Alternative Deicer from Organic Waste Streams

This report describes a comprehensive laboratory and field evaluation intended to determine the performance of CDS (Condensed Distillers Soluble) in particular and with chloride salt co-products on ice control operations. The study shows when mixed with co-products, CDS is effective for ice control operations, able to melt ice faster and at lower temperatures than traditional ice control agents, with little or no adverse effects on infrastructure or the environment.
The following three basic objectives for the evaluation of CDS and co-products have been established:

1. To characterize the physio-chemical properties.
   
2. To determine performance in melting ice and resolve operational issues.
   
3. To determine effects on the environment. 

Significant research has been carried out recently on the development of deicers from agricultural by-products including corn, wheat, and rice. These developed materials are all proprietary products and little information is available in the technical literature, however, information about similar products is found in the patent literature. Table 1 in Appendix A lists the existing deicing agents from agricultural products reviewed in this study. Of these, Ice-B-Gone and IceBan are found to have particular qualities suitable for comparisons to CDS in the absence of test data.

PHYSIO-CHEMICAL PROPERTIES
CDS is the concentrated liquid residue from the processing of distillers grains having an involved chemical composition consisting primarily of complex soluble carbohydrates and proteins. CDS can be used alone or mixed with co-product as stockpile treatment pre-wetting agent and in anti-icing or deicing liquid programs.

CDS is typically sold as a 40% solids (w/w) solution off-the-shelf, processed to the desired solids content, and mixed with additives or co-products. DDGS (Dried Distillers Grain with Solubles) specimens were available, therefore, liquid residues were extracted by steeping DDGS in hot tap water to achieve 10 - 20 percent solids w/w solution (Figure 1) subsequently evaporated until the appearance of a tactile solution formed between the fingers. The solution is similar to molasses in color, has a pleasant odour comparable to that of cooked corn, but is less viscous, and appears to have non-newtonian properties beneficial as a melting agent. The solution dissolves readily in water and dries to a dark brown cake.

Although beyond the scope of this project, a thorough chemical composition of CDS from dry-grind by-products was conducted by the Laboratory of Renewable Resources Engineering [d1] and serves as a suitable comparison. Table 1 below is a summary of major CDS components from a typical brewery process.

Similarly, the physio-chemical properties of chlorinated salt co-products are well known and documented in other literature. Figure 1 in Appendix A shows the most common co-products used along with useful operating parameters. A brief summary of co-product controlling factors as they relate to CDS performance are outlined below.
 

CO-PRODUCTS
Standard co-product solutions were prepared by dissolving appropriate amounts of reagent grade salts at room temperature, cooled down to 3±2ºC for 24 hours, and supernatant collected to produce a solutions at working temperature. Three additional test solutions of 1:1 (by volume) with CDS were prepared for each co-product. Raw data and calculations for the make-up of each solution are included in Appendix A, Figure 2.

Table 2 below shows various combinations of CDS and co-product selected for study. In order to facilitate end users, CDS can be prepared at concentrations specific to the mix ratios for a particular process. CDS N50 for example, would designate a required mix ratio of 50:50 with sodium chloride, C20 would designate a 20:80 mix with calcium chloride, M30 for 30:70 with magnesium chloride and so on, however, only the concentration below were tested.
 

Table 2 - Test Solution combinations
I.D.	Combination
A	50% CDS
B	23% NaCl
C	22% MgCl2
D	30% CaCl2
E	50% A + 50% B
F	50% A + 50% C
G	50% A + 50% D
H	BlueFuzionTM

In solid form, salts are unable to melt ice or snow until a brine is formed, which lowers the freezing point of the water until the solution becomes so diluted that its freezing point approaches the ground temperature.

In addition to having lower eutectic points and working temperatures, the hygroscopic nature of calcium and magnesium chlorides allow them to begin working immediately upon contact with ice or snow. Moreover, calcium and magnesium chlorides produce exothermic reactions, releasing heat as they dissolve into a brine solution. One kilogram of calcium chloride releases 640 British Thermal Units (Btu) as it dissolves, raising the temperature of the water. Magnesium chloride has less heat-release capability, about 57 Btu per kilogram, because it is a hexahydrate salt (about 47% MgCl2/ 53% H2O). The remaining deicers such as sodium chloride, potassium chloride and urea produce endothermic reactions (1 kg NaCl = 86 Btu, Urea = 234 Btu, KCl = 375 Btu), lowering the temperature of the water as they form a brine.

Magnesium and calcium chlorides also have higher theoretical melting capacities per unit weight at temperatures much lower than sodium chloride. For reasons mentioned above, the chloride salts of magnesium and calcium exhibit eutectic compositions and freezing point depressions substantially lower than predicted via the freezing point depression constant for water (KF = 1.86).

HYDROGEN ION CONCENTRATION (pH)
Initially, pH values of straight solutions were erratic and gave somewhat unexpected results. For example, a 1:1 mix of A & D was expected to have pH somewhere between 3.5 and 10, however, initial readings of 2.5 were measured. To remedy the situation, samples were diluted 1:4 with water to prevent the conductivity from the relatively high chloride content from overwhelming the pH test probe. Raw data are included in Appendix A, Figure 3 and summarized below.

Table 3 – Solution pH
I.D.	Description	pH
A	50% CDS	3.7
B	23% NaCl	7.0
C	22% MgCl2	6.0
D	30% CaCl2	9.3
E	50% A + 50% B	3.8
F	50% A + 50% C	3.5
G	50% A + 50% D	3.8
H	BlueFuzionTM	6.3

As shown in Table 3 above, traditional deicers (B,C,D) are either neutral or alkaline, whereas A and blends with co-products (E,F,G) are acidic. Lower pH is generally associated with greater corrosion of metals, however, it should be noted that CDS was found to be less corrosive than pH neutral, pure water. [ASCE 13] It is hypothesized that in the presence of minute electrical currents that cause corrosion, the hydrocarbon and protein combination reportedly “forms a gel or film which acts as a cathodic protection agent against corrosion.” Therefore, factors associated with pH may be different than expected and the rational for restricting acidity/alkalinity on corrosion effects are no longer controlling.

SOLIDS & INSOLUBLES CONTENT
The total solids content and the amount of insoluble material can affect the performance and handling characteristics of the product. A high insoluble content may lead to settling out during transport and storage, plug nozzles, or cause other operational problems. The total solids content is directly proportional to the amount of solute and is indicative of the freezing point depressions associated with eutectic points.

A straightforward approach was used to measure the total solids in CDS specimens: A volume of solution was weighed and dried to determine % solids. Any attempts to determine insoluble content of CDS was met with great difficulty despite different methods (gravity filtering, vacuum methods). Due to the high viscosity, the 2.5 micron filter became immediately clogged. Nonetheless, after appropriate dilution and vacuum filtering, a sufficient specimen was collected to measure total insolubles content. Raw data and calculations for solids and insolubles are included in Appendix A, Figure 4.

Straight CDS (A) was determined to have a measure solids content of 49 percent of which almost all is soluble and insolubles content of 4 percent. When mixed 1:1 with 30 percent magnesium chloride solution for example, the resulting solution has a solids content of about 40 percent.

VISCOSITY
CDS is significantly less viscous than oil at lower temperatures. The fact that CDS is relatively viscous to water will have both positive and negative effects. End users may need to adjust their equipment to ensure that the product is applied correctly. On the other hand, a highly viscous liquid tends to resist flow and forms a more tenacious bond to the various surfaces to which it is applied (salt, abrasives, or ice/pavement), thereby providing better ice melting performance.

The absence of a viscometer precluded measurement of the effects of CDS specimens mixed with co-products. However, a literature review did provide estimates of viscosity for various solutions at working temperature and are listed in Table 4 below.
 

Table 4 - Viscosity of Solutions [d3]
I.D.	Description	Viscosity cps @ 0ºC
A	50% CDS	100 to 140[d3]
B	23% NaCl	9
C	22% MgCl2	-
D	30% CaCl2	10
E	50% A + 50% B	-
F	50% A + 50% C	-
G	50% A + 50% D	-

CDS has high solids content composed of complex hydrocarbon and protein chains that are likely to
impart non-newtonian properties to the liquid. It was observed that the viscosity of the syrup mixture increases as the moisture level of the mixture decreases and the lower moisture specimens have properties consistent with that of pressure sensitive adhesives.

If so, the dilatant nature of CDS equates to greater splash resistance and adhesion by increasing the liquid viscosity as shear forces increase. In addition, higher viscosity means more resistance to cool currents of air. CDS is readily soluble in water, hence, viscosity is easily controlled by dilution. Moreover, patent holders claim the pH of CDS may also be adjusted to reduce the viscosity of the syrup mixture to a desired level.
 

DENSITY
The density of any engineered product is an important consideration for transport or when sizing holding tanks and application equipment. Additionally, converting brine volume to weight of ice melted requires a determination of the specific volume of the deicer (the reciprocal of its density). The density of chilled CDS and co-products were measured in a straightforward fashion using 10ml volumetric pipettes and an analytical balance. Raw data and calculations for the density tests performed on CDS and co-products are included in Appendix A, Figure 5 and summarized in Table 5 below.

Table 5 - Density of Solutions
I.D.	Description	Density (g/cm3)
A	50% CDS	1.24
B	23% NaCl	1.22
C	22% MgCl2	1.25
D	30% CaCl2	1.29
E	50% A + 50% B	1.16
F	50% A + 50% C	1.17
G	50% A + 50% D	1.21
H	BlueFuzionTM	1.29 [d7]

Despite the high solids content, CDS has a density slightly higher than sodium chloride, but less than magnesium and calcium chloride co-products.

PHASE DIAGRAM
While beyond the scope of this report, a literature review did provide an estimation for the freezing point depression of CDS in relation to various co-products. CDS from corn mixed with magnesium chloride (Ice Ban Magic) were reported by NASA testing [ASCE 45] to have a lower minimum freezing point than sodium and magnesium chloride, but higher than for calcium chloride. The results of NASA’s freezing point determination are shown in Figure 2 below. The eutectic concentration for a 40 percent solids solution is higher than that for the common chloride based deicers (23.3 percent for sodium, 21.6 percent for magnesium, and 29.8 percent for calcium chlorides).


ICE MELT TEST
To determine the effectiveness of CDS as a deicing agent in general and its performance compared to chloride salts in particular, a series of tests were conducted in accordance with the "Handbook of Test Methods for Evaluating Chemical Deicers", SHRP-H/WP-90, Strategic Highway Research Program, National Science Counsel, Washington, D.C., (1992)" protocols and guidelines. More specifically, H-205.2 ice melting test and H-205.4 ice penetration test were performed in addition to rudimentary field tests in order to make reasonable estimates on various parameters likely to affect or enhance performance of CDS and co-products as deicing agents.

The first series of tests provided a measure of two fundamental characteristics; the amount of ice melted by each of the products (g product/g ice melted) and the rate of melting (g/min.). Strictly speaking, the test calls for a special apparatus fabricated from Plexiglass and testing within a cold room enclosure over a range of temperatures. To make ends meet, disposable Petri dishes (Figure 3) where recycled into an apparatus and the tests were performed in a make-shift enclosure (Appendix A - Figure 6) set at 8ºF (-13.3 ºC).

Each test consisted of applying 5ml volume of deicer containing a small amount of dye (red=NaCl, green=MgCl2, blue=CaCl2) to an 8mm thick layer of ice (about 40ml water), then decanting and measuring the volume of brine generated at selected time intervals. Raw data accumulated in the ice melting test for liquids is included in Appendix A, Figure 7 to 8, and results are tabulated in Table 6 below.
 

Table 6 - Melt Test Results
Mix	Description	Brine Volume (ml/g)	Unit Quantity of Melt (g/g)
A	50% CDS	1.3	0.5
B	23% NaCl	1.3	0.5
C	22% MgCl2	1.7	0.9
D	30% CaCl2	1.8	1.1
E	50% A + 50% B	1.6	0.8
F	50% A + 50% C	2.0	1.2
G	50% A + 50% D	2.4	1.6

A two-step treatment of raw data obtained in the ice melting tests was conducted. The first step consists of conversion of brine volumes to volumes per unit weight of deicer as charged (ml brine/g deicer). The second step consists of calculating the quantity of ice melted, expressed as grams of ice melted per gram of deicer liquid. Figure 4 below charts the brine volumes generated and the rate of ice melting for combinations of CDS and co-products.
 

Initial melt rates (within the first ten minutes) remain relatively the same for each combination of CDS and co-product, however, it is evident that solutions containing CDS are “slower acting” than solutions without, shortly after application. In the case of NaCl, it is ineffective after 30 minutes, whereas CaCl2 and MgCl2 are about twice the capacity becoming ineffective only after 50 minutes when used alone. The addition of CDS however, not only increases the melt rate of the brine moving forward but continues to work long after conventional salt brines fail. Perhaps more interesting is the combined effects of the CDS and co-products together. As shown in the chart at the top of Figure 4, CDS is as effective as NaCl brine alone, however, an apparent synergistic relationship exists between the two which allows the brine solution to work long after either would fail. The same is true for mixtures of magnesium or calcium chlorides and CDS.

Figure 5 below shows the unit quantity of ice melted per gram of deicer applied for combinations of CDS and co-products.
 

As shown in Figure 5, gram for gram, CaCl2 provides the best melt capacity of any other chloride salt alone, although the effects are greatly magnified in each case with the addition of CDS. Not only does the addition of CDS increase the amount of ice melted per gram of solution, it lowers the freezing point of the brine while potentially doubling the working time.

ICE PENETRATION TEST
The second series of tests measured the ability of the ice control agents to penetrate vertically through a given thickness of ice and the rate of penetration. This ability to cut through an ice layer to reach the pavement surface is an essential prerequisite for the deicer to perform successfully in weakening or destroying the bond at the ice/pavement interface. For liquids, this action is achieved once it pools on the surface, forming a cone as it descends, where it reaches the pavement and continues to spread.
 

Once again, recycled materials were utilized in an unorthodox fashion to accomplish test objectives. Each test consisted of placing a few drops (about 0.5ml) of solution containing dye on ice contained in a special test fixture as shown in Figure 6 and recording the depth of penetration at regular intervals of 10 minutes over a one-hour period. The deicers were placed on the ice in the test cell at preset temperatures of 8ºF (-13.3ºC).

When penetration occurred uniformly and evenly in the cavity, one depth was recorded. When penetration deviated and tendrils appeared, two depths were recorded. The first depth recorded was the uniform depth and the second the tendril depth. These two numbers were added together to obtain the effective penetration.   Raw data and calculations are included in Appendix A, Figure 9 to 10, and results are tabulated in Table 7 below.
 

Table 7 - Ice Penetration Results
Mix	Description	Ice Penetration (mm)
A	50% CDS	2.0
B	23% NaCl	0.5
C	22% MgCl2	3.5
D	30% CaCl2	4.5
E	50% A + 50% B	2.0
F	50% A + 50% C	4.0
G	50% A + 50% D	5.5

Figure 7 below shows the rate of ice penetration for combinations with CDS and co-products.

As shown in Figure 7, calcium chloride penetrates faster and farther than other chloride salts examined, although combinations of co-products with CDS consistently penetrated ice to a greater depth and at a faster rate than did the chloride salts alone. In the case of sodium chloride alone, there is negligible penetration within the first 10 minutes and it becomes ineffective after 30 minutes. Conversely, magnesium and calcium chlorides are seen to begin working immediately and remain effective almost twice as long as sodium chloride.
 

ECOTOXICOLOY
Behind all of the issues mentioned above, is the added concern that the compounds eventually wash off pavement onto the soil or into water treatment works. Materials that are toxic are therefore not acceptable deicing materials. The objective of this section is to determine if the proposed deicing product and co-products pose a significant risk to the environment and to provide a measure for determining whether those risks are sufficient to preclude use of the material or to prescribe limitations for its use.

The first series of tests involve the exposure of lettuce seed to co-products at specific concentrations under controlled conditions and measuring the mortality rates or evidence of chronic effects. Exposure levels range from those required to cause mortality to levels near estimated environmental concentrations. The second series of tests evaluates the effects of a stream containing CDS might have on bacteria such as that found in and an activated sludge process or specialized population of organisms. To this end, the Polytox™ test is used to measure respiration rates of standard aerobic bacterium in the presence of CDS solution and to evaluate the inhibition rates. Finally, in conjunction with other studies, a test was designed to characterise the effects on vermicompost biota, abiota and to describe effective mitigation measures towards improving system relationships and performance outputs.

SEED GERMINATION/ROOT ELONGATION
Lettuce seed was selected as a suitable indicator for addressing environmental impacts in accordance with the EPA’s 1996 Ecological Effects Test Guidelines. More specifically, the Seed Germination/ Root Elongation Toxicity Test [d4] was conducted on brines of sodium chloride and magnesium chloride. Brine specimens were prepared from materials obtained from the Ville-Marie stockpile although tests were not conducted on calcium chloride as it is not considered toxic to the environment [d5] in relative quantities expected for the design. By the same token, CDS is an agricultural product commonly sold as feed for livestock or fertilizer and has been shown to have benefits at the fruiting stage [d6], however, a separate series of tests was conducted with CDS on seed germination to observe effects.

Fresh lettuce seed were sourced from Johnny’s Selected Seeds (Appendix A, Figure 11). A control group was initially prepared on three types of substrates; sand, Whatman filter paper (Figure 8), and off the shelf paper towels. While tests performed in sand were successful, it was deemed unsuitable as a substrate due to additional preparation and handling requirements. The Whatman filter paper proved to be ineffective at retaining moisture and no better than 80% seed germination could be achieved. After the first 24 hours, water droplets were seen forming on the lid of Petri dishes containing filter paper with sections having lifted (bubbled) from the bottom surface and dried out. Consequently, some seeds were not in direct contact with water and could not germinate. Off-the-shelf paper towel, however, proved to be effective, and the remaining tests were conducted using the later substrate.

Fifteen seeds were placed on paper towel saturated with 6ml of bracketed concentrations of salt solutions, then incubated at 25 ± 1ºC in the dark for 120 hours (5 days). After 5 days, the number of seeds germinated was counted and the radical length was measured to the nearest mm as shown in Figure 9. Concentration response curves as well as LD50s for seed germination and root elongation are determined statistically and reported for each of the solutions tested.

Raw data and calculations are attached in Appendix A, Figures 12 to 13, and are tabulated in Table 8 below.

Concentration (mg/L)	B		H
	% Germinated	Mean Radicle Length (mm)	% Germinated	Mean Radicle Length (mm)
0	100	33	100	34
375	93	31	93	33
750	87	30	93	32
1500	87	28	87	27
3000	73	22	87	22
6000	73	18	80	20
9000	60	11	60	15
12000	47	7	53	10

Figure 10 below plots the percentage of seeds germinated for varying concentrations of sodium chloride and magnesium chloride. Additionally, best fit curves are plotted for each solution with corresponding equations and confidence. An exponential fit provided the best estimates and was selected after applying linear, log, and 2nd curve fits in Excel.
 

From the best fit curves it can be estimated that sodium chloride has an LD50 of approximately 11,000mg/L. By comparison, the LD50 for magnesium chloride is estimated to be around 15,000mg/L, demonstrating a 36% increase in tolerance over sodium chloride alone.

Figure 11 below is a plot of lettuce seed radical lengths at varying concentrations of sodium and magnesium brines. Again, it is seen that magnesium chloride produces longer average radical lengths than sodium chloride. In fact, it is observed that there is on the order of a 5-10% increase in radical length overall for magnesium salt in comparison to sodium chloride.
 

The results indicate that sodium chloride is toxic to lettuce seed at concentrations above 11,000 mg/L and there are adverse effects on radical length (i.e. 10% reduction) at concentrations as low as 1,500mg/L. By comparison, the addition of magnesium chloride increases tolerance of lettuce seed to concentrations over 15,000 mg/L, however, there is also a negative effect on radical length at concentrations similar to sodium chloride as observed by a higher incidence of tugor (dark discoloration of the radical) in seeds sown with magnesium chloride (Figure 9 above). Nonetheless, there is clear evidence that magnesium chloride is less toxic to lettuce seed than sodium chloride by the lower LD50 and overall root length increase. This conclusion is further justified given that less magnesium chloride is needed to maintain the same level of service as sodium chloride and therefore, less will enter the environment.
 

Because CDS is increasingly being patented as an anti-icing application for crops, it was also tested on lettuce seed to determine if there were benefits associated with the fertilizer effects as reported by patent holders. Seeds sown in 1:4 solution of CDS and distilled water did not produce significant germination (only 30%) or radical length (≤ 22mm) after 5 days as shown in Figure 12. Results from another series of tests on calcium chloride using filter paper were observed to promote bacterial growth, likely due to contamination during handling as is evident by the colony formations as shown in Figure 13.

Perhaps more interesting is the dark brown spot at the bottom of Figure 13. After 3 days of incubation, there were still no seeds germinated nor any visible signs of coliform units forming. Still, the test was considered a failure at this point, but allowed to progress with a fresh drop of straight CDS placed over one seed in order to examine if it would promote growth and study the effects at the end of the 5 days. Apparently, it is the healthiest seed having germinated and is free of bacterial growth in the vicinity of the spot.

Also noticeable is the lighter color at the center of the CDS drop. At this point, the radical penetrates the paper and is where the transport layer forms between paper and root. It is hypothesize that the lighter color indicates the root is taking up nutrients from the CDS and effectively removing it from the substrate. It is further hypothesized that CDS has antiseptic or herbicidal properties and although not well understood, might explain why it produces low germination rates in seeds, perhaps by chemically interfering with enzyme functions at the germination stage or by disrupting osmosis across the transport layer, yet serve as a plant nutrient and antiseptic agent in other respects. In one application [d8], CDS was used as an herbicide and a fertilizer in the use of crop production and showed it to also be part of an effective mitigation strategy in weed control.
 

TOXICITY TO BACTERIA
This study is designed to evaluate the effects of a stream containing CDS might have on bacteria such as that found in and an activated sludge process or a specialized population of organisms. Towards this goal, a rapid toxicity test was employed using PolyTox™ [d6] standard inoculums on samples of CDS at various concentrations. PolyTox™ is a standard preparation of surrogate microbial cultures and nutrients which allows for a simple and economical testing.

The process evaluates the inhibitory effects of different concentrations by measuring the respiration rates of standard aerobic bacterium. The respiration rate or DOUR (Dissolved Oxygen Uptake Rate) is the oxygen consumed by the aerobic bacterial cultures and is expressed in mg of oxygen per liter per minute. Deionised water was aerated for 1 hour prior to testing and continuously throughout the experiment (Figure 14). At the same time a saturated solution of distiller’s grains was prepared by soaking 200g of DDGS in 400ml of DI (Deionised) water with stirring and gentle heating for 1 hour to produce a 5 to 10 percent solids aliquot after settling. A baseline (DOURS) of DI water and PolyTox™ was conducted to account for any oxygen depletion caused by the PolyTox™ population standard.

Additionally, a background sample (DOURB) without PolyTox™ was run to account for oxygen depletion caused by either microbes present in the sample or by the stripping away of COD during aeration. Finally, test solutions (DOURT1 and DOURT2) of 33% & 66% by volume CDS were prepared and run to determine the actual DOUR (dissolved oxygen uptake rate) of the samples. Raw data and calculations are included in Appendix A, Figure 14 to 16 and tabulated in Table 9 below.
 

Dissolved Oxygen Uptake Rate (mg/L/min)
DOURS	0.1
DOURB	0
DOURT1	0.1
DOURT2	0.1
DOURC1	0.1
DOURC2	0.1
% Inhibition #1	0
% Inhibition #2	0

The recorded DOURS value of 0.1mg/L/min. was lower than expected; 0.20 to 0.50mg/L as recommended by the supplier’s application procedure. However, the instrument used (Sartorius Oxygen Meter, Model TE3102S, Figure 15) did not provide sufficient precision and therefore, actual results may be higher than reported. Nonetheless, calculations show that DDGS remains nontoxic at concentration levels much higher than anticipated for design.

Figure 16 is a plot of dissolved oxygen in the presence of microbial inoculums and nutrient over time showing a marked reduction in O2 levels immediately following the addition of DDGS which increases with concentration, while the rates at which oxygen is depleted remains the same independent of the concentrations used. Perhaps more interesting is the zero oxygen uptake rate of the DOURB run, further indicating an absence of native microbes or COD (Chemical Oxygen Demand) compounds in the specimen.
 

Despite the lack of instrument precision, exponential best fit plots were selected based on confidence after trying various methods in addition to linear, log, and polynomial fits in Excel.

While there is very little variance in the standard and test runs (R2 ≥ 0.99) predicted by the curves, the background parameter (DOURB) is not well defined (R2 = 0.54). It is observed that there was a marked increase in DOURB during the initial minutes and it is believed an observed air bubble trapped under the sensor was the cause. Assuming the DOURB is in fact 0.00 mg/L/min, the model predicts zero percent inhibition of CDS specimens. Based on these findings there would not appear to be significant inhibitory effect on biological systems or processes caused by CDS at pragmatic design levels, however, the lack of instrument precision and level of expertise preclude any concrete evidence to support this claim without further testing under more appropriate conditions.

FIELD TESTING
The objective of this section is to empirically determine field effects and resolve operational performance issues associated with the use of CDS and co-products. Where applicable, brines were prepared using specimens obtained from the Ville-Marie stockpiles.
 

Solution 1 (Figure 17 - Left) is a control solution of sodium chloride prepared by dissolving about 140g of rock sourced from the Ville-Marie stockpile into 400ml of water. The stockpile contained about a 9:1 mix of rock salt to gravel and although the gravel fraction was screened from the test specimen, suspended particles are observed to impact a light grey color and opacity to the brine.

Solution 2 (Figure 17 – Middle) is a mixture of 1:4 CDS (A) and calcium chloride solution (D). Immediately evident is the dark color imparted by the high solids content of CDS, which improves the albedo effect during daytime and heat retention at night.
 

Solution 3 (Figure 17 – Right) is a mixture of BlueFuzionTM prepared similarly to solution 1. The blue dye impacts color to the solution which also improves albedo, however, after standing for a few hours, the blue dye component is seen to settle out with the gravel dust (Figure 18), likely having sorbed to the suspended particles, whereas solution containing CDS do not settle out.

ANTI-ICING
A simple set up consisting of 61cm by 61cm concrete patio blocks were placed end-to-end on the ground at a slight incline (Figure 18) and brines were applied to each block before a snow event along with a control receiving no application. The blocks and solutions were set out 12 hours ahead of anticipated precipitation and subsequently coated with solution using spray bottles, then allowed to stand while precipitation fell. Figure 19 shows the surface layer of liquid formed shortly after application.
 

Straight sodium chloride (left) is observed to have formed the least amount of film. Moreover, some areas quickly dried out or the liquid simply drained away and more solution had to be applied to obtain an effective cover. Solutions of BlueFuzion™ (center) and CDS with calcium chloride (right) provided much better cover and although faint; a tinge of blue imparted by dyes in BlueFuzion™ and brown from the solids in CDS are discernable.

The blocks were inspected (Figure 20) and it was observed that while only a few mm of snow had fallen, blocks receiving anti-icing agents had no snow accumulation while the control, having not received any treatment, still had cover. Most evident is the column of liquid remaining on the block applied with BlueFuzion™ (second from left), however, it should be noted that CDS does form a cake when air dried (Appendix A, Figure 17) which is likely to provide greater friction on some surfaces. Moreover, CDS is observed to be less mobile than saturated salt solutions (Appendix A, Figure 18) as determined by a blot test and therefore, is less likely to funnel off inclined pavements.

Tip blockage was frequently encountered with the solution containing CDS and had to be flushed before continuing by shaking the spray bottle to dislodge particles at the bottom end of the screen. Moreover, foam was generated using this technique and it is hypothesized that the extra pumping effort and reduced pathway in the spray tip causes the lighter fractions of CDS to be squeezed out of solution and entrained with air. It should be noted that the spray tip of the bottle is somewhat different than a nozzle and would generally have a higher friction coefficient and more turbulent flow. Nonetheless, the frequent jamming further points out the importance of proper viscosity adjustments and the added level of care required during preparation by end users in order to avoid clogging of hoses, valves, connectors, pumps, and related equipment.

SUMMARY
Due to the hygroscopic/exothermic nature of magnesium and calcium chlorides, eutectic compositions and freezing point depressions are substantially better than other alts examined, and have been shown to produce better performance (gram for gram) than sodium chloride in particular, making them suitable co-products with CDS in anti-icing/de-icing programs. The addition of CDS is shown to substantially reduce the alkalinity of brines and improve anticorrosive properties. The addition of CDS imparts a concentrated dark brown color to aqueous preparations that does not bleed out and will likely be effective at increasing albedo, particularly as a stockpile pre-treatment. Similarly, the high solids content of CDS provides additional thermal protection to brine solutions by allowing them to retain more heat, hence, remaining effective longer. Moreover, pre-wetting with a higher solids content equates to more mass on the salt crystal and therefore deeper penetration into snow cover.

Solutions of CDS as high as 50% solids have a freezing point well below -13° C (as tested), are free flowing, and readily soluble in water. When CDS is combined with traditional chlorinated deicers, the synergistic effects are observed to substantially increase the performance of brine solutions by providing more melt capacity, penetration depth, extended working time and temperatures, as well as aiding in prevention of the “slickness” period that occasionally occurs with chloride brines and magnesium chloride in particular.

Because CDS can be applied in solution form by itself or mixed with co-products, tighter quality control, ease of use, and more even applications can be achieved. It can be sprayed using conventional spraying equipment upon most surfaces, applied onto accumulated ice at ambient temperatures or can be heated before its application to allow for even lower working temperatures. Due to its viscous nature, comparatively small amounts are required as it tends to remain in place and is not easily blown away by the wind or action of passing traffic. Furthermore, since less material will leave the roadway, residual deicing effects can be expected between applications. Viscosity can be controlled by dilution or as some proponents claim, adjusted by pH, however, care must be taken by end users to ensure adequate equipment and handling procedures are followed in order to maintain smooth operation while providing adequate service levels.

A second consideration relating to spray applications is the moisture content of CDS compositions that can be used in admixtures with salt, sand or gravel, cinders, sawdust, or other skid-reducing agents, subsequently applied to roadways or other surfaces. In these cases, the application rates to said substrate are likely controlled by the moisture content of the CDS solution and the hygroscopic nature of the substrate. It is hypothesized that higher CDS solids content and/or viscosity of the solution would provide more effective cover on solid stockpiles by limiting the moisture content and subsequent salt losses due to leaching, while allowing for adequate ratios of CDS to co-product salts, in order to remain effective as a pre-wetting agent.

Compositions of CDS have been shown to be neither overly corrosive nor environmentally unacceptable. This is a significant advantage over inorganic deicers which are shown to damage infrastructure and the surrounding environment. Furthermore, CDS is a biodegradable substitute for inorganic salts, in particular, sodium chloride, where it is observed to be as effective at melting and penetrating ice. By the same token, the addition of CDS to brines provides mitigating measures towards enhancing vegetation along roadways while showing no ill-effects on bacterial cultures found in waste water streams.

 

RERERENCES
[d1] C. H. Choi, D. S. Chung, P. A. Seib and K. M. Chung,”Effects of Brewers’ condensed solubles (bcs) on the production of ethanol from low-grade starch materials”, Journal of Applied Biochemistry and Biotechnology, Volume 50, Number 2, Page 175-186, Feb. 95

[d2] American Society of Civil Engineers (ASCE) , “Summary of Evaluation Findings for the Testing of Ice Ban “, Nov. 98

[d3]National Concrete Pavement Center, “Development of an Improved Agricultural-Based Deicing Product”, Page 45, Jan. 10

[d4] Ecological Effects Test Guidelines OPPTS 850.4200 Seed Germination, EPA, 1996, http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/Drafts/850-4200.pdf

[d5] A Study of Dust Suppressants in Ontario – Final Report, Ontario Ministry of Environment and Energy, 1993, http://ia331416.us.archive.org/1/items/studyofdustsuppr02torouoft/studyofdustsuppr02torouoft.pdf, p14

[d6] InterLab, PolyTox® Application Procedure, 2007, http://www.polyseed.com/applproc/Polytox%20Application%20Procedure.pdf

[d7] SEBCI Inc.,”MSDS Blue-Fuzion”, Jan. 2008

[d8] Blume, David (534 Lattouda Dr., Aptos, CA, US), US Patent 7183237, http://www.freepatentsonline.com/7183237.pdf