University of Manitoba
With the large number of
manure storage lagoons that are in place in Manitoba or
being planned, there is naturally an interest by
producers and government regulatory agencies in the use
of chemical and biological materials that are purported
to reduce or eliminate the odours associated with these
swine manure storage lagoons. It is extremely difficult
to rate the effectiveness of odour-reducing products
because there are no reliable machines that can measure
odours as effectively as the human nose. Of the numerous
odour-control products available it is likely that some,
under the appropriate environmental and management
conditions, may be effective for reducing odour intensity
and/or improving odour quality. However, some may prove
to be ineffective. Information regarding the efficacy of
commercial products for odour control is needed by
The purpose of these
studies was to develop a protocol to measure swine manure
odour from lagoons and to concurrently test some
commercial odour abatement products using this protocol.
Further, analytical chemical studies were done to measure
the level of known odour-causing constituents in the
manure and the effect of certain odour control products
on swine manure to lower the level of these constituents.
Study 1 - Field Study
A preliminary field
experiment was initiated in the late summer of 1997
to determine whether a system could be devised to measure
odorous gases emitted from a swine manure storage lagoon.
Various sites were visited and a facility at Domain Pork
with four identical lagoons attached by pipe to four
barns with similar numbers of animals was selected. This
facility allowed the testing of three products plus a
control nontreated lagoon. Two of the lagoons were
already under treatment with commercial products. The
third lagoon was treated with a product named CB-PA.
An odour panel was
simultaneously formed and trained to determine
differences inodour levels. Ten butanol standard
solutions (0 to 5000 ppm) were prepared and used by the
panel in evaluating odour levels.
Samples of odorous air
from the lagoons were collected by pumping 32 litres (2
litres/minute for 16 minutes) through a plastic cassette
originally designed to collect airborne dust. This
cassette contained approximately 30-mm diameter circle of
cotton cloth. The cloth was designed to absorb the
odours. Cotton swatches similar to this have been
used by other researchers for this purpose under
different conditions (Litcht and Miner, 1978). The
cassette was sealed after the 16-minute collection period
and transported to the University of Manitoba for odour
intensity evaluation. The odour panel compared and/or
ranked each cassette according to odour levels.
Results and Discussion
downwind of lagoons
Odour samples were
collected approximately 3-4 metres downwind of the
various lagoons. Three commercial products, CB-PA, ESP
Enzyme (ESP) and a Link 2000 product (L-2000) plus a
control lagoon were tested. The testing started three
weeks after the CB-PA lagoon (the last lagoon to be
treated) was treated. One treated lagoon was tested
against the control lagoon each week. The odour panel
chose the lagoon with the stronger odour in comparison
testing. The CB-PA treated lagoon was
determined by the panel to be lower in odour compared to
the untreated lagoon. The same lagoon (CB-PA) on a
subsequent week tested lower than the L-2000 treated
lagoon. The ESP treated lagoon tested stronger than the
control lagoon. Therefore, of the three products tested,
the CB-PA seemed to perform the best in odour abatement.
Odour of air pumped
through liquid samples removed from the lagoons.
The same three treated
lagoons were tested using a slightly different protocol.
The top liquid was sampled from three locations around
the lagoon, mixed and 200 ml were placed in a glass
Erlenmeyer flask. Eight litres of air (2 litres/minute
for 4 minutes) was pumped through the manure. The
exhausted air was passed through a plastic cassette
containing a swatch of cotton cloth. The cassettes were
compared by a panel as to which lagoon was stronger in
odour. The ESP lagoon was lower in odour compared to the
control. The CB-PA lagoon was also lower than
the control lagoon and lower than the L-2000 lagoon.
Intensity of lagoon
odours compared to a butanol numerical scale.
The odorous downwind
lagoon air (Table 1.) was ranked by the odour-testing
panel to standard butanol samples ranging in
concentration from 0 to 5000 ppm similar to the
procedures of Williams and Schiffman (1996). Due to the
protocol set up only a few samples were tested on the
numerical butanol scale. These samples were collected on
different days under various environmental conditions.
The measurements, however, seemed to be consistent from
day to day and between replicate sampling. The numerical
values for the CB-PA lagoon and the L-2000 lagoon
compared lower than the FSP treated lagoon which supports
the previous comparison testing. The value
of the CB-PA lagoon was 2.44 butanol units which were
approximately 50% of the average control lagoon values of
5.46. Again these studies seem to indicate the
effectiveness of the CB-PA material.
of odour from treated lagoons compared to a
butanol standard scale.
||Downwind air sample
||Air pumped through manure
Samples are duplicates, collected and tested
separately by panel.