Others would do the same, using hot water. Indeed, fat starts to dissolve at 35 ° C ( 95 ° F ) and see this may help a little. Few count the cost of heating up the water. Few count the electricity consumed by high pressure cleaners producing more than 100 bars. But , especially in industrialised countries, labour is the highest cost, counting for some 85 % of the cleaning cost.

But without good detergents or chemical energy, organic matter or "biofilm" will persist on the walls, harbouring microbes. When the pigs scrub themselves against a wall with biofilm, they will open it up and release the bugs.

Table 1: Characteristics Of Detergents
Wettening	decrease surface tension
Dispersing	split up dirt particles
Emulsifying	float oil and fat
Suspending	float dirt particles
Carrying	of dirt to the sewage
Sequestring	dissolve salts (in case of hard water)

The need of detergents

Four factors will affect the cleaning job :

1. physical energy ( scrubbing or "elbow grease" or using a high pressure cleaner)
2. temperature (as from 35 ° C or 95 ° F, fat starts to dissolve)
3. chemical energy in function of the pH (alkaline detergents will dissolve organic waste) and concentration of active ingredients like surfactants, sequestring agents, etc.
4. contact time (needed for the chemical to do it's job).

As 1. is always used, and 2. often, let's now zoom in on number 3 : what is it that the chemical is doing and how can we justify its cost ?

The characteristics of a detergent are explained in table 1 :

How do they do this ?

The functions described above are mainly achieved by the "surfactants" in the detergent. Surfactants or "tensio-actives" decrease the surface tension of the dirt. The lower this surface tension, the easier it is to remove the dirt.

The molecule of a surfactant (also called "wetting agent") is composed by two parts : a soluble head (hydrophilic) and a non soluble tail (hydrophobic).

The tails will form a network of "threads", called "micelles" to contain the fatty particles from inside and will finally encapsulate them by attaching themselves to it.

The "binded" dirt will act as an emulsion when agitated ( at the rinsing).

Figure 2: surfactants binding dirt

We need chemicals because a good cleaning job should already eliminate more than 85 % of the micro-organisms (present in the biofilms) , and will allow the disinfectant to work much better to kill that last bug!

Using a detergent, after a rinse with water only, will eliminate another 80 % more bugs, as shown in a study of North Carolina State University in broiler houses :

The detergent will break open the "biofilm" in which many bugs hide. If we don't do this, we disinfect the outer layer of the biofilm (leaving bugs alive inside it) and later, the pigs will scrub themselves and open up the biofilm and release the bugs.

Now, let's zoom in on number 4 : contact time. This is the time needed for the detergent to do it's job. However, if a foam detergent has ran of the surface by gravity or dried up, any extra contact time is useless. If the foam has dried up, we will need even more energy, more water and more time to rinse it off ! Typically, the chemistry of detergents need 15 to 30 minutes to break down and remove the soiling in animal farming. On vertical walls, on ceiling and on tubes, a classical foam detergent doesn't stay on that long because it can't resist the gravity.

The benefits of rheology

"Gel " is the latest generation of detergents : it does not dry on the wall and it resists the gravity , hence assuring a long lasting, efficient cleaning action, allowing to save on :

1. electricity (no need to use warm water)
2. cleaning time (labour) : no scrubbing needed, faster covering of the surfaces than trying to remove it with water only
3. water consumption for applying and waste water for rinsing off (gel should not re-foam when rinsing because of the special shear thinning reology).

Rheology is "the science of the deformation and flow of matter". BIOGEL ™ is indeed more liquid in concentrate than in dilution. Applied with a foam lance and a pressure lance ( using 40 bars only or 580 psi), it is sufficiently viscous (almost like shaving cream) to resist the gravity and clings on for a very long time, exceeding the necessary 15 - 30 minutes to do the cleaning job. Thus, the cleaning job can be done properly.

The Sinner circle explains how increasing contact time allows for saving on water, labour and energy as shown below:

Moreover, BIOGEL™ has been developed to use on typical "corrosion sensitive" surface materials found in animal production, such as galvanised, brass, cupper, etc. and hence it's not corrosive at in use dilutions on those surfaces.

So, it allows to save on water, labour, energy and replacement of equipment compared to any other cleaning chemical.

June 2006