An effluent decontamination system (EDS) is a device, or suite of devices, designed to decontaminate or sterilise biologically active or biohazardous materials in fluid and liquid waste material. Facility types that may utilise an EDS include hospitals, food and beverage industry plants, research laboratories, agricultural and animal research facilities, pharmaceutical production facilities, and governmental or military facilities... [1] In fact, all facilities in the United States of America that produce liquid waste of Biosafety Level 2 and above must decontaminate their waste before discharging it into a public sewer system [2] Examples of liquids sterilised in an EDS include the shower water from personnel decontamination rooms, and the waste water from washing down animal rooms in laboratory environments. [3]
While EDS are designed chiefly to sterilise liquid waste, they can in some instances sterilise solid material carried by the liquid effluent. However the EDS may require grinders [4] to break down the solid materials before they enter site of sterilisation in the EDS, and macerating paddles [5] to stir effluent held in tanks, reducing congelation.
EDS vary in their design and function, however the use of either chemical or heat sterilisation is common.
A Batch EDS consists of at least one sterilisation tank (also known as a kill tank, or a cook tank). The sterilisation tank is commonly a jacketed vessel, which is a container with hollow walls. Effluent flows into the kill tank either by gravity or through being pumped into the tank. Once the tank is full of effluent, high-temperature pressurised steam is passed through the cavity in the walls of jacketed vessel, raising its temperature of over 121 °C. Once all the effluent has been heated to at least 121 °C for at least 30 minutes, all biologically hazardous material within the kill tank will have been sterilised. [6] At this point, the tank may be emptied by gravity or by fluid displacement.
While a batch EDS must have at least one sterilisation tank, multiple sterilisation tanks can be used and fed from dedicated storage tanks. It is noteworthy that when a kill tank is not running, it can function like a storage tank – collecting effluent and wastewater until it is full enough to sterilise. [7]
Batch steam injection systems function similarly to a batch steam EDS, but steam is passed directly through the effluent during the sterilisation stage. This procedure increases the speed at which the effluent can reach the required sterilisation temperature, increasing the throughput time. Speed of processing is offset against the volume of effluent that can be sterilised, as the steam takes up space that could be used to hold effluent. Steam injection is a very noisy process – steam rushing through the effluent can sound like a jet engine. [8] The process can also cause solid material to stick to the sides of the sterilisation tank, which can hinder heat transference from the walls of a jacketed vessel. [9] Low temperature and pressure variants of batch steam injection EDS have been shown capable of decontaminating biosafety level 2 waste by subjecting it to a sterilisation temperature of 82.2 °C. This low temperature requires a long time period of six hours to achieve sterilisation. [10]
Continuous flow EDS pass liquid effluent through a distance of heated pipework to sterilise it. The heated pipework is frequently coiled to minimise heat loss and the space required. The length and bore of the heated pipework can vary greatly, depending on the rate of flow of the effluent and the temperature that the pipework is heated to. As a hotter temperature sterilises faster, the hotter the temperature of the pipework, the higher the flow rate of the continuous flow EDS. Natural gas, steam or electricity can provide the heat required for sterilisation. [11]
For smaller scale systems of less than 100 gallons a day, chemical effluent decontamination systems can be used. Effluent is collected in a sterilisation tank, where it is mixed with a chemical sterilant such as bleach. The effluent and sterilant mixture are then held for sufficient time to ensure all micro-organisms in the effluent have been sterilised. After sterilisation, the sterilant must be neutralised before the effluent can discarded into a sewer. As such, a batch chemical EDS requires a large quantity of chemicals, both sterilants and neutralisers, to operate [12]
Studies show that Bacillus spores within effluent containing a mixture of animal effluent, humic acid, and fetal bovine serum can be deactivated in a bleach-based chemical EDS effectively at a sterilant concentration of less than 5700 part per million over two hours of exposure [13]
A biosafety level (BSL), or pathogen/protection level, is a set of biocontainment precautions required to isolate dangerous biological agents in an enclosed laboratory facility. The levels of containment range from the lowest biosafety level 1 (BSL-1) to the highest at level 4 (BSL-4). In the United States, the Centers for Disease Control and Prevention (CDC) have specified these levels in a publication referred to as BMBL. In the European Union, the same biosafety levels are defined in a directive. In Canada the four levels are known as Containment Levels. Facilities with these designations are also sometimes given as P1 through P4, as in the term P3 laboratory.
An autoclave is a machine used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure and/or temperature. Autoclaves are used before surgical procedures to perform sterilization and in the chemical industry to cure coatings and vulcanize rubber and for hydrothermal synthesis. Industrial autoclaves are used in industrial applications, especially in the manufacturing of composites.
Applied psychology is the use of psychological methods and findings of scientific psychology to solve practical problems of human and animal behavior and experience. Educational and organizational psychology, business management, law, health, product design, ergonomics, behavioural psychology, psychology of motivation, psychoanalysis, neuropsychology, psychiatry and mental health are just a few of the areas that have been influenced by the application of psychological principles and scientific findings. Some of the areas of applied psychology include counseling psychology, industrial and organizational psychology, engineering psychology, occupational health psychology, legal psychology, school psychology, sports psychology, community psychology, neuropsychology, medical psychology and clinical psychology, evolutionary psychology, human factors, forensic psychology and traffic psychology. In addition, a number of specialized areas in the general area of psychology have applied branches. However, the lines between sub-branch specializations and major applied psychology categories are often mixed or in some cases blurred. For example, a human factors psychologist might use a cognitive psychology theory. This could be described as human factor psychology or as applied cognitive psychology. When applied psychology is used in the treatment of behavioral disorders there are many experimental approaches to try and treat an individual. This type of psychology can be found in many of the subbranches in other fields of psychology.
Ultrafiltration (UF) is a variety of membrane filtration in which forces such as pressure or concentration gradients lead to a separation through a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained in the so-called retentate, while water and low molecular weight solutes pass through the membrane in the permeate (filtrate). This separation process is used in industry and research for purifying and concentrating macromolecular (103–106 Da) solutions, especially protein solutions.
Sterilization refers to any process that removes, kills, or deactivates all forms of life and other biological agents such as prions present in or on a specific surface, object, or fluid. Sterilization can be achieved through various means, including heat, chemicals, irradiation, high pressure, and filtration. Sterilization is distinct from disinfection, sanitization, and pasteurization, in that those methods reduce rather than eliminate all forms of life and biological agents present. After sterilization, an object is referred to as being sterile or aseptic.
A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than sterilization, which is an extreme physical or chemical process that kills all types of life. Disinfectants are generally distinguished from other antimicrobial agents such as antibiotics, which destroy microorganisms within the body, and antiseptics, which destroy microorganisms on living tissue. Disinfectants are also different from biocides—the latter are intended to destroy all forms of life, not just microorganisms. Disinfectants work by destroying the cell wall of microbes or interfering with their metabolism. It is also a form of decontamination, and can be defined as the process whereby physical or chemical methods are used to reduce the amount of pathogenic microorganisms on a surface.
Soft matter or soft condensed matter is a subfield of condensed matter comprising a variety of physical systems that are deformed or structurally altered by thermal or mechanical stress of the magnitude of thermal fluctuations. These materials share an important common feature in that predominant physical behaviors occur at an energy scale comparable with room temperature thermal energy, and that entropy is considered the dominant factor. At these temperatures, quantum aspects are generally unimportant. Soft materials include liquids, colloids, polymers, foams, gels, granular materials, liquid crystals, flesh, and a number of biomaterials. When soft materials interact favorably with surfaces, they become squashed without an external compressive force. Pierre-Gilles de Gennes, who has been called the "founding father of soft matter," received the Nobel Prize in Physics in 1991 for discovering that methods developed for studying order phenomena in simple systems can be generalized to the more complex cases found in soft matter, in particular, to the behaviors of liquid crystals and polymers.
In fluid mechanics, two-phase flow is a flow of gas and liquid — a particular example of multiphase flow. Two-phase flow can occur in various forms, such as flows transitioning from pure liquid to vapor as a result of external heating, separated flows, and dispersed two-phase flows where one phase is present in the form of particles, droplets, or bubbles in a continuous carrier phase.
A bioreactor refers to any manufactured device or system that supports a biologically active environment. In one case, a bioreactor is a vessel in which a chemical process is carried out which involves organisms or biochemically active substances derived from such organisms. This process can either be aerobic or anaerobic. These bioreactors are commonly cylindrical, ranging in size from litres to cubic metres, and are often made of stainless steel. It may also refer to a device or system designed to grow cells or tissues in the context of cell culture. These devices are being developed for use in tissue engineering or biochemical/bioprocess engineering.
A chiller is a machine that removes heat from a liquid coolant via a vapor-compression, adsorption refrigeration, or absorption refrigeration cycles. This liquid can then be circulated through a heat exchanger to cool equipment, or another process stream. As a necessary by-product, refrigeration creates waste heat that must be exhausted to ambience, or for greater efficiency, recovered for heating purposes. Vapor compression chillers may use any of a number of different types of compressors. Most common today are the hermetic scroll, semi-hermetic screw, or centrifugal compressors. The condensing side of the chiller can be either air or water cooled. Even when liquid cooled, the chiller is often cooled by an induced or forced draft cooling tower. Absorption and adsorption chillers require a heat source to function.
The kraft process (also known as kraft pulping or sulfate process) is a process for conversion of wood into wood pulp, which consists of almost pure cellulose fibres, the main component of paper. The kraft process involves treatment of wood chips with a hot mixture of water, sodium hydroxide (NaOH), and sodium sulfide (Na2S), known as white liquor, that breaks the bonds that link lignin, hemicellulose, and cellulose. The technology entails several steps, both mechanical and chemical. It is the dominant method for producing paper. In some situations, the process has been controversial because kraft plants can release odorous products and in some situations produce substantial liquid wastes.
Thermosiphon is a method of passive heat exchange, based on natural convection, which circulates a fluid without the necessity of a mechanical pump. Thermosiphoning is used for circulation of liquids and volatile gases in heating and cooling applications such as heat pumps, water heaters, boilers and furnaces. Thermosiphoning also occurs across air temperature gradients such as those utilized in a wood fire chimney or solar chimney.
A fusible plug is a threaded cylinder of metal usually of bronze, brass or gunmetal, with a tapered hole drilled completely through its length. This hole is sealed with a metal of low melting point that flows away if a pre-determined, high temperature is reached. The initial use of the fusible plug was as a safety precaution against low water levels in steam engine boilers, but later applications extended its use to other closed vessels, such as air conditioning systems and tanks for transporting corrosive or liquefied petroleum gases.
Clean-in-place (CIP) is an automated method of cleaning the interior surfaces of pipes, vessels, equipment, filters and associated fittings, without major disassembly. CIP is commonly used for equipment such as piping, tanks, and fillers. CIP employs turbulent flow through piping, and/or spray balls for large surfaces. In some cases, CIP can also be accomplished with fill, soak and agitate.
Aseptic processing is a processing technique wherein commercially thermally sterilized liquid products are packaged into previously sterilized containers under sterile conditions to produce shelf-stable products that do not need refrigeration. Aseptic processing has almost completely replaced in-container sterilization of liquid foods, including milk, fruit juices and concentrates, cream, yogurt, salad dressing, liquid egg, and ice cream mix. There has been an increasing popularity for foods that contain small discrete particles, such as cottage cheese, baby foods, tomato products, fruit and vegetables, soups, and rice desserts.
Soil steam sterilization is a farming technique that sterilizes soil with steam in open fields or greenhouses. Pests of plant cultures such as weeds, bacteria, fungi and viruses are killed through induced hot steam which causes vital cellular proteins to unfold. Biologically, the method is considered a partial disinfection. Important heat-resistant, spore-forming bacteria can survive and revitalize the soil after cooling down. Soil fatigue can be cured through the release of nutritive substances blocked within the soil. Steaming leads to a better starting position, quicker growth and strengthened resistance against plant disease and pests. Today, the application of hot steam is considered the best and most effective way to disinfect sick soil, potting soil and compost. It is being used as an alternative to bromomethane, whose production and use was curtailed by the Montreal Protocol. "Steam effectively kills pathogens by heating the soil to levels that cause protein coagulation or enzyme inactivation."
Sewage treatment is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable to discharge to the surrounding environment or an intended reuse application, thereby preventing water pollution from raw sewage discharges. Sewage contains wastewater from households and businesses and possibly pre-treated industrial wastewater. There are a high number of sewage treatment processes to choose from. These can range from decentralized systems to large centralized systems involving a network of pipes and pump stations which convey the sewage to a treatment plant. For cities that have a combined sewer, the sewers will also carry urban runoff (stormwater) to the sewage treatment plant. Sewage treatment often involves two main stages, called primary and secondary treatment, while advanced treatment also incorporates a tertiary treatment stage with polishing processes and nutrient removal. Secondary treatment can reduce organic matter from sewage, using aerobic or anaerobic biological processes.
A biosafety cabinet (BSC)—also called a biological safety cabinet or microbiological safety cabinet—is an enclosed, ventilated laboratory workspace for safely working with materials contaminated with pathogens requiring a defined biosafety level. Several different types of BSC exist, differentiated by the degree of biocontainment they provide. BSCs first became commercially available in 1950.
Electrochemical engineering is the branch of chemical engineering dealing with the technological applications of electrochemical phenomena, such as electrosynthesis of chemicals, electrowinning and refining of metals, flow batteries and fuel cells, surface modification by electrodeposition, electrochemical separations and corrosion.
Microbes can be damaged or killed by elements of their physical environment such as temperature, radiation, or exposure to chemicals; these effects can be exploited in efforts to control pathogens, often for the purpose of food safety.