Expected positive effects of the public drainage and treatment system
The primary purpose of this project is the protection of drinking water sources against pollution accompanied by the environmental protection at its broadest, including the protection of the sea. Currently valid are two completely different requirements regarding wastewater disposal: what it should be and what it trully is. The Decision on Sanitary Protection Zones in the Region of Istria regulates that the residential facilities in Zones III and IV of water source protection must have a septic tank or a standard-type biological device, while the source protection Zone II as well as Zones II and III of the accumulation protection must be equipped with the watertight collecting pit with a discharge control performed by certified institutions.
In the reality, septic tanks are mostly not watertight, which leads to pouring or draining of untreated water into the soil, there is no control over regular septic tank cleanouts nor over taking its content to adequate processing, nor enough reception facilities in Istria sufficiently equipped for septic tank content. Such a condition may result in the consequences hazardous to water supply safety in light of the following:
- a more demanding drinking water treatment process,
- the need to use more chemical substances in the treatment process,
- increased unsafety of the water supply system until the final threat to drinking water health safety.
Adverse environmental consequences are also significant in light of a growing microorganism concentration (of which many might be pathogenic) in surface and subterranean water. The concentration of nitrogen and phosphorus also rises in the accumulation and the sea-shore, which causes algae and other unwanted organism to flourish and finally leads to surface or sea water quality degradation. The erection of watertight collectors for wastewater drainage as well as of efficient equipment used in a third level water treatment will prevent the following:
- the pollution of surface and subterranean water flows by pathogenic microorganisms,
- the pollution of the accumulation and the sea-shore by nitrogen and phosphorus as well as their long-term degradation and deterioration.
- environmental aesthetics deterioration.
The possibility of reusing purified water in processing or for watering will emerge, which is especially important for Istria in view of its limited water resources during summer. The objectives and challenges of IVS – Istarski vodozaštitni sustav (Istrian water protection system) are as follows: the construction and management of the water protection system of Istria, the construction of drainage system and of wastewater treatment facilities for small settlements under highest standards, and system maintenance as designed while providing its customers with the high quality of service.