Typical Drainage system Depuration Plant Regulations D. Lgs. 152/99 Domestic/industrial wastewater Separate Drainage system Storm drain Treatment

A CONVENTIONAL DEPURATION PLANT DESCRIPTION The aim of a depuration plant it to remove polluting substances contained in urban sewage, respecting the limits imposed by the current regulations to sink. Polluting substances removal trough sediments production obtained trough a chemical- phisical, biological or chemical transformtion Treatment to remove sediments from the water line Water flowing back Depurated water flowing back Treatment mud Mud line Draining Supernatant Wastewater treatment aims to extract the polluting component contained in the water flowing back, generating the “mud line”.

Water Flowing Back characteristics

Water Flowing Back characteristics Temperature Water Flowing Back characteristics Temperature varies from 18-20°C in summer to 14-15C° in winter

Water Flowing Back characteristics PH Water Flowing Back characteristics The pH is generally between 6,8 and 7,4

Water Flowing Back characteristics BOD Water Flowing Back characteristics In the urban wastewater The B.O.D. ( Biological Oxygen Demand) varies from 100 mg/l to 300mg/l BOD Sensor Set B.O.D

Water Flowing Back characteristics Elements Water Flowing Back characteristics The elements and the most relevant compounds are: – Nitrogen (NH3, NO2-, NO3-) – Phosphorous – Surface-active agents (cleansing detergent) – Oil and grease – Heavy Metals (iron , copper , zinc, mercury, chrome ecc.)

Activated sludge In general, activated sludge plants encompass a variety of mechanisms and processes that use dissolved oxygen to promote the growth of biological floc that substantially removes organic material The process traps particulate material and can, under ideal conditions, convert ammonia to nitrite and nitrate and ultimately to nitrogen gas.

Water Line Pre- treatments : - Pre – aereation; - Grit chamber ; Sand collecting; Primary treatment TRATTAMENTI PRIMARI: -primary sedimentation Secondary treatments TRATTAMENTI SECONDARI: - Biological treatment; Secondary sedimentation TRATTAMENTI TERZIARI: Filtration processes -disinfection; Clean up

Pre- treatments : WATER LINE - Pre – aereation; - Grit chamber ; sand collecting; Primary treatment primary treatment is done entirely with specific machinery and by itself for reducing fat, coarse solids, oils and amount of sand present in the wastewater -primary sedimentation Secondary treatment : breaks down the biological content of the wastewater that is a product of human trash, such as food waste, detergents and soaps, among others - Biological treatment; Secondary sedimentation Tertiary Treatment : the final step which increases the water quality standard before it is discharged into rivers, lakes or other place Filtration processes -disinfection; Clean up

MUD LINE THICKENING • STABILIZATION • DRAINING • DEHYDRATATION

SLUDGE TREATMENT •Thickening A volume reduction of approximately 30 – 80 % can be reached with sludge thickening (da 15g/l a 45-60 g/l) •Stabilizzazione (digestione) Stabilization Through biological treatments the organic substances are degradated It occurs through three phases: Hydrolysis, acidification, methanization • Sludge drying Aimed both to volume reduction (generally, dry peso secco 20%) that to increase the energetic content of mud submitted to an incineration process • Draining Dump, agricultural uses, incineration .

Water flowing back characteristics Bacterial cells or procariots.There are two kinds of aerobic and anaerobic bacteria; they can be divided In"cocci", "vibrions“and "bacilli".They reproduce through fission and in a suitable habitat they can double in about 20 minutes .

Processes in the primary, secondary and tertiary levels The purification of different types of water is conducted through various treatments and processes to the characteristics of them. In the case of wastewater treatment has three stages, primary, secondary and tertiary education, within each there are different procedures that undergoes this type of water to make it reusable. Called primary treatment is done entirely with specific machinery and by itself for reducing fat, coarse solids, oils and amount of sand present in the wastewater. Part of the process to which wastewater is subjected are the two types of removal, for solids and one that treats the sand. The removal of solids is a wastewater treatment based on filtering the liquid in chambers composed of bars to separate large objects such as cans, rags, towels and more. Another treatment that is made to the wastewater is the removal of sand, this implies the existence of a sand channel where more care should be paid to the speed of the liquid, so that the stones and sand to be carefully separated. These two processes are necessary to prevent other machines that participate in secondary and tertiary stages from being damaged by an object or stone. On the other side is the secondary treatment which breaks down the biological content of the wastewater and which are products of human trash, such as food waste, detergents and soaps, among others. At this stage you can classify important processes such as roughing filters, which are filters that will tackle the different variables and high organic loads, which are peculiar to industrial activities. The liquid resulting from this process is already in a position to submit to conventional treatment processes of water. Finally there is the tertiary stage, the final step which does increase the water quality standard and acceptable level, before it is discharged into rivers, lakes or other place if it finally to reach the receiver. In this final phase are also different filtration processes to be one of the first and foremost, through the filtration is done to remove a large percentage of waste that are suspended and the so-called activated carbon is left of this process is responsible for remove those toxins in wastewater.