A case study on application and commissioning of coal pyrolysis wastewater treatment project

Abstract

Due to the increase of the company's production capacity and wastewater production, the existing biological enrichment tank can not meet the requirements, the coal pyrolysis wastewater treatment device faced technical optimization and capacity expansion transformation. This project used polyurethane (PU) filler to optimize and expand the capacity. In biological enrichment tank, PU filler had good sedimentation performance, which can ensure the efficient and stable operation of the biological enrichment tank. After 10 d of dosing, the PU fillers in the tank basically sank and were fully mixed with the wastewater. The presence of protozoa such as ciliates, vorticella, and paramecium on PU fillers could better promote the removal of organic pollutants in coal pyrolysis wastewater, and better promote the flocculation of activated sludge and biofilm on PU. The chemical oxygen demand (COD) concentration of the influent was 800–1000 mg/L. The final COD concentration in the effluent was stabilized at approximately 150 mg/L, and the corresponding COD degradation ratio was approximately 80%–85%. The NH4+-N concentration in the influent was 150–200 mg/L. The final NH4+-N in the effluent was less than 10 mg/L, the corresponding NH4+-N removal ratio was higher than 93%. Compared with that before the addition of PU filler, the NH4+-N concentration in the effluent decreased by approximately 90 mg/L, and the corresponding removal ratio increased by 40%–60%. The removal efficiency of organic typical pollutants and NH4+-N can be effectively improved by adding PU filler in the biological enrichment tank, so as to effectively ensure the demand for technical optimization and capacity expansion of the project. This research could provide technical and data support for the actual application of the PU fillers and the transformation of the treatment project.