Contents lists available at ScienceDirect Journal of Water Process Engineering journal homepage: www.elsevier.com/locate/jwpe Experimental veriﬁcation of tertiary treatment process in achieving eﬄuent quality required by wastewater reuse standards M. Vojtěchovská Šrámková ⁎ , V. Diaz-Sosa, J. Wanner Department of Water Technology and Environmental Engineering, University of Chemistry and Technology, Prague. Technická 5, 166 28, Prague 6 – Dejvice, Czech Republic ARTICLE INFO Keywords: Wastewater reuse Industrial reuse Tertiary treatment UV disinfection Legislation ABSTRACT Modern technologies in wastewater treatment can produce high quality eﬄuents, therefore wastewater is now considered a valuable product suitable for reuse. However, water reuse needs to be regulated based on ap- plicable and legally binding guidelines, therefore the lack of a regulatory framework hampers this practice and its beneﬁts. The Czech Republic, as many other countries, has an absent water reuse legislation. In this study, a pilot-scale tertiary treatment was installed at Milevsko Waste Water Treatment Plant (WWTP) in South Bohemia (20,000 P.E.) to demonstrate the eﬄuent quality that can be achieved and evaluate the reuse potential, espe- cially on non-potable applications, such as industry and irrigation. WWTP secondary eﬄuent was treated by three separated technologies: Dissolved Air Flotation (DAF), sand ﬁlter and Filtra-lite ® ﬁlter; followed by ul- traviolet (UV) disinfection. Results on water quality were compared to Czech standards for drinking and non- drinking water, and to some international benchmark regulations for water reuse. Our results have led us to initiate the introduction of legislation regulating wastewater reuse in the Czech water management framework. 1. Introduction Wastewater reuse has become a desirable manner of dealing with this product due to its fairly high quality and the sustainable use of the urban water resources. Applications for reuse are quite diverse, but an essential part in this process is the implementation of valid and binding legislation that sets clear policy for wastewater reuse. Often, eﬄuent quality not only ensures adequate protection of recipient waters but, in some cases, exceeds the requirements of environmental protection. An extending shortage of drinking and fresh water coupled with steadily increasing potable water prices is leading to widespread investigation of WWTP eﬄuent reuse options [1]. Various modiﬁcations to WWTP technology can produce diﬀerent qualities of treated wastewater to suit particular reuse requirements [2,3]. For each application of treated wastewater reuse, safety criteria must be established and the potential risks associated with these processes must be deﬁned according to World Health Organisation guidelines (WHO) [4,5]. In Europe, treated wastewater has to comply with both EU and national water law, and depending on the ﬁnal use of the treated water, it would have to comply with many other EU directives. Applicable legislation must consist of several fundamental components which can be divided into basic parts: deﬁned terms based on guidelines of the WHO, speciﬁed wastewater reuse areas, raw material quality for speciﬁc applications and regions, and processes able to achieve the required quality. To facilitate this process, a pilot plant project assessing three dif- ferent simple tertiary treatment devices was installed in a WWTP with a capacity of 20,000 PE located in South Bohemia, Czech Republic. To ensure hygienization of the eﬄuent, an UV unit was used downstream of all devices under evaluation. Data from these experiments were compared with existing legislative requirements from the Czech Republic as well as the U.S. and European Guidelines for Wastewater Reuse. The main aim of this project is to demonstrate the achievable quality of real WWTP eﬄuent and evaluate its potential for reuse in the industrial sector, mainly. Additionally we aspired to characterize and compare the removal eﬃciency of water quality indicator parameters of the three simple tertiary treatment devices employed. Water reuse is not a current practice in the Czech Republic although the technologies to produce clean eﬄuents are available. Up to now, the eﬄuent of WWTPs are discharged into recipient waters, usually rivers or streams nearby the plant, only applying extra measurements to improve the quality of the eﬄuent when the discharge is made on protected or sensitive areas [7,8]. In this pilot plant project we tested three devices for removal of residual pollution from WWTP eﬄuent, including a separation process by DAF unit, a Sand Filter and a Filtra-lite ® ﬁlter containing expanded crushed clay material. The performance of these devices was improved https://doi.org/10.1016/j.jwpe.2018.01.003 Received 24 September 2017; Received in revised form 18 December 2017; Accepted 9 January 2018 ⁎ Corresponding author. E-mail address: sramkova.michaela@seznam.cz (M. Vojtěchovská Šrámková). Journal of Water Process Engineering 22 (2018) 41–45 2214-7144/ © 2018 Elsevier Ltd. All rights reserved. T