Application of multiple toxicity tests in monitoring of landfill leachate treatment efficiency.

Leachate from a closed landfill used for co-disposal of municipal and tannery waste was submitted to coagulation treatment, air stripping, adsorption on granular activated carbon, and Fenton oxidation with the aim to reduce toxicity of the leachate. Optimal operational conditions for each process were identified. The performance of the treatment was monitored by determination of organic matter (COD, DOC, BOD5), inorganic components (N-NH4(+), Cl(-), alkalinity, metals), organic compounds (BTEX, PAHs, PCBs, OCPs) while changes in toxicity were followed by multiple toxicity tests. Among the applied treatment techniques, adsorption on granular activated carbon was the most efficient method for removal of organic matter and metals while air stripping was the most efficient for removal of N-NH4(+) and reduction of toxicity. Lower reduction of organic matter content and toxicity was obtained during coagulation treatment. Fenton oxidation was effective for removal of COD; however, it negatively affected toxicity reduction. The combination of adsorption on granular activated carbon and air stripping led to an appreciable reduction of organic and inorganic pollutants and to leachate detoxification. Application of bioassays was helpful for assessing suitability of treatment methods and demonstrated that they are, together with physicochemical parameters, an indispensable part for monitoring of treatment efficiency.

Development of a water-related disaster decision model for nurses in Thailand.

BACKGROUND: Disasters, be they natural or manmade, are catastrophic events that confront nursing managers with the challenge of acting to reduce the impact of such events upon society as a whole. OBJECTIVE: Provide nursing management personnel with a guide organized in such a fashion as to facilitate the decision making process in water related disasters. To develop a model to guide the decision-making process regarding water-related disaster management. MATERIAL AND METHOD: The combination of the two-round of modified Delphi method and The Simple Multi-attribute Rating Technique (SMART) was used to develop a decision tool. Thirty-four experts, including nurses, physicians and manager from three hospitals situated in previous disaster zones participated in this project. Delphi consensus was reached when the mean score of agreement was above 4.0 and standard deviation was below 1.0. Kendall's Coefficient of Concordance and the Kruskal Wallis H-test were performed to determine the degree of agreement and association of criteria rankings. RESULTS: The 36 variables were constructed with seven alternatives: policy, communications, materials, human resource management, operation effectiveness, health and stakeholder participation. An agreement in attribute ranking among the experts was found. The trade-off scores of model variables were presented to identify feasible arrays of disaster planning needs. CONCLUSION: The authors proposed a practical method to develop a decision model based on the input of key individuals in disaster management. The model can be used to guide the decision making for nurse managers resulting in the best practice for water-related disaster management.

Product and cost perspectives of phosphorus recovery from human urine using solid waste ash and sea salt addition - A case of Thailand.

Phosphorus (P) recovery from human urine was evaluated using the addition of MgCl2, sea salt and solid-waste (SW) incinerated ashes. The study objectives were to assess and compare their efficiency for P recovery, costs of chemicals added and relevant crystal characteristics. Results from the experiments conducted between pH range of 7-11 revealed that P precipitation efficiency was increased to 89-97% and 72-88% when MgCl2 and sea salt were added, respectively. Precipitates obtained from both cases were found to contain 10.8-17.1% P dry weight which is superior to commercial fertilizer (8.80% P). Based on SEM-EDS examination and chemical equilibrium thermodynamics, about 83% and 68% of precipitates were in the form of struvite for the addition of MgCl2 and sea salt, respectively. Although 18% less struvite was formed with sea salt added, cost was found to be reduced from 4.07 USD·(kg P)-1 for MgCl2 addition to 2.91 USD·(kg P)-1 using sea salt addition, representing a 28% cost reduction. Furthermore, SW ashes added into the urine increased P recovery efficiency about 6-17%. Addition also lowered the costs to 1.75 and 1.68 USD·(kg P)-1 for SW fly ash and bottom ash, respectively. Thus, ash addition reduced cost and provided an alternative to landfill disposal. However, addition of SW bottom ash might result in recovered P solids with lead concentration exceeding the EC limit for inorganic fertilizer. In summary, results of this study have demonstrated a pragmatic way to recover P from human urine with the use of sea salt and ash as alternative Mg source and seed. Results indicate that this practice not only produces a good-quality fertilizer as struvite for sustainable P management, but also helps protect the water environment, and support circular economy of P in human ecosystem.

Green residues from Bangkok green space for renewable energy recovery, phosphorus recycling and greenhouse gases emission reduction.

Effective ways to integrate human life quality, environmental pollution mitigation and efficient waste management strategies are becoming a crisis challenge for sustainable urban development. The aims of this study are: (1) to evaluate and recommend an optimum Urban Green Space (UGS) area for the Bangkok Metropolitan Administration (BMA); and (2) to quantify potential renewable resources including electricity generation and potential nutrient recovery from generated ash. Green House Gases (GHGs) emissions from the management of Green Residues (GR) produced in a recommended UGS expansion are estimated and compared with those from the existing BMA waste management practice. Results obtained from this study indicate that an increase in UGS from its current 2.02% to 22.4% of the BMA urban area is recommended. This optimum value is primarily due to the area needed as living space for its population. At this scale, GR produced of about 334kt·y-1 may be used to generate electricity at the rate of 206GWh·y-1 by employing incineration technology. Additionally, instead of going to landfill, phosphorus (P) contained in the ash of 1077 t P·y-1 could be recovered to produce P fertilizer to be recycled for agricultural cultivation. Income earned from selling these products is found to offset all of the operational cost of the proposed GR management methodology itself plus 7% of the cost of BMA's Municipal Solid Waste (MSW) operations. About 70% of the current GHGs emission may be reduced based on incineration simulation.

Phosphorus leakage from fisheries sector - A case study in Thailand.

Although phosphorus (P) is an essential element needed for all lives, excess P can be harmful to the environment. The objective of this study aims to determine P flows in the fisheries sector of Thailand consisting of both sea and freshwater activities of captures and cultures. Currently, the annual fisheries catch averages 3.44 ± 0.50 Mt. Most comes from marine capture 1.95 ± 0.46 Mt, followed by coastal aquaculture 0.78 ± 0.09 Mt, freshwater aquaculture 0.49 ± 0.05 Mt, and inland capture 0.22 ± 0.01 Mt. Of this total, about 11% is contained in fresh products directly sold in local markets for consumption, while 89% is sent to processing factories prior to being sold in local markets and exported. The quantities of P entering the fisheries sector come from captures, import of fisheries products and feed produced from agriculture. This P input to the fisheries sector is found to average 28,506 t P.y-1 based on the past ten-year records. Of this total, P input from captures accounts for 76%; while, 11% represents aquatic feeds from agriculture and animal manures. About 13% is obtained from the imports of fishery products. Coastal and freshwater aquacultures are found to be P consumers because their feeds are almost all produced from agricultural crops grown inland. Moreover, these activities cause most of P losses, approximately 10,188 t P·y-1, which account for 89% of the total P loss from the fisheries sector. Overall, P in the fisheries sector is found to mobilize through three channels: (a) 44% is consumed within the country; (b) about 16% is exported; and, (c) 40% is lost from the ecosystem. Based on the results of this work it is recommended that future research be directed on ways to minimize P loss and maximize P recycle in Thailand's fisheries sector as to enhance its food security and curtail water pollution.

Quantification of phosphorus flows throughout the consumption system of Bangkok Metropolis, Thailand.

Due to unequal distribution of the world's Phosphorus (P) sources for fertilizer production, an evaluation of P flows throughout the consumption system of a city is needed. The prime objective of this paper is to assess and prioritize P recovery options as to bring about, as much as possible, a close-looped P-for-food system. Using the Bangkok Metropolitan Administration (BMA) as a case study, the aim of this work is to quantify the potential mass flow of P for four major types of urban wastes: domestic wastewater (DWW), septage sludge (SS), food waste (FW) and green garbage (GB) and to determine the recoverable stock of P available. The consumption of food and supplements such as cleansing products and fertilizer is estimated at a rate of 1146.4 g P·cap(-1)·year(-1). P contained in wastes being discarded from its average 7.9 million population plus 33.8 million Bangkok-visiting tourists per annum is determined to be 8.01 kt P annually. Only 4% of the above quantity is recycled and used internally for cultivating plants grown in public parks. An annual amount of 7.68 kt P was found to be disposed of in landfills (6.23 kt P) and in the river systems (1.45 kt P). From the findings of this study, therefore, it is recommended that P recovery efforts from BMA's urban wastes should be focused on wastes enrouted to landfills since these constitute 81% of P discarded. As a consequence, solid waste combustion coupled with energy recovery from P-binding organics may be an appropriate means of P recovery. This technology has the potential to reduce waste volume, generate electricity, and produce P-containing ash that can be used for further application on farm lands.

Influence of size and density on filtration rate modeling and nutrient uptake by green mussel (Perna viridis).

This study investigates green mussel filtration rates based on variation of the mussel size and density, and attempts to correlate these with the amount of Chaetoceros calcitrans consumed by kinetic modeling. The filtration rates were found to be more effective in small mussels and with greater volumes of seawater/mussel which represent low mussel densities in the mussel farms. Under field condition, the first order kinetic model is useful for evaluation of mussel filtration rate. However, the composite exponential kinetic model was determined to better describe filtration rates in a close system. Higher ratios of seawater volume L/g DW mussel tissue, resulted in an increasing filtration rate until a maximum plateau was reached at 10.37 L/h/g DW tissue as determined by first order kinetics. Based on the filtration rate, carbon, nitrogen, and phosphorus uptake by green mussels were found to be 2128.72, 265.41, and 66.67 mg/year/indv, respectively.

Microbial contamination in Lake Pontchartrain Basin and best management practices on microbial contamination reduction.

The Lake Pontchartrain Basin is a complex system of physical and biological elements. Due to the actions of man, the Basin's ecosystem has changed significantly over the past half century. These changes have impaired water quality and habitats throughout the Pontchartrain Basin. Recreational activities including swimming have been banned in areas of the lake. This paper discusses sources of microbial contamination impacting designated use criteria and the need of disinfection for water quality enhancement. Quantification of microbial loadings and identification of organisms of particular concern are made. Alternative Best Management Practices (BMPs) are suggested with emphasis on disinfection and engineered microbial reduction technologies.