Eugene Appiah-Effah (Ghana)

KNUST│Ghana

Destruction of Helminth eggs by composting drums (Ghana)

In Ghana, faecal sludge treatment is only available in four big cities. This study therefore sought to investigate the performance of a rotary drum composter in the destruction of helminths (Ascaris and Trichuris eggs). A rotary drum composter with a volume of 75 L was used for the composting at the laboratory scale. The composter was fabricated with a plastic and galvanized metal sheet of 5 mm thickness and was batch operated. The main units of the composter are the drum (metal and plastic) and a mixer (rotating paddle/baffle). Five complete rotations of the drum were manually carried out on the first day and subsequently every three days for the first three weeks and afterwards every 10 days until the end of the composting process. Composting with the rotary drums revealed some interesting results, such as:

• The study found that all the compost feedstock (faecal sludge and shredded corn cobs) samples analyzed were infected with Ascaris and Trichuris eggs, with Ascaris being more prevalent;
• The temperatures generated within the rotary drums (54-62 ^°C) were sufficient to enable a high removal rate of Ascaris and Trichuris at the end of the composting process;
• The die-off of Ascaris and Trichuris at the end of the compost process was statistically significant (p<0.0001) when compared with their initial concentrations;
• It was seen that the viability of the counted Ascaris and Trichuris eggs decreased during the course of the composting process;
• Composting of raw faecal sludge and shredded corn cobs using a rotary drum is an effective means of reducing the Ascaris and Trichuris population in faecal sludge intended for agricultural use as an organic fertilizer.

 
The rotary drum composter is an efficient and promising technology to treat faecal sludge at the household level in peri-urban and rural areas. This technology will be used to turn the compost in the vaults of the latrine which previously involved manual turning with a shovel. Overall the rotary drum technology will reduce the cost of hauling faecal sludge over long distances to treatment sites and also significantly reduce human contact with faeces, thus improving public health.