River and Lake Water Treatment

DAF Dissolved Air Flotation Machine for High Turbidity River and Lake Water Treatment.
Now many rivers and lakes are significantly polluted all around the world. A primary reason for this is that all three major sources of pollution (industry, agriculture and domestic) are concentrated along the rivers.

Industries and cities have historically been located along rivers because the rivers provide transportation and have traditionally been a convenient place to discharge waste. Agricultural activities have tended to be concentrated near rivers, because river floodplains are exceptionally fertile due to the many nutrients that are deposited in the soil when the river overflows.

Too many of nutrients flow to rivers and lakes and result into Eutrophicationor. Eutrophicationor, is when a body of water becomes overly enriched with minerals and nutrients which induce excessive growth of algae. This process may result in oxygen depletion of the water body.

One example is an "algal bloom" or great increase of phytoplankton in a sandy body as a response to decreased levels of nutrients. Eutrophication is often induced by the discharge of nitrate or phosphate-containing detergents, fertilizers, or sewage into an aquatic system.

Because of the excessive growth of algae on water surface, sunlight and wind are obscured, river reoxygenation is affected. Suspended solids in rivers or lakes will settle out at a various points or be carried longer distances, depending on their size and the rate of the flow.

The higher the amount of suspended solids is, the cloudier or more turbid is the water. Suspended matter can affect the amount of light entering water and therefore restrict the amount of photosynthesis that can occur. Small particles settling out in large amount on the bottom of a water body can prevent some organisms from living there as well as preventing green plants from photosynthesising.

And when algae die, they decompose and the nutrients contained in that organic matter are converted into inorganic form by microorganisms. This decomposition process consumes oxygen, which reduces the concentration of dissolved oxygen. The depleted oxygen levels in turn may lead to fish kills and a range of other effects reducing biodiversity.

River and lake water are fed into dissolved air flotation by pump. And dose flocculant and coagulant into and thoroughly mix with wastewater for flocculation reaction to coagulate the oil & grease, colloidal particles and micro suspended solids to conglomerate the particles into bigger clusters.

Dissolved air flotation machine will release millions of tiny bubbles into water, these bubbles attach to, and form within, the solids or chemical flocculants entering the vessel, causing them to float to water surface where they are retained and forms scum layer, which is then subsequently removed by DAF skimmer.

The micro bubble releasing process is also an oxidation process, which transfer oxygen from air to water. Dissolved air flotation removes the most part of suspended solids (TSS), also will remove part of BOD and COD.