1. 1 III. Water Treatment Technologies Topic III. 7. Water Stability. General Arrangement of Water Treatment Plant Water Stability §Stability index (Index of Langeliet) - J pH - hydrogen index of pure water pH s - hydrogen index of water with CO 2 saturated at stability level

2. 2 Water Stability Stability index - J §When J > 0 l Water is vulnerable to release HCO 3, which leads to pipes incrustation with CaCo 3 l Water stability balance is recovered by introduction of strong acids into the water §When J < 0 l Water is aggressive (contains surplus of CO 2 ) in respect to the iron and concrete pipes l Water stability balance is recovered by introduction of strong bases into the water

3. 3 General Arrangement of Water Treatment Plant Auxiliary Facilities Included §Inlet Chamber §Bypass channels and pipes §Emergency WTP bypass §Water meters §WTP service reservoir §Technological wastewater treatment facilities §Laboratories for water quality test and control §Workshop §Despatch centre §Personal offices and reception hall §Service premises (canteen, coffee bar, resting room, bathing room, WC, etc.) §Local heating plant §Garage §Reagents stores §Filtering materials stores

4. 4 General Arrangement of Water Treatment Plant General Requirements I. Facilities arrangement §First stage facilities - separately, mostly at open air l Reaction chambers l Settling tanks l Upflow sludge blanket clarifiers l Some of the auxiliary facilities §Second stage facilities - in compact building l Filters l Reagents management facilities l Some auxiliary facilities

5. 5 General Arrangement of Water Treatment Plant General Requirements II. Facilities plane disposition §WTP respecting the consumer disposition §Minimization of technological communication length §WTP considering regional electricity and road networks §WTP considering local geological and hydro-geological conditions §Insuring possibility for WTP expansion in the future III. Facilities vertical disposition §Treated (clean) water reservoir - at command elevation §Filters - respecting command water level in the reservoir §Possibilities for gravity water flowing between treatment facilities §Adaptation to the terrain topography

6. 6 General Arrangement of Water Treatment Plant General Plane of Two-stages WTP 1 - administrative/laboratory building; 2 - high rate sand filters; 3 - settling tanks; 4 - service bridges; 5 - service pathway; 6 - reagents storage building; 7 - chlorine storage building; 8 - distribution chamber; 9 - storage spare terrain; 10 - micro-mesh screen (spare terrain); 11 - pumping station; 12 - flow meter; 13 - residential building; 14 - door-keeper kiosk