Advanced Materials Research Vols. 955-959

Abstract: Innovations in the design and construction of a large scale modified UNITANK wastewater treatment plant (WWTP) are introduced in this paper. Long term operation results indicate that the Qianfeng II WWTP shows good pollutants removal performance and reduces operation cost greatly by saving phosphorus removal chemicals, which demonstrates that these innovations are practical and could be popularized for the similar projects in the future.

Abstract: The paper presents a numerical algorithm for simulating the trajectories of charged dust particles moving horizontally in the vicinity of an oppositely charged droplet. With taking the air drag, electrical and gravitational into account, the trajectories of charged dust particles are traced by solving the Newton equation. Calculation results show that the dust particles deposit in the whole surface of charged droplet by the effect of electrical force. Electrical force becomes the main factor for dust deposition at low Stokes.

Abstract: The objective of this work was to evaluate the performances of A lab-scale innovative sequencing batch biofilm reactor (SBBR) to treat domestic wastewater,in which a acryl cylinder (height 200 mm, diameter 70 mm) was equipped and many fiber threads were attached to the surface of the cylinder as the bacteria carrier. No time and volume for settling was required in this system. After one year’s operation, each parameter achieved the wastewater discharged criterion in 2 cycles (4 h). It was found that COD removal efficiency was up to 90% in 3 h, and ammonium nitrogen concentration approached the least value; total nitrogen removal efficiency reached 55%-71%. In this SBBR system simultaneous nitrification and denitrification was completed at the end of 2 cycles.

Abstract: The biological treatment process of landfill leachate in Beijing Liulitun landfill is a multistage A/O technology, in which a large amount of ANAMMOX (Anaerobic ammonia oxidation, ANAMMOX) bacteria were found in the sludge. There are several factors impacting the activity of ANAMMOX bacteria, including pH value, temperature and HRT which in this process are suitable for the survival of ANAMMOX bacteria. Especially, low dissolved oxygen is an essential factor as the provider of electron donor for nitrite formation. Although the high concentrations of organic matter, ammonia nitrogen and nitrite will inhibit the occurrence of ANAMMOX, ANAMMOX bacteria can self-detoxification by forming a low-poison habitat by consuming ammonia and nitrite as well as organic matter by heterotrophic ANAMMOX bacteria.

Abstract: On the membrane contactor test unit, chose monoethanolamine (MEA) as absorption solution to absorb CO₂ of simulated flue gases, studied effects of operating parameters on CO₂ capture. Operating parameters included initial CO₂ contents in flue gas, flue gas flow and absorption solution flow. Experimental results showed that: the greater the absorption of fluid flow, the higher the CO₂ removal rate;While the greater the flue gas flow or the higher the initial CO₂ concentration in flue gas, the lower the CO₂ removal rate. In order to study the influence of the regeneration solution on CO₂ absorption efficiency, regeneration experiments were done. Since the loss of solvent in regeneration solution, CO₂ removal efficiency by regeneration solution was lower than that by original absorption solution.

Abstract: The flashboard was installed in the circulation compartment of the modified oxidation ditch in order to regulate the mixed reflux from aerobic zone to anoxic zone. The differences of the nutrient removal efficiencies and the phosphate-removal bacteria content were researched before and after flashboard installation. The results showed that the average removal efficiencies of COD, NH₄⁺, TN, TP were 93.3%, 87.1%, 78.1% and 96.0% respectively, and the proportion of denitrifying phosphate-removal bacteria (DPB) to total phosphorus accumulating organisms were 46.1% after the flashboard installation. However, the average removal efficiencies of COD, NH₄⁺, TN, TP were 91.2%, 82.7%, 67.2% and 86.4% respectively, and the proportion of denitrifying phosphate-removal bacteria to total phosphorus accumulating organisms were 17.54% before the flashboard installation. So, the modified oxidation ditch with flashboard could enrich denitrifying phosphate-removal bacteria and and improve the nutrient removal efficiencies.

Abstract: The photodegradation behavior of bisphenol AF (BPAF) in TiO₂ suspension was investigated. The influence of dissolved oxygen, TiO₂ dosage, fluoride, and initial BPAF concentration on the degradation of BPAF was studied and described in details. The main purposes were to clarify the degradation kinetics of BPAF and quantify the fluoride concentration during the degradation. At an initial concentration of 40 mol/L, more than 97% of TOC was removed efficiency was achieved within 540 min irradiation, and the concentration of fluoride was 0.98 mg/L. Degradation of BPAF followed the Langmuir–Hinshelwood kinetics rate model and the reaction rate constant kre was 1.21 μM/min. The results obtained indicated that TiO₂ photocatalytic degradation is a highly effective way to remove BPAF without any generation of more toxic products or fluoride pollution.

Abstract: Supercritical water oxidation (SCWO) is an alternative to effectively dispose many varieties of organic wastewaters. In this article, a high concentration pesticide wastewater with very complicated components was handled by SCWO in a batch experimental plant at 25 MPa, 410–580 °C within the oxidant coefficient of 1.1–4.0 and the residence time of 1.0–10.0 min. The results show that reaction temperature, oxidant coefficient, residence time can improve X_COD (removal efficiency of chemical oxygen demand) of reactor effluent. X_COD reaches up to 99.89% at 550 °C, 25 MPa with the oxidant coefficient of 3.0 and the residence time of 5.0 min, and the corresponding COD concentration is 73 mg/L. Residence time indicates a relatively more important influence on COD₁ at higher reaction temperatures and OCs. Furthermore, possible reaction pathways for SCWO of organic matters in the pesticide wastewater were also proposed primarily.

Abstract: The sewage diffusion is an environmental material for protecting marine environment. It plays an important role in port engineering. Its effect under deep water was carried out between different diffuser design parameters based on the hydraulic model test, and Xian ren-dao port sewage marine disposal project was taken as an example. For South port project, jet angle was controlled to be 0 degree, and horizontal angle was controlled to be 0 degree. It not only can ensure that sewage fully diluted mixed, also can avoid the premature convergence and sewage lifting. It is feasible for selecting large angle nozzle under deep water and there are some technical bases have been provided for other sewage marine disposal project.

Abstract: Compared with the common wet process desulfurization in power engineering, this paper emphasis on seawater desulfurization process and characteristics ,and provide the reference for seawater desulfurization in foreign electric power engineering in the future.