Wastewater treatment plants discharges disseminated more <i>Giardia</i> than <i>Cryptosporidium</i>


Onursal A., Içgen B.

WATER ENVIRONMENT RESEARCH, vol.95, no.2, 2023 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 95 Issue: 2
  • Publication Date: 2023
  • Doi Number: 10.1002/wer.10839
  • Journal Name: WATER ENVIRONMENT RESEARCH
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Agricultural & Environmental Science Database, Applied Science & Technology Source, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Compendex, Environment Index, Geobase, MEDLINE, Pollution Abstracts, Veterinary Science Database, DIALNET
  • Keywords: cryptosporidiosis, Cryptosporidium parvum, Giardia intestinalis, giardiasis, protozoa removal, WWTP, PATHOGENS, REMOVAL, PROTOZOA, SAMPLES, TIME
  • Middle East Technical University Affiliated: Yes

Abstract

Parasitic protozoa Giardia intestinalis and Cryptosporidium parvum are causative agents for giardiasis and cryptosporidiosis, respectively. These infections are mostly associated with waterborne diseases. The discharges from wastewater treatment plants (WWTPs) that reach surface waters cause waterborne transmission because there are no regulations for monitoring these protozoa. This emphasizes how crucial the removal capacities of WWTPs to prevent the spread of infectious parasitic pathogens. For this reason, in this study, five different types of WWTPs including conventional activated sludge (CAS), biological nutrient removal (BNR), sequencing batch reactor (SBR), membrane bioreactor (MBR), and WWTP with coagulation-flocculation and UV disinfection (CoFlUV) units were investigated over a year, seasonally in terms of their G. intestinalis and C. parvum removal capacities. The seasonal abundances of these protozoa-specific genes in both the influents and effluents of each WWTP were determined by qPCR. The reduction of protozoan rDNA copies in the effluent wastewater samples compared with the influent wastewater samples was assessed as log(10) reduction values (LRVs). LRVs >3 were reachable for C. parvum in all types of WWTPs tested. However, only LRVs 1-2 were reachable for G. intestinalis in CAS, SBR, CoFlUV, and MBR. Significant seasonal variations were just observed in SBR and CAS for G. intestinalis and C. parvum (p < 0.05), respectively. The findings depicted that WWTPs tested disseminated more giardiasis causative agents than cryptosporidiosis. Therefore, G. intestinalis needs to be monitored in WWTPs' discharges to reduce any potential damage of this parasite to public health. Practitioner Points Removal of G. intestinalis and C. parvum in WWTPs was affected by the process.LRV 2.92 was the highest LRV achieved for G. intestinalis.LRV >3 was reachable for C. parvum.WWTPs discharges disseminated more G. intestinalis than C. parvum.WWTPs effluents should be monitored in terms of G. intestinalis.