Chemicals for a Septic Field

A septic field, or septic drain field (also known as a leach field or leach drain), is primarily intended to clean sewage, impurities and contaminants that come out from a septic tank. A septic field is basically an arrangement of sewage pipes. The main advantage of using a septic field is that the pipes are laid beneath the surface, which helps prevent the wastewater from leaching into underground sources of drinking water. The application of chemicals is an integral part of a septic drainage system. There are two types of chemical additives that are used in septic drain fields: inorganic chemicals and organic solvents.

Inorganic Chemicals

• Inorganic chemicals, usually acids (sulfuric acid) or alkalis (caustic hydroxides) are generally employed in septic fields for opening clogged drains. The basic ingredients of inorganic chemicals include formaldehyde, paraformaldehyde and zinc sulfate. Chemicals such as hydrogen peroxide were once thought to rejuvenate clogged soil absorption systems. However, studies now reveal that they excite soil granules, destroying soil structure and affecting its permeability. Inorganic additives such as sulfuric acid and caustic hydroxides should not be used indiscriminately because their high corrosive properties could damage pipe systems. They can also destroy the beneficial microbial population in septic tanks and soil absorption systems, and seriously contaminate the groundwater.

Organic Solvents and Chemicals

• The wastewater may contain fine solid granules and soap-scums, which clog the soil absorption system. Organic chemicals, often chlorinated hydrocarbons, are particularly effective in unclogging a soil absorption system since they can easily break down oils and greases. The basic constituents of an organic solvent or product include methylene chloride, trichloroethylene, oils, paints, thinners, disinfectants, pesticides and poisons. Organic chemicals also pose a threat to beneficial microbes in the septic field, hamper the wastewater treatment process and pollute the groundwater. Therefore, homeowners should avoid excessive use of powdered detergents containing non-biodegradable fillers because these products can plug a septic system, rendering it ineffective.

Effects

• Chemicals in septic systems can facilitate bio-solid digestion and scum breakup. They can also enliven clogged soil absorption systems and enhance settling by coagulation. But you don't necessarily need to add excessive chemicals to a septic tank, and when sewage starts to collect on the ground surface or the household plumbing system clogs, it is an indication that the septic system has probably failed. Under these circumstances, consider repairing your septic field rather than using more chemicals.