Analyzing and reusing industrial wastewater sludge in cement production: Environmental and economic implications

Industrial wastes require special attention due to the chemical substances and compounds generated at various production stages, which can have significant environmental impacts. In the petrochemical industries' wastewater treatment units, a wide range of environmental pollutants with different compounds such as olefin and polycyclic aromatic hydrocarbons, heavy metals, and other pollutants are formed based on the type of their products. These contaminants can cause severe problems for the environment. Recovering and reusing as many of these compounds as possible can eliminate their polluting effects and provide economic benefits. Since the wastewater treatment system in many petrochemical complex utility units are based on the biological treatment by activated sludge method, most of these materials and contaminants accumulate in the form of sludge from the wastewater treatment system. Therefore, to analyze the chemical and biological constituents of sludge and sludge ash, at first, the X-ray fluorescence and X-ray emission methods were applied. Then, appropriate solutions were proposed to investigate the industrial use of biological sludge from the industrial effluent treatment unit of a petrochemical company in production of sludge ash cement samples were studied. This study showed that the average compressive strength of concrete tested in three days reached 246 kg / cm2, 361 kg / cm2, and 495 kg / cm2 within curing durations of 3, 7 & 28 days accordingly.