impianto depurazione acque EcopakCL di Depur Padana Acque

Operating sequence of the CL process:

Collection Section: Once civil waste water has gone through suitable pre-treatments in adequate Septic Tanks and Grease Separators (not included in our supply), it falls by gravity into the collection tank which, based on the size of the plant, is comprised of one or more underground tanks, accordingly connected on the bottom. The waste water is relaunched from the collection section by submersible pumps MP1-MP2, continuously and with a constant flow rate distributed over the course of the entire day, to the following Oxidation Section for the actual biological purification treatment.

Biological Oxidation Section: the biological section, based on the size of the plant, is comprised of one or more underground tanks, accordingly connected on the bottom. The biological process is developed inside the oxidation tanks through the action of aerobic micro-organisms, known as “activated sludge”, which is inoculated into the plant and develops by using the pollution of organic origin contained in the waste water as its food source. The pollutants are accordingly metabolised and broken down. Therefore, based on the daily flow rate of water requiring treatment, the oxidation tanks are sized to ensure an adequate retention time so that all of the organic substances contained in the waste water are completely broken down. To ensure the survival of the activated sludge and the subsequent effectiveness of the purification treatment, the Oxidation Tanks are equipped with a suitable compressed air circuit, supplied by blowers PS1-PS2 and distributed on the bottom of the tanks through fine bubble diffusing plates which homogenise the water being treated with activated sludge. The Oxygen contained in the air is also transferred to the mass of sludge, creating the necessary conditions for the biological oxidation of the organic pollution contained in the waste water, through the activated sludge. A specific solution of nutrients is also dosed inside the biological Oxidation Section, prepared for this purpose in containment tank S1, and dosed in a timed fashion by peristaltic pump MP3. Considering that the Nitrogen and/or Phosphorus levels contained in the waste water may be low, this solution of nutrients is required to integrate the metabolic activity of the activated sludge so that the ratio between BOD, NITROGEN and PHOSPHORUS stays balanced in a proportion of 100, 5 and 1, achieving excellent performance from the biological section.

Denitrification Section (optional): normally, by nature, civil waste water has quite a balanced Organic Load in terms of their BOD, NITROGEN and PHOSPHORUS ratio. If the in-feed waste water to the plant has an excess of Nitrogenous Substances (Ammonia, Nitrites or Nitrates), it is possible to optionally install a Dentrification section in the Oxidation Section, comprised of a specific submerged mixer (MX2). The Dentrification phase is always carried out by the activated sludge, in this case however, it develops in anoxic conditions, i.e. in the absence of oxygen, and completely breaks the Complex Nitrogenous Substances down into simple gas Nitrogen, which is released into the atmosphere. At certain points during treatment blowers PS2-PS3 automatically switch off, and Mixer MX2 switches on at the same time, keeping the mass of sludge suitably homogenised, without, however, adding any Oxygen and therefore creating the anoxic environment required for Dentrification.

Decantation Section: the last treatment section is located downstream of the Biological Oxidation process, where the activated sludge is separated from the purified water. The sludge mixture feeding out from the Oxidation Tanks collects by gravity inside the Decantation Tank, built with a tapered floor, where the activated sludge, having a greater specific weight, settles by gravity, while the clarified water remains on top and flows out through the spillway installed in the decanter, directly to the drain, with characteristics that comply with the Regulations in force. The activated sludge that sediments on the floor of the decanter, as the very bacterial flora used to reduce the pollutants, is made to recirculate again and continuously in the Oxidation Vats through a specific hydro-pneumatic lifting system (Air-Lift), which uses part of the compressed air supplied by the oxidation blower.

IMPORTANT NOTE REGARDING THE INITIAL PRE-TREATMENT SECTION:
in order to guarantee correct plant operation, suitable Septic Tanks (not included in the supply) must be set up upstream of it, sized based on the type of hygienic services that it will be connected to it. It will also be necessary to install suitable Grease Separator tanks for waste water from kitchens/canteens. This is necessary to avoid large foreign objects from getting into the plant’s collection tank (toilet paper, feminine hygiene products, q-tips, etc.) and greasy-oily substances that could clog up the installed electro-mechanical equipment, jeopardising the operation of the purification process.

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