西安建筑科技大学：《水资源利用与保护》参考资料_Wastewater as a resource_Water reuse and recycling

Water reuse and recycling a case in Xran

Water reuse and recycling – a case in Xi ’an

Schematic of water reuse in Beishigiao region of Xian Effluent Xi an Electrical Power 100*103m3/d Plant( cooling system and boiler water) XI an Coke and Gasification plant Influent I Secondary Tertiary (cooling system) 150*103mad treatment treatment Production plant ( cooling system) Beishiqiao wwtp Others(small companies municipal and so on)

Schematic of Water Reuse in Beishiqiao region of Xi ’an Secondary treatment Tertiary treatment Xi’an Electrical Power Plant(cooling system and boiler water) Xi’an Coke and Gasification Plant (cooling system) Xi’an Chemical Production Plant (cooling system) Others(small companies, municipal and so on) Beishiqiao WWTP Influent 150*103 m3/d Effluent 100*103 m3/d 15*103 m3/d 10*103 m3/d 1 0* 1 03 m3/d 15*103 m3/d

Secondary Treatment Process in Beishiqiao WwTP Coarse Pump Fine Alternative Secondary selector Disinfectio greenI removal oxidation ditch clarifier Effluent Influent judge return Solid disposal Sludge thickening Disposal

Secondary Treatment Process in Beishiqiao WWTP Coarse screening Alternative oxidation ditch selector Grit removal Secondary clarifier Disinfection Sludge thickening Fine screening Sludge dewatering Disposal Influent Sludge return Pump Effluent Solid disposal

Water Quality from Secondary Treatment Item Influent Effluent pH 7.72 7.78 BOD~ (mg/L) 194.28 11.14 CODcr(mg/L) 315.66 20.32 ss(mg/)42414 1045 TP(mg/L) 3.13 1.15 NHa N(mg/L) 17.60 1.11

Water Quality from Secondary Treatment Item Influent Effluent pH 7.72 7.78 BOD 5(mg/L) 194.28 11.14 CODcr (mg/L) 315.66 20.32 SS (mg/L) 424.14 10.45 TP (mg/L) 3.13 1.15 NH 3-N (mg/L) 17.60 1.11

Tertiary treatment process in Beishiqiao WWTP Coagulate Disinfection agent Filtration Disinfection Effluent from Coagulation+Sedimentation. Secondary treatment Coagulator PAC PAM Disinfection agent: CI

Tertiary treatment process in Beishiqiao WWTP Coagulation Sedimentation Filtration Disinfection Effluent from And equalization Secondary treatment Pump Coagulator User Pump Disinfection agent Disinfection agent: CI2 Coagulator: PAC + PAM

Main process parameters (Tertiary Treatment) Capacity: 50*103 m3/d HRT in coagulation 30 min o Coagulator concentration PAC: 30 mg/L; PAM: 1.0 mg/L O hRT in sedimentation : 2.oh e Filtration velocity: 8 m/h

Main Process parameters (Tertiary Treatment) Capacity: 50*10 3 m 3/d; HRT in coagulation: 30 min Coagulator concentration: PAC: 30 mg/L; PAM: 1.0 mg/L HRT in sedimentation: 2.0h; Filtration velocity: 8 m/h

Pilot Plant Experiment Results (Tertiary Treatment) Item Influent Effluent pH 7.7 7.2 BOD,(mg/L)15.66 3.38 CODcr(mg/L) 28. 37 8.24 ss(mg)2124 0.78 TP(mg/L) 0.51 0.35 NHa N(mg/L)0.65 0.39

Pilot Plant Experiment Results (Tertiary Treatment) Item Influent Effluent pH 7.7 7.2 BOD 5(mg/L) 15.66 3.38 CODcr (mg/L) 28.37 8.24 SS (mg/L) 21.24 0.78 TP (mg/L) 0.51 0.35 NH 3-N (mg/L) 0.65 0.39

Schematic of water reuse in Xan Electrical power plant 0000 m/d- Cooling system Water from Beishiqiao L5000 mld- Pretreatment H Desalt system > Boiler- WWTP supply

Schematic of Water Reuse in Xi ’an Electrical Power Plant Cooling system Pretreatment Desalt system Boiler Heat supply 5000 m3/d 10000 m3/d Water from Beishiqiao WWTP

Pretreatment Process for Boiler Water Lime Sand filtration GAC adsorption Desalt system Water from Precipitation Beishiqiao WWTP Process specification Lime precipitation to remove Ca2+ and Mg2+ from water Sand filtration to remove ss from water GAC adsorption: to remove soluble COd from water

Pretreatment Process for Boiler Water Lime Precipitation Sand filtration GAC adsorption Desalt system Process specification • Lime precipitation: to remove Ca2+ and Mg2+ from water; • Sand filtration: to remove SS from water; • GAC adsorption: to remove soluble COD from water Water from Beishiqiao WWTP

Main process parameters ● Capacity:5000m3/d s HRT in lime precipitation: 2.Oh, in which Mixed and reaction: 0.5h: sedimentation :1.5h Lime concentration: 100 mg PAC concentration: 40 mg/L g Filtration velocity in Sand Filter: 10 m/h e Filtration velocity in GAC Adsorption 10/h

Main Process Parameters Capacity: 5000 m3/d HRT in lime precipitation: 2.0h, in which Mixed and reaction: 0.5h; sedimentation: 1.5h Lime concentration: 100 mg/L PAC concentration: 40 mg/L Filtration velocity in Sand Filter: 10 m/h Filtration velocity in GAC Adsorption: 10/h