Cover Systems used in Anaerobic Lagoon Systems

Odor emissions are a major health concern that methane producers need to address as the noxious smells from agitation and land application of anima waste products occur during the process of storage and extraction. The use of cover systems while not perfect offers a win-win solution to reduce emissions and keep it from going to nearby residential areas.

Cover Systems

Cover systems may either be permeable which allow gases to escape or impermeable or those that do not allow the gas to dissipate. Methane producers use different kinds of covers for different purposes. The most popular cover system are permeable floating covers like geotextile or straw. More often than not, natural crusts develop on dairy manure storages and therefore maybe classified as a form of permeable cover.  Impermeable plastic covers are also used a lot in farms and may either be negatively pressurized or inflatable.  Most cover systems have a lifespan of about a decade. However, there are reports of cover failure from as early as one year of use.  The average for many covers is four years. Compared to plastic covers, geotextile covers have a lessened life expectancy  and some do not have any protection from ultraviolet radiation which in turn causes greater deterioration and therefore reduced life expectancy.

Warranties

This of course depends largely on which type of vendor however plastic cover vendor normally offers warranties of up to ten years but for workmanship it does not usually extend to more than two.  For geotextile vendors, warranty on the material may be up to three years but workmanship is usually limited to a year.  According to floating tank cover experts, if the cover is likely to fail as a result of workmanship, it usually happens within the 1st year of use.

Impermeable Covers

They feature tightly sealed storage edges. It is important to note that provisions for the collection and removal of rainwater should be considered especially in areas where there is low evaporation but high precipitation.  The runoff that collected from the cover could be drained via a series of perforated collection pipes established on the surface of the cover,  these are in turn connected to a pumping system that is manually activated. Due to their impermeable nature, they will require some form of exhaust ventilation in order to prevent pressure from building up inside as a result of manure gas production. Facilities to collect and remove methane may be done through the installation of perforated gas collection pipes or exhaust fans during installation.