International Journal of Environmental Engineering (9 papers in press)
CHARACTERIZATION OF NANO-SIZED PARTICLES IN CHEMICAL MECHANICAL POLISHING WASTEWATER
by NOOR AINA MOHAMAD ZUKI, NORLI ISMAIL, FATEHAH MOHD OMAR
Abstract: Treatment of chemical mechanical polishing (CMP) wastewater and fluoride-containing wastewater in semiconductor manufacturing are conventionally separated. The combined treatment of these two streams of wastewater was studied in terms of zeta potential and z-average hydrodynamic diameter profiles as a function of pH 2 to 12. Optimum pH for CMP wastewater was at pH 6 with zeta potential value of -10 mV and mean particle size of 180 d.nm. Meanwhile, for fluoride-containing wastewater the optimum pH obtained was at pH 9 with zeta potential of 10 mV and mean particle size of 5214 d.nm. These two streams were combined together at their respective optimum pH and resulted a zeta potential value of 0.55 mV and mean particle size of 12590 d.nm. Results indicated that the combined treatment for both polishing and fluoride-containing wastewater were beneficial as a larger flocs of fluorosilicate (SiF62-) was generated without the presence of coagulation chemicals. It is proposed that positively charged particles present in fluoride-containing wastewater become adsorbed on the surface of silica nanoparticles in CMP wastewater in which act as nuclei and enhances flocculation since repulsive force of both wastewater is decreased.
Keywords: Semiconductor wastewater; chemical mechanical polishing; pH; zeta potential; particle size; aggregation; disaggregation.
Treatment of 4-hydroxyphenylazobenzene (yellow azo dye) using microwave-photocatalyzed reactor
by Vitthal Gole, Archana Nagawade
Abstract: Present work investigates the treatment of environmentally hazardous and persistence 4-hydroxyphenylazobenzene (yellow azo dye) using the intensified technologies such as photocatalysis (UV), microwave (MW) and successive effects of microwave and photocatalysis (MW-UV). The treatment studies were further investigated in the presence of hydroxyl radical promoters such as hydrogen peroxide, copper oxide and titanium oxide. Our results confirmed that the maximum degradation was obtained for MW-UV compare to individual effects of MW and UV. The maximum degradation was obtained in the presence of titanium dioxide (91.6
Keywords: Yellow azo dye; Microwave; Photocatalysis; Hydroxyl Radicals; Wastewater treatment.
The Selection of Palm Oil Mill Effluent for Phytoremediation Treatment System Using Cyperus alternifolius
by Siti Kamariah Md Sa'at, Nastaein Qamaruz Zaman, Mohd Suffian Yusoff, Hossein Farraji
Abstract: Phytoremediation approach attains more attention recently due to the sustainable and green technology requirement. This technology promotes the utilisation of various aquatic macrophytes in agricultural, domestic, and industrial effluent treatment. In order to enhance the water quality of palm oil mill effluent (POME) ponds, the phytoremediation potential of Cyperus alternifolius, also known as umbrella sedge, was studied using different sources and concentrations of POME. The plant was selected due to their tolerance in high concentration of pollutants, extensive root systems, and aesthetic appearance as an ornamental plant. The phytoremediation of C. alternifolius was tested with aerobic, facultative, and polishing pond POME for 30 days of batch treatment in 6 L buckets for chemical oxygen demand (COD), total suspended solids (TSS), ammonia (NH3-N), and total phosphorus (TP) removal. For aerobic pond POME, the removal achieved 94.7% of TSS, 95.5% of COD, 92.7% of NH3-N, and 99.3% of TP. Meanwhile, for facultative pond POME, the removal of TSS, COD, NH3-N, and TP was 86.5%, 85.6%, 90.7%, and 99.5%, respectively. The removal for polishing pond POME was slightly lower than aerobic and facultative pond removal, except for TP, where the polishing pond showed a great removal of TP with 99.8%. The study suggests C. alternifolius as a macrophyte in the phytoremediation treatment of POME, particularly for the polishing step of treatment with a promising prospect.
Keywords: Phytoremediation; Water Quality; Palm Oil Mill Effluent; Aquatic plant; Cyperus alternifolius.
Sub- Surface Constructed Wetland System as Alternative Treatment for Effluent Discharge from Atenda Abattoir, Ogbomoso Southwestern Nigeria
by Oladipupo Seun Oladejo, Adewoye Olanipekun, Olayemi Samuel Diekola, Olasunkanmi Habib Olaniyan
Abstract: Abattoir is a slaughter house constructed for killing and dissecting animals for human consumption. Location within residential neighborhoods posed dangers on their immediate environment due to abattoir wastes and threat to available surface water bodies. The phyto-treatment of effluents from the Atenda abattoir in Ogbomoso, western Nigeria was investigated. Two cells were planted with Typha Orientalis and Sorghum Arundinaceum. The unplanted cell served as control. Wetland cells were fed with wastewater from abattoir and treated effluents were collected for analyses during a retention period of 10 days. Results showed Typha Orientalis has better contaminants removal ability (59.3- 99.9%) than Sorghum Arundinaceum (32.0- 98.65%), except in TDS where Sorghum has highest removal percentage (99.9%). Phytoremediation reduced 89.8% Turbidity, 99.89% Phosphate, and 99.5% of Biochemical Oxygen Demand (BOD). Heavy Metals in treated wastewaters were reduced within range of 83.5- 99.8% by Typha Orientalis, and 59.5- 84.9% by Sorghum Arundinaceum. The control cell has a competitive remediation efficiency with Typha. Quality of treated effluent proved phytoremediation as effective technology for abattoir wastewater treatment using locally available macrophytes and eventual application for irrigation purpose.
Keywords: Constructed Wetland; Abattoir wastewater; Phyto-removal; Typha Orientalis; Sorghum Arundinaceum.
Comparison of performance of three different seeding sludge under three different hyper-thermophilic temperatures
by Isaac Mbir Bryant, Marko Burkhardt, Marion Martienssen
Abstract: Performance of three seeding sludge under three different hyper-thermophilic temperatures, 60°C, 65°C and 70°C was investigated and compared with mesophilic (37°C) and thermophilic (55°C) temperatures using the same seeding sludge and substrate in batch tests. Based on German guidelines for batch tests, the seeding sludge were selected for the batch tests using eudiometer tubes. Daily volumes of methane production for the three sludge were measured. Methane yields and degrees of COD degradation of the black water were also calculated and compared. Cow manure at 65°C recorded the highest net normalised cumulative volume of methane content (387.2 mlNCH4−%), methane yield (231.7 mlNCH4/gVS) and degree of COD degradation (79.1%) while BTU at 70°C recorded the least performance of methane yield (0.0 mlNCH4/gVS) and content (0.0 mlNCH4−%) and degree of COD degradation (0.0%). Cow manure at 65°C should be considered when setting-up large-scale hyper-thermophilic digesters.
Keywords: methane yield; net cumulative methane content; degree of COD degradation; hyper-thermophilic temperatures; seeding sludge; biogas.
Evapotranspiration for cotton in plain and hilly areas in Chuadanga and Rangamati districts in Bangladesh using Penman method
by Mahbub Hasan, Aschalew Kassu
Abstract: Water management and its appropriate application for cultivating cotton have been a promising issue to ensure the best quality and quantity of production. Rainfall intensity and pattern, differences in temperature and cloudiness and non-cloudiness during the growing season, will affect crop water requirement. Different studies showed that excess or less water uses result into a lower yield. Evapotranspiration of any crop is predominantly dependent on environmental factors and crop factors. The environmental factors are further critical for energy requirement for crop development where sunshine hours, intensity of sunshine, duration of sunshine, temperature and relative humidity play the vital role. Due to the change in geographical location, the energy availability for contributing in the evapotranspiration is also different. Hence, the water requirement for the same cotton crop may vary for two different locations. A dependable and reliable scheduling system for irrigating is desirable for timeliness and quantity of water to irrigate for potential yield of cotton. In this article, a reliable approach to determine crop water requirement for cotton cultivation is proposed using the Penman method for Chuadanga, representing the flat land and Rangamati, representing hilly areas of Bangladesh.
Keywords: Penman method; reference crop coefficient; Kc; cotton irrigation; evapotranspiration; ETc; net radiation; Rn; energy balance; Bangladesh.
The influencing factors study on environmental responsibility motive of oil and gas enterprises
by Yanling Xiao, Yanmei Sheng, Yuanyuan Liu
Abstract: In China, as heavily polluting enterprises, oil and gas enterprises, while playing a major role in national economy and the people's livelihood, should assume the environmental responsibility of state-owned enterprises. Through in-depth corporate research, the influencing factors of the environmental responsibility motive of oil and gas enterprises are explored. Principal component analysis method was used to reduce dimensionality of influencing factors, extract four main influencing factors. Then the relationship between each influencing factor and the implementation of environmental responsibility of oil and gas enterprises, so as to the relationship between various factors, was analysed in depth, and the causality diagram was creatively drawn according to the system dynamics principle. On this basis, the realisation path of the environmental responsibility dynamic mechanism of oil and gas enterprises is proposed, which is of great significance for promoting the fulfilment of the environmental responsibility of oil and gas enterprises and achieving ecological sustainable development.
Keywords: oil and gas enterprise; environmental responsibility; influencing factors; dynamic mechanism.
Analysis of vegetation community landscape structure based on eco-tourism management
by Chunjiang Yang, Yujiang Yang, Xiuli Tan
Abstract: Vegetation community is an important factor to enrich green landscapes and an important index to evaluate their greening level. With the development of economy and the acceleration of urbanisation, single vegetation landscapes have failed to meet people's aesthetic vision. For ecotourism management, this study takes the two cities of Anshan, Liaoning and Yantai, Shandong as an example to analyse the forest vegetation community in Anshan and the road vegetation community of Yantai. The results showed that herb coverage, shrub coverage, shrub frequency, proportion of arbours and needles, number of shrubs and average diameter had a certain influence on forest community landscape. The relationship between the number of arbours and shrubs and the diameter of arbours had significant influence on forest landscape. Besides, a structural design was carried out on road landscape based on colour and space in order to meet the cooling, noise reduction and shadowing functions to highlight the uniqueness of urban road landscape, combining with the speed of the pacers and drivers. Through the structural analysis of the two plant community landscapes, the related support for the structural design of the future plant community landscapes is provided.
Keywords: ecotourism; vegetation community; landscape structure.
Modelling of the predicted thermal comfort of the metro passengers under different crowd densities
by Zhiying He, Chunjun Chen, Gang Yang, Lei Yan
Abstract: The aim of this study is to find out the nature of the metro passenger's thermal comfort under different crowd densities and different ambient environment factors. Taking the human factors, garment factors and ambient environmental factors into consideration, a sub-model human thermal perception was investigated based on the Fanger's heat balance equation. Also, a steady thermal sub-model of the B-type metro vehicle was built based on the heat conservation among the passengers, the outside-vehicle environment and the air of human-vehicle system. Then, the human thermal perception and its alternation were quantified by applying the PMV index. Simulation results show that the passenger's thermal perception cannot only variates with the airflow velocity, the relative humidity and the volume of the new air, but also with the crowd density.
Keywords: thermal comfort; metro; crowd density; thermal balance; predicted mean vote; PMV.