Refer to Wastewater Treatment System 400m3/day

A footwear factory in Binh Dinh has a capacity of 6,800,000 pairs/year. During operation, wastewater is generated with a flow rate of 380m3/day and night. The factory owner has invested in a wastewater treatment system of 400m3/day and night so that the factory is eligible for an environmental license and can go into operation. If you are planning to invest in a wastewater treatment system with a similar capacity, you can refer to the details of the wastewater treatment system at this factory through the content below.

1. Refer to the wastewater treatment system 400m3/day

The factory’s wastewater is mainly domestic wastewater (wastewater from bathrooms, sinks, wastewater from the canteen, wastewater from the canteen) and a small amount of production wastewater (from the shoe sole washing stage).

1.1. Wastewater collection and drainage system

Wastewater from toilet > 3-compartment septic tank > 400m3/day.night wastewater treatment system

Wastewater from the canteen > Grease trap > Wastewater treatment system 400m3/day.night

Wastewater from bathroom, sink > Wastewater treatment system 400m3/day.night

Waste water from product washing machine (shoe sole) > pH neutralization tank.

For domestic wastewater

Wastewater from the canteen will be collected and led to the oil separator tank before being sent to the project’s centralized wastewater treatment system. The oil separator tank collects all water generated from the canteen into the oil separator tank to remove grease content.

Operating principle: The grease trap consists of two partitions to separate oil and sediment. Wastewater overflows into the first compartment and is kept for a certain period of time to settle out the solid residue in the wastewater, the oil layer on the surface will overflow into the oil collection trough. Clear water flows through the drain in the tank body into the second compartment. Wastewater after passing through the oil trap will reduce 98% of the amount of oil in the water.

For production wastewater

Wastewater from RB washing machine is collected to pH neutralization tank located behind the rubber sole factory. Wastewater after neutralization tank reaches pH from 6 – 9 and will be led to the project’s local wastewater treatment system by self-flowing.

Wastewater from the production process (except wastewater from RB washing machine) is collected by PVC pipes to the centralized wastewater collection manhole into the project’s local wastewater treatment system in the form of self-flow.

All generated wastewater will be collected and led to a centralized wastewater collection pit, then led to a wastewater treatment system with a capacity of 400 m3/day and night.

1.2. Technological diagram of wastewater treatment system

Wastewater > Coarse waste filter > Collection tank > Fine waste filter > Equalization tank > Anaerobic tank > Anoxic tank > MBBR aerobic tank > Aerotank aerobic tank > Sedimentation tank > Intermediate tank > Pressure filter tank > Disinfection tank > Treated water tank > Receiving source

Process Description

The operating process of the 400m3/day/night wastewater treatment system is as follows:

– Collection tank + Filter

• • Wastewater is collected into a collection tank through a coarse trash rack to remove large and small trash sizes such as paper, plastic, leaves, etc., helping to reduce the organic content in wastewater and minimize the impact on mechanical equipment and subsequent treatment works.

• • The wastewater will then flow down to the Equalization Tank.

• • The trash rack is periodically cleaned manually.

– Air conditioning tank

• • The balancing tank has the task of stably regulating the flow and concentration of pollutants in wastewater before being introduced into the following units, especially the biological tank cluster, which helps microorganisms adapt to wastewater in stable conditions, avoiding the situation of microorganisms being shocked by the load.

• • The equalization tank is continuously supplied with air to mix and release residual chlorine (generated by disinfection) in the wastewater, while partially decomposing organic matter in the wastewater. Aeration provides preliminary ventilation to avoid anaerobic decomposition that causes odors.

• • After the wastewater has its flow and concentration stabilized in the Equalization Tank, it will be pumped into the biological treatment cluster, first the Anaerobic tank.

– Anaerobic tank

• • Anaerobic tanks are used to reduce the concentration of organic substances through the activity of anaerobic bacteria. The function of decomposing organic substances is expressed by the following equations: CxHyOzNt + Anaerobic bacteria → CO2 + H2S + CH4 + new biomass.

• • Wastewater after Anaerobic Tank will continue to flow into Anoxic Tank combined with nitrification.

– Anoxic tank

• • Anoxic tanks are used for the purpose of denitrification from the conversion of nitrate to free nitrogen. Stirring, keeping sludge in suspension and creating contact between food sources and microorganisms. The tank is completely oxygen-free.

• • Two enzyme systems are involved in nitrate reduction:
    • • Assimilation: NH3 → NO3-,

     

    • • Dissimilatory → denitrification process in wastewater.

     

– MBBR aerobic tank

• • MBBR aerobic tank is a biological treatment tank using biofilm attached to the carriers. Microorganisms can be optimally supplied with nutrients and metabolic products are transported effectively. Microorganisms attached to the carriers have the function of completely treating organic compounds in wastewater. Under continuous aeration conditions, the carriers are suspended and move in the wastewater. The biofilms formed on the carrier surface have 3 different layers.

• • The innermost layer is anaerobic biofilm, the middle layer is anaerobic biofilm and the outermost layer is aerobic biofilm. Thanks to the formation of different biofilm layers, the MBBR Aerobic Tank is highly effective in treating nitrogen, phosphorus and BOD5.

– Aerotank

• • The tank has the role of reducing the concentration of organic substances through the activity of aerobic autotrophic microorganisms. The air blower operates continuously to provide oxygen for both groups of aerobic microorganisms to operate. For the aerobic autotrophic microbial population, under continuous aeration conditions, this microbial population will decompose organic compounds in wastewater into simple inorganic compounds such as CO2 and H2O in 3 stages:
    • • Oxidation of organic substances: CxHyOz +O2 CO2 + H2O + ΔH

     

    • • New cell synthesis: CxHyOz + NH3 + O2 Bacterial cell + CO2 + H2O + C5H7NO2 – ΔH

     

    • • Intracellular decomposition: C5H7NO2 + 5O2 5CO2 + 2H2O + NH3 ± ΔH

     

– Settling tank

• • In the settling tank, the phase separation process takes place and the sludge (microorganisms) are retained. This settled sludge is mainly microorganisms that flow out of the Anoxic Tank. A part of the settled sludge is pumped back to the Anoxic Tank to maintain the sludge concentration in the biological tank cluster.

• • The remaining excess sludge is pumped into the Sludge Tank.

• • The clear water after passing through the biological settling tank will automatically flow to the disinfection tank.

– Intermediate tank

• • The intermediate tank acts as a buffer tank to store enough flow for the horizontal pump to pump wastewater into the pressure filter tank to completely treat the suspended solids content in the wastewater.

– Pressure filter tank

• • Wastewater from the intermediate tank is pumped to the pressure filter tank. The pressure filter tank is a closed filter tank, the filtration process occurs thanks to the water pressure above the filter material layer. The composition of the filter material layer can be used as sand, gravel. Through the pressure filtration mechanism, the remaining suspended solids in the wastewater will be treated to be very small in size and cannot be settled by gravity.

• • After a period of operation, dirt sticks to the filter material layer, causing the filter holes to clog, affecting the treatment efficiency of the filter tank. Therefore, it is necessary to wash the filter, the wastewater flows from bottom to top with high water pressure to clean the dirt stuck on the filter material layer. The filter washing water containing dirt stuck on the filter material will then be led back to the Equalization Tank for further treatment.

– Disinfection tank

• • The clear water from the biological settling tank will flow to the Disinfection Tank, where Javen disinfectant is added to the tank to kill disease-causing bacteria in wastewater such as E.Coli and Coliform.

– Wastewater tank after treatment

• • The treated wastewater tank has the function of monitoring the quality of treated wastewater.

• • Clean water after the disinfection tank will flow automatically to the treated wastewater tank for reuse for flushing toilets and washing bathrooms. The remaining water will be connected to the centralized wastewater treatment plant of the industrial park for further treatment before being discharged into the environment.

– Sludge tank (Sludge compression tank)

• • The aerobic biological treatment process will continuously increase the amount of microbial sludge in the Biological Tank. At the same time, the initial amount of sludge after a period of growth and development will reduce the ability to treat pollutants in wastewater and die. This amount of sludge is also called excess sludge and is sent to the Sludge Tank.

• • The sludge tank has the effect of reducing the moisture content of the sludge because the sludge pumped back from the biological settling tank often contains a large amount of moisture. The sludge after the moisture content has been reduced will be pumped to the sludge press.

– Sludge press

• • The sludge press has the function of producing dry sludge, high solid retention rate, moderate energy requirement, low operating and investment costs.

• • The sludge press used for chemical and biological sludge selected by the contractor is the Belt Sludge Press with the following advantages: dry sludge production, high solid retention rate, moderate energy requirements, low operating and investment costs.

2. Technical specifications of wastewater treatment system with capacity of 400m3/day.night

3. Investment cost of wastewater treatment system with capacity of 400m3/day.night

The investment cost for a wastewater treatment system with a capacity of 400m3/day and night ranges from 5 billion VND to 9 billion VND.

Note, this cost is for reference only and will vary from place to place depending on many factors such as:

– Type of wastewater to be treated (domestic wastewater or production wastewater);

– Nature and level of pollution of wastewater;

– Wastewater treatment technology;

– Water quality requirements after treatment;

– Construction and installation area;

– Construction and installation type;

– Origin of machinery and equipment in the wastewater treatment system;

– Price of materials, machinery and equipment at each point in time.

– Other factors.

 

Above is some information about the 400m3/day.night wastewater treatment system . If your business is in need of designing and constructing a wastewater treatment system and needs more specific advice, please contact Hotline: 0938.857.768 directly for quick support.