Landfill gas (LFG) utilization which means a synergy between environmental protection and bioenergy recovery was investigated in this study. Pressure swing adsorption technology was used in LFG purification, and laboratory experiment, pilot-scale test, and on-site demonstration were carried out in Shenzhen, China. In the laboratory experiment, A-type carbon molecular sieve was selected as the adsorbent by comparison of several other adsorbents. The optimal adsorption pressure and adsorption time were 0.25 MPa and 2 min, respectively, under which the product generation rate was 4.5 m3/h and the methane concentration was above 90%. The process and optimization of the pilot-scale test were also reported in the paper. The product gas was of high quality compared with the National Standard of Compressed Natural Gas as Vehicle Fuel (GB18047-2000), when the air concentration in feed gas was under 10.96%. The demonstration project was composed of a collection system, production system, and utilization system. The drive performance, environmental protection performance, and economic feasibility of the product gas – as alternative fuel in passenger car, truck, and bulldozer – were tested, showing the feasibility technology for LFG utilization.
In order to achieve high-efficiency conversion of CO2 into valuable chemicals, and to exploit new applications of organobismuth compounds, cationic organobismuth complex with 5,6,7,12-tetrahydrodibenz[c,f]
In this study two types of biological contact oxidation processes (BCOP), a step-feed (SBCOP) unit and an inter-recycle (IBCOP) unit, were designed to investigate the treatment of heavily polluted river water. The Daqing River, which is the largest pollutant contributor to the Dianchi Lake, one of the most eutrophic freshwater lakes in China, was taken for the case study. It was found that the SBCOP had higher adaptability and better performance in the reduction of COD, TN, and TP, which made it applicable for the treatment of polluted river water entering the Dianchi Lake. Nitrification rate was observed to be greatly affected by the influent temperature. During each season, the nitrification in the SBCOP was higher than that in the IBCOP. TN removal efficiency in the SBCOP was higher than that in the IBCOP during the winter and spring but poorer during the summer, possibly due to the inhibition of denitrification by higher dissolved oxygen level in the summer. Moreover, symbiotic algae-bacteria growth may be conducive to the removal of pollutants.
Based on common phenomena of biochemical interaction between plants and microorganisms, the inhibitive effects of three common terrestrial compositae plants, namely
Hydrophobic organic contaminants (HOCs)—pyrene, and natural organic matters (NOM) from different sources were taken as the test compounds to investigate the impact of physicochemical characteristics of NOM on HOCs’ partition to the NOM in this study. The effects of solution property, NOM characteristics, and modification by ozone preoxidation on pyrene partition to NOM were systematically evaluated. According to the fluorescence quenching method, the partition coefficient
In order to investigate the contribution of various black carbon (BC) contents to nonlinearity of sorption and desorption isotherms for acetochlor on sediment, equilibrium sorption and desorption isotherms were determined to measure sorption and desorption of acetochlor in sediment amended with various amounts of BC. In this paper, two types of BC referred to as BC400 and BC500 were prepared at 400°C and 500°C, respectively. Higher preparation temperature facilitated the formation of micropores on BC to enhance its sorption capacity. Increase of the BC content obviously increased the sorption amount and reduced the desorption amount for acetochlor. When the BC500 contents in total organic carbon (TOC) increased from 0 to 60%, Freundlich sorption coefficient (
In order to provide basic data for practical application,photodegradation experiment of
For effective wastewater reclamation and water recovery, the treatment of natural and effluent organic matters (NOM and EfOM), toxic anions, and micropollutants was considered in this work. Two different NOM (humic acid of the Suwannee River, and NOM of US and Youngsan River, Korea), and one EfOM from the Damyang wastewater treatment plant, Korea, were selected for investigating the removal efficiencies of tight nanofiltration (NF) and ultrafiltration (UF) membranes with different properties. Nitrate, bromate, and perchlorate were selected as target toxic anions due to their well known high toxicities. Tri-(2-chloroethyl)-phosphate (TCEP), oxybenzone, and caffeine, due to their different
The anaerobic-anoxic oxidation ditch (A2/O OD) process is popularly used to eliminate nutrients from domestic wastewater. In order to identify the existence of denitrifying phosphorus removing bacteria (DPB), evaluate the contribution of DPB to biological nutrient removal, and enhance the denitrifying phosphorus removal in the A2/O OD process, a pilot-scale A2/O OD plant (375 L) was conducted. At the same time batch tests using sequence batch reactors (12 L and 4 L) were operated to reveal the significance of anoxic phosphorus removal. The results indicated that: The average removal efficiency of COD,
The purpose of this study is to present a library of analytical solutions for the three-dimensional contaminant transport in uniform flow field in porous media with the first-order decay, linear sorption, and zero-order production. The library is constructed using Green's function method (GFM) in combination with available solutions. The library covers a wide range of solutions for various conditions. The aquifer can be vertically finite, semi-infinitive or infinitive, and laterally semi-infinitive or infinitive. The geometry of the sources can be of point, line, plane or volumetric body; and the source release can be continuous, instantaneous, or by following a given function over time. Dimensionless forms of the solutions are also proposed. A computer code FlowCAS is developed to calculate the solutions. Calculated results demonstrate the correctness of the presented solutions. The library is widely applicable to solve contaminant transport problems of one- or multiple- dimensions in uniform flow fields.