| | To evaluate the suitability of Snowfluent for treatment of food processing wastewaters, Alberta Agriculture Food and Rural Development conducted two pilot scale trials in the winter of 1997, and a production scale trial in the winter of 1998. Delta Engineering, Ottawa and Westcan Malting, Alix, were industry partners in the study. In a parallel study, a pilot scale trial to evaluate the suitability of Snowfluent for the treatment of liquid hog manure was also conducted in the winter of 1997. Detailed reports and papers discussing the results of these trials have been published (Wuite et al., 1997a and 1997b; Wuite and MacAlpine, 1999; MacAlpine et al., 1999; and Wuite et al., 1999)
Several questions regarding the use of Snowfluent for the treatment of food processing wastewater were addressed in this study. The extent to which the constituents of the wastewater are changed or removed in this process, and the potential for the meltwater to contaminate groundwater were not known. The health risk to operators or nearby population through exposure to pathogens in any bioaerosols that is created during the snowmaking process was not known. This study was undertaken to address these concerns. The specific goals of the study were to determine:
1. The degree of treatment achieved by applying the Snowfluent-process to a food processing wastewater.
2. How the treatment is achieved during snowmaking and the subsequent aging of the snowpack.
3. The effects of the Snowfluent-treated wastewater on the soil and shallow water table
4. The concentration and distribution of bioaerosols produced during the snowmaking process.
The pilot scale trials were conducted at the Alberta Research Council facilities in Vegreville, Alberta. Fresh untreated malting effluent, trucked from WestCan Malting Ltd. in Alix, Alberta, was processed using Snowfluent. In each trial approximately 100 m3 of effluent were processed. The manufactured snow was directed onto 15 by 15 metre plots on solenetzic soils. The plots were surrounded with berms into which runoff outfalls, with H-flumes to measure flow, were incorporated. One plot was lined with an impermeable liner and the other was left unlined. Nests of shallow watertable piezometers were installed above, in and below the unlined plot.
Samples of the manufactured snow and effluent were collected throughout the snowmaking process. Samples of snow were collected as the snowpacks aged and samples of runoff water were collected during the snowmelt. All the effluent, snow and meltwater samples were analyzed for the water quality parameters listed in Table 1. The flow of the runoff through the H-flumes was measured throughout the snowmelt event. Results from the early stage of runoff were unreliable due to the H-flume float freezing at night.
A field scale trial was undertaken in the winter of 1998, in a field next to the municipal lagoons of the Village of Alix, Alberta. Over 43 days, approximately 23,000 m3 of malting plant wastewater stored in the Village of Alix lagoons were processed with Snowfluent. The snow was made on a twenty-acre site from which there was no off-site drainage. The site consisted of natural pasture, bush, and an area planted in alfalfa. Its soils were predominantly pea-gravel to coarse sand, underlain (1.5 to 4.5 meters) with clay. Prior to snowmaking, 14 piezometer nests and three shallow groundwater monitoring wells were installed at the site to monitor groundwater levels and the movement of effluent constituents (Figure 1. 1998 Production scale study site at Alix, Alberta).
Table 1. Standard water quality parameters analyzed in food processing wastewater, manufactured snow, meltwater runoff, groundwater and soil.
| Parameter Group | Water Parameters | Soil Parameters |
| Microbiological | Fecal Coliform |  |
| Routine | pH | pH |
| Conductivity | Conductivity |
| Sodium (Na+) | Sodium (Na+) |
| Potassium (K+) | Sodium (Na+) |
| Calcium (Ca2+) | Potassium (K+) |
| Magnesium (Mg2+) | Calcium (Ca2+) |
| Bicarbonate (HCO3+) | Magnesium (Mg2+) |
| Chloride (Cl-) | Sulphate (SO42-) |
| Floride (F-) | |
| Carbonate (CO32+) | |
| Sulphate (SO42-) | |
| Total Hardness | |
| Total Dissolved Solids (TDS) | |
| Total Organic Carbon (TOC) | |
| Metals | Iron (Fe) | Iron (Fe) |
| Manganese (Mn) | Manganese (Mn) |
| | Copper (Cu) |
| | Zinc (Zn) |
| Nutrients | Total Phosphorus | Total Phosphorus |
| Dissolved Phosphorus | Soluble Phosphate |
| o-Phosphate (PO43-) | Total Nitrogen |
| Total Kjeldahl Nitrogen (TKN) | Ammonia (NH3) |
| Ammonia (NH3) | Nitrate + Nitrite (NO3-+NO2-) |
| Nitrate + Nitrite (NO3-+NO2-) | |
| Nitrite (NO2-) | |
| Other | Biochemical Oxygen Demand (BOD) | |
This site was ideal to measure the impacts of land application of wastewater on groundwater because of its permeable soils, shallow water table and the protection of an impermeable layer of clay. Contaminants had the maximum opportunity to leach and be measured in a shallow water table in one season. However, these site conditions also represented a "worst-case scenario" for land application. This site did not meet Alberta Environment’s draft Guidelines for Municipal Wastewater Irrigation (AE 1997). Its soils are too permeable and too low in water holding capacity. The water table also is too shallow to meet guidelines. When the wastewater was tested in the winter, it also failed to meet wastewater irrigation guidelines for Total Dissolved Solids (TDS) and Sodium Absorption Ratio (SAR). The wastewater quality in combination with the site’s soil and groundwater characteristics were a "worst-case test" for Snowfluent treatment of food processing wastewater in a land application mode. However, these conditions were optimal for detecting impacts. |
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