Livestock sewage dewatering technology is a physical, chemical and biological method to reduce the concentration of sewage, reduce pollution, and achieve the purpose of turning waste into treasure and comprehensive use. The general Livestock sewage dewatering project consists of pre-treatment, anaerobic treatment, subsequent purification treatment and biogas utilization (also called three-stage sewage treatment process). Among them, the pre-treatment process is the primary principle in the three principles of livestock farming sewage treatment process of reduction, resourcefulness and harmlessness.
The characteristics of Livestock sewage: first, large and concentrated discharge volume, strong hydraulic impact load; second, high concentration of organic matter, rapid hydrolysis and acidification, good precipitation performance; third, Livestock sewage is often accompanied by disinfection water, heavy metals, residual veterinary drugs and various zoonotic pathogens and other pollutants. Through the pre-treatment process for fresh manure water solid-liquid separation, exclusion of sink (floating) slag and pretreatment (adjustment of water quality, water quantity), can achieve effective improvement of the subsequent anaerobic biological treatment effect, while reducing investment costs.
The pre-treatment process mainly includes equipment and facilities such as grating, sand settling tank, water collection well, solid-liquid separator, sedimentation regulating tank, drying field, livestock waste dewatering machine, poultry farm sludge dehydrator, etc., as well as measures such as rain separation and dry manure removal should be taken in pig houses.
Grille
Intercept long fibers, hair and other debris in livestock waste water. Use manual method to clean the surface debris of the grille regularly.
Sand sedimentation tank
Precipitates larger particles of sand in livestock sewage and cleans them regularly to reduce the wear and tear of sludge lifting pumps in the water collection wells and the amount of sludge in the later process.
Water catchment well
It is used for temporary storage of livestock sewage to ensure the normal work of the subsequent solid-liquid separator. The well is equipped with agitation device, sludge lifting pump and water level self-control level probe.
Poultry farm sludge dehydrator
livestock waste dewatering machine is an important measure in livestock waste water treatment technology. The wastewater can achieve the following purposes through solid-liquid separation: first, to prevent larger solids from entering the subsequent treatment link, to avoid channel blockage and improve the reliability of operation; second, to reduce the organic load, shorten the anaerobic residence time and achieve the purpose of reducing investment costs.
Sedimentation adjustment tank
Use the characteristics of good settling performance of solids and fast decomposition of organic matter (hydrolysis, acidification) in livestock and poultry wastewater to fully reduce the concentration of manure and sewage; store and adjust the water quality and quantity of anaerobic fermentation treatment, so that the concentrated, intermittent water intake becomes balanced and continuous water discharge.
The top of the pool is equipped with floating slag ramp, and the bottom is equipped with inverted cone sinkhole and sludge discharge pipe, and the supernatant of settled sewage enters the subsequent anaerobic fermentation device through the outlet regulator in a balanced manner. Settled sludge through the sludge pipe (ditch) can be automatically discharged into the sludge drying field, floating slag from the pool side of the floating slag ramp into the floating slag drying field.
Drying field
The flotsam and sludge produced by the process of livestock wastewater treatment technology is not only the main reason why the channels of each treatment facility are easily blocked, but also a large amount of flotsam and sludge aggravates the treatment load and eventually affects the effect of sewage treatment, so the drying field process is an effective measure to ensure the long-term normal operation of the sewage treatment project facilities.
The project is designed to discharge sludge facilities at the bottom of all types of treatment tanks, and the sludge discharged regularly is concentrated to the sludge drying field through the sludge pipeline to be dewatered and dried using natural conditions (3-7 days). The effluent filtered out from the drying field is returned to the water collection wells for re-purification treatment.
Because of the special nature of the sludge, after discharging into the drying field, the phenomenon of obvious stratification of the sludge, floating sludge and clear liquid is soon produced, and the clear liquid is in the middle of the sludge and floating sludge, which is more difficult to discharge. The design of the filter screen of the drying field adopts the positioning type filter screen, which can adjust the position of the gap of the screen according to the height of the clear liquid to achieve the purpose of retaining the sediment and floating slag and discharging only the clear liquid.
Advantages of pre-treatment process
① The concentration of suspended solids, protein, grease, surfactant, Ca+, NH4+, S2- and other substances in the sewage are fully reduced in the pre-treatment stage through the process of removing manure sludge, sediment and scum, and the CODcr concentration of manure sewage entering the anaerobic tank is reduced by 50-70%, which effectively reduces the impact and toxic effect of the above substances (including disinfected sewage) on the anaerobic sludge activity. It shortens the anaerobic residence time and reduces the volume of anaerobic tank, while avoiding the phenomenon of anaerobic tank blockage and ensuring the normal work of anaerobic fermentation device.
② By adjusting the water quality, the sewage has been initially hydrolyzed and acidified before entering the anaerobic tank, so that the parthenogenic and specific anaerobic bacteria are rapidly multiplying and active, which is conducive to the production of biogas.
③ Adopt balanced water discharge, so that the hydraulic load is uniform and the effect of anaerobic degradation of sewage is stable.
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