Effect of Vermicomposting on the Presence of Helminth Ova (Necator americanus, Trichuris trichiura, Ascaris lumbricoides) in Human Feces
Michael Z. Nuesca1, Stephen O. Lee2, Lasse Trappe3, Robert J. Holmer4
Student (4th year), Bachelor of Science in Agriculture, Xavier University College of Agriculture, 9000 Cagayan de Oro City, Philippines; Home Address: Paasa St. Lower Tambo, Macasandig, 9000 Cagayan de Oro City; Email ; Tel.: +63 915 3405533
2 Agronomist , Periurban Vegetable Project (PUVeP), Xavier University College of Agriculture
3 Agronomist, Periurban Vegetable Project (PUVeP), Xavier University College of Agriculture
4 Director, Periurban Vegetable Project (PUVeP), Xavier University College of Agriculture
Abstract
A two-factorial field experiment was conducted at the Manresa Farm in Cagayan de Oro City, Philippines, to assess the feasibility of vermicomposting as a method to reduce the helminth ova present in dried human feces. Eisenia foetida earthworms were seeded, and fed on composts with human feces for sixty days.
The number of hookworm ova had decreased very significantly in the boxes where earthworms were present with an average number of 7.13ova per 2 grams of substrate compared to 30.31 ova/ 2 grams substrate in boxes without earthworms after 60 days. The number of Ascaris ova decreased significantly to 0.19 ova/ 2 grams substrate in boxes with earthworms compared to 2.63 ova/2 grams substrate in boxes without earthworms; while no more Trichuris ova could be found in either treatment.
This indicates that vermicomposting can reduce the number of helminth ova after 60 days of treatment, but not fully eliminate them.
Key Words: Vermicomposting , Helminth Ova , Earthworms , Human Feces
Introduction
The proper collection, treatment and disposal if not utilization of human waste is key in promoting health as well as improving the quality of the environment. However, many local communities here in the Philippines are used to disposing their feces in open fields or surface waters especially in poor and coastal areas without adequate sanitation facilities.
The practice however posed a health risk because the same surface waters, too often, are the communities' sources of food, and water for drinking, domestic and personal cleaning. (Navarro, 1994)
Of the population that have sanitation facilities, 90 percent use septic tanks for disposal of human waste, which experts view as unsustainable because of emerging water shortage and lack of treatment facilities. Less than 10 percent of the country is connected to a sewerage plant that treats effluents before they go out to the waterways. Untreated effluents contaminate groundwater, while most usually go straight to canals and rivers. (Manalo, 2006)
Contaminated groundwater is a common source of feco- oral infections as the human feces usually contains pathogenic organisms including fecal coliforms, Salmonella sp, Enteric viruses and helminth ova.
The World Health Organization indicates that soil-transmitted helminths more commonly called intestinal worms, are the most common infections worldwide, affecting more than 2000 million people.
The causal agent of soil-transmitted helminthiasis is any of the following worms: round worm (Ascaris lumbricoides), whipworm (Trichuris trichiura) and the hookworms (Necator americanus). Recent estimates suggest that A. lumbricoides infects 1.221 billion people, T. trichiura 795 million, and N. americanus 740 million. The greatest numbers of soil-transmitted helminth infections are seen in sub-Saharan Africa, the Americas, China and East Asia. Infection is commonly caused by ingestion of the eggs from contaminated soil (A. lumbricoides and T. trichiura) or by active penetration of the skin by larvae in the soil (hookworms).
Soil-transmitted helminths produce a wide range of symptoms including intestinal manifestations (diarrhoea, abdominal pain), general malaise and weakness that may affect working and learning capacities and impair physical growth. Hookworms cause chronic intestinal blood loss that results in anaemia. (WHO, 2007)
The continuing cycle between parasites and humans is often the result of poverty and cultural or behavioural practices such as exposing bare feet to soil or standing water, eating undercooked or raw meat and fish, defecating in open soil, and inappropriately using human excrement for fertilizer. (Talaro, 1993)
To ensure the safe use of human waste (biosolids) as fertilizer, the Environmental Protection Agency of the United States has set several guidelines in the utilization of biosolids. Their pathogen reduction requirement indicates that certain specified technologies be used to treat the biosolid such as thermally treating biosolids or treating it through high temperature-high pH processes.
Included in the list of other processes that further reduce pathogens is composting because of the high temperatures involved in the process. A modified version of the composting method is the vermicomposting which is similar to the traditional composting method except that earthworms, usually Eisenia foetida, are introduced into the composting bins and allowed to feed on the decaying composting materials.
Earthworms in composting are also cited for several advantages including increased porosity and drainage through their tunnelling, helping stabilize the soil pH, among others. Their cast was also found to be rich in several beneficial micro organisms like Azospirillum actinomycetes. Observation of the intestinal tract of earthworms showed they contained pseudomonas, coryform bacteria, nocordia, streptomyces and bacillus. (Kale, 2005)
Bruce R. Eastman et. al. (2001) showed that vermicomposting successfully reduced the fecal coliforms, Salmonella spp., enteric viruses and helminth ova in an experiment conducted in Florida, USA.
This study was conducted to verify the effectiveness of vermicomposting in reducing the helminth ova under the Philippine condition especially here in Misamis Oriental where helminthic infection is high. Also, results of this study would help appease local farmers who still are apprehensive over the use of processed human waste due to health concerns.
Materials and Methods
The dried human feces were collected from two urine-diverting dehydration (UDD) toilets located in different allotment gardens of the city. The first source was the UDD toilet located in city district Gusa, which was used by 6 urban poor families, who covered their feces with ash and stored it for 6 months prior to the experiment. The second source of feces came from the UDD toilet at the St. Ignatius Allotment Garden in Manresa Farm, which was used by 10 staff members of the Periurban Vegetable Project of Xavier University, who covered their feces with a mixture of lime and sawdust. It was stored for 8 months before it was used in this trial.
Three parts dried cow manure and one part freshly shredded sweet corn stalks were gathered. Both the cow manure and the human feces were positively tested for the presence of ova of hookworm (Necator americanus), whipworm (Trichuris trichiura) and roundworm (Ascaris lumbricoides) prior to the start of the experiment. The cow manure and shredded sweet corn stalks were mixed and left for initial decomposition for 14 days to be ready as food for the earthworms.
Sixteen wooden boxes were prepared to contain the substrate. They were lined with flour sacks to prevent the earthworms and the substrate to have contact with the soil below the boxes. One part of dried feces from either location (Gusa or Manresa) was then added to the initial substrate of cow manure and cornstalks. 8 boxes were filled with 5 kg of mixed substrate containing human feces from Gusa and further 8 boxes with 5 kg of mixed substrate containing human feces from Manresa Farm. Factor 2 of the trial was the presence of earthworms. 1.33 kg of earthworms (Eisenia fetida) was added to 4 boxes each for the locations Gusa and Manresa, representing 4 replications.
The boxes were then arranged in a randomized complete block design. Samples were taken at day 1, day 30, and day 60. The number of helminth ova was then determined for 2 g substrate of each box and subjected to an analysis of variance and mean comparison using the Duncan’s Multiple Range Test (DMRT).
Results and Discussion
Helminth ova / With vermicomposting / Without vermicompostingHookworm (Necator americanus)
Day 1 9.69 9.38
Day 30 4.06 13.5
Day 60 7.13 30.31
Whipworm (Trichuris trichuria)
Day 1 2.25 1.38
Day 30 0.81 1.19
Day 60 0.00 0.00
Roundworm (Ascaris lumbricoides)
Day 1 0.94 0.94
Day 30 0.38 1.81
Day 60 0.19 2.63
The initial average count (mean) of hookworm ova with vermicomposting was 9.69. It decreased to 4.06 after 30 days and increased to 7.13 after 60 days. The analysis of variance showed that the effect of vermicomposting is highly significant while did not significantly affect the results. Mean comparison using the Duncan’s Multiple Range Test (DMRT) indicated mean differences were significant.
Samples without vermicomposting initially had an average count of 9.38. After 30 days, the average number increased to 13.50 and by 60 days, it was as high as 30.31.
Table 1. Mean Count of Helminth Ova per 2 g substrate from Manresa and Gusa
Figure 1. Average Number of Hookworm ova in 2 gram Figure 2. Average Number of Whipworm ova (Trichuris
substrate from Manresa and Gusa. trichuria) in 2 g substrate from Manresa and Gusa
The initial count of whipworm with vermicomposting was 2.25. It decreased to 0.81 after 30 days. The bins without earthworms were at first, 1.38 but also decreased to 1.19 after 30 days. No more whipworm could be found in either treatment after 60 days.
Roundworms had the initial count of 0.94. The number lowered to 0.38 in day 30. It then decreased significantly to 0.19 after 60 days of vermicomposting while the bins without vermicomposting rapidly increased in count from 0.94 in day 1 to 1.81 in day 30 and 2.63 after day 60.
Analysis of variance indicates that vermicomposting as well as the location had highly significant effects to the reduction of roundworm ova in samples with vermicomposting between the initial count to the one in day 60. The DMRT shows that the mean differences were significant.
Figure 3. Average Number of Roundworm ova (Ascaris
lumbricoides) in 2 g substrate from Manresa and Gusa
Conclusion and Recommendation
Although whipworm ova were fully eliminated, hookworm and roundworm ova were still present. The hookworm lessened highly significantly in the composts seeded with the earthworms while roundworms decreased significantly after 60 days of study.
The result showed that vermicomposting can reduce the population of helminth ova but not fully eliminate them.
Further studies are recommended to verify the effect of longer-period use of vermicomposting to the reduction of helminth ova. Other fecal pathogens may also be considered for future analysis, as well as the fate of these constituents once the materials are applied to an agricultural site. It is also recommended that, the potential for other environmental impacts on water resources from runoff or infiltration, and the long term effects on the environment upon application be studied.
Acknowledgement
I would like to acknowledge Dr. Robert J. Holmer, the Director of PUVeP for guiding me in this research. Guiller F. Sumampong of Polymedic General Hospital for providing laboratory services. Stephen Lee, Lasse Trappe, Paul Bryan Manda, and Glenda Sol for their assistance and maintenance in the vermicomposting area.
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