Emerging disinfection by-products formation of various molecular weight organic matter fractions in raw water contaminated with treated wastewater.

Combining dissolved organic matter (DOM) in raw water (RW) with DOM in treated wastewater (TWW) can react with chlorine and pose emerging disinfection by-products (DBPs). This study evaluated DOM based on the molecular weight (MW) size fractionation, trihalomethane, iodinated-trihalomethane, haloacetonitrile, and trichloronitromethane formation potential (THMFP, I-THMFP, HANFP, and TCNMFP) of the RW from the U-Tapao Canal, Songkhla, Thailand and the RW mixed with TWW (RW + TWW) samples. The RW and RW + TWW were treated by coagulation with poly aluminum chloride. The DOM of RW and RW + TWW and their treated water was distributed most in the MW below 1 kDa. The MWs of 3-10 kDa and 1-3 kDa were the active DOM involved in the specific THMFP for the RW + TWW. The MW of < 1 kDa in the RW + TWW resulted in a slightly high specific I-THMFP and HANFP. The MW of 1 - 3 kDa in the coagulated samples had a high specific I-THMFP. The MW of > 10 kDa in the coagulated RW + TWW was a precursor for a particular HANFP. Monitoring systems for measuring the level of TWW mixed with RW and an effective process to enhance the efficiency of traditional water treatment must be set up to produce a consumer-safe water supply.

Enhanced coagulation process for removing dissolved organic matter, microplastics, and silver nanoparticles.

Dissolved organic carbon (DOC), microplastics (MPs), and silver nanoparticles (AgNPs) in water are of major concern because of their direct and indirect toxic effects on aquatic organisms and human exposure via water. This work investigated the effect of poly aluminum chloride (PACl) coagulation for reducing DOC, MPs, and AgNPs. This work used water from a canal in Thailand with a DOC of 5.2 mg/L in the experiment. AgNPs of 5-20 mg/L were added to canal water to create synthetic water for the PACl coagulation. Polyethylene and polypropylene (PP) type MPs were identified in the raw water with Fourier transform infrared spectroscopy. Coagulation with 15 mg/L of PACl performed better in the PP removal. The PACl coagulation at dosages of 15, 40, and 70 mg/L removed DOC by 16-20%, 44-52%, and 46-63% and AgNPs by 34-90%, 53-93%, and 81-95%, respectively. The presence of AgNPs at high levels could inhibit the efficiency of DOC reduction by the PACl coagulation. The FESEM identified the adsorption of silver-containing nanoparticles onto the flocs with increased dosages of PACl. So, PACl is a coagulant in the removal of AgNPs that can reduce health hazards and eco-toxicological risks in water sources due to the release of silver.

Characterization of DBP precursor removal by magnetic ion exchange resin using spectroscopy and high-resolution mass spectrometry.

The characteristics of dissolved organic matter (DOM) play an important role in the formation and speciation of carcinogenic disinfection byproducts. This study investigated changes in the characteristics and reactivity of DOM caused by the magnetic ion exchange resins, MIEX® DOC and MIEX® GOLD, using fluorescence excitation-emission matrix (EEM) with parallel factor (PARAFAC) analysis and Orbitrap mass spectrometry (Orbitrap MS) with unknown screening analysis. A five-component PARAFAC model was developed and validated from 208 EEMs of raw and MIEX®-treated water samples. The two resins exhibited preferential removal of the humic-like components (67-87% removal) and successfully removed protein-like components to a lesser extent (5-61% removal). Unknown screening analysis indicated removal of most condensed aromatic structures and lignin-like features that had high O/C values and refractory characteristics of lipid-like features by MIEX® treatments. MIEX® preferentially removed DOM molecules with more oxidized and shorter CH2 chains. The two resins had similar performance in trihalomethanes formation potential removal, but MIEX® GOLD achieved greater haloacetonitriles formation potential removal owing to its larger pore opening. Over 100 CHOCl DBP features were commonly found in all the samples while tens of CHOCl DBPs were uniquely formed in the samples with and without pre-treatments by MIEX®. Treatments by MIEX® before chlorination resulted in more intermediate CHOCl DBPs formed after chlorination compared to chlorinated raw waters. By optical spectroscopic analysis together with Orbitrap MS molecular characterization, we were able to confirm both quantitative and qualitative changes in DOM properties by MIEX® treatment related to DBP formation.

Effect of silver nanoparticles and chlorine reaction time on the regulated and emerging disinfection by-products formation.

Silver nanoparticles (AgNPs) are used in many industries for multiple applications that inevitably release AgNPs into surface water sources. The formation kinetics of disinfection by-products (DBPs) in the presence of AgNPs was investigated during chlorination. Experiments were carried out with raw water from a canal in Songkhla, Thailand, which analyzed the formation potential (FP) of trihalomethanes FP (THMFP), iodo-trihalomethanes FP (I-THMFP), haloacetonitriles FP (HANFP), and trichloronitromethane FP. Increased AgNP concentrations by 10-20 mg/L led to a higher specific formation rate of chloroform which is described by zero- and first-order kinetics. The increase in the specific formation of chloroform as increasing chlorine contact time could enhance both the THMFP rates and the maximum THMFP concentrations in all tested AgNPs. The AgNP content did not have a significant influence on I-THMFP and HANFP concentrations or speciation. The I-THMFP and HANFP increased in a short-chlorination time as mostly complete formation <12 h, and then the rate decreased as the reaction proceeded. The levels of THMs and many emerging DBPs are related to the presence of AgNPs in chlorinated water and chlorine reaction time. THMFP had a higher impact on integrated toxic risk value (ITRV) than I-THMFP and HANFP because of the chlorination of water with AgNPs. The chlorine reaction time was more effective for increasing the ITRV of THMFP than the level of AgNPs. Water treatment plants should control the DBPs that cause possible health risks from water consumption by optimizing water distribution time.

Non-target screening of dissolved organic matter in raw water, coagulated water, and chlorinated water by Orbitrap mass spectrometry.

This study aimed to classify the possible molecular formulas of precursors for disinfection by-products (DBPs) in raw, coagulated, and chlorinated water samples from the U-Tapao Canal, Songkhla, Thailand. The molecular formulas of DBPs in chlorinated water were investigated. Polyaluminum chloride (PACl) was employed as a coagulant. Orbitrap Fourier transform-mass spectrometry was able to estimate the composition of dissolved organic matter (DOM) with the carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sulfur (S) elements contained and DBPs at the molecular level. The molecular formulas of the DOM in the raw water primarily consisted of CHO and CHON when extracted by lichrolut EN. The CHO and CHON species were rich in lignin-, tannin-, and condensed aromatic-like substances. The DOM with high-molecular-weight from 300 to 500 Da were preferentially removed by coagulation. The PACl coagulation decreased the abundances of lignin-, tannin-, and condensed aromatic-like substances in the CHO formulas, while lignin- and condensed aromatic-like substances in the CHON formulas remained. The remaining precursors corresponded to CHON molecules in the coagulated water, which may result in the formation of some chlorine (Cl)-containing molecules. Several DBPs among the CHOCl and CHONCl species were produced in the chlorinated water through the addition reaction of chlorine. New chlorinated N-DBPs of 21 formulas were detected.

Assessing the water scarcity footprint of food crops by growing season available water remaining (AWARE) characterization factors in Thailand.

Water scarcity problems are a national agenda that must be prioritized. Thailand is an agricultural country with agriculture consuming a large amount of water. Sustainable water management for the agricultural sector is urgently needed. This study assessed the impacts of water consumption by agricultural products using a water scarcity footprint (WSF) assessment. This study presents the use of the growing season available water remaining characterization factors (AWARE CFs) of specific crops, based on growth months of that crop, instead of the annual AWARE CFs of agricultural products to assess the value of this approach for an appropriate assessment of water resource and the planning of crop production priorities. The original marginal AWARE CF was considered for determining the growing season AWARE CFs of major rice, second rice, sugarcane, maize, and cassava in 25 Thai watersheds. The growing season AWARE CFs of the food crops were used to determine their WSFs for the 25 Thai watersheds. The growing season AWARE CFs of major rice, second rice, sugarcane, maize, and cassava for Thailand were 1.74, 11.5, 6.01, 3.28, and 7.96 m3 world-eq. per m3 consumed, respectively. There were statistical differences between the means of annual AWARE CFs and growing season AWARE CFs for all Thai food crops in almost all watersheds. The WSFs using growing season AWARE CFs of major rice, second rice, sugarcane, maize, and cassava were 0.05-3.66, 1.10-193, 0.51-7.99, 1.09-8.28, and 1.65-30.3 m3 world-eq. per kilogram, respectively. This work identified suitable watersheds for growing food crops and compiled them as databases for the use of zoning food crop cultivation by the Thai government. Regarding WSF values, the least suitable watershed for growing major rice, second rice, sugarcane, and cassava was the Petchaburi watershed. The least suitable watershed for growing maize was the Chao Phraya watershed.

Characterization of lower Phong river dissolved organic matters and formations of unknown chlorine dioxide and chlorine disinfection by-products by Orbitrap mass spectrometry.

Dissolved organic matter (DOM) have been reported as precursors of disinfection byproducts (DBPs) and its molecular characteristics are rarely investigated due to its complexity. In this study, changes in the characteristics of DOM were investigated in the lower Phong River in Thailand in dry season and after the first rain in rainy season, using a non-targeted analysis with Orbitrap mass spectrometry. The river was rich with CHO features dominated by lignin-like molecules, while lipid-like molecules increase after domestic wastewater discharges. Wastewater discharge released DOM with higher molecular weight (MW) that was less oxygenated (low O/C) and less oxidized (low carbon oxidation state [Cos]). A lake affected by anthropogenic activities contributed more oxidized DOM into the river, while surface runoff carried DOM that is more oxygenated (high O/C), less hydrogenated (low H/C), and more oxidized (high Cos) to the stream. Water treatment further modified DOM to be lower MW. Approximately three hundred Cl-containing features (CHOCl) detected upstream were also found downstream. Disinfection by chlorine (Cl2) or chlorine dioxide (ClO2) formed both CHO and CHOCl DBPs. Low chlorine dosage applied to upstream and downstream samples resulted in many common unknown DBPs while increasing chlorine dosage resulted in more unique DBPs. At the same dosage, Cl2 reacted with DOM more than ClO2, including more oxidized molecules that are refractory to ClO2. Both Cl2 and ClO2 produced chlorinated and non-chlorinated DBPs, and some DBPs were commonly found by both disinfections. Cl2-produced DBPs were more unsaturated (higher [DBE-O]/C) and oxidized (higher Cos) than ClO2-DBPs.

Vacuum ultraviolet irradiation for mitigating dissolved organic nitrogen and formation of haloacetonitriles.

The main objective of this work was to investigate the feasibility of using vacuum ultraviolet (VUV, 185 + 254 nm) and ultraviolet (UV, 254 nm) for the reduction of dissolved organic nitrogen (DON) and haloacetonitrile formation potential (HANFP) of surface water and treated effluent wastewater samples. The results showed that the reduction of dissolved organic carbon (DOC), DON, hydrophobicity (HPO), absorbance at 254 nm (UV254), and fluorescence excitation-emission matrix (FEEM) of both water samples by VUV was higher compared to using UV. The addition of H2O2 remarkably improved the performances of VUV and UV. VUV/H2O2 exhibited the highest removal efficiency for DOC and DON. Even though HANFP increased at the early stage, its concentration decreased (19-72%) at the end of treatment (60 min). Decreases in DON (30-41%) and DOC (51-57%) led to HANFP reduction (53-72%). Moreover, FEEM revealed that substantial reduction in soluble microbial product-like compounds (nitrogen-rich organic) had a strong correlation with HANFP reduction, implying that this group of compounds act as a main precursor of HANs. The VUV/H2O2 system significantly reduced HANFP more than UV/H2O2 and therefore is suitable for controlling HAN precursors and HAN formation in drinking water and reclaimed wastewater.

Kinetics of the formation and degradation of carbonaceous and nitrogenous disinfection by-products in Bangkok and Songkhla source waters.

The kinetics of the formation and degradation of disinfection by-products (DBPs) in the treated water from the Bangkhen and Hatyai water treatment plants in Thailand were investigated. The DBPs studied included trichloromethane (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), trichloroacetonitrile (TCAN), dichloroacetonitrile (DCAN), bromochloroacetonitrile (BCAN), and trichloronitromethane (TCNM). When the chlorination time was increased, the levels of TCM, BDCM, DBCM, and TCNM increased, while the levels of TCAN, DCAN, and BCAN decreased. The kinetic rates of DBPs' formation were assessed based on the formation and degradation rates, which were best described by first-order kinetics. TCM had the highest formation rate with a range of rate constants from 5.5 × 10-3 to 7.3 × 10-3 h-1. TCAN had the lowest degradation rate with a range of rate constants from 0.6 × 10-3 to 2.9 × 10-3 h-1. Good correlations were observed between chlorination time and DBPs' formation normalized by LC50, lowest cytotoxicity, and lowest genotoxicity. A high formation rate of TCM and a low degradation rate of TCAN normalized by their toxicity were observed. The optimal retention time providing low DBPs' formation together with high DBPs' degradation was determined. The retention time of three days decreased the sum of the DBPs/LC50, DBPs/lowest cytotoxicity, and DBPs/lowest genotoxicity from a retention time of one day by 40-60%, 45-65%, and 25-36%, respectively.

Degradation of N-nitrosodimethylamine and its amine precursors by cumene-induced Rhodococcus sp. strain L4.

N-nitrosodimethylamine (NDMA) is a potential carcinogen that is produced as a disinfection by-product of chloramination or chlorination process in water and wastewater treatment systems. The ability of the dioxygenase-expressing bacteria, Rhodococcus sp. strain L4, to degrade NDMA after induction with cumene was examined in the presence and absence of its potential precursors. Dimethylamine (DMA), aniline (AN) and humic acid (HA) were selected as the precursors. The induced bacteria were able to degrade NDMA from initial concentrations ranging between 1 and 10 mg L-1 to an undetectable level (< 0.24 µg L-1) while there was no degradation of NDMA by the corresponding non-induced strain. The specific first-order degradation rate of NDMA ranged from 0.337 to 0.426 µg g-protein-1 h-1. Successful removal of all precursors was achieved by the induced bacteria. The presence of DMA had no negative effect on NDMA degradation. In contrast, a lag period was observed for the degradation of NDMA when AN or HA was present (except for the presence of 0.1 mg L-1 AN). In the presence of all precursors, NDMA degradation was negatively affected by the increased concentration (from 1 to 10 mg L-1) of all precursors.

Emerging disinfection by-products' formation potential in raw water, wastewater, and treated wastewater in Thailand.

Raw water (RW) from the Bangkok and Sing Buri water treatment plants located on the Chao Phraya River, river water, domestic wastewater (WW), and treated wastewater (TWW) from two wastewater treatment plants in Thailand were collected three times to investigate disinfection by-products' (DBPs) formation potential (FP) including trihalomethane FP (THMFP), iodo-THMFP (I-THMFP), haloacetonitriles FP (HANFP), and trichloronitromethane FP (TCNMFP). High THMFP levels were observed in river water, WW, and TWW. Considering average value, the THMFP of TWW was about two times higher than that of RW. Relatively high levels of I-THMFP were found in WW and TWW. The I-THMFP of TWW was three to seven times higher than that of RW. The HANFP of TWW was one to three times higher than that of RW. High levels of TCNMFP were found in WW and TWW. TCNMFP of TWW was six to thirteen times higher than that of RW. The discharge of TWW to RW must be prevented and controlled. The moderately positive linear relationship was obtained between dissolved organic carbon and TCNMFP in TWW. Considering measured weight concentration, THMFP was found as the highest DBPs. The highest lethal concentration 50-weighted and lowest cytotoxicity-weighted concentrations of DBPs were determined for HANFP.

Improving regional water scarcity footprint characterization factors of an available water remaining (AWARE) method.

Increasing water demand and decreasing freshwater availability in an area can cause water scarcity leading to damage to human health, ecosystem quality, and natural resources. Many countries around the world, including Thailand, have recognized the importance of this problem. The available water remaining (AWARE) characterization model provides water scarcity footprint characterization factors (WSF CFs) for assessing the WSF of products. AWARE CFs were prepared from WaterGAP model's data and are available in watershed and country levels. They were not provided for specific areas and could not accurately explain water scarcity situations in certain regions, potentially leading to inappropriate water management. This work calculates the annual and monthly local CFs from local data in the Chao Phraya watershed in Thailand. The monthly local CFs with local environmental water requirement (EWR) calculations ranged from 0.10 to 100. The mean difference between AWARE CFs and local CFs was statistically significant. The most sensitive parameters for local CFs in the dry season were water availability (WA) and agricultural water consumption and that in the wet season was WA. The weighting of AWARE CFs by each type of water consumption and an aggregate of AWARE CFs for product production has been recommended for WSF assessment. The AWARE methodology was modified to assess the individual water scarcity of each water user based on the order of priority. For the Chao Phraya watershed, the ranges of the monthly local individual CFs using local EWR calculations of domestic, environment, livestock, agriculture, and industry were 0.10-0.33, 0.10-0.37, 0.10-0.37, 0.10-100, and 0.10-100, respectively. This assessment of individual water scarcity is helpful for prioritizing the level and timing of water use to minimize their impacts on critical water scarcity.

Reduction by enhanced coagulation of dissolved organic nitrogen as a precursor of N-nitrosodimethylamine.

Raw water from the Banglen (BL) water treatment plant (WTP) and Bangkhen (BK) WTP in central Thailand and Hatyai (HY) WTP in southern Thailand was investigated for dissolved organic nitrogen (DON) reduction. The DON(mg N/L) and the dissolved organic carbon (DOC)/DON ratio were 0.34 and 21, 0.24 and 18, and 1.12 and 3 for the raw waters from BL, BK, and HY WTPs, respectively. Polyaluminum chloride (PACl) dosages of 150, 80, and 40 mg/L at pH 7 were the optimal coagulation conditions for the raw waters from BL, BK, and HY WTPs, respectively, and could reduce DON by 50%, 42%, and 42%, respectively. PACl and powder activated carbon (PAC, both in mg/L) at 150 and 20, 80 and 20, and 40 and 60 could reduce DON in the raw waters from BL, BK, and HY WTPs by 71%, 67%, and 29%, respectively. DOC/DON values of water treated with PACl were similar to those of raw water. DOC/DON values of water treated with PACl and PAC were lower than those of raw water. N-nitrosodimethylamine (NDMA) formation potentials of raw water, water treated with PACl, or both PACl and PAC, and organic fractions of BL, BK, and HY WTPs were below the detection limits of 542 and 237 ng/L, respectively. Reductions in fluorescence intensities of tryptophan-like substances at peaks 240/350 and 280/350 (nmEx/nmEm) were moderately (correlation coefficient, R = 0.85 and 0.86) and fairly (R = 0.59, 0.67, and 0.75) correlated with DON reduction.

The presence of aliphatic and aromatic amines in reservoir and canal water as precursors to disinfection by-products.

This research aimed at determining the dimethylamine (DMA), diethylamine (DEA), dibutylamine (DBA), and aromatic aniline (AN) in reservoir and canal water in the U-Tapao River Basin, Songkhla, Thailand. The trihalomethane formation potential (THMFP) and N-nitrosodimethylamine formation potential (NDMA-FP) of the reservoir and canal water were analyzed. Water samples from two reservoirs and raw water from water treatment plants at upstream, midstream, and downstream locations of the canal were collected twice. The analysis of the DMA, DEA, DBA, and AN were conducted using gas chromatography and spectrofluorometry techniques. The DMA, DEA, and DBA levels in the reservoir and canal waters ranged from not detectable (ND) to 10 µg/L and from ND to 21.2 µg/L, respectively. AN was detected from 123 to 129 ng/L and from 112 to 177 ng/L in the reservoir and canal waters, respectively. The DMA, DEA, DBA, and AN exhibited two fluorescent peaks at 230nmEx/345nmEm and 280 nmEx/355nmEm. These two peaks corresponded to the peak positions of tryptophan. Detection limits of DMA, DEA, and DBA for fluorescent analysis were 500 µg/L whereas that of AN and tryptophan were 10 and 0.5 µg/L, respectively. The NDMA-FP measured in all the water samples was lower than the detection limit of 237 ng/L. THMFP ranged from 175 to 248 µg/L and 214 to 429 µg/L was detected in the reservoir and canal waters, respectively. The THMFP/dissolved organic carbon (DOC) of the reservoir and canal waters were comparable within the ranges of 73 to 131 µg THMFP/mg DOC.

Formation of trihalomethanes of dissolved organic matter fractions in reservoir and canal waters.

The formation of trihalomethanes (THMs) of hydrophobic organic fraction (HPO), transphilic organic fraction (TPI), and hydrophilic organic fraction (HPI) of reservoir and canal waters from the U-Tapao River Basin, Songkhla, Thailand was investigated. Water samples were collected three times from two reservoirs, upstream, midstream, and downstream of the U-Tapao canal. The HPO was the major dissolved organic matter (DOM) fraction in reservoir and canal waters. On average, the HPO accounted for 53 and 45% of the DOM in reservoir and canal waters, respectively. The TPI of 19 and 23% in reservoir and canal waters were determined, respectively. The HPI of 29% of the reservoir water and HPI of 32% of the canal water were detected. For the reservoir water, the highest trihalomethane formation potential (THMFP)/dissolved organic carbon (DOC) was determined for the HPI, followed by the TPI and HPO, respectively. The average values of the THMFP/DOC of the HPI, TPI, and HPO of the reservoir water were 78, 52, and 49 µg THMs/mg C, respectively. The highest THMFP/DOC of the canal water was detected for the HPI, followed by HPO and TPI, respectively. Average values of the THMFP/DOC of HPI of water at upstream and midstream locations of 58 µg THMs/mg C and downstream location of 113 µg THMs/mg C were determined. Average values of THMFP/DOC of HPO of water at upstream and midstream and downstream locations were 48 and 93 µg THMs/mg C, respectively. For the lowest THMFP/DOC fraction, the average values of THMFP/DOC of TPI of water at upstream and midstream and downstream locations were 35 and 73 µg THMs/mg C, respectively.

Water footprints of products of oil palm plantations and palm oil mills in Thailand.

The water footprint (WF) of fresh fruit bunches (FFBs) from oil palm plantations and crude palm oil (CPO) from palm oil mills in southern and eastern Thailand were determined over 25 years. Climatic conditions, soil characteristics, and the characteristics of oil palm growth were considered. The WF of FFBs was 1063 m(3)/ton (t) on average. Green, blue, and grey waters comprised of 68, 18, and 14% of total WF, respectively. The oil palm plantations in Thailand required smaller amounts of indirect blue water. The average WF for producing a ton of CPO of seven mills was 5083 m(3). Most of the waters used in the mills originated from indirect green, blue and grey waters from the plantations. The direct blue water used in the mills had less impact on the total WF, lower than 1% of the total WF. Average percentages of green, blue, and grey waters of 69, 16, and 15% of total WF were determined for the mills, respectively. The water deprivation of the FFBs and CPO ranged from 0.73-12.9 and 3.44-58.3 m(3)H2Oeq/t, respectively. In 2013, the CPO production in Thailand including green, blue, and grey waters from plantation and blue water from mills required 11,343 million m(3) water. If the oil palm variety Suratthani 7 is used in the plantation, it would increase the yield from 15.2 to 22.8 t FFBs/ha-year and decrease the WF to 888 m(3)/t FFBs. The average value of the oil extraction rate (OER) of mills was 18.1%. With an increase in the OER of 1%, a reduction of the WF of 250 m(3)/t CPO or 5.1% of total WF could be obtained.

Alternative technologies for the reduction of greenhouse gas emissions from palm oil mills in Thailand.

Alternative methodologies for the reduction of greenhouse gas (GHG) emissions from crude palm oil (CPO) production by a wet extraction mill in Thailand were developed. The production of 1 t of CPO from mills with biogas capture (four mills) and without biogas capture (two mills) in 2010 produced GHG emissions of 935 kg carbon dioxide equivalent (CO2eq), on average. Wastewater treatment plants with and without biogas capture produced GHG emissions of 64 and 47% of total GHG emission, respectively. The rest of the emissions mostly originated from the acquisition of fresh fruit bunches. The establishment of a biogas recovery system must be the first step in the reduction of GHG emissions. It could reduce GHG emissions by 373 kgCO2eq/t of CPO. The main source of GHG emission of 163 kgCO2eq/t of CPO from the mills with biogas capture was the open pond used for cooling of wastewater before it enters the biogas recovery system. The reduction of GHG emissions could be accomplished by (i) using a wastewater-dispersed unit for cooling, (ii) using a covered pond, (iii) enhancing the performance of the biogas recovery system, and (iv) changing the stabilization pond to an aerated lagoon. By using options i-iv, reductions of GHG emissions of 216, 208, 92.2, and 87.6 kgCO2eq/t of CPO, respectively, can be achieved.

Identification of dissolved organic matter in raw water supply from reservoirs and canals as precursors to trihalomethanes formation.

The characteristic and quantity of dissolved organic matter (DOM) as trihalomethanes precursors in water from the U-Tapao Basin, Songkhla, Thailand was investigated. The sources of water in the basin consisted of two reservoirs and the U-Tapao canal. The canal receives water discharge from reservoirs, treated and untreated wastewater from agricultural processes, communities and industries. Water downstream of the canal is utilized as a raw water supply. Water samples were collected from two reservoirs, upstream and midstream of the canal, and the raw water supply in the rainy season and summer. The DOM level in the canal water was higher than that of the reservoir water. The highest trihalomethane formation potential (THMFP) was formed in the raw water supply. Fourier-transform infrared peaks of the humic acid were detected in the reservoir and canal waters. Aliphatic hydrocarbon and organic nitrogen were the major chemical classes in the reservoir and canal water characterized by a pyrolysis gas chromatography mass spectrometer. The optimal condition of the poly aluminum chloride (PACl) coagulation was obtained at a dosage of 40 mg/L at pH 7. This condition could reduce the average UV-254 to 57%, DOC to 64%, and THMFP to 42%. In the coagulated water, peaks of O-H groups or H-bonded NH, CË­O of cyclic and acyclic compounds, ketones and quinines, aromatic CË­C, C-O of alcohols, ethers, and carbohydrates, deformation of COOH, and carboxylic acid salts were detected. The aliphatic hydrocarbon, organic nitrogen and aldehydes and ketones were the major chemical classes. These DOM could be considered as the prominent DOM for the water supply plant that utilized PACl as a coagulant.

Removal of organic impurities in waste glycerol from biodiesel production process through the acidification and coagulation processes.

Treatment of waste glycerol, a by-product of the biodiesel production process, can reduce water pollution and bring significant economic benefits for biodiesel facilities. In the present study, hydrochloric acid (HCl) was used as acidification to convert soaps into salts and free fatty acids which were recovered after treatment. The pH value, dosages of polyaluminum chloride (PACl) and dosage of polyacrylamide (PAM) were considered to be the factors that can influence coagulation efficiency. The pH value of waste glycerol was adjusted to a pH range of 3-9. The PACl and PAM added were in the range of 1-6 g/L and 0.005-0.07 g/L. The results showed best coagulation efficiency occurs at pH 4 when dosage of PACl and PAM were 2 and 0.01 g/L. The removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD(5)), total suspended solids (TSS) and soaps were 80, 68, 97 and 100%, respectively. The compositions of organic matters in the treated waste glycerol were glycerol (288 g/L), methanol (3.8 g/L), and other impurities (0.3 g/L).