Supply of buried sewage treatment equipment

1. Features of HJ Equipment

u Can be buried underground

u No sludge generation

u No impact on the surroundings

u Fully automatic control, no personnel management required

u Easy operation and maintenance

u Advanced technology, effective results

u Long service life

2. Several Usage Methods of HJ Equipment

u The equipment is generally installed underground, with the upper part usable as green space, parking lots, roads, etc.

u The equipment can also be semi-buried, with the burial depth determined according to your needs.

u The equipment can also be placed above ground outdoors.

u If the equipment is used in cold regions, the inspection holes can be raised to bury the equipment below the frost line.

u The equipment does not need to be arranged in a standard layout and can be placed as needed.

3. Material Description of HJ Equipment

u All-stainless steel structure

u A₃ steel plate structure

u Fiberglass reinforced plastic structure

u Two external shapes: modular and cylindrical

4. Process Description of HJ Equipment

The design of HJ equipment is mainly for the treatment of domestic sewage and similar industrial organic wastewater. The primary method uses the mature biochemical treatment technology of contact oxidation. Water quality design parameters are calculated based on general domestic water quality, with an average influent BOD₅ of 200 mg/l and effluent BOD₅ of 20 mg/l. It consists of six parts: (1) Anaerobic tank, (2) Multi-stage contact oxidation tank, (3) Secondary sedimentation tank, (4) Disinfection tank and disinfection device, (5) Sludge tank, (6) Blower room and blower. They are described as follows:

(1) Anaerobic Tank

Regulating tank wastewater is pumped to the anaerobic tank for anaerobic treatment. The tank is equipped with special fillers, and the oxygen content is controlled below 0.5 mg/L. The wastewater stays in the anaerobic tank for about 2.5 hours.

(2) Multi-stage Contact Oxidation Tank: The effluent from the anaerobic tank flows into the contact tank for biochemical treatment. The contact tank is divided into three stages, with a total retention time of 5-6 hours. For enhanced equipment, the contact oxidation time can exceed 8 hours. The filler is a novel elastic filler, easy to form biofilm and not prone to clogging. The specific surface area of the filler is 160 m²/m³, and the air-to-water ratio in the contact tank is about 12-15:1. (Note: HJ-0.5 m³/h contact tank has two stages.)

(3) Secondary Sedimentation Tank: The biologically treated wastewater flows into the secondary sedimentation tank. The upward flow rate is 0.1-0.15 mm/s, and sludge is lifted to the sludge tank by air.

(4) Disinfection Tank and Disinfection Device: The disinfection tank follows the standard "TJ14-74" with a 30-minute retention time. For hospital wastewater, the retention time can be increased to 1-1.5 hours.

Disinfection uses solid chlorine tablets that dissolve on contact. The disinfection device can adjust the dosing amount based on the effluent flow, ensuring more dosing for more flow and less for less flow. Other disinfection devices can be configured as needed. (Note: For industrial wastewater, the disinfection tank and device may be omitted.)

(5) Sludge Tank: All sludge from the primary and secondary sedimentation tanks is lifted to the HJ equipment's sludge tank for aerobic digestion. The supernatant from the sludge tank is returned to the contact oxidation tank for further treatment. The remaining sludge after digestion is minimal, generally requiring cleaning every 1-2 years. Cleaning can be done using a vacuum truck inserted into the sludge tank through the inspection hole for suction and transport.

(6) Blower Room and Blower: The blower room is built separately with color steel plates, with double-layer sound insulation at the inlet, and includes silencers and blower filters to ensure no noise during operation. Two Roots blowers are used, capable of alternating automatically, with a single blower's service life exceeding 30,000 hours.

5. Equipment Technical Parameters

Technical Parameters Table

Note: 1. When the influent BOD₅ ≤ 200 mg/l, the effluent BOD₅ ≤ 20 mg/l.

2. The company reserves the right to modify technical parameters without prior notice to users.

HJ Treatment Capacity and Influent/Effluent BOD Relationship Table

6. Structure and Construction of HJ Equipment

Since HJ equipment is buried underground, maintenance and upkeep are relatively difficult. Therefore, the design considers its maintenance-free nature. The entire equipment has a reasonable and reliable structure, and even if some faults occur, they can be accessed through the inspection holes. All facilities of the HJ equipment are set in several tanks, which can be made of stainless steel plates. The tanks are connected with stainless steel pipes to ensure a service life of over 30 years.

If users have budget constraints, they can opt for Q235A steel plates with a thickness of 8 mm. The tanks are connected with seamless steel pipes. Both the inside and outside of the equipment are coated with epoxy coal tar or fiberglass anti-corrosion coatings recommended by the Chemical Industry Ministry. Generally, the equipment is coated with 6 layers: 2 primer coats and 4 top coats. The anti-corrosion life can generally exceed 10 years.

The entire HJ equipment is designed for maintenance and upkeep over 10 years.

7. HJ Equipment Matching Water Pumps

The water pumps matched with HJ equipment are used to lift wastewater from the regulating tank into the HJ equipment. The pumps are anti-clogging, tearing-type submersible sewage pumps.

The pumps have strong sewage discharge capabilities, are clog-free, and can effectively pass solid particles with diameters of φ30-φ80 mm. The tearing mechanism can shred long fibrous materials, eliminating the need for filters on the pumps. The pumps can operate safely for over 8,000 hours.

The pumps are equipped with electrical protection switches, float switches, and automatic coupling devices. HJ equipment is matched with two pumps, one of which is a backup. For specific parameters, refer to "5. Technical Parameters Table".

8. Selection of HJ Equipment

Before selecting HJ equipment, it is essential to understand the nature of the wastewater, influent quality, quantity, and the required discharge standards.

The regulating tank is provided or constructed by the user, usually as a concrete tank. The capacity of the regulating tank must be determined based on drainage cycles, production processes, and other factors, generally 6-10 times the treatment capacity.

In the design, HJ equipment can be buried underground, placed above ground, or semi-buried. The pipelines between the tanks are provided by our company. Before HJ operation, simply connect the tank pipelines, inlet and outlet pipes, and connect the cables to start operation.

If the equipment is used in cold regions, the inspection holes can be raised to bury the equipment below the frost line for normal operation. In southern regions, the equipment can also be placed on outdoor ground without the need for a building.

The equipment can be arranged in a standard layout. If there are special circumstances, the tanks can be arranged according to the terrain.

9. HJ Equipment Fully Automatic Microcomputer Control Cabinet

9-1. Manual and inspection circuits;

9-2. Automatic control circuits;

9-3. Specific usage instructions are as follows:

a. Each unit is equipped with two water pumps, two blowers, and 1-3 solenoid valves;

b. The water pumps are one working and one standby, alternating operation; they start automatically at the working water level, lock at low water level, and both start simultaneously at the alert water level; the two pumps can operate jointly or separately;

c. The blowers are one working and one standby, alternating operation; the two blowers can operate jointly or separately;

d. If the equipment is idle for more than 10 hours, to ensure normal biofilm growth, the blowers start intermittently on a timer to prevent biofilm death and shedding;

e. The blowers and pumps are equipped with automatic detection, audible and visual alarm systems, and have overcurrent, overvoltage, and phase loss protection circuits;

f. Sludge discharge from the sedimentation tank is time-sequence controlled.

h. Two drainage pumps can be set after the effluent as per user requirements.

10. Installation, Use, and Maintenance of HJ Equipment

10-1. Installation: This equipment can be installed in two ways: above ground or below ground. According to the installation and foundation drawings, the concrete base specifications are the same as the plane installation drawing (foundation). The foundation must bear an average pressure of 5 t/m² or more and must be level. If the equipment is installed below ground, the relative elevation of the foundation should match the equipment height. The excavation width around must be at least 500 mm from the foundation edge for pipeline installation.

Position according to the installation drawing, use a crane to lift the equipment into place. Ensure the tank positions and directions are correct, with accurate spacing between them, and connect the pipelines.

After installation, fill the equipment with water and check all pipelines for leaks. Adjust the two secondary sedimentation tank submerged weirs to the same level. After further confirmation that everything is proper, backfill the gaps around the equipment with soil and level the ground. Connect the control lines from the electrical control cabinet to the equipment, and connect the electrical control cabinet to the power supply. When wiring, ensure the rotation direction of the blowers and motors matches the direction indicated on the blowers.

Precautions: After installation, ensure no water accumulation during rain; the equipment's discharge pipeline must be below -0.6 m relative to the ground; no heavy objects should be placed on the equipment, and no large vehicles should pass over it; generally, do not empty the internal wastewater to prevent groundwater from floating the equipment.

10-2. Debugging: Use the sewage pump to draw wastewater into the equipment at the rated flow rate, start the blower for aeration. Observe the filler in the contact tank daily. If an orange or orange-black film forms on the filler, the biofilm is cultivated. This process usually takes 7-15 days. For industrial organic wastewater, it is best to cultivate the biofilm with domestic sewage first, then gradually introduce industrial wastewater for biofilm acclimation.

10-3. Equipment Maintenance: HJ equipment must have a regular maintenance system. The main vulnerable parts are the blowers and pumps. Ensure the blower rotation direction is correct; if sewage enters, clean and replace the oil before use. Before starting the blower, ensure the air damper is open. The blower must be maintained every 10,000 hours of operation, and the pump every 5,000-8,000 hours.

11. Equipment Layout Plan

Equipment Dimensions Table          (Unit: mm)

12. Blower Room

The blower room is made of color steel plates with internal sound absorption measures. It houses two blowers and an electrical control cabinet. The sides of the blower room have air inlets or louvers. The equipment base can be a general concrete platform. Pre-embed four 250×250×12 steel plates at the four corners of the blower room for fixed welding of the blower room.