Use

Secondary treatment of residential black water with drain into the

ground according to Table 4, Legislative Decree 152/06, Annex 5.

The evapotranspiration plant is a complete system for drain into

the ground composed of Imhoff and a sandwich of sheets for the

evapotranspiration basin and wastewater recirculation station.

Operation

Evapotranspiration is a system of natural purification of domestic,

agricultural and industrial wastewater, which reproduces the

typical self-purification principle of aquatic environments and

wetlands.

Purification is carried out through the combined action between

the permeable substrate, plants, wastewater and microorganisms.

The mechanisms of removal of pollutants (organic matter,

nitrogen, phosphorus and pathogens) are similar to those of

trickling filters, and are physical, chemical and biological.

The wastewater coming from the loads are conveyed in the

primary Imhoff tank where, thanks to this system of sedimentation

in it there is the first removal of all those substances, which by

their specific weight tend to sediment in the water. Sedimented

substances will be conveyed to the digesting compartment

below where they will undergo digestion by anaerobic bacteria.

The waters coming out of the Imhoff through the inlet tank are

distributed to the basin. Within the basin, there are different types

of “water greedy” plants/shrubs, which due to their characteristics

and thanks to the dry climates where the system is installed

enable the complete evapotranspiration of the wastewater.

Downstream of the basin, there is an outlet tank complete with

overflow created in such a way that a hydraulic head is retained in

the basin that allows the constant presence of the wastewater at

the height of the roots of the planted areas present in the basin.

Downstream of the same, there is a revival in the head station

of the facility that will allow the wastewater not evaporated and

rainwater that has infiltrated to restart the cycle. The pumping

station is equipped with an overflow drain that in turn, in the case

of lack of electricity or power disconnection, would permit the

wastewater to be drained into the surface body or the ground.

Maintenance

For the correct management of Evapo and to achieve the required

purification results, please follow these guidelines:

•

Ensure the good health of vegetation planted;

•

Regularly inspect the purifying chain components to check that

there is no gross material received accidentally to clog the pipes;

•

Regularly clean the Evapo pipes;

•

Regularly empty the Imhoff tank. The removal of sludge must be

carried out by a specialized company;

•

Inspect and drain the wastewater booster station whenever

necessary;

•

As provided for by the Consolidated Act on Water (Legislative

Decree 152/06 as amended), and suggested by the normal

hygiene practice, periodically inspect and wash the inspection

well.

Specification Item

A complete system composed of 1 Imhoff tank and evapotranspiration

basin suitable for treating domestic wastewater and confluent

into surface water or soil designed considering an area of

evapotranspiration of 8 m

2

per Inhabitant Equivalent.

The system is composed of 1 Imhoff tank made of 100% recyclable

polyethylene, complete with wastewater inlet and outlet system and

maintenance lid; 1 evapotranspiration basin composed of sandwich

waterproof sheeting which is resistant to laying on various types of

ground, complete with electro-welded sheath for the insertion of

the wastewater inlet and outlet piping and guaranteeing the perfect

hydraulic Seal. The plant is also complete with perforated pipes for

distribution of the wastewater, non-woven fabric and two wells that

guarantee a constant hydraulic head inside the basin. The supply

also includes a pumping station complete with electric pump for re-

launching the wastewater to the plant.

RESIDENTIAL WASTEWATER

SECONDARY TREATMENT - DRAIN TO THE GROUND

PROJECT PARAMETERS

Basin area

m

2

/a.e.

8

1

2

3

1

2

3

Figure 10

Plant for domestic use, drain into the ground composed of the DG, IMHOFF, 1) EVAPO models

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