| | Odour problems associated with treating large volumes of liquid hog manure in open lagoons and liquid manure spreading during the summer months can be greatly reduced by simply storing the wastewater created during the summer, and making snow during the winter.
Water quality data from a pilot scale test indicate that Snowfluent is a method of decanting much improved wastewater from a nutrient rich residue. The decanted water is then available for irrigation or reuse in the barn. The nutrient value of the residue is quite high, so application at crop uptake rates is essential.
The levels of nutrient retained in the solid residue in this trial are likely lower than would be expected in a Snowfluent operation engineered for nutrient retention rather than sample collection. Operation methods and site-specific engineering which reduce plot slope, increase solid content of raw manure, and chemically facilitate the precipitation of nutrients from soluble to insoluble (pH adjustment) could be investigated as methods to increase the nutrient value and overall mass of residue.
When Snowfluent operators are required to work within the plume, they are exposed to bioaerosol levels above what are normally encountered in the hog barns. This, in combination with the lack of available information linking specific bioaerosols levels to human health, would suggest that a standard respirator mask be worn during snowmaking.
Snowfluent is economically comparable to direct injection and conventional spreading-incorporating techniques of manure management.
Snowfluent appears to be a preferential option for Alberta's hog producers due to its ability to convert the manure into spreadable residue and reusable water without the odour associated with conventional manure spreading. For hog producers with neighbours close-by, Snowfluent is a preferential alternative to conventional spreading based only solely on its ability to tackle the odour issue. Any level of nutrient value achieved by using the residue as a crop input is an additional benefit. The loss of ammonia dissolved in the liquid fraction of the manure represents a substantial loss of fertilizer value. For producers who rely on their manure a major source of natural fertilizer, the nutrient losses to the air are economically important.
Based on the conclusions of this pilot test study, a production-scale test of the Snowfluent process is warranted, provided that it incorporates the following:
- An investigation into methods to make Snowfluent's separation process more efficient. This will maximize the nutrient value retained in the solid residue and improve the water quality of the decanted water.
- Some quantification of the process's atmospheric inputs, and comparison of those inputs to conventional methods of treatment.
- A more quantitative analysis of odour conditions (ie. Alberta Research Council's olfactometer and Aromascan equipment) produced during the Snowfluent process.
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