Laboratory for the Solid Waste, Sediments and Sludge Analysis Proposal

Summar

The proposal covers a proposed laboratory for a university that is planning to establish a new environmental laboratory to serve Master students enrolled in Master Program, offer services to the Dubai community, and be a third-party environmental laboratory. The intended use for the laboratory includes solid waste, sediments and sludge analysis. This laboratory proposal will account for air, water, soil sampling, and analysis.

Functions of the Proposed Laboratory

The proposed laboratory for the university will be a collaborative space for analysis and research projects whose participants, including students, the community, and third-party environmental researchers seek to analyze solid waste, sediments, and sludge with samples obtained from air, water, and soil. Hence, the laboratory will help in waste analysis from different perspectives. The laboratory is guided by the principle that the most effective approach to solid waste, sediments, and sludge analysis should be comprehensive and robust.

Organizational Structure of the Proposed Laboratory

The Quality Project Teams will act as laboratory advisors and/or observers. They will however not be in the same rank as the Laboratory Manager. Besides, the Quality Project Teams will not have authority, but their roles would be merely to offer valuable inputs on quality control and quality assurance to the Laboratory Management team. While this is a proposed organizational structure, it would be vital if the Laboratory Manager determines the most efficient structure for its organization. It is proposed that the laboratory should remain as lean as possible with not more than four assistants under any division. The laboratory Manager is expected to administer and direct various technical issues related to scientific or research based on the specialized operations, including analysis of solid waste, sediments, and sludge with samples obtained from air, water, and soil. In addition, the manager will act as a technical advisor for all other employees to ensure that they meet analysis schedules and resolve all technical issues. The Manager will set budgets, analysis schedules, and expected performance standards.

During analysis processes, the Manager is expected to interact with other laboratory members and other outside laboratories to ensure that all activities are coordinated with regard to costs, methods of analyses, and employees’ capabilities. The Laboratory Manager will be tasked with the overall responsibilities of schedule management and decisions on technical analyses while ensuring that all standard analysis procedures and technical aspects are used and maintained. The manager will possess the following qualifications.

• An undergraduate or a graduate degree in biochemistry, chemistry, or environmental science
• Proficient background experiences, skills, and knowledge in certain areas, including equipment, systems and technical processes of the laboratory (processes in the preparation of samples for analysis, analytical and automation experience, and laboratory management experience)
• Leadership and motivation
• Effective communication
• Good interpersonal and communication skills
• Organization and efficiency
• Teamwork and cooperation
• Customer Service Orientation

It is imperative to note that there are no universal qualifications for this position. Hence, experience and competencies are vital for all laboratory managers.

The Quality Project Team will contribute toward scientific research and analysis in the laboratory by ensuring that all processes meet scientific rigor and standards through expected technical skills and analysis. The Team will provide support to more complex analytical procedures during the analysis of large samples to ensure that the laboratory delivers quality results that meet the laboratory objectives and the required scientific standards in solid waste, sediments, and sludge analysis. It is also expected that the Team will maintain a wide range of collaborative networks across Dubai, other universities, government agencies, the community, and within the region to get the necessary support to deliver quality results. Finally, the Quality Project Team will offer timely advice and effective communication to concerned stakeholders across the university and outside regarding ongoing training, quality management programs, information management and confidentiality, and environmental protection to ensure that the university laboratory adheres to the technical processes expected in various standard guidelines.

The general functions of the laboratory Section Supervisor include planning, managing and supervising all activities in various sections while ensuring that all standard and safety procedures in chemical tests are adhered to in all areas of solid waste, sediments and sludge analyses. Hence, the supervisor will ensure that tests are accurately done, and results delivered in a timely manner.

The university laboratory technologist will conduct a diverse range of analytical procedures in all major areas of solid waste, sediments, and sludge analyses for samples obtained from soil, air, and water under technical supervision. The technologist will also perform other related duties.

Under technical supervision, the laboratory technician will conduct all laboratory analytical procedures on samples that require technical expertise, critical thinking, and independent judgment in solid waste, sediments, and sludge analysis.

Finally, the laboratory attendant is expected to perform certain simple and moderately simple laboratory procedures under the direct supervision of appropriate professionals. These procedures performed must strictly adhere to the provided guidelines and standards for solid waste, sediments, and sludge analysis.

Qualifications for all other personnel, including supervisors

• A bachelor’s degree in biochemistry, environmental science, physical sciences, physics, and/or waste management related studies (laboratory assistants may have related college certificates)
• At least two years of experience (five years for supervisors and quality assurance team) analyzing organic and inorganic samples
• Good laboratory practices and familiar with ISOs
• Effective communication skills
• Unwavering integrity
• Attention to details
• Task prioritization

Recommended Location of the Laboratory in the Campus

The proposed location for the laboratory will consider the most favorable place based on the topographic features of the university. Specifically, it will consider the overall direction of the wastewater discharge and the point of discharge of the treated waste. Precisely, the laboratory will be located at the last point of discharge of treated waste materials. In this regard, as previously noted, the topography will guide site selection, size of the laboratory, the expected flow of waste materials from institutional, domestic to laboratory hazardous wastes. In addition, the location will take into account all utility systems required to serve and support the operations of the laboratory. The topographical features shall guide piping arrangements through all the individual units while the hydraulic systems shall consider the flow of wastewater and sludge. It is also imperative to note that the laboratory will not be located near any sources of groundwater of the university or community.

With an adequate floor plan for all analysts, the laboratory will also be located away from noise, vibrating objects, or any other sources of high temperatures and pressure. This approach is necessary to avoid adverse impacts or interference with instruments, experiments, and staff.

These location considerations are aimed at enhancing safety and environmental protections.

Ventilation of the Laboratory and Room Temperature

For the laboratory temperature and ventilation, the American National Standard for Laboratory Ventilation ANSI/AIHA Z9.5-2003 used for chemical laboratories will be applied.

The university and designer will agree on some distinct room ventilation rates. A common ventilation system will be installed for the removal of used air and offers the optimal temperature, humidity, and air quality necessary for different experiments and analyses in the laboratory without exposing chemicals to extreme conditions.

The laboratory will have dilution ventilation for fugitive emissions and odors, and the temperature of the laboratory will generally depend on cooling necessary to offset internal heat gains while the optimal temperature will be provided for humans in the laboratory (Siemens Industry, Inc. 2013).

Recommended Experiments for the Laboratory

For various analyses, the laboratory will conduct the following experiments.

• The laboratory will conduct an analysis to determine the pH of any sample of sewage sludge

This experiment will help in determining the pH of sludge to control anaerobic treatment due to acidity levels. Hence, pH optimization will be achieved through alkali or acid to treat wastewater effectively. Further, optimal pH is also necessary for sludge dewatering and cyanide oxidation. A good pH value is required for most chemical reactions, including water softening, soil treatment, corrosion control, disinfection, and coagulation of chemicals.

• It will also conduct experiments to determine total solids in a sample of sludge

This experiment will be particularly useful to local community members interested in farming. It helps in assessing the suitability of sewage farming, possible water supply for different uses, water treatment procedures, and corrosion control.

• The experiments will further focus on total dissolved solids in a sample of sludge

Organic chemicals dissolved are known to consume oxygen in the receiving water. Moreover, some could be inactive during biological oxidation while others are carcinogens. This experiment is also useful in determining the suitability of agricultural sludge.

• It will also conduct experiments to determine total settleable solids in a sample

This experiment is common in industrial effluent analysis to identify specific requirements for settling tanks for plants that use biological treatment approaches. Besides, the laboratory will conduct this experiment to identify the efficacy of wastewater treatment plants specifically for sedimentation sections.

• Experiments will also be conducted to find out the total suspended solids in a sludge

The experiment will be suitable for determining the quality of wastewater effluent and influent, analysis of water pollution, domestic wastewater toxic levels, and effectiveness of the treatment plant.

• The laboratory will also conduct experiments on the quantity of dissolved oxygen available in the sludge

Oxygen poorly dissolves in water and, therefore, the laboratory will perform experiments to determine the levels of dissolved oxygen, assess stream levels of pollution, understand aerobic biological wastewater treatment, corrosion control, the strength of pollution from domestic and industrial effluent, and assess the nature of biological chemical processes in a given pH status and related smell.

• Other analyses will be performed for biochemical oxygen demand in a sample of sludge

BOD (biochemical oxygen demand) test is the primary test to determine the biodegradability of a given wastewater sample and the level of sample strength. Hence, this experiment is for determining the extent of pollution in sludge and controlling it. It is also vital for assessing the self-purification capacity of wastewater while the local government will use the test for the evaluation of effluent discharged. The BOD assessment will assist other stakeholders to design their treatment plant well, determine the most effective treatment method, use it to approximate an adequate population for analysis and efficiency of treatment plants.

• The laboratory will also conduct studies on sludge to determine chemical oxygen demand

The COD (Chemical oxygen demand) test is vital for industrial waste analysis to identify and control losses attributed to sewer systems. COD test may be used instead of BOD to increase the speed of obtaining results. The test will also help the laboratory to determine the level of toxins and certain biologically resistant organic elements in sludge samples.

• It will also conduct studies on the effects of sludge on sanitary fittings

This experiment is important to determine how sludge affects various sanitary fitting materials, including metal and plastic parts.

Other analyses will be more specific for sludge. For instance, gasification in a fluidized bed reactor for air samples (Calvo, Garcia, & Otero 2013), electroosmotic dewatering will be conducted on specific samples (Chen, Mujumdar, & Ragbaran 1996).

The university will also be active in emerging applications of sludge to generate renewable energy by collecting all samples from residential, industrial, and municipal wastewater treatment facilities (Siddiquee & Rohani 2011). Other experiments will be unique to the desired outcomes. For instance, analysis of samples to determine how oily pollutants can be separated through electroflotation and adsorption will also be performed (Ibrahim, Sakthipriya, & Balasubramanian 2012).

Experiments for solid waste and sediments

Trace analysis

The laboratory will conduct trace analysis on various samples using various standard methods to ensure detailed sampling and analysis of wastewater and soil samples at trace levels (Wuana & Okieimen 2011). To ensure accuracy and adherence to scientific processes and procedures, the laboratory will rely on various standards provided by different organizations, such as Australian Standards, Methods of Seawater Analysis, and Chemical and Biological Methods for Seawater Analysis among others.

In Situ Analyses

These are considered as common, basic experiments in the laboratory. They will include experiments related to pH, turbidity, temperature, dissolved oxygen, ion detection, and conductivity. Ion detection may focus on fluoride and sulfide among others.

The laboratory will adhere to specific standards and guidelines provided by instrument manufacturers. These processes must also include strict calibration. Besides, the laboratory will need to ensure continuous monitoring while considering the available reliable information on the nature and behaviors of the effluent stream. Specific procedures are available in various handbooks for processes controls.

Radioactivity Analysis

The laboratory will conduct radioactivity measurements using various standards, including ISO standards. For soil sample analysis, certain manuals on environmental radiation analysis will be followed (Xu et al. 2013).

Leachability tests

Certain organic materials are considered volatile and semi-volatile. Metals and inions, apart from cyanide, will be evaluated using the standard provided by various environmental research agencies, including EPA. Otherwise, other appropriate test methods and standards for leachability tests will be considered (Svensson et al. 2005).

The laboratory will consider experiments with a wide range of reagents to ensure that the desired leaching requirements in the environment are achieved to detect existing pollutants. It is imperative to recognize that the laboratory will choose its leaching reagents based on specific environmental conditions within the laboratory or conditions from which the wastes are obtained. For leaching cyanide, the laboratory will adopt various methods, including leaching with de-ionized or distilled water and others (Svensson et al. 2005). It is important to use specific methods identified for wastewater and water for the obtained leachate samples to enhance result accuracy.

Flammability or ignitability

The laboratory will also have the capacity to conduct ignitability and flammability analyses by using some standard procedures. These experiments will be used to determine if waste samples will be able to burn when ignited and use available methods to conduct the experiment.

Corrosivity experiments

Corrosivity reflects the ability of a sample to irritate human skin, equipment, or plant usually because of extreme concentration of acid or alkaline. Hence, the laboratory will monitor waste pH. It will conduct a test to determine the corrosivity of wastewater on various materials, such as steel and plastic among others using different test methods.

Free liquid analysis

Available tests will be used to determine free liquids – “liquids that readily separate from solid samples” (Zhang et al. 2015, p. 8717). For instance, Paint Filter Liquids Test will be applied to indicate the presence of free liquids in a sample (Zhang et al. 2015). The laboratory must conduct solid/liquid separation procedures for the separate disposal of some waste materials. The test will be particularly useful for samples obtained from the Gulf coastline.

Volatile analysis

It is not recommended to obtain a sample for highly homogenized large samples due to the issue of representation (Kalanatarifard & Yang 2012). Hence, it will be vital for the laboratory to conduct tests with sufficient amounts or samples with the aim of enhancing the accuracy of measurements (Majumdar & Srivastava 2012). Purge and trap tests will be done for volatile elements. Headspace concentrations may not be applicable for thorough analysis. Instead, the laboratory will apply them for screening purposes.

Toxicity screening tests

The laboratory will also determine toxicity levels of various samples for analysis (Kwan 1993). Various proficient test methods will be used, including the Microtox® test (Carlson-Ekvall & Morrison 1995).

Other tests that the laboratory will perform

Chlorine residual

The laboratory will conduct this experiment to determine the amount of chlorine left in wastewater samples. It will be imperative for both residential and industrial wastewater chlorination to avoid excessive chlorination.

Temperature

Temperature assessment for different samples will be done in the laboratory to get imperative measurements that support dissolved oxygen, pH, turbidity, and other suspended solid particles.

In final effluent, most discharge consents are given when the temperature drops to about 4ºC. This implies that microorganisms can still survive. Moreover, temperatures greatly influence effluent treatment.

Sludge Age

Sludge age is an essential factor in activated sludge processes. It influences effluent concentrations of some microorganisms or micropollutants eliminated through adsorption.

The laboratory will assess how an increase in the age of sludge affects the concentration of micropollutants in both solid and liquid samples.

The laboratory will also determine how the concentration of some metals, such as lead and cadmium among others, is affected by sludge age.

Coliform Group Bacteria

The laboratory will conduct experiments to determine the fecal coliform bacteria present in water. This experiment will detect possible contamination of domestic water with sewage.

The Essential Instruments

Availability of laboratory instruments will generally be influenced by the expertise of users and the proximity to another fully equipped laboratory of the same purpose. Nevertheless, the following instruments will be readily available. They include instruments for routine activities, such as BOD and COD monitoring.

• Analytical balance
• Filter papers and apparatus
• Buffer chemicals
• Purge and trap accessories
• Vacuum pump
• Containers such as Polyethylene, PTFE or glass, Amber glass
• Ice
• Glass with PTFE or PTFE lined lid/cap fluoropolymer cap
• Acid washed polyethylene
• Refrigerator
• Sealable plastic bag
• Borosilicate glass with PTFE screw top cap

These are mainly containers and other instruments for assessment and preservation. The laboratory will acquire instruments that are more specialized once it starts handling more technical and specialized analyses.

Sample Handling and Custody

Discrete samples from different sludge, sediments, and solid waste materials will be physically handled. Thus, any individuals involved in laboratory sample handling must pay particular attention to recommended handling procedures because several potential measurement errors emanate from sample handling. As such, all laboratory personnel will follow specified standard operating procedures (SOPs). During sample handling, laboratory personnel will have to observe the following.

• Laboratory sample collection, preparation, and identification
• Transportation

Analysis

Storage and archival

Samples require written records, and this highlights the relevance of the chain of custody. The chain of custody reflects best practices in the laboratory.

The chain of custody will show sample integrity. It ensures that samples, sampling, and data analyzed are similar to the samples and data reported for specific analyses collected at a given period.

The laboratory will ensure that critical elements of records, such as names and signatures of personnel handling samples are captured on the sheet for physical tracking. Only individuals allowed to monitor sampling processes will handle these processes. In fact, only a few specific personnel will handle samples to protect sample integrity.

Every individual handling samples must clearly identify the source, time of delivery, and the sender. Hence, samples will be tracked across various stages, involving collection, storage, processing, and analysis.

It is recommended that the custody form should be kept safe. If the laboratory will use outside services for sample transportation, then only reliable professional bodies will perform the task.

The bill of lading should have all relevant information about the sample. In addition, shipping and tracking documents should be readily available to concerned personnel.

While all laboratory personnel is recognized, the laboratory will establish a procedure to ensure that only appropriate individuals receive samples in the right condition – not damaged or opened.

The laboratory will develop an appropriate system to ensure personnel availability when samples are delivered outside regular office hours.

The General Quality Control and Quality Assurance Procedures

To ensure reliable and valid tests, the laboratory will obtain accreditation from various bodies. For instance, NATA accredited laboratories can conduct multiple experiments on various samples. The laboratory will work closely with accrediting institutions.

It will also apply only approved analytical methods for accurate results. For any applied method, the laboratory will have to prove that the procedures are reliable and yield intended results. It will always conduct proficiency tests and/or use standard reference materials and other relevant reference materials to ensure that tests meet the required standards.

The laboratory will ensure test precision (ability to be reproduced and repeated), selectivity for specific tests and specific test methods for specific samples. All procedures for all methods will be obtained from recommended published guidelines.

The laboratory will observe the recommended thresholds for sample detection and reporting. This approach will ensure that results are as accurate and reliable as possible.

The laboratory will meet various quality assurance standards provided by different accrediting organizations. In addition, it will also engage in various inter-laboratory proficiency seminars and enhance collaboration with other experts with the aim of delivering quality analyses and services. Quality assurance (QA) involves all activities, procedures, processes, and decisions used to guarantee the accuracy and reliability of analytical results. The laboratory will refer to some already published standards for quality assurance from various bodies.

• NEPC or NEPM guidelines on analysis of possibly contaminated soil
• APHA standards for water and wastewater evaluation
• US EPA standards for solid waste evaluation
• NATA technical notes for laboratory analyses

Quality control (QC), which is a component of quality assurance, will assist the laboratory to monitor and gauge the efficacy of its test processes and procedures in the application of various reagents, use of apparatus, and control of result quality among others.

The laboratory will adhere to specific quality control procedures for a given set of analytical tests or for every 20 samples.

• Replicate analysis will be used to repeat at least a single test or analysis from every batch
• Laboratory control samples, such as tap water or distilled water for comparative purposes
• The laboratory will adopt surrogate spikes or reference samples to offer a way of assessing possible gross mistakes that could lead to vital analytical sample errors at any stage during analysis
• Internal standards are adopted to ensure that all procedures related to sample extraction, purification, and concentration are successful
• The laboratory will use homogenous reference materials with different analytical procedures. It will strive to develop in-house reference materials, but all these materials would be reliable and certified by recognized accrediting institutions.

The laboratory will also have quality control records to create reliable analytical methods, results, and specific procedures for determining result precision and accuracy. It will also refer to some quality standards established by the above-mentioned reputable bodies.

All analytical reports will have sufficiently accurate information, and data will be reviewed before presentation to guarantee their accuracy.

ASTM for General Quality Control and Quality Assurance Procedures

The ASTM waste management standards offer multiple guides, procedures, and different test methods applicable for diverse processes used in the handling of wastes from various sources, including residential, commercial, and industrial wastes (ASTM International 2016). The ASTM will assist the laboratory to ensure effective gathering, transporting, processing, and reusing or disposing of used waste materials. In fact, ASTM is indispensable to laboratories that handle waste materials from various sources.

While these few ASTM standards have been selected for demonstration, it is imperative to recognize that the laboratory will select the most appropriate standards for analytical methods, planning for sampling, sampling equipment, sampling techniques, and screening methods.

Analytical Methods

• D4843 – 88(2009): Standard Test Method for Wetting and Drying Test of Solid Wastes
• D5232 – 13: Standard Test Method for Determining the Stability and Miscibility of a Solid, Semi-Solid, or Liquid Waste Material
• D5231 – 92(2008): Standard Test Method for Determination of the Composition of Unprocessed Municipal Solid Waste
• D5198 – 09: Standard Practice for Nitric Acid Digestion of Solid Waste
• D7858 – 13: Standard Test Method for Determination of Bisphenol A in Soil, Sludge and Biosolids by Pressurized Fluid Extraction and Analyzed by Liquid Chromatography/Tandem Mass Spectrometry

Planning for Sampling

• D4687 – 14: Standard Guide for General Planning of Waste Sampling
• D6009 – 12: Standard Guide for Sampling Waste Piles

Sampling Equipment

• D5495 – 03(2011): Standard Practice for Sampling with a Composite Liquid Waste Sampler (COLIWASA)
• D6538 – 12: Standard Guide for Sampling Wastewater with Automatic Samplers

Sampling Techniques

• D4547 – 15: Standard Guide for Sampling Waste and Soils for Volatile Organic Compounds
• E884 – 82(2012): Standard Practice for Sampling Airborne Microorganisms at Municipal Solid-Waste Processing Facilities

Screening Methods

• D5928 – 96(2010) e1: Standard Test Method for Screening of Waste for Radioactivity
• D4982 – 12: Standard Test Methods for Flammability Potential Screening Analysis of Waste

The Essential Laboratory Health and Safety Procedures

All laboratory employees and other stakeholders will be reminded to observe fundamental safety and health measures. Such procedures will focus on the following areas.

• Accidents and emergencies – employees shall lookout for any unplanned events
• Chemical safety would focus on safe storage, handling and transportation of chemicals
• A COSHH assessment will offer practical training on hazards and risks at the workplace
• Fire safety in the laboratory is critical for all employees
• Staff will understand laboratory guidelines and procedures
• The laboratory will adhere to safe waste disposal
• The lone working environment will adhere to maximum safety procedures
• The laboratory will conduct a risk assessment for new and expectant mothers
• There will be regular assessment of risks
• The laboratory will keep a safety data sheet
• The laboratory will also conduct a risk assessment for workers with disabilities

The laboratory will adopt and enforce technical measures to curb occupational-related conditions and injuries (Verbeek & Ivanov 2013).

There is evidence that the implementation of technical measures enforced by regulation can prevent occupational diseases and injuries.

Reference List

ASTM International 2016, Waste Management Standards, Web.

Calvo, L, García, A & Otero, M 2013 ‘An Experimental Investigation of Sewage Sludge Gasification in a Fluidized Bed Reactor’, The Scientific World Journal, vol. 2013, no. 2013, pp. 1-8. Web.

Carlson-Ekvall, CA & Morrison, GM 1995, ‘Contact Toxicity of Metals in Sewage Sludge: Evaluation of Alternatives to Sodium Chloride in the Microtox® Assay’, Environmental Toxicology & Chemistry, vol. 14, no. 1, pp. 17–22. Web.

Chen, H, Mujumdar, A & Ragbaran, G 1996, ‘Laboratory Experiments on Electroosmotic Dewatering of Vegetable Sludge and Mine Tailings’, Drying Technology: An International Journal, vol. 14, no. 10, pp. 2435-2445. Web.

Ibrahim, DS, Sakthipriya, N & Balasubramanian, N 2012, ‘Electro-coagulation Treatment of Oily Wastewater with Sludge Analysis’, Water Science & Technology, vol. 66, no. 12, pp. 2533-2538. Web.

Kalanatarifard, A & Yang, GS 2012, ‘Identification of the Municipal Solid Waste Characteristics and Potential of Plastic Recovery at Bakri Landfill, Muar, Malaysia’, Journal of Sustainable Development, vol. 5, no. 7, pp. 11-17. Web.

Kwan, K 1993, ‘Direct toxicity assessment of solid-phase samples using the Toxi-Chromotest Kit’, Environmental Toxicology and Water Quality, vol. 8, no. 2, pp. 223 – 230. Web.

Majumdar, D & Srivastava, 2012, ‘Volatile Organic Compound Emissions from Municipal Solid Waste Disposal Sites: A Case Study of Mumbai, India’, Journal of the Air & Waste Management Association, vol. 62, no. 4, pp. 398-407. Web.

Siddiquee, M & Rohani, S 2011, ‘Experimental Analysis of Lipid Extraction and Biodiesel Production from Wastewater Sludge’, Fuel Processing Technology, vol. 92, no. 12, pp. 2241–2251. Web.

Siemens Industry, Inc. 2013 Laboratory Ventilation Codes and Standards, Web.

Svensson, B-M, Mårtensson, L, Mathiasson, L & Eskilsson, L 2005, ‘Leachability Testing of Metallic Wastes’, Waste Management & Research, vol. 23, no. 5, pp. 457-467. Web.

Verbeek, J & Ivanov, I 2013, ‘Essential Occupational Safety and Health Interventions for Low- and Middle-income Countries: An Overview of the Evidence’, Safety and Health at Work, vol. 4, no. 2, pp. 77–83. Web.

Wuana, R & Okieimen, F 2011, ‘Heavy Metals in Contaminated Soils: A Review of Sources, Chemistry, Risks and Best Available Strategies for Remediation’, ISRN Ecology, vol. 2011, no. 2011, pp. 1-20. Web.

Xu, Q, Powell, J, Tolaymat, T & Townsend, T 2013, ‘Seepage Control Strategies at Bioreactor Landfills’, Journal of Hazardous, Toxic, and Radioactive Waste, vol. 17, no. 4, pp. 342-350. Web.

Zhang, Y, Leu, Y-R, Aitken, RJ & Riediker, M 2015, ‘Inventory of Engineered Nanoparticle-Containing Consumer Products Available in the Singapore Retail Market and Likelihood of Release into the Aquatic Environment’, International Journal of Environmental Research & Public Health, vol. 12, no. 8, pp. 8717-8743. Web.