4 December 2023

Wastewater treatment plants: complete guide to purification

In recent years, the drought in Italy has become an emergency of significant proportions. Climate crisis, rising temperatures, environmental pollution and poor maintenance of the network have contributed to a dramatic water shortage.

One of the possible solutions to effectively tackle the problem is the purification of waste water, and their recovery and reuse. The legislation in this regard exists, and it is also very specific in indicating what waste water is, and how to reuse it.

What are wastewater, and how to collect it?

There are several regulations to follow for the installation of a sewage treatment plant. First, the D.Lgs n.106 provides for the exclusive use of products in compliance with the CE marking. Therefore, D.M. 37/08 prescribes that the installation is operated by a qualified company, able to issue the Declaration of Conformity.

In addition, art. 74 of Legislative Decree D. 152 of 3/4/2006 divides the wastewater into three main categories:

• Domestic waste water. This is water from buildings and residential activities.
• Industrial waste water. This includes all commercial or industrial waste water.
• Urban waste water. It is a mixture of domestic, industrial waste water and rainwater piped into sewers.

The D. Lgs. 152 of 3/4/2006 also identifies several final addresses for sewage treatment:

• Sewerage.
• Surface water, such as canals, ditches, streams, rivers, artificial water basins, lakes and seas.
• Soil and surface layers of the subsoil, or the agricultural, urban or uncultivated land surface.
• Groundwater and subsoil, then groundwater and groundwater.

Depending on the different types of treatment, the waste water will then have a different discharge. Wastewater, in fact, and rainwater and run-off water, can contain potentially toxic and harmful pollutants, and must therefore be purified to prevent them from harming the environment and health. That’s what wastewater treatment plants are for.

Waste water treatment plants

Wastewater treatment plants are waste water collection and purification systems. These are conveyed to a specific sewage plant according to the type of wastewater, and the final discharge.

From a first collection basin, or an imhoff biological tank  where coarse solids and slurry from civil wastewater settle, the water is conveyed to the collector, often with the help of lifting stations. The waste water lifting stations or relaunch stations, are a series of pumps that raise the water to retention tanks arranged at higher altitudes than the starting point. There are different types of lifting stations, depending on the type of water to be treated: for every need, Di Camillo offers different lifting stations  in polyethylene, mono or double pump, with different capacities and also equipped with extension PRO X 600, and Grid GRI Y600., mono o doppia pompa, con diverse capacità e dotate anche di prolunga PRO X 600, e di Griglia GRI Y600.

The first treatment, in fact, is the screening, which removes the coarse material that may be present in suspension so that it does not clog pipes and pumps before desalination and de-oiling. These two processes are common to all water purification plants, both wastewater, but also first rain water and water from yards, parking lots and workshops.

IIn these tanks, the natural sedimentation of the sands takes place, and the rising of oils and fats on the surface. In the plants of first rain in accumulation and continuous Di Camillo, this first treatment system is already present, but for the run-off water of aprons, parking lots and workshops, there are also corrugated gravity deoleators (or separators), smooth or coalescence filter.

At this point, the water is conveyed into a primary sedimentation tank, where gravity separates the solids, while the sludge that accumulates on the bottom is pushed to subsequent treatments. The aim is to eliminate dissolved substances, especially if the final delivery of waste is on a watercourse, or in sub-irrigation. An active sludge tank, is used, a secondary treatment that further reduces the organic load through the metabolic action of bacteria and micro-organisms.

The bacteria present in the mud are then separated from the water in a sedimentation tank, and the outgoing water at this point can be defined as clean.

How to use purified wastewater?

Depending on the different treatment systems, water can have three intended uses:

• Urban. The purified water can be used for cleaning roads, bins, or to supply heating and cooling systems.
• Industrial. The purified waste water can also be used for fire protection systems, for industrial processing cycles, with the exception of the food, cosmetic and pharmaceutical sectors.
• Irrigated. Purified water can also be used for crops and irrigation of lawns, gardens, sports fields and green spaces.

For your purification needs, and your waste water treatment plants and their componentsi, contact Di Camillo: for over fifty years, Di Camillo Serbatoi has specialized in the design and construction of plants tailored to any need. Here you will find expertise, professionalism, and a wide range of solutions and components tailored to all your needs.