Toilet Chemicals

The following paragraphs will hopefully shed some light on the basic processes of toilet chemicals and how best to dispose of waste solutions.

PART A: THE WASTE ENVIRONMENT

Many living bacteria are present in sewage and these natural organisms break down the waste materials over time. Bacteria get their energy for these processes through the composting of organic material. Oxygen, which is vital to the composting process, is supplied in one of two ways, aerobically or anaerobically.

Aerobic (with oxygen)
The greater the concentrations of oxygen in the waste solution the more efficient the bacterial digestion will be. The by-product of aerobic breakdown is odourless carbon dioxide.

Anaerobic (without oxygen)
When the oxygen is used up in a closed system such as a waste tank in a motorhome, the oxygen required for the composting process is derived from the sulphates found in waste material. Two by-products of the anaerobic process are Hydrogen Sulphide and Methane gas. Methane is a flammable and odourless gas. Hydrogen Sulphide is highly corrosive and smells putrid. Hydrogen Sulphide will mix with the water in the waste materials to form another extremely corrosive by-product, Sulphuric acid.

PART B: TREATMENTS

There are two 'schools of thought' on the treatment of sewage in Chemical Toilets.

Biocide agents (Chemical Sterilisation)
By using chemicals, these products essentially sterilise the sewage, break the solids down into a slurry for easy disposal and cover the smell with perfumes. Some of the chemicals used in the process include formaldehyde, chlorine and hydrogen peroxide.

Formaldehyde
Formaldehyde is toxic to humans, animals and plants and any products that contain it are discouraged from use.

Chlorine
Chlorine is a very strong biocide that stops all bacterial action. Chlorine dissipates rapidly within hours. Although Chlorine is cheap and available in many forms, it is detrimental to people, animals, and the environment.

Hydrogen Peroxide
Hydrogen Peroxide is also a strong biocide that stops all bacterial action. Hydrogen peroxide is an unstable compound that is easily made into water by sunlight and dissipates in hours. Hydrogen peroxide can be expensive and difficult to store and use.

Perfumes or "Masking Agents"
Perfumes or "Masking Agents" are more acceptable odours that simply compete with and cover the original odour of the waste solution. It has no real power to eliminate the source of the odours and does not contribute to the digestion of the sewage.

Bio-Stimulants (Accelerated Natural Processes)
The action of a bio-stimulant is to accelerate the natural processes working on the sewage and break it down rapidly.

Bacteria
Adding bacteria will accelerate the digestion of a sewage solution. However the amount of oxygen available to the bacteria will be a limiting factor in the effective rate of sewage digestion. Bacteria have a limited shelf life.

Enzymes
Enzyme products have a short shelf life and are basically a catalyst that allows the existing bacteria to utilise the available oxygen more effectively.

Oxygen
Oxygenating products increase the productivity of the existing bacteria and promote the growth of the bacterial population of the sewage. The effect is an increase in the efficiency and speed of the natural process of sewage digestion.

By optimising the waste solution for oxygenated digestion the noxious smells produced from the anaerobic digestion processes are significantly reduced.

PART C: DISPOSAL

Biocide agents do not mix well with septic and natural waste systems and should only be tipped into a sewerage system.

Bio-stimulant products should be safe to dispose of into any natural waste system, septic system, long drop type toilet, composting system or reticulated system.

As always, if in doubt, get in touch with the manufacturer or sales person of the product about safe disposal and storage.

PART D: MAKING A CHOICE

The sterilising agents definitely do their job effectively and offer a cheap solution to the issues surrounding mobile toilets. Care however must be taken with their storage and disposal.

Bio-stimulants act to accelerate natural processes and so are more prone to variations in required concentrations. When the flexibility and safety of disposal and storage is taken into consideration they certainly compete well with the sterilising agents for convenience and ease of use.

Whatever your choice, the CMCA strongly advocates the use of formaldehyde-free toilet chemicals and biodegradable products.

Source: Product brochures and manufacturer websites.

Aaron Bristow, ( Former Webmaster/Information Officer)