a water treatment plant, (5) replacing pressure‐reducing valves with turbines to make use of excess hydraulic capacity, and (6) avoiding energy waste of wastewater treatment plant blowers by keeping oxygen sensors properly calibrated. The main partner WWU achieved a 13% improvement in energy efficiency after less than two years of focused energy management, with an average payback period per measure of 1.2 years.
Zwischen Juni 2014 und Oktober 2015 wurde beim Zweckverband für Wasserver- und Abwasserentsorgung „Mittleres Erzgebirgsvorland“ (ZWA) Hainichen ein Energiemanagementsystem (EnMS) gemäß der DIN EN ISO 50001 eingeführt und zertifiziert. Die gesamte Energienutzung des ZWA wurde sichtbar gemacht und kann nun gemanagt werden. In zahlreichen Beratungen mit ZWA-Mitarbeitern wurden Arbeitsprozesse analysiert, Schwächen und Stärken aufgezeigt. Das Energieeffizienz-Netzwerk des ZWA wurde deutlich gestärkt und ein Mitarbeiter als Energiemanager gewonnen. Energieeffizienz besitzt nun einen höheren Stellenwert und wird durch Maßnahmen kontinuierlich gefördert.
Common sediment samplers for microplastics (MP) such as grab samplers or corers are limited to certain grain sizes and known to cause disruption of sediments which results in a loss of fine and low-density particles such as MP. However, this loss has not been quantified yet and its occurrence is commonly tolerated during MP sediment sampling. In the present study we evaluate the recovery of MP of various common sediment samplers used in most recent studies. The samplers were tested on a model plant simulating a riverine environment with MP spiked sediments. Also, we investigated the feasibility of less frequently used freeze coring. The results of this study suggest that a combination of common methods is crucial in order to sufficiently evaluate a sampling site until standardized MP samplers for sediments are available. Freeze coring indicates a promising potential to monitor MP in river sediments in the future but is costly and should be optimized for regular field sampling campaigns.
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