Standard and new faecal indicators and pathogens in sewage treatment plants, microbiological parameters for improving the control of reclaimed water

Abstract

This study involved collaboration between three centres with expertise in viruses, bacteria and protozoa. The focus of the research was the study of the dissemination and removal of pathogens and faecal indicators in two sewage treatment plants (STP1 and STP2) using tertiary treatments. Samples were collected over a period of five months through the sewage treatment processes. Analysis of the samples revealed that the plants were not efficient at removing the faecal indicators and pathogens tested during the study. From entry point (raw sewage) to effluent level (tertiary treatment effluent water), the experimental results showed that the reduction ratios of human adenoviruses were 1.2 log₁₀ in STP1 and 1.9 log₁₀ in STP2. Whereas for Giardia spp. and Cryptosporidium spp. the reduction ratios were 2.3 log₁₀ for both pathogens in STP1, and 3.0 and 1.7 log₁₀ in STP2, respectively. Furthermore, the presence of faecal indicators and pathogens at different sampling points was evaluated revealing that the tested pathogens were present in reclaimed water. Human adenovirus and Arcobacter spp. showed positive results in infectivity assays for most of the tertiary effluent water samples that comply with current legislation in Spain. The pathogens detected must be evaluated using a risk assessment model, which will be essential for the development of improved guidelines for the re-use of reclaimed water.

Integral Management of Irrigation Water in Intensive Horticultural Systems of Almería

“…Nevertheless, its nutrient content and the nutrient demand of the crops need to match in order to achieve these benefits [101]. The use of reclaimed water involves major disadvantages as it can lead to the accumulation of heavy metals in the soil and to the transmission of pathogens [102]. The accumulation of these heavy metals, which are carcinogenic, as well as their oxidized derivatives can lead to the pollution of the water and the generation of genotoxicity [103].…”

Cryptosporidium Attenuation across the Wastewater Treatment Train: Recycled Water Fit for Purpose

“…Nevertheless, it is paramount that the health of both the public and the environment is protected, as reuse water has the potential to pose a high risk from viruses, bacteria, and protozoans (1,3,4). Therefore, water destined for reuse must be treated accordingly and be fit for purpose (5).…”

Request for scientific and technical assistance on proposed EU minimum quality requirements for water reuse in agricultural irrigation and aquifer recharge

“…In the JRC draft report it is indicated that information is often not available on concentrations, dose-response relationships and disease burden for various waterborne pathogens in treated wastewater in Europe. However, the EFSA experts have identified various scientific papers addressing some of the most relevant pathogens (Montemayor et al, 2005;Levantesi et al, 2010;Rodríguez-Manzano et al, 2012;Rusiñol et al, 2015;Spanakos et al, 2015;Eftim et al, 2017). This should by no means be considered as an extensive literature search on the topic, but is given as an illustration that relevant data are available that address the previous point.…”

“…In a study by Rodríguez-Manzano et al (2012), norovirus GII was quantified by quantitative reverse transcription polymerase chain reaction (q(RT)PCR) at the effluent level of two UWWTP producing reclaimed water after a disinfection treatment (four of seven effluent water samples were positive in the first UWWTP and four of five were positive in the second) showing mean values of 3.75 × 10 2 and 3.34 × 10 2 GC/100 mL, respectively. It is known that positive q(RT)PCR does not represent infectious…”