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Compost from sewage sludge no slouch


January 4, 2010
By Dave Harrison


Topics

Jan. 4, 2010 – Sewage sludge can be successfully converted
into compost that can enhance growth and flowering of landscape plants,
according to recent research in Malaysia.



 

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Jan. 4, 2010 – Sewage sludge can be successfully converted
into compost that can enhance growth and flowering of landscape plants,
according to recent research in Malaysia.

Biosolid compost could be beneficial to plants. Studies are
being carried out to establish the effectiveness of biosolid compost derived
from sewage sludge as soil enhancers in promoting plant growth. Researchers
from University Technology MARA, Sarawak, Malaysia used compost, chicken manure
and topsoil to collect data to gauge the growth response in Canna (Canna
orientalis), locally known as “Bunga Tasbih,” an ornamental plant.

The findings indicate that biosolid compost derived from
sewage sludge has the potential to be a good soil enhancer as compared to other
soil enhancers commonly used in horticultural cultivation. Biosolid compost is
derived from treated sewage sludge, also known as biosolids. Biosolids are
known to be high in organic content that helps improve the quality of soil. Its
suitability is further enhanced due to its biologically aerobic process
producing high temperatures that is caused by microbial activity during the
composting processes that kill pathogenic microorganisms and helps reduce pile
volume in two to three weeks.

Other studies have shown that sewage sludge composting can
effectively decompose biodegradable organic matter of sewage sludge and destroy
pathogens enriched in sewage sludge into a stable end product, which can be
used as fertilizer or soil conditioner.

The researchers conducted a complete randomized block design
experiment, replicated three times, to investigate the growth response of Canna
orientalis to the compost. Six treatments were used: biosolid compost, dry aged
chicken manure and topsoil, each with or without potassium. Potassium was added
to gauge the effects on flowering and the number of shoots produced in each
treatment over a six-month period.

The mean number of shoots by the end of the experiment ranged
from 6.68 to 8.30 among the four soil treatments (compost with and without
potassium, dried chicken manure with and without potassium). Over the duration
of the experiment, compost fared as well or better than chicken manure with
respect to mean number of shoots.

During the initial stages, the plants treated with dried
chicken manure had shoots relatively longer when compared to the shoots on
plants treated with the compost. At the end of the experiment, the mean height
of the additional shoots, which totalled 14 in the compost treatment, was to be
significantly taller than the chicken manure treatment plants, which produced
only 11 shoots.

However, it was noted that the production of leaves throughout
the experiment was significantly higher on the plant treated with chicken manure
as compared to those treated with the compost. Flowering occurred after the
fourth month of planting. The flowering of plants treated with chicken manure
showed the highest percentage of early flowering, during which the compost
treatment had not yet shown any flowering. It was presumed that the early
flowering in the chicken manure treatment was triggered by stress that resulted
in the early flowering, as plant stress is known to trigger “bolting” or
unseasonably early flower production.

Despite being a late starter in flowering, the compost
treatment plants showed a higher percentage of flowering, recording a 74 per
cent rate at harvest as compared to 60 per cent for plants treated with chicken
manure with potassium.

This study demonstrated that sewage sludge can be successfully
converted into compost with beneficial qualities for landscape applications.
Compost from sewage sludge showed accelerated growth and higher percentage of
flowering. A point to note was that plants treated with sewage compost were
able to flower profusely without the addition of potassium, a significant
cost-saving consideration,

Sewage sludge compost has proven itself to be superior in
propagating significantly accelerated plant growth and higher percentage in
flowering, therefore qualifying as a potential plant growth enhancer for plant
nurseries.