Skip to main content

Table 5 Overview of results on Taenia spp. egg presence in the sludge of wastewater treatment systems

From: The survival and dispersal of Taenia eggs in the environment: what are the implications for transmission? A systematic review

Country

Sludge type and/or treatment

Egg recovery

Presence (N = sample size)

Year of publication

Reference

South Africa

Treatment: sludge drying beds for 2 months

Flotation, sedimentation

54 Taenia spp. eggs/g with 20 eggs/g viable (N = 60)

2018

[90]

Senegal

Treatment: sludge drying beds for 2 months

Flotation, sedimentation

0 eggs (N = 3)

2018

[90]

Brazil

Dry matter sludge biosolids

Filtration, sedimentation, centrifugation and flotation

4.85 helminth eggs/g; of which 0.3% Taenia spp. (N = 22)

1997

[116]

Slovakia

Raw sludge, activated sludge and drained stabilised sludge

Sedimentation, centrifugation, flotation

2.27% raw sludge, 1.14% activated sludge and 2% drained stabilised sludge (N = 276)

2015

[117]

France

Anaerobically digested sludge

Modified Faust technique (flotation)

Between 2200 and 2400 Taenia spp. eggs/kg* sludge (N = 21)

1990

[118]

England/Wales

/

/

Taeniid eggs in at least one sample/water authority (N = 162)

1984

[119]

Morocco

3 systems: Natural lagooning; infiltration–percolation sludge followed by sand filtration; and activated sludge plant

Applied flotation method for the analyses of biowastes

Taenia spp. eggs in natural lagooning: 2 eggs/g; in infiltration–percolation sludge: 8 eggs/g; in sand filtration: 2 eggs/g; in activated sludge: 4 eggs/g (N not indicated)

2019

[120]

Mexico

Sludge from 3 systems: Conventional APT* with parallel plates; sludge blanket APT; and sand-assisted sedimentation

Treatment: Lime stabilization

US EPA technique

90% of helminth eggs destroyed (N not indicated)

2000

[91]

Australia

Treatment: Chlorine, copper sulphate, slaked lime, ferric sulphate, UV light, drying, moist heat and cold

In vivo: feeding to calves

Only drying, keeping dry for 1 day in the presence of a small amount of common salt and boiling for 5 min killed the eggs (N not indicated)

1937

[92]

  1. APT, Advanced primary treatment (coagulation/flocculation/sedimentation); US EPA, United States Environmental Protection Agency