Method for biochemically treating and discharging refinery wastewater within controlling index of national standard

Abstract

The invention provides a biochemically treating and discharging refinery wastewater within controlling index of national standard. The method comprises oil removal, floatation and biochemical treatment, wherein the biochemical treatment is performed in sequence through an anaerobic flow bed biofilm reactor, an anoxic basin and an aerobic flow bed biofilm reactor; and a part or all of mixed liquidflowing out of the aerobic flow bed biofilm reflows into the anaerobic flow bed biofilm reactor. According to the method, refinery wastewater is treated by adopting an 'aerobic flow bed biofilm reactor-anoxic method-aerobic flow bed biofilm reactor' process which has high impact resistance and is safe during running. High instantaneous impact resistance is achieved, and the treatment effect is hardly influenced. The entire biochemical system has high salt resistance, and the treatment effect is hardly influenced by the change of temperature. The refinery wastewater does not need to be subjected to subsequent further oxidation after being treated with the process, the effluent COD (Chemical Oxygen Demand) meets the national primary discharge standard less than or equal to 60 mg / l, and investment cost and running cost are saved. The entire system has a compact structure, so that the floor space is reduced.

Description

technical field [0001] The invention belongs to sewage treatment technology, in particular to a biochemical combination treatment method for oil refinery sewage. Background technique [0002] With the continuous development and utilization of crude oil, the output of heavy crude oil is increasing, and its density, viscosity, sulfur content, and acid value increase accordingly. According to preliminary statistics on the crude oil market in recent years, the global production of high-acid crude oil has accounted for 5.5% of the total development volume, and is increasing at an average annual rate of 0.3%; With obvious price advantages, centralized or large-scale processing of inferior crude oil has become the development trend of refining and chemical industry. At the same time, with the rapid development of my country's national economy, the contradiction between the increase in energy demand and the shortage of oil resources will become more and more prominent. From the com...

AI Technical Summary

Problems solved by technology

(2) The emulsification phenomenon of the drainage of the electric desalination device will increase, the salt content, oil content, and COD will all increase significantly, and the biochemical performance will decrease, which will affect the degreasing of the sewage treatment plant and the operation effect of the biochemical treatment unit

(3) Influential water quality fluctuations in sewage treatment plants increase, water quality deteriorates, and high-concentration sewage impacts frequently increase, which affects the stability of sewage compliance

This process has a good removal effect on petroleum and suspended solids in sewage, but the treatment effect on COD in sewage is not obvious, and has disadvantages such as low load, poor impact resistance, and low ability to remove ammonia nitrogen.

However, in recent years, many oil refining companies have blended high-salt and high-acid crude oil, and the state has further raised the sewage discharge standards of the oil refining industry, requiring them to meet the first-level discharge standards. Continued use of the "old three sets" process will not meet the national discharge standards

Images