Skip to main content

INACTIVATION OF HELMINTH EGGS IN WASTEWATER STABILIZATION POND SLUDGES

Buy Article:

$17.50 plus tax (Refund Policy)

Or sign up for a free trial

Abstract:

The inactivation rates of helminth eggs in the sludge layer of three Mexican wastewater stabilization ponds (WSP) were studied using two different methods: (1) stratified sludge cores, to investigate the apparent inactivation rate of the indigenous helminth eggs, and (2) Sentinel ChambersTM, to investigate the inactivation rate in samples inoculated with Ascaris suum. The inactivation rate of Ascaris eggs in the sentinel chambers, about 50% after 1 year, was similar to the initial apparent inactivation rate determined by the sludge core method in the same pond. Based on the sludge core data it was found that the apparent inactivation rate of Ascaris eggs decreased with time, and varied between the three ponds. The eggs of Ascaris survived longer than the eggs of other helminth species present in the sludge, which included Hymenolepis, Trichuris, and Toxocara. The concentration of eggs in the sludge varied widely between ponds and according to location and depth within each pond; the maximum concentration found was 650 eggs/g total solids (TS). Viable Ascaris eggs were found in 52 of 53 sludge core samples, some of which were estimated to be over 10 years old. Because most WSPs are operated continuously, new sludge and new eggs are constantly deposited at the top of the sludge layer. Therefore, even if the concentration of viable eggs in the oldest sludge is reduced to levels meeting the standards set by biosolids regulations, upon removal this sludge will be mixed with the more recent sludge containing higher concentrations. The mean concentrations of viable helminth eggs in the sludge were 25, 25, and 48 eggs/g TS in the Mexicaltzingo, Texcoco, and Xalostoc ponds, respectively; therefore further treatment of the sludge is recommended before it is disposed or reused.

Document Type: Research Article

DOI: https://doi.org/10.2175/193864701784993623

Publication date: 2001-01-01

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free ContentFree content
  • Partial Free ContentPartial Free content
  • New ContentNew content
  • Open Access ContentOpen access content
  • Partial Open Access ContentPartial Open access content
  • Subscribed ContentSubscribed content
  • Partial Subscribed ContentPartial Subscribed content
  • Free Trial ContentFree trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more