Centrifugal extraction machine in the activated sludge process technology, the application of low concentration phenol wastewater treatment
The coking plant is the main harmful waste water of phenol and cyanide wastewater.
Not just the phenol and cyanide, and containing tar, sulfide and other substances.
For high concentration (
Phenol above 1000 mg/L)
Should first consider the phenol wastewater containing phenol recovery, by the methods of extraction, steam to take off the recovery after phenol 100 ~ 300 mg/L, need further processing can be discharged into water bodies, reduce pollution.
For low concentration phenol wastewater treatment, generally using the activated sludge method, because such high processing efficiency, mature technology and reliable.
Principle activated sludge process based on activated sludge as the main body of the phenol wastewater treatment method, it is mainly used in the activated sludge aerobic bacteria and other organisms, first of all, phenol, cyanide and other organics in the wastewater containing phenol adsorption, and then to oxidative decomposition of organic matter, using its nutrition substances necessary for synthesis of its own, regenerates the aerobic bacteria and protozoan, etc, finally organic compounds into CO2 and H2O.
Process high concentration phenol wastewater treatment by precipitation, to remove tar slag first, then using the method of extraction of removing phenol pretreatment, the lower the concentration of phenol.
Decrease phenolic wastewater in the separation tank after removal of light oil and heavy oil after the homogenizing pool, phenol treatment, make the phenol concentration down to about 200 mg/L, then introduce the adsorption, aeration and after regeneration of activated sludge, the mixture of aeration treatment, wastewater with activated sludge, the mixture after aeration clear separation in the secondary sedimentation tank, clarified the purified water can be used outside or cycle.
External factors impact on the normal growth of activated sludge, biochemical treatment is the key to the original biological reproduction and growth, which requires the active sludge should have good quality, should have loose particles, easy adsorption oxidation of organic matter, good cohesion, settling performance.
Therefore, in practice, to strictly control the performance of the activated sludge.
Control concentration of phenol in wastewater containing phenol with phenol and other organic matter caused by biochemical need oxygen content should be appropriate.
For phenol wastewater treatment, want to consider the toxic effects on biochemical treatment of phenol, phenol concentration is too high, will hinder the creature's birth and death;
Phenol concentration is too low, the sludge under low load production for a long time, can cause malnutrition, proliferation at a slow pace.
Therefore, phenol concentration control in commonly 200 ~ 300 mg/L.
Oil etc. the control of harmful impurities such as tar, hydrogen sulfide, ammonia, metal salts such as the content of harmful substances are controlled within allowable concentration.
Tar and oil material in activated sludge showed that cover easily, cause oxygen to stop, destruction of microbial activity.
Oilseed materials, therefore, it is advisable to less than 50 mg/L.
the regulation of water temperature stability is a bacteria thrive and reproductive factors of traditional Chinese medicines, biochemical treatment bacteria belongs to the medium temperature as needed.
Bacteria in the body and the original biological enzyme is protein, temperature is too high, too low will affect the growth and reproduction of bacteria.
In the cold region in north China are harder to control water temperature, the north at the beginning of coking plant generally USES cold water to adjust water temperature, or in the air blower zhongtong pipe into steam, and keep a steady temperature in aeration tank.
The water temperature control between 20 ~ 30 ℃ in general.
PH control appropriate PH value of wastewater containing phenol, one of the important factors is to keep sludge activity, high PH value is too low, can decreased the activity of sludge, and even the deactivation.
Therefore, control the PH value is generally 6.
5 ~ 8.
Between 5 more appropriate.
The supply of nutrients in the biochemical treatment, microbial needed nutrients in the general sewage didn't distinguish, but the content of phosphorus is often inadequate, and phosphorus is synthetase and microbial cells are indispensable material.
Therefore need to cic add right amount of phosphorus wastewater, the water containing phosphorus at about 1 mg/L.
Dissolved oxygen supply in the biochemical treatment of activated sludge bacteria for aerobic bacteria, only under the condition of sufficient oxygen, the metabolism of bacteria to be strong, organic materials decomposition efficiency is high.
If high dissolved oxygen, can make the sludge microbial oxidation decomposition;
Low dissolved oxygen, sludge anaerobic bacteria in the breeding, aerobic bacteria is restrained.
Therefore, general control dissolved oxygen aeration in 2 ~ 4 mg/L.