Rural domestic sewage treatment equipment

Integrated sewage treatment equipment mainly refers to the wastewater discharged from hospital wastewater, daily living facilities such as kitchens, bathrooms, shower rooms, laundry rooms, etc. Due to the presence of substances such as sediment, oil, soap, food scraps, bacteria, and debris, it is reflected in water quality indicators, namely high biochemical oxygen demand (BOD5), chemical oxygen demand (COD), suspended solids (SS) content, high nitrogen and phosphorus content, and eutrophication. If discharged directly into water bodies (rivers, lakes, seas, and groundwater) and soil without treatment, it will result in high concentrations of organic matter in the water and soil, leading to eutrophication of the water and soil. 

Design principles:

(1) Strictly implement the relevant national regulations on environmental protection, ensuring that the effluent indicators meet the national and local pollutant discharge standards; 

(2) Adopting mature and practical domestic processing techniques to achieve stable and reliable governance goals and requirements; 

(3) Under the above premises and requirements, achieve low investment and low operating costs; 

(4) The technical route is simple and clear, and the operation and management are convenient; 

(5) Adapt measures to local conditions and construct a sewage treatment plant on the existing site that is aesthetically pleasing and coordinated with surrounding buildings. 

Drainage volume, water quality, and discharge standards

1. Water volume: 200 people's domestic water consumption. If each person consumes 250kg of domestic water per day, the daily drainage volume is 50 tons. 

2. Water quality and discharge concentration (according to conventional domestic sewage)

BOD5：100-250 mg/l

CODcr：150-400 mg/l

SS：100-300 mg/l

NH3-N：30-40 mg/l

pH：6-9

Water quality standards for treated effluent

Design the effluent quality to comply with the first level standard in the Comprehensive Wastewater Discharge Standard (GB8978-96):

COD≤100mg/l

BOD≤20mg/l

SS≤70mg/l

Animal and vegetable oils ≤ 10mg/l

pH:6-9

Ammonia nitrogen ≤ 15mg/l

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Process flow description:

(1) Preprocessing

The sewage is discharged from the sedimentation tank and combined with other domestic sewage before entering the sewage treatment plant. The grid tank is used to remove larger impurities and floating debris, and the sewage flows automatically to the regulating tank. This can regulate the water volume and balance the water source. The regulating pool is buried underground, and grass can be planted on the top of the pool. The regulated sewage is lifted to the biochemical tank by a sewage pump. 

(2) Aerobic tank

In the aerobic zone, the vitality of polyphosphate accumulating bacteria is restored, and excess phosphorus is stored in the form of polyphosphate for growth. Energy is generated through PHB/PHV oxidation metabolism for phosphorus absorption and polyphosphate synthesis. The energy is captured and stored in the form of polyphosphate high-energy bonds, and phosphate is removed from the liquid phase. The generated phosphorus rich sludge will be discharged in the form of residual sludge in the subsequent operating units, thereby removing phosphorus from the system. Throughout the entire biological phosphorus removal process, it manifests as the synthesis and decomposition of PHB. 

(3) Sedimentation tank

A structure that separates the sludge carried by the effluent from the aerobic tank from the clean water. We use a horizontal sedimentation tank here. 

(4) Sludge treatment system

The sludge is subjected to aerobic digestion, and the digested and stabilized sludge is regularly transported by fecal suction trucks. 

Construction of WSZ-F equipment

1. NZP-11 type filler

The filler is composed of specially made plastic and resin, with a scientific and innovative structure. The specific surface area of the filler reaches 1000m2/m3, and the specific gravity is light at 0.97g/cm3. It is non clogging and easy to hang film. 

This packing material is a spherical packing material composed of slender spheres, a network shell, and a through porous column. It only needs to be directly added, does not need to be fixed, and has good removal efficiency for difficult to degrade substances. It has high removal efficiency for nitrogen, phosphorus, and sulfides, and no residual sludge is generated. 

2. Aeration

Adopting a central corridor style aeration, the aeration pipe is set in the middle of the pool. During aeration, air can drive water to circulate to both sides, forming two loops. The tank is circular, so there are no dead corners. Its pores are small, not easily clogged, and easy to adjust and replace. The oxygen transfer rate is greater than 18%, which is 2-3 times higher than that of a typical aeration head. 

3. Pipeline

All pipelines of the equipment are made of UPVC pipes, and the connections between pipelines are bonded with UPVC adhesive. 

4. Grille

The grille is made of stainless steel, with a spacing of 2mm between the bars, which is not easy to block and has good separation effect. 

5. Fan, control cabinet

The fans and distribution cabinets of WSZ-F are both installed in the fan room, with two fans running alternately in the fan room. The fan room is located above the ground and adopts a sound insulation and rain proof structure.

WSZ-F adopts a Japanese PepsiCo rotary blower, which has a small volume, high air pressure, no vibration during operation, and the operating noise of the blower is below 45 decibels; And it has a long lifespan. This fan has been used in Japanese clean tanks for 20 years and has reliable performance. 

The WSZ-F40-50F adopts two Japanese made three blade Roots blowers, with noise levels below 10-20 decibels lower than domestic blowers, and reliable performance with a long service life. 

The complete set of distribution cabinets adopts imported electrical appliances and a computer "simulation" control system, with the main control contents as follows:

Two water pumps can automatically backup, and sound and light alarms can be triggered when the water level exceeds the warning level. Two fans alternate operation, and when one fan is damaged, the other can be started to ensure continuous operation of the equipment; When the sewage is cut off, the fan can automatically operate intermittently to protect the normal growth of biofilm. 

The control cabinet has automatic protection functions for faults such as overcurrent, phase loss, overvoltage, and long-term voltage. 

6. WSZ-F equipment supporting water pump

This water pump is a Japanese imported submersible sewage pump with strong discharge capacity, no blockage, and can effectively pass solid particles with a diameter of 30-80 millimeters. The tearing mechanism of this water pump can tear long fibrous materials without the need for a filter screen on the pump. 

The WSZ-F equipment is equipped with two water pumps, one of which is standby. The water pumps are equipped with electrical protection switches, float switches, and automatic coupling devices. 

7. WSZ-F wrapped fiberglass tank body

This equipment and technology have reached the international advanced level in the 1990s. In addition to using electrical cabinets for control from product design to molding processes, our factory also has a complete set of quality inspection systems. A complete quality assurance system and a skilled installation team ensure scientific product design, strict process operation, rigorous quality control, and fast and accurate installation. The product has stable quality, reliable performance, and satisfies users. 

WSZ-F basic installation, use, and maintenance

1. Foundation: If the WSZ-F equipment is placed above the floor, only a concrete floor with the same appearance as the equipment needs to be prepared as the foundation. The basic pressure must be greater than 4T/M2, and it is also required to be horizontal and flat. 

If the WSF-F equipment is buried below the ground level, the foundation standard must be less than or equal to the equipment elevation and ensure that there is no water accumulation during rain. The foundation is generally made of plain concrete (whether reinforcement is required depends on the local geological conditions). To prevent equipment from floating, anti floating rings should be pre embedded in the foundation. (See equipment installation diagram for details)

2. Installation: Position according to the installation diagram, and place each box in sequence. The position and direction of the boxes must not be misplaced, and the spacing between them must be accurate, and the pipes must be connected properly. After the equipment is in place, use bandages to connect the equipment to the anti floating ring on the foundation to prevent the equipment from floating up. 

3. Inject sewage into the equipment and check for any leaks in the pipes. If there are no leaks, inject clean water into the foundation to a depth of 30-50cm, covering the area around the box with soil until the equipment inspection hole is reached and the ground is leveled. Connect the control line of the electrical control cabinet to the water pump, and connect the electrical control cabinet to the power supply. When wiring, pay attention to the direction of the fan and motor, which must be the same as the direction pointed by the fan. 

4. Debugging: The sewage pump pumps sewage into the equipment according to the rated flow rate, starts the fan for aeration, and observes the filling situation in the contact tank every day. If an orange or yellow film grows on the filling, this process usually takes 7-15 days. If it is industrial organic wastewater, it is best to first cultivate biofilm with domestic sewage, and then gradually introduce industrial sewage for biofilm training. 

5. Equipment maintenance: A regular maintenance system must be established for WSF-F equipment. The main vulnerable components are the fan and water pump, and the fan direction cannot be reversed. Once sewage enters the fan, it must be cleaned and the engine oil replaced before use. Before starting the fan, it is necessary to pay attention to whether the air gate is open. The fan must be maintained every 10000 hours of operation. The water pump must be maintained every 5000-8000 hours of operation. 

operating cost

1. Electricity consumption cost:

The electricity consumption per ton of sewage treatment is RMB 0.435. 

2. Labor cost:

The requirements for sewage treatment management are simple and part-time personnel can be employed. Just a little training is enough. 

Pharmaceutical cost:

This processing system does not require medication, this item is zero. 

Conclusion:

Operating cost (without dedicated personnel): 0.435 yuan

PLC electrical control instructions:

This process control system adopts fully automatic PLC program control, and its control principle is as follows:

1. Automatically start and stop the sewage lift pump according to the liquid level of the regulating tank; 

2. Automatic control of sludge pump for regular reflux; 

3. Both the fan and water pump are used as backup and automatically switched; 

4. When there is no sewage in the regulating tank, the fan aerates according to the time interval; 

5. Automatic alarm when the sewage treatment system malfunctions.

Classification composition

Classification of fiberglass products:

Fiberglass tanks: fiberglass storage tanks, hydrochloric acid storage tanks, sulfuric acid storage tanks, reaction tanks, anti-corrosion storage tanks, chemical storage tanks, transportation storage tanks, food tanks, fire protection tanks, etc;

Fiberglass pipes: Fiberglass pipes, Fiberglass sand pipes, Fiberglass air ducts, Fiberglass cable ducts, Fiberglass top pipes, Fiberglass process pipes, etc;

Tower equipment: drying tower, washing tower, desulfurization tower, acid mist purification tower, exchange column, etc;

Toilet: Toilet chassis, Toilet ceiling.