Treatment of Slightly Polluted Wastewater in an Oil Refinery Using a Biological Aerated Filter Process

The slightly polluted wastewater from oil refinery contains some COD, oil pollutants and suspended solids （SS）. A small-scale fixed film biological aerated filter （BAF） process was used to treat the wastewater. The influences of hydraulic retention time （HRT）, air/water volume flow ratio and backwashing cycle on treatment efficiencies were investigated. The wastewater was treated by the BAF process under optimal conditions： the HRT of 1.0 h, the air/water volume flow ratio of about 5 ： 1 and the backwashing cycle of every 4-7 days. The results showed that the average removal efficiency of COD, oil pollutants and SS was 84.5%, 94.0% and 83.4%, respectively. And the average effluent concentration of COD, oil pollutants and SS was 12.5, 0.27, 14.5 mg·L^-1, respectively. The experimental results demonstrated that the BAF process is a suitable and highly efficient method to treat the wastewater.

Treatment of tunnel wash waters-experiments with organic sorbent materials. PartⅡ: Removal of toxic metals

In the first part of the article, the column and the bag experiments concerning removal of polycyclic aromatic hydrocarbons (PAHs) and nonpolar oil (NPO) from tunnel wash waters using organic sorbent materials have been described. This part presents the results of removal of toxic metals. The metals of concern (Al, As, Cd, Cr, Cu, Fe, Pb, Mo, Ni, and Zn) were selected based on the priority toxicant pollutants defined in surface water quality criteria. Concentrations of these metals in the collected effluent...

Application Progress of Nanofiltration Combination Technology in the Treatment of Landfill Leachate

Under the impetus of environmental protection policies,the discharge requirements for leachate are becoming more and more stringent.Therefore,the treatment technology of landfill leachate has become a hot research topic at present.In this paper,the chemical composition and water quality characteristics of landfill leachate were briefly introduced,and the characteristics and performance of nanofiltration technology were summarized at first.Afterwards,the recent advances in the application of nanofiltration combination technology in the treatment of landfill leachate at home and abroad were summarized,and the research and application of the combination of membrane separation,chemical coagulation,chemical oxidation and adsorption methods with nanofiltration membrane in the treatment of landfill leachate were mainly introduced.Finally,it is proposed that the combination of nanofiltration technology is feasible and economical,and its reasonable selection and optimization are the directions of future research and have good application prospects.

EFFECT OF ALKOXYSILANE-BASED TREATMENT ON THE DURABILITY OF NORTH CYPRUS STONES FOR CONSTRUCTION

Limestones are generally vulnerable to various weathering effects, hence, protection and consolidation of them is necessary. Locally available limestones of Northern Cyprus have been used in both historical buildings dated back to the 16th century for conservation applications and new buildings mostly as a cladding material. However, certain decay patterns exist on these stones. In the current study, the service life of Cyprus stones was inspected. Alkoxysilane-based consolidation and protection treatments were applied on new quarried stones to enhance the stone properties and aged stones to conserve and protect the architectural heritage. Service life assessment was performed by applying accelerated aging tests on both new and aged stones before and after treatments. The treatments improved the physical, mechanical and durability properties of the stones in terms of unchanging the water vapor diffusion resistance factor, decreasing the porosity and the water absorption ratio, increasing the ultrasound pulse velocity, the compressive and the flexural strengths, and improving the resistance of the stones against wetting-drying, freeze-thaw, salt crystallization and SO2 vapour effects. The combination of consolidation and protection treatment (K2) was more efficient on the properties of the stones compared to only protection treatment (K1) due to the better penetration capacity, higher decreasing ratio of the porosity, and higher improvement of the physical, mechanical and durability proper-ties. The treatments also improved the properties of the aged stones;thus, it may be inferred that treatment would benefit the conservation of historical buildings.