Assessment of water quality of Batang Rajang at Pelagus Area, Sarawak, Malaysia

This study was carried out to examine the water quality of Batang Rajang at Pelagus area, Sarawak, Malaysia. Water quality was determined at 12 stations along Batang Rajang and its tributaries in terms of in-situ and ex-situ water quality parameters. The results showed that most stations at main river were categorized as slightly polluted while most tributaries were clean according to the Water Quality Index. The river is suffering from organic pollution where almost all stations along the river contained high chemical oxygen demand (≈ 43.1 mg/L) and total ammonia nitrogen (≈ 0.520 mg/L) and were classified as Class III and IV at most of the stations. High suspended solids (218.3 mg/L) and low dissolved oxygen (4.6 mg/L) were observed at the main river. The low dissolved oxygen content from the Bakun dam upstream of the study area has an impact on the river particularly during dry season where DO dropped below the minimum required for sensitive aquatic organisms. As seven tributaries are within Class II indicating healthy freshwater ecosystems, they should be conserved as habitats for sensitive aquatic organisms. Conversely, proper management need to be initiated in particular, Sungai Merit tributary and the main river where DO were below the minimum required for sensitive aquatic organisms

Assessment of Water Quality of Batang Rajang at Pelagus Area, Sarawak, Malaysia

This study was carried out to examine the water quality of Batang Rajang at Pelagus area, Sarawak, Malaysia. Water quality was determined at 12 stations along Batang Rajang and its tributaries in terms of in-situ and ex-situ water quality parameters. The results showed that most stations at main river were categorized as slightly polluted while most tributaries were clean according to the Water Quality Index. The river is suffering from organic pollution where almost all stations along the river contained high chemical oxygen demand (≈ 43.1 mg/L) and total ammonia nitrogen (≈ 0.520 mg/L) and were classified as Class III and IV at most of the stations. High suspended solids (218.3 mg/L) and low dissolved oxygen (4.6 mg/L) were observed at the main river. The low dissolved oxygen content from the Bakun dam upstream of the study area has an impact on the river particularly during dry season where DO dropped below the minimum required for sensitive aquatic organisms. As seven tributaries are within Class II indicating healthy freshwater ecosystems, they should be conserved as habitats for sensitive aquatic organisms. Conversely, proper management need to be initiated in particular, Sungai Merit tributary and the main river where DO were below the minimum required for sensitive aquatic organisms

Water and sediment quality of Rajang River at Pelagus area, Sarawak

This study was carried out to examine the water and sediment quality of Rajang River at Pelagus area to produce a baseline reference of the environment before the construction of a hydroelectric power dam that has been scheduled in the development plan of Sarawak. Samples were collected at 12 stations along the Rajang River from Pelagus Rapid to Punan Bah on 27th to 28th August 2014 and 14th to 15th January 2015. Results of this study show that water quality was affected by logging, vegetation and waste from households and animals around the study area. The total suspended solids and turbidity of stations 1, 5, 6, 7, 10, 11 and 12 exceeded Class II limit of 50 mg/L while dissolved oxygen of stations 1, 6 and 11 fall into Class III (3 – 5 mg/L) based on INWQS. Biochemical oxygen demand of stations 1, 2, 4, 5, 6, 7, 8, 9, 10, 11 and 12 are not complied with Class II (1 – 3 mg/L) while chemical oxygen demand of all the stations are exceeded Class II limit 25 mg/L based on INWQS. Moreover, total ammonia nitrogen of all the stations except station 8 exceeded Class II limit of 0.3 mg/L According WQI, only stations 2, 3, and 4 which are tributaries are classified under Class II (76.5 – 92.7) while stations 1, 6, 7 and 11 that are located at main river and other stations 5, 8, 9, 10 and 12 which are located at tributaries are not compliance with Class II. WQI of station 7 – 12 which are more nearer to the Bakun Dam are classified in Class III as the chemical oxygen demand and biochemical oxygen demand of them are higher than others. Dissolved oxygen, turbidity, total suspended solids and total sulphide of most of the stations that located at main river are higher than stations at tributaries. Sediment samples are mineral acidic and higher organic matter has recorded with higher weight of water content whereas the total phosphorus and total nitrogen in sediment are 46.53 – 102.86 mg/kg and 0.73 – 6.17 mg/kg

Synthesis and Characterization of Unsymmetrical α,β-Conjugated Keto Derivatives and their Complexes for Dye Sensitizer Solar Cell (DSSC) Application

A total of 3 novel compounds of unsymmetrical bis-chalcone, namely, compound 1A, 1B and 1C had been synthesized by the Claisen-Schmidt condensation reaction. The synthesized unsymmetrical bis-chlacone compounds were further proceeded to the complexation with cis-dichlorotetrakis(dimethylsulfoxide) ruthenium(II) precursor and boron trifluoride diethyl ether to produce the new ruthenium(II) complexes, 2A, 2B and 2C and borondifluoride complexes, 3A, 3B and 3C. The molecular structure of the synthesized compounds and complexes were spectroscopically characterized and confirmed by fourier transform infrared spectrophotometer, proton and carbon nuclear magnetic resonance spectrometer, UV-visible spectrophotometer and CHN analysis. The single crystal of complexes 2C and 3C were analyzed by X-ray crystallography and resolved using Apex III and Olex 2.0 software. At last, all synthesized compounds and complexes were applied as the dye sensitizer in the dye-sensitized solar cell (DSSC) by using FTO glass coated with titanium dioxide (TiO2) as the working electrode and the ITO glass coated with platinum as the counter electrode. The conversion efficiency was tested using the San Ei XES-40S1 Solar Simulator under monochromatic light of air mass 1.5 global (AM 1.5G) with the incident light intensity of 100 mW/cm2. Results showed that complex 3C that consists of OMe and borondifluoride substituents in the same molecule achieved the highest efficiency at 0.091% with 14% IPCE at 430 nm. Conversely, the ruthenium complexes have the lowest efficiency at 0.001 – 0.002% with 0.32-2.55% IPCE at 430 nm. Aside from the importance of push-pull effect in the conversion efficiency, the results from X-ray crystal data also discovered the pi-conjugation that allows charge transfer which plays vital role in the conversion efficiency of a DSSC

Monitoring of Ammoniacal Nitrogen and Phosphate in the Leachates When Diluted Palm Oil Mill Effluent was Used as a Fertilizer

Palm oil mill effluent (POME) contains a high amount of nutrients and organic matter; therefore, it has been considered as an alternative liquid fertilizer (LF). However, the studies on the reuse of POME as fertilizer have been mostly limited to nutrients absorption but the leachates were neglected. Such approach caused potential impacts on ground water pollution. Thus, this research aimed to compare the leachabilities of ammoniacal nitrogen (NH3-N) and phosphate (PO4 3- ), as well as the growth rates of oil palm seedlings in three different watering conditions. Six oil palm seedlings were watered with either POME, LF or tap water. The leachates from each seedling pot were collected weekly and analyzed for their NH3-N and PO4 3- concentrations. The pots which were watered with tap water showed the highest leaching rate of 0.0251 mg.L-1 .week-1 for NH3-N and 0.0392 mg.L1 .week-1 for PO4 3-. The average concentrations of NH3-N in the leachates from the POME, LF and tap water pots were 0.45, 0.38 and 0.36 mg/L, respectively, whereas for PO4 3- , the average concentrations were 1.09 (POME), 0.96 (LF) and 0.66 (tap water) mg/L. The quickest plant growth rates were recorded in tap water (0.56 cm/day), followed by LF (0.51 cm/day) and POME (0.42 cm/day)