Treatment And Design Of Drilling Sewage Based On Micro-nano Air Flotation

In this paper,the micro-nano air flotation generating device was designed and fabricated firstly.By optimizing the parameters of the device,it can stably generate nano-scale dissolved gas water,and it is successfully applied to the treatment of drilling sewage.Then,according to the Fluent simulation test results,the advective air flotation tank was fabricated,which provided the basic design for the processing of the skid-mounted equipment for field test drilling sewage treatment.For the treatment of drilling wastewater,this paper firstly carried out water quality characterization.The results show that the Henan Oilfield Mi 446# drilling wastewater sample has a high pollutant concentration,with suspended solids of 704.5 mg/L,COD of 5080 mg/L,and salinity of 5080 mg/L.It is 1680 mg/L,the oil content is 271.4 mg/L,the pollutant indicators are all high,the water sample is weakly alkaline,and the Pb content in the water sample is 2.4 mg/L,and the high content of heavy metals will lead to its biological toxicity.Very high,B/C is 0.03,far less than 0.2,and the biochemical degree of water samples is low.The follow-up study using micro-nano air flotation is as follows:(1)The micro-and nano-bubble water was obtained by the pressurized dissolved air method.The research results show that the higher the dissolved air pressure,the smaller the micro-nano bubble size(the nano-bubble size is about 300 nm),and the longer its apparent residence time(up to 62s).When the dissolved gas pressure is 0.3 MPa,nano-sized bubbles can be generated.At this time,the maximum dissolved gas volume is 26 m L/L,and the dissolved gas efficiency is 48%.(2)The micro-nano air flotation method was used to treat Henan Mi 446# drilling sewage,which has high COD concentration,complex composition and certain toxicity.The best treatment effect was achieved when the dosage of ferric sulfate was 0.8 g/L,the dosage of cationic polyacrylamide(CPAM)was 8 mg/L,the dissolved gas pressure was 0.3 MPa,and the dissolved gas time was 3 mins.,the removal rate of COD in drilling wastewater was 98%,and the absorbance value of effluent turbidity decreased to 0.001 Abs.(3)The design of the suspended solids removal system of the pressurized dissolved air system was completed,and the advective micro-nano air flotation device was optimally designed through calculation and Fluent simulation.The air flotation tank is2.115 m long,1.2 m high and 0.9 m wide,and is equipped with a slag scraper,a distribution box,and a dosing tank.Combined with the previous micro-nano bubble generating device,it provides a basic design for the processing of skid-mounted equipment for drilling sewage treatment.