Environmental impact assessment of centralized municipal wastewater management in Thailand

Purpose

Urbanization and industrial development intensify water utilization and wastewater generation. The efficiency of wastewater treatment systems varies and depends on system design and wastewater condition. The research aims to examine seven existing centralized municipal wastewater treatment plants (WWTPs) in Bangkok to discover which system configuration yields the best environmental and economic performance. The degree of environmental impact and operational costs from different system designs were investigated to help select future wastewater treatment systems.

Methods

Life cycle assessment (LCA) has been conducted to evaluate environmental impacts from centralized municipal wastewater treatment systems. Life cycle impact assessment method based on endpoint modeling (LIME) was applied, with three major potential environmental impact categories including eutrophication, global warming, and acidification. All seven centralized municipal WWTPs in Bangkok were investigated as case studies. The system configurations are classified into five types of activated sludge (AS) systems. The contribution of impacts from individual processes in each type of AS system was analyzed. The methodology covered major on-site and off-site operational processes excluding construction and maintenance phases. Average annual data were calculated to develop an inventory dataset. JEMAI-Pro software was utilized in this study to analyze the life cycle impact of the systems.

Results and discussion

The level of environmental impact from a WWTP depends on the configuration of the AS system. The highest potential environmental impact from a municipal WWTP is eutrophication, which is obviously affected by ammonium and phosphorous discharges into water bodies. The vertical loop reactor activated sludge (VLRAS) system yielded the best treatment performance among the five AS sub-systems. The consumption of electricity used to operate the system contributed significantly to global warming potential and correlated considerably with operating costs. Comparing among three system sizes, the large-scale WWTP revealed inefficient electricity consumption, whereas the medium plant provided better performance in chemical use and operating costs.

Conclusions

Centralized municipal WWTPs with capacities ranging from 10 to 350?×?10³ m³/day were evaluated with respect to environmental performance and costs during the operating phase. Among all case studies, a medium-scale WWTP with a VLRAS system offered the best operating performance in terms of low environmental impact, resource consumption, and cost. To enhance WWTP management, it is vital to improve the efficiency of electricity consumption in primary and secondary treatment processes and increase wastewater collection efficiency to maximize the plant operating capacity and minimize overall environmental impacts.

     

Quantification of risk from fetal exposure to diagnostic ultrasound

Biomedical ultrasound may induce adverse effects in patients by either thermal or non-thermal means. Temperatures above normal can adversely affect biological systems, but effects also may be produced without significant heating. Thermally induced teratogenesis has been demonstrated in many animal species as well as in a few controlled studies in humans. Various maximum ‘safe’ temperature elevations have been proposed, although the suggested values range from 0.0 to 2.5° C. Factors relevant to thermal effects are considered, including the nature of the acoustic field in situ, the state of perfusion of the embryo/fetus, and the variation of sensitivity to thermal insult with gestational stage of development. Non-thermal mechanisms of action considered include acoustic cavitation, radiation force, and acoustic streaming. While cavitation can be quite destructive, it is extremely unlikely in the absence of stabilized gas bodies, and although the remaining mechanisms may occur in utero, they have not been shown to induce adverse effects. For example, pulsed, diagnostic ultrasound can increase fetal activity during exposure, apparently due to stimulation of auditory perception by radiation forces on the fetal head or auditory structures. In contrast, pulsed ultrasound also produces vascular damage near developing bone in the late-gestation mouse, but by a unknown mechanism and at levels above current US FDA output limits. It is concluded that: (1) thermal rather than nonthermal mechanisms are more likely to induce adverse effects in utero, and (2) while the probability of an adverse thermal event is usually small, under some conditions it can be disturbingly high.     

Impact of wastewater fouling on contact angle

Capillary dependent systems are highly influenced by surface fouling and may degrade as material surface properties change. In anticipation of a spacecraft microgravity fluids management system exposed to highly variable wetting conditions, the impact of urine wastewater fouling on capillary contact angle was examined. The results indicate that, in general, surface fouling can decrease the contact angle when crystalline structures or biofilms form. Small crystalline growth on the order of 10 μm can lower advancing contact angles θ_adv by approximately 30°, while biofilm growth can lower it by approximately 15°. Vacuum drying of fouled surfaces increased θ_adv by about 8°, and defects greater in height than 5% of the capillary length increased θ_adv by approximately 30°. These trends may indicate that promotion of wastewater fouling may improve the performance of capillary dependent fluids management systems. These results may also influence terrestrial technologies, including medical catheters and sustainable wastewater treatment systems exposed to wastewater fouling.     

Anaerobic ponds treatment of starch wastewater: case study in Thailand

Anaerobic ponds are particularly effective in treating high-strength wastewater containing biodegradable solids as they achieve the dual purpose of particulate settlement and organic removal. Performance of an anaerobic pond system for treatment of starch wastewater containing high organic carbon, biodegradable starch particulate matter and cyanide was assessed under tropical climate conditions. Approximately 5000 m3/d of wastewater from starch industry was treated in a series of anaerobic ponds with a total area of 7.39 ha followed by facultative ponds with an area of 29.11 ha. Overall COD and TSS removal of over 90% and CN removal of 51% was observed. Active biomass obtained from the anaerobic ponds sediments and bulk liquid layer exhibited specific methanogenic activity of 20.7 and 11.3 ml CH4/g VSS d, respectively. The cyanide degradability of sludge at initial cyanide concentration of 10 and 20 mg/l were determined to be 0.43 and 0.84 mg CN-/g VSS d, respectively. A separate settling column experiment with starch wastewater revealed that a settling time of approximately 120 min is sufficient to remove 90-95% of the influent TSS.     

Quantification of pathogenic micro-organisms in the sludge from treated hospital wastewater

The sludge from hospital waste treatment facilities is a potential source of infectious organisms. The average numbers of micro-organisms in the sludge of hospital wastewater in Taiwan were as follows: total count 8·1 × 10⁷ cfu g⁻¹ (dry weight of sludge), and 1·4 × 10⁶, 3·6 × 10⁵, 1·6 × 10⁵, 2·2 × 10⁵ and 5·5 × 10⁴ cfu g⁻¹ (dry weight of sludge) for total coliforms, faecal coliforms, faecal streptococci, Pseudomonas aeruginosa and Salmonella spp., respectively . Salmonella spp. were detected in 37% (10 of 27) of the sludges from hospital wastewaters. Therefore, the treatment of such sludge to reduce pathogenic micro-organisms should be considered.     

腹泻及其微生态防治的相关进展

益生菌可能对不同病因引起的不同类型的腹泻有预防的疗效.已经成功的通过调查各种各样的益生菌和确立益生菌性质来证明其对健康的益处和预防、治疗(或缓和)腹泻的作用.其它有益生作用的微生物、某些双歧杆菌、肠球菌以及益生菌酵母菌属的酵母菌作为单个株或复合益生菌在其药用方面的价值也得到肯定.本文主要综述了益生菌在腹泻方面的治疗作用和机制.     

Quantification of bias related to the extraction of DNA directly from soils

In recent years, several protocols based on the extraction of nucleic acids directly from the soil matrix after lysis treatment have been developed for the detection of microorganisms in soil. Extraction efficiency has often been evaluated based on the recovery of a specific gene sequence from an organism inoculated into the soil. The aim of the present investigation was to improve the extraction, purification, and quantification of DNA derived from as large a portion of the soil microbial community as possible, with special emphasis placed on obtaining DNA from gram-positive bacteria, which form structures that are difficult to disrupt. Furthermore, we wanted to identify and minimize the biases related to each step in the procedure. Six soils, covering a range of pHs, clay contents, and organic matter contents, were studied. Lysis was carried out by soil grinding, sonication, thermal shocks, and chemical treatments. DNA was extracted from the indigenous microflora as well as from inoculated bacterial cells, spores, and hyphae, and the quality and quantity of the DNA were determined by gel electrophoresis and dot blot hybridization. Lysis efficiency was also estimated by microscopy and viable cell counts. Grinding increased the extracellular DNA yield compared with the yield obtained without any lysis treatment, but none of the subsequent treatments clearly increased the DNA yield. Phage lambda DNA was inoculated into the soils to mimic the fate of extracellular DNA. No more than 6% of this DNA could be recovered from the different soils. The clay content strongly influenced the recovery of DNA. The adsorption of DNA to clay particles decreased when the soil was pretreated with RNA in order to saturate the adsorption sites. We also investigated different purification techniques and optimized the PCR methods in order to develop a protocol based on hybridization of the PCR products and quantification by phosphorimaging.     

Highly heterogeneous residual malaria risk in western Thailand

Over the past decades, the malaria burden in Thailand has substantially declined. Most infections now originate from the national border regions. In these areas, the prevalence of asymptomatic infections is still substantial and poses a challenge for the national malaria elimination program. To determine epidemiological parameters as well as risk factors for malaria infection in western Thailand, we carried out a cohort study in Kanchanaburi and Ratchaburi provinces on the Thailand-Myanmar border. Blood samples from 999 local participants were examined for malaria infection every 4 weeks between May 2013 and Jun 2014. Prevalence of Plasmodium falciparum and Plasmodium vivax was determined by quantitative PCR (qPCR) and showed a seasonal variation with values fluctuating from 1.7% to 4.2% for P. vivax and 0% to 1.3% for P. falciparum. Ninety percent of infections were asymptomatic. The annual molecular force of blood-stage infection (_molFOB) was estimated by microsatellite genotyping to be 0.24 new infections per person-year for P. vivax and 0.02 new infections per person-year for P. falciparum. The distribution of infections was heterogenous, that is, the vast majority of infections (>80%) were found in a small number of individuals (<8% of the study population) who tested positive at multiple timepoints. Significant risk factors were detected for P. vivax infections, including previous clinical malaria, occupation in agriculture and travel to Myanmar. In contrast, indoor residual spraying was associated with a protection from infection. These findings provide a recent landscape of malaria epidemiology and emphasize the importance of novel strategies to target asymptomatic and imported infections.     

Quantification and stability of human adenoviruses and polyomavirus JCPyV in wastewater matrices

Human adenoviruses (HAdV) and human polyomavirus JCPyV have been previously proposed as indicators of fecal viral contamination in the environment. Different wastewater matrices have been analyzed by applying real-time quantitative PCR procedures for the presence, quantity, and stability of a wide diversity of excreted HAdV and JCPyV. High quantities of HAdV and JCPyV were detected in sewage, effluent wastewater, sludge, and biosolid samples. Both viruses showed high stability in urban sewage. These results confirm the suitability of both viruses as indicators of human fecal viral pollution.     

Quantification of proton budgets in soils of cropland and adjacent forest in Thailand and Indonesia

Mechanisms for tolerance and avoidance of salinity at germination were examined in five self-regenerating annual pasture legumes of Mediterranean origin (Medicago polymorpha, Melilotus siculus, Trifolium subterraneum, T. michelianum and T. tomentosum). The maximum NaCl concentrations, for which no reduction in germination percentage occurred, were 300 mM for M. siculus, 240 mM for M. polymorpha and 120 mM for T. michelianum, T. subterraneum and T. tomentosum. Following 21 days exposure to 300 mM NaCl, imbibed seeds of T. subterraneum showed reduced germinability upon transfer to non-saline solution, whereas those of the four other species recovered full germinability. Following exposure to 600 mM NaCl, however, only T. michelianum and Melilotus siculus had some degree of recovery, with 38% and 31% germinability, respectively. Na⁺ in imbibed seed tissues of all species increased markedly with increasing NaCl concentration, while K⁺ decreased in all but Melilotus siculus. Seed coat impermeability (‘hard seeds’) acted as protection against the toxic effects of salinity. Melilotus siculus, Medicago polymorpha and T. tomentosum showed a delay in hard-seed breakdown (‘seed softening’) over the summer–autumn period, compared to T. subterraneum and T. michelianum, which acts to defer germination until soil surface salinity levels are likely to be lower. These three species also had higher levels of residual hard seeds. The results from this study support field observations that Melilotus siculus and Medicago polymorpha are the best adapted annual pasture legumes for highly saline soils in southern Australia, T. tomentosum and T. michelianum have some adaptation to moderately and mildly saline soils, respectively, whereas T. subterraneum has no adaptive traits for even mildly saline environments. A model for annual legume germination on saline land in southern Australia is also presented.     

Quantification of substratum contact required for initiation of Colletotrichum graminicola appressoria

Colletotrichum graminicola, like many plant pathogenic fungi develop appressoria on germling apices, to facilitate penetration of their host. Induction of these structures occurs after contact with the host surface has been established by the germling. Surface contact and subsequent development of appressoria by germlings of C. graminicola was assessed using interference-reflection microscopy (IRM) and microfabricated pillared silicon substrata. Observations with IRM revealed that under low nutrient conditions, 90% of the germlings developed appressoria once they established 4.5 microm of continuous contact with the substratum. Substrata bearing pillars < or =5 microm in width supported < or =10% appressoria; however, as pillar width was increased the percentage of appressoria formed increased in a sigmoid fashion to a maximum of 80%. The percentage of appressoria produced experimentally on these surfaces was compared to data sets generated from a model designed to calculate the probability of appressorium development on similar pillar arrays at various germ tube contact lengths. These results indicate that germ tubes of C. graminicola require more than 4microm of continuous contact with a hydrophobic substratum for induction of appressoria.     

Exposure to electrical contact currents and the risk of childhood leukemia

The objectives of this study were to examine the association between contact current exposure and the risk of childhood leukemia and to investigate the relationship between residential contact currents and magnetic fields. Indoor and outdoor contact voltage and magnetic-field measurements were collected for the diagnosis residence of 245 cases and 269 controls recruited in the Northern California Childhood Leukemia Study (2000-2007). Logistic regression techniques produced odds ratios (OR) adjusted for age, sex, Hispanic ethnicity, mother's race and household income. No statistically significant associations were seen between childhood leukemia and indoor contact voltage level [exposure ≥90th percentile (10.5 mV): OR = 0.83, 95% confidence interval (CI): 0.45, 1.54], outdoor contact voltage level [exposure ≥90th percentile (291.2 mV): OR = 0.89, 95% CI: 0.48, 1.63], or indoor magnetic-field levels (>0.20 μT: OR = 0.76, 95% CI: 0.30, 1.93). Contact voltage was weakly correlated with magnetic field; correlation coefficients were r = 0.10 (P = 0.02) for indoor contact voltage and r = 0.15 (P = 0.001) for outdoor contact voltage. In conclusion, in this California population, there was no evidence of an association between childhood leukemia and exposure to contact currents or magnetic fields and a weak correlation between measures of contact current and magnetic fields.     

Health risk assessment of residential exposure to cypermethrin among young children in agricultural communities in northeastern Thailand

This study aimed to identify factors associated with dermal exposure to cypermethrin and assess the health risks among young children in an agricultural community in Thailand. Face-to-face interviews were conducted with the parents/caregivers of 58 children (aged 1–3 years). Wipe samples were analyzed for cypermethrin by gas chromatography-microelectron capture detection (GC-µECD). Health risk assessments were based on the cypermethrin concentration on the children’s hands and feet. Spearman’s correlation indicated significant associations among cypermethrin concentrations on the hands, feet, floors/wooden beds, and toys (rho?=?0.438–0.613, p-value <0.001). Cypermethrin concentrations on the hands were significantly and inversely correlated with the child’s caregiver being the child’s mother and insecticide use (p?<?0.01). Concentrations on the feet were significantly correlated with insecticide use (p?<?0.05) and showering (p?<?0.01). The hazard quotient calculated from dermal exposure via the hands and feet showed no risk for potential noncarcinogenic effects (5.586?×?10^?5 in the dry season and 4.301?×?10^?4 in the wet season). These findings suggest that young children might not be at risk for cypermethrin exposure through the dermal route. Residential exposure among young children may be reduced by improved hygiene. Health risk assessments of environmental insecticide exposure via the oral and inhalation routes require further investigation.     

High risk maternal factors related to fetal wastage in rural Bangladesh

An analysis of the relationship between fetal mortality (early fetal death and stillbirth), pregnancy order, maternal age, and previous fetal deaths in a rural Bangladesh population characterized by high fertility and mortality and the virtual absence of obstetric and other medical care indicates that early fetal wastage and stillbirth are higher among pregnancy orders 1 and 6, or higher than among orders 2 and 3, with the increased risk particularly apparent among those pregnancies following 2 or more previous fetal deaths. The data consist of the 21,144 pregnancies that occurred to the women in Matlab, Bangladesh, 1966-1969. By a multiple regression technique allowing for pregnancy order and previous fetal deaths, adjustments were made for age of the mother, and after allowances were made for previous fetal deaths, adjustments were made for pregnancy order. Results show the fewest fetal deaths in 2nd and 3rd pregnancies, and most at the highest parities. 10% of all pregnancy terminations 1966-1969 were registered as fetal deaths. Women in the higher pregnancy orders who have not experienced previous fetal deaths or only 1 fetal death have only a slight increase in the risk of fetal death compared to women in pregnancy orders 2 and 3. It is concluded that the virtual absence of medical care facilities is responsible for the large numbers of fetal deaths due to complications of gestation, delivery, and environmental influences. It also results in a higher maternal mortality of women with pregnancy complications related to fetal deaths. This absence of obstetric care and the high maternal mortality in this population may allow only women without reproductive impairments to reach the higher pregnancy orders.     

Astrocytoma risk related to job exposure to electric and magnetic fields

To investigate the association between occupational exposure to low-frequency electric and magnetic (EM) fields and risk of brain tumors, a study was performed in Los Angeles County on 272 male adults with primary intracranial gliomas or meningiomas and 272 neighborhood controls. Complete occupational histories were collected. Risk associated with employment for more than 10 years in jobs that are presumed to entail exposure to EM fields was computed for various histological groupings. A nonsignificantly elevated risk of 1.7 was found for gliomas (all types pooled: 95% confidence interval 0.7-4.4), and a nonsignificantly reduced risk of 0.3 (95% confidence interval 0.03-3.2) was found for meningiomas. For astrocytomas, which form a subtype of the gliomas, a significantly elevated risk of 10.3 (95% confidence interval 1.3-80.8) was found; a significant upward trend (P = .01) of tumor incidence with increasing length of employment was observed. Most astrocytoma patients who worked in occupations involving exposure to EM fields were electricians or electrical engineers.     

Quantification of thigmotropism (contact sensing) of Candida albicans and Candida tropicalis

To quantify the thigmotropism, we adapted the our previous method using a chemotaxifilter system in combination with a bioluminescent adenosine triphosphate (ATP) assay based on firefly luciferase-luciferin system and analyzed the relationship between the ability of germ tube formation and thigmotropism of C. albicans and C. tropicalis. Both the ability to form germ tube and the amount of hyphae exhibiting thigmotropism varied depending upon both the species and strains of Candida. C. albicans formed more germ tubes than C. tropicalis. A good correlation was observed between the ability to form a germ tube and the capacity for thigmotropism, and the results gave a level of significance (p<0.05). Further, SEM observation revealed that relatively long hyphae of C. tropicalis with penetrated through the pores of filter membrane. This phenomenon may be of importance in the development of pathogenesis of C. tropicalis as well as C. albicans. This revised version was published online in August 2006 with corrections to the Cover Date.     

Health related quality of life among patients with tuberculosis and HIV in Thailand

Introduction

Health utilities of tuberculosis (TB) patients may be diminished by side effects from medication, prolonged treatment duration, physical effects of the disease itself, and social stigma attached to the disease.

Methods

We collected health utility data from Thai patients who were on TB treatment or had been successfully treated for TB for the purpose of economic modeling. Structured questionnaire and EuroQol (EQ-5D) and EuroQol visual analog scale (EQ-VAS) instruments were used as data collection tools. We compared utility of patients with two co-morbidities calculated using multiplicative model (U_CAL) with the direct measures and fitted Tobit regression models to examine factors predictive of health utility and to assess difference in health utilities of patients in various medical conditions.

Results

Of 222 patients analyzed, 138 (62%) were male; median age at enrollment was 40 years (interquartile range [IQR], 35–47). Median monthly household income was 6,000 Baht (187 US$; IQR, 4,000–15,000 Baht [125–469 US$]). Concordance correlation coefficient between utilities measured using EQ-5D and EQ-VAS (U_EQ-5D and U_VAS, respectively) was 0.6. U_CAL for HIV-infected TB patients was statistically different from the measured U_EQ-5D (p-value<0.01) and U_VAS (p-value<0.01). In tobit regression analysis, factors independently predictive of U_EQ-5D included age and monthly household income. Patients aged ≥40 years old rated U_EQ-5D significantly lower than younger persons. Higher U_EQ-5D was significantly associated with higher monthly household income in a dose response fashion. The median U_EQ-5D was highest among patients who had been successfully treated for TB and lowest among multi-drug resistant TB (MDR-TB) patients who were on treatment.

Conclusions

U_CAL of patients with two co-morbidities overestimated the measured utilities, warranting further research of how best to estimate utilities of patients with such conditions. TB and MDR-TB treatments impacted on patients'' self perceived health status. This effect diminished after successful treatment.     

Bovine viral diarrhea virus infection affects the expression of proteins related to professional antigen presentation in bovine monocytes

The complete annotation of the cattle genome allows reliable protein identification by tandem mass spectrometry (MS(2)) and greatly facilitates proteomics. Previously, we reported that differential detergent fractionation (DDF) analysis of bovine monocytes reveals proteins related to antigen pattern recognition, uptake and presentation to immunocompetent lymphocytes. Here we have identified 47 bovine proteins, involved in immune function of professional antigen-presenting cells (APC) that have been significantly altered after cytopathic (cp) Bovine Viral Diarrhea Virus (BVDV) infection. In particular, proteins related to immune responses such as cell adhesion, apoptosis, antigen uptake, processing and presentation, acute phase response proteins, MHC class I- and II-related proteins and other molecules involved in immune function of professional antigen presentation have been significantly altered after BVDV infection. Our data suggest that cp BVDV, while promoting monocyte activation and differentiation, is inhibiting their antigen presentation to immunocompetent T cells, thus resulting in the uncontrolled inflammation mediated by activated macrophages, enhanced viral spread, and impaired anti-viral defense mechanisms in the host.