Floating Covers

Floating covers are constructed for various reasons and various design elements are incorporated into the final design to best accomplish the client’s objectives. Objectives of a floating cover may include an intended reduction in evaporation, impede algae growth, enhance anaerobic digestion, prevent contamination, control rainwater, collect bio-gas, and control odors. Quality Lining Company, Inc. has fabricated and installed floating covers for applications ranging from closed tank applications to reduce oxygen uptake in demineralized water storage tanks at nuclear facilities to reservoir covers for municipal water plants. Properly designed reservoir floating cover systems prevent fluid loss due to evaporation, reduce chemical demand and improve water quality by preventing contamination from bird droppings, airborne particulates, dead animals pollen and other pollutants. Floating covers block off sunlight preventing algae bloom. They also reduce the production of trialomethane (THM) type compounds such as chloroform from forming that result from the combining of organic substances with chlorine due to reductions in chlorine demand. In anaerobic digester systems, floating covers are increasingly being used to capture organic gases and to reduce biological oxygen demand (BOD).

Floating covers may be installed in storage tanks with the cover either attached to the perimeter of the tank or may be designed to float on the surface.

A floating cover can be used to collect rainwater in a wastewater treatment reservoir to shed the clean water to a location sump that is built into the cover. The rainwater may then be pumped from the cover. A pond may be downsized as there is a reduction in the amount of water that must be treated.

Agricultural uses include manure storage tanks and reservoirs. There are multiple benefits with regard to this type of application including odor control, less rainwater to treat, and it can be designed to collect gases.

Floating covers may be constructed in a modular fashion to connect separate “cells” through a cable system. By covering most of the surface area odors are reduced and much of the rainfall can be collected. Another type of cover design utilizes flotation cells with a continues geomembrane system that extends into an anchor trench around the perimeter. This type of cover is a barrier to precipitation, prevents evaporation, eliminates odors, and may be used to collect pond gases for treatment. In methane producing ponds the cover may be utilized to collect the gas for use as a fuel.

Geomembrane covers are cost effective solutions to covering contaminated soil, agricultural byproducts, and are used in landfill applications to direct rainwater from the refuse pile to drain outside the contained area and eliminate the need for water treatment. The geomembrane selected is based on environmental conditions and what the end user requires regarding life expectancy of the product.