LEAKING WATER
Leachate composition (NRR) is often unstable and depends on many factors such as landfill time, type of landfilled waste, seasonal weather changes, rainfall levels and temperature of the landfill. All of these factors make NRR treatment difficult and complicated.
To determine the specific leachate concentration in a landfill site, it is necessary to take measurements and analyze water samples from different sample points in the area. This process is usually carried out by environmental experts and waste treatment companies.
| No. | Indicator name | Unit | New landfill (<2 years) | Old landfill (>10 years) | QCVN 40:2011/BTNMT (column A) |
|
1 |
pH |
- |
4,5 – 7,5 |
6,5 – 8,5 |
6-9 |
|
2 |
TSS |
mg/l |
300 – 2.000 |
50 - 100 |
50 |
|
3 |
COD |
mg/l |
3.000 – 85.000 |
1.500 – 2.500 |
50* |
|
4 |
BOD |
mg/l |
2.000 – 5.000 |
700 – 1.500 |
30* |
|
5 |
Total P |
mg/l |
10 – 100 |
5 - 30 |
4 |
|
6 |
Total N |
mg/l |
150 – 1.000 |
100 – 200 |
15* |
|
7 |
Amoni |
mg/l |
100 - 800 |
50 - 100 |
5* |
|
8 |
Fe |
mg/l |
10 – 100 |
10 – 50 |
1 |
|
9 |
Zn |
mg/l |
5 – 50 |
3 – 30 |
3 |
There are several treatment methods that have been used to treat NRR, such as biological treatment, advanced oxidation techniques, wetland applications, membrane filtration, coagulation and electrocoagulation. Below is the leachate treatment technology proposed by Nanoen:
Proposed technology for leachate treatment
Technology description
-
Equalization tank:
- Wastewater generated from the landfill will be collected by a system of leachate collection pipes and domestic wastewater will be led to the collection and equalization tank through the drainage lines. Before entering the tank, wastewater will pass through a trash rack to remove impurities: trash, leaves, large solids to avoid affecting the following equipment in the system. Trash will be collected and treated.
- The collection and equalization tank has the function of collecting and equalizing the flow and concentration of pollutants in wastewater.
Advantages of designing an equalization tank are as follows:
+ Store wastewater generated during peak hours and distribute water evenly to the downstream treatment items;
+ Control wastewater flows with high pollution concentrations;
+ Avoid overloading downstream processes;
+ Act as a wastewater tank when the system stops for repair or maintenance.
-
Coagulation and flocculation tank:
Wastewater from the equalization tank will be pumped to the flocculation and flocculation tank, where the wastewater will be mixed with coagulant chemicals added from the chemical tank through a metering pump. The coagulant helps suspended solids to coalesce to form larger particles.
-
Physicochemical settling tank:
The physicochemical settling tank has the function of removing flocs in the flocculation and flocculation tank based on the gravity method. Wastewater is fed into the distribution pipe of the settling tank, the flocs will settle to the bottom of the tank, the clear water will overflow through the water collection trough and flow through the intermediate tank 01 to adjust the pH.
-
Intermediate tank 01:
This tank has the function of containing wastewater after physicochemical settling and lowering the pH of the wastewater. The H2SO4 chemical will be added to the tank by the metering pump system to lower the pH of the wastewater to about 34 to perform the Fenton process. The pH in this tank will be controlled and monitored by an automatic pH measuring device. Next, the wastewater will be pumped to the Fenton treatment tank.
-
Fenton treatment tank:
Fenton agent is used to decompose many pollutants. The advantage of Fenton agent is that it can convert many pollutants into biodegradable substances.
Water from intermediate tank 01 will be pumped to the Fenton treatment tank. The Fenton treatment process is batch-based, including the following stages: water intake, mixing, reaction, sedimentation, water withdrawal + sludge discharge.
-
Intermediate tank 2:
Wastewater from the Fentone tank will flow through intermediate tank 2. Intermediate tank 2 has the function of raising the pH of the wastewater to about 9 - 10 thanks to the chemical NaOH. The NaOH chemical is added to the tank thanks to the chemical dosing pump system, the chemical is mixed with the wastewater thanks to the gas distribution system. Next, the wastewater is pumped to the Air Stripping Tower.
-
Air Stripping Tower:
The wastewater from the intermediate tank 2 will be pumped horizontally to the tower through the water distribution system. The wastewater is fed from top to bottom, through the cushion material system, and the air is blown from bottom to top, the air and water are in opposite directions to increase the contact. During the contact between the air and wastewater, this amount of air will push the NH3 gas in the wastewater out.
-
Intermediate tank 03:
This tank has the function of containing wastewater after the Air Stripping tower. H2SO4 chemical is added to the tank to lower the wastewater pH to 7.58 to ensure the biological treatment process later. Next, the wastewater will be transferred to the following tank clusters for treatment.
AO tank module combined with reverse flow sedimentation (USBF) includes:
-
Anoxic tank:
Next, water is pumped through the anoxic tank. Here, the process of denitrification and nitrite release nitrogen gas into the environment. Wastewater rich in nitrate and nitrite will be added to the tank thanks to the water circulation from the biological tank later, activated sludge is also circulated from the biological sedimentation tank to supplement enough sludge density during the wastewater treatment process.
-
Aerobic tank:
In the aerobic tank, air is supplied into the tank to create conditions for mixing activated sludge and wastewater. Microorganisms use the supplied oxygen to consume organic pollutants in wastewater.
-
Upstream Filter (USBF):
After the biological treatment process, the wastewater mixture enters the USBF from bottom to top and in the opposite direction to the vertical sedimentation of the sludge. During the process of passing through the activated sludge bed, small sludge flakes tend to stick together or stick to the existing sludge flakes to form larger ones until the water level rises to equalize with the speed of the sludge flakes, then they begin to accumulate and are retained in the bed (sludge). The settled water will overflow through the sawtooth trough to the disinfection tank.
-
Disinfection tank:
Wastewater is mixed with disinfectants supplied by a chemical mixing tank regulated by a metering pump to remove bacteria and pathogens. Chemicals are added to the mixing tank by aeration, in addition, wastewater flows through baffles to ensure the mixing of wastewater and the contact time of chemicals.
-
Sludge tank:
Sludge from the bottom of the physicochemical settling tank, Fenton cluster and USBF tank will be collected to the sludge tank. The sludge in the tank will be pumped and treated according to regulations. The clear water above the surface will be circulated to the collection and conditioning tank.
A reputable unit providing environmental records and wastewater treatment system construction services
Nanoen is a unit operating in the environmental field. During its operation, Nanoen has received the trust of customers for its honesty, dedication and responsibility to customers and the company's products.
With a team of experienced staff, we have a full range of services from environmental profile consulting to construction design, environmental treatment system operation, microbiological supply, sludge pressing for hire...
Nanoen is always ready to bring the best service experience, suitable for the needs of our customers.
Nanoen
NANO ENVIRONMENT TECHNOLOGY - CONSTRUCTION LIMITED LIABILITY COMPANY
Address: 661E/29, đường Võ Văn Kiệt, KV Bình Yên A, P. Long Hòa, Q. Bình Thủy, TP. Cần Thơ
Hotline: 0941.777.519 - 0907.803.678 - 0901.229.798
Email: nanoentech@gmail.com
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