A German company with extensive engineering know-how and experience in industrial wastewater treatment, production-integrated processes and water recycling, offers a new combination of patented processes for water therapy, i.e. lake restoration and catchment area decontamination.

Decontamination measures in catchment areas are usually targeted at reducing the supply of nutrients and lowering the nutrient impact to an extent that no augmented algae growth occurs. Every reduction of the phosphate impact leads to improved water quality. Measures must reduce the punctual nutrient discharge (via municipal waste water treatment plants) as well as diffuse nutrient discharge (agricultural wash-away, erosion etc.).

A further impact on water bodies is the discharge of street wastewater. This surface water is heavily polluted due to air pollution and steadily increasing traffic. Pollutants include not only the traffic-related heavy metals, such as lead, copper, zinc, dust and soot particles, mineral oil hydrocarbon and polycyclic aromatic hydrocarbons, but also biologically degradable materials, such as leaves. These pollutants are usually discharged with the street wastewater into open water bodies without prior treatment. In order to clean such discharge effectively this water therapy treatment was developed.

The German company's technology is tried and tested to restore eutrophic water bodies. The process makes use of the limnological characteristics of bedded water bodies.

The process treats not all of the water body: Only the water near the sediment that has a high nutrient load is restored. Phosphate is eliminated by a specifically tailored and optimised process combination uniting precipitation, flocculation and micro-flotation.
The water to be treated is conveyed into the treatment plant by an underwater pump. A precipitation agent is applied to transform the solved water ingredients, especially the phosphate, into a hardly soluble state.
Flocculation of the particles starts immediately after the dosing of the precipitation agent. The flakes thus evolving can be separated from the water by means of a micro-flotation process. This separation process is characterised by high collection efficiency and low maintenance requirements.
Once restored, the water is introduced into the water body again and places itself according to its temperature and density in a layer above the original hypolimnion. This guarantees that there is no thinning effect, i.e. no mixing of treated and polluted water.

Continuous plant operation is possible since no change of filters and no flush back of the filters is necessary. The bubble surface required for the separation is continually renewed during flotation. The plant is installed in containers of common standard sizes. These can be easily transported. The plant can be extended by adding modules and is easy to install or uninstall. The supply and drain pipelines must be provided as well as electricity.
Alternatively plants can be operated on swimming pontoons.

Innovative Aspects:
" Innovative combination of processes " Effective technology based on limnologic conditions. Not the whole water body but only the polluted layer is treated. " Low maintenance " Easy installation and transport " Low energy consumption " Low precipitation requirements

 

Patents/Rights: Patent(s) granted

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