Chemicals glue
Antiseptic by chloramines
Exit to the general drainage network
Figure 4.6. Technological diagrams wastewater treatment Wastewater cooled Domestic
wastewater
SCR + Anaerobic SCR + Conditioning
Aeration tank
React
Settles stand Mud tank
Absorption filter
Sterilization tank
Presentation technological line
Preliminary treatment of domestic wastewater
After domestic wastewater along escape through trash screens flows into the anaerobic tank then here occurs the decomposition process of organic matter in the absence of oxygen and light. Step processing enabling anaerobic microbes decompose organic compounds pollutants in wastewater. This process occurs in 2-3 days.
After exiting the anaerobic tank wastewater flows to the aeration tank. The principle is the use of microorganisms to oxidize ammonia, organic compounds and inorganic capable of biological transformation in the environment of air from outside.
Simultaneously the microorganisms use the organic part and the energy extraction from the oxidation to the synthesis of their biomass. Biological agent of treatment process aerobic is microorganism aerobic respiration: Psendomonas Putida, Psendomonas Stuteri, Aerobacter Aerogenes, Nitrososmonas, Vinogratski, Bacillus Subtilis (hydrolysis), Flavo Bacterium, Alealigenes (wealthy S, Fe). Method of air supply is forced method. Wastewater is usually saved at this stage about 24-48 h. After exiting the aeration tank, wastewater has been cleaned of organic compounds in the form of soluble organic residues in water.
Water flows from the aeration tank to the reaction tank.
Preliminary treatment cooling water
Given the characteristics of the cooling water is contains many inorganic residues should slightly soluble in water, and cooling water often have temperature higher ambient temperature.
Wastewater, after through the device separation are put on conditioning tank (tank collector). Conditioning flow is method applied to overcome the problems caused by the fluctuation of the flow, to improve the operational efficiency of the process followed, to reduce the size and capital construction investment the next works. The basic benefit of regulating flow are: conditioning quality and wastewater flow, reduce wastewater temperature.
Wastewater flows from the conditioning tank to the reaction tank.
Concentrated treatment wastewater
The waste water after preliminary treatment stage of two sources exhaust flow to reaction tank, where chemical flocculation be granted have quantitative in tank to create cotton flocculation have size and weight greater then flows to settling tank.
In settling tank stand with retention time about 3 hours and will enable cotton residue precipitate to the bottom an easy way, remaining water in the upper settling tank will be forwarded to the next processing equipment.
Water from the settling tank flowing to adsorbed tank, adsorbed tank using adsorption materials is activated carbon with level activation high ease adsorbed color, smell and organic matter exists in wastewater which untreated in aerobic biofiltration tank.
Finally, water flows to disinfection tank, disinfection tank is calculated with storage time water in the tank is 30 minute. Use Chloramines B (or chloride of lime - Clorin) dosing pump accurate amounts of chemicals enough to remove pathogenic microorganisms in the water before it is discharged into the environment.
Sludge treatment
Sludge microbial in aerobic tank a part returned conditioning tank order to treatment again, and part rough mud with mud in settling tank returned sludge dewatering filter. Sludge in the mud tank is sucked periodically by specialized vehicles or use presses to pressed into pieces and then provide for production base of organic fertilizers micro.
Assess the quality of water before and after treatment - Measurement results before treatment
Table 4.3. Measurement results and analysis before treatment
Ordinal numbers
Indicator
analysis Unit
Result before treatment
QCVN 40:2011/
MONRE
1 TSS mg/l 68 100
2 BOD5 mg/l 46 50
3 COD mg/l 85 150
4 Fe mg/l 0.78 5
5 Nitrat mg/l 7.51 50
6 Phosphat mg/l 2.27 10
7 Amoni mg/l 4.72 10
8 Animal fat and vegetable oil
mg/l 3.53 20
9 Mineral oil and fat
mg/l 4.68 10
10 Coliform MPN/100ml 6200 5000
(Source: Centre for Monitoring and Environmental Protection Tuyen Quang)
Comment: Concentration of the substances in water before treatment were almost reached QCVN 40:2011/MONRE, only have Coliform concentration before treatment is 6200 MPN/100ml has exceeded QCVN 40:2011/ MONRE 1200 MPN/100ml.
- Measurement results after treatment
Table 4.4. Measurement results and analysis after treatment
Ordinal
numbers Indicator analysis Unit
Result after treatment
QCVN 40:2011/
MONRE
1 TSS mg/l 19 100
2 BOD5 mg/l 14 50
3 COD mg/l 27 150
4 Fe mg/l 0.21 5
5 Nitrat mg/l 4.82 50
6 Phosphat mg/l 0.96 10
7 Amoni mg/l 1.46 10
8 Animal fat and vegetable oil
mg/l 1.04 20
9 Mineral oil and fat
mg/l 1.26 10
10 Coliform MPN/100ml 50 5000
(Source: Centre for Monitoring and Environmental Protection Tuyen Quang) Comment: Concentration of the substances in water after treatment lower than compared with QCVN 40: 2011 / MONRE greatly.
Table 4.5. Performance of wastewater treatment
Ordinal
numbers Indicator
analysis Unit Result (before)
Result (after)
Treatment performance
(%)
QCVN 40:2011/
MONRE
1 TSS mg/l 68 19 72.1 100
2 BOD5 mg/l 46 14 69.6 50
3 COD mg/l 85 27 68.2 150
4 Fe mg/l 0.78 0.21 73.1 5
5 Nitrat mg/l 7.51 4.82 35.8 50
6 Phosphat mg/l 2.27 0.96 57.7 10
7 Amoni mg/l 4.72 1.46 69.1 10
8 Animal fat and vegetable oil
mg/l 3.53 1.04 70.5 20
9 Mineral oil and fat
mg/l 4.68 1.26 73.1 10
10 Coliform MPN/
100ml
6200 50 99.2 5000
Comment: Overall, treatment performance of pollutants is high.
Treatment performance of BOD5, COD, Fe, TSS, Amoni, Animal fat and vegetable oil, Mineral oil and fat were almost reached from 68 to 74(%).Treatment performance Coliform highest achieved 99.2 (%). Treatment performance Phosphate lower reaches 57.7(%). Treatment performance Nitrate lowest reached 35.8(%).
Can see concentrations of substances be processed effective.