Lab-scale pilot study report on high-salinity wastewater from a petrochemical plant

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This post was last edited by CoCo070563 on 2015-8-5 at 17:07. 1. Project background: The acid-base neutralization wastewater generated by a certain factory comes from a combination of wastewater from the power plant’s acid-base regeneration process, desulfurization wastewater, RO concentrated water, and waste alkali solution from ethylene production. The flow rates of these three types of wastewater are 31 m3/h, 116 m3/h, and 3 m3/h respectively, resulting in a total flow rate of 150 m3/h. The COD level of this wastewater is approximately 400 mg/l, TN is around 60 mg/l, ammonia nitrogen ranges from 20 to 30 mg/l, and the conductivity is about 10,000 us/cm. It belongs to high-salinity organic wastewater, characterized by high salt content, which makes microbial cultivation difficult； High TN, containing both nitrate nitrogen and ammonium nitrogen ； It has a high COD and poor biodegradability; it is an organic wastewater characterized by high salt and nitrogen levels, low B/C ratios, and low C/N ratios, with a severe lack of available carbon sources. The main objective of its treatment is to remove TN and COD so that they meet the requirements of **Grade A discharge standards. At present, laboratory pilot tests have been completed for the wastewater from this project. 2. Conclusions of the laboratory pilot tests: Laboratory studies were conducted on the acid-base neutralization wastewater generated by a certain factory; the main conclusions are as follows: 1) Through techniques such as targeted microbial amplification, bio-stimulation, and sludge acclimatization, efficient microbial communities capable of treating the high-salt wastewater from this project can be cultivated ； 2) By adding certain carriers to the biological selection tank and converting it into an AMBBR process, the biodegradability of wastewater can be significantly improved; its B/C ratio is 1.5 times that of the system without carriers ； 3) By adding a certain amount of carrier to the SBR tank and converting it into an MBBR system, the system’s ability to remove organic pollutants can be significantly improved. The COD removal rate is twice that of the system without the carrier. Moreover, the MBBR system is capable of effectively removing TN from wastewater under aerobic conditions; after 24 hours of treatment, the COD level drops to around 80 mg/l, while the TN level falls below 15 mg/l. The core of the LEVAPOR MBBR technology lies in its unique biofilm carrier. This carrier is based on polyurethane sponge, and through modification, it is able to adsorb 20%-30% powdered activated carbon, resulting in a specific surface area of 20,000 m2/m3 – more than 10 times that of other existing MBBR carriers ； The adsorption function of the powder activated carbon attached to the carrier allows microbial communities to reproduce rapidly on its surface, thereby forming highly active biofilms quickly ； Activated carbon powder can effectively absorb and degrade toxic substances, improving system stability. Levapor biofilm carriers prove to be highly effective for treating high-salinity wastewater. Firstly, our company has strains capable of withstanding 5% salinity levels. The Levapor filler is a polyurethane carrier containing 30% powdered activated carbon, with a specific surface area of over 20,000. In the first step, the first biofilm formation is achieved through the adsorption of microorganisms by activated carbon; subsequently, a second biofilm formation is carried out by selecting and training microorganisms, resulting in the cultivation of many microorganisms with strong salt resistance, thereby meeting the requirements for treating high-salinity wastewater.