Pollution and Control Laboratory
Abstract: This paper analyzes China's current type of laboratory contamination and hazards exist, stating the laboratory is a source of pollution can not be ignored, complex types of pollution, poisoning large. And for not
With the corresponding pollution control measures. Drawing on international management experience related to proposed pollution control measures for laboratories to implement green laboratories.
Keywords: Laboratory; waste; environmental pollution; control
As China's scientific and technological development, the demand for more and more types of laboratories, the Laboratory of disciplines, schools, the focus of the laboratory system after another. From the laboratory of distribution, mainly in schools (including universities and secondary schools), research institutions, testing organizations and enterprises in the research department inspection. Enterprise Lab pollution can be summarized as corporate environmental issues, are easy to attention at all levels, enterprises in dealing with their own environmental problems, pollution issues have been dealt with accordingly. The various types of laboratory are mostly independent of the administrative units, regional spread, single, less pollution, easy to be ignored.
China now has all kinds of institutions of higher education 1100 (1999 statistics), 15,000 high school, junior high 6.3. Research institutes, quality control, health and epidemic prevention, environmental monitoring, agriculture, forestry and other inspection agencies at all levels, more than nearly 20,000, has become a huge system. Laboratory practice is a typical small sources of pollution, building more, the greater the contamination. These laboratories, especially in urban and residential areas of the laboratory particularly harmful to the environment, because many laboratories sewer connected with the residents of the sewer, the formation of cross-contamination by sewage pollution *, and finally into the river or into the ground, its incalculable harm. Scientists become scientists or future environmental polluters, it is very regrettable. Environmental protection is a matter of grand strategy for sustainable economic development. In environmental protection and equality before must the spirit of "who pollute the environment, who is responsible for processing" principle implemented. Laboratory charges should include cost accounting and external environmental costs, including laboratory.
Types of complex laboratory sources, varieties, poisoned large, should be based on specific circumstances, treatment programs were developed.
A laboratory environment, types of pollution and damage [1]
1.1 divided by the nature of pollution
1.1.1 chemical pollution
Chemical pollution, including pollution, organic pollution and inorganic. Organic pollution is mainly organic reagent contamination and pollution of organic samples. In most cases, the lab is not directly involved in the organic reagents react only from the solvent effect, the consumption of organic reagents in various forms released into the surrounding environment, emissions roughly equivalent to the consumption of reagents the amount. Day after day, year after year, emissions are substantial. Organic contamination of samples, including some toxic organic samples, such as pesticides, benzo (α) pyrene, aflatoxin, nitrosamines, etc. Contaminated with inorganic acid, alkali pollution, heavy metals, cyanide pollution. Including mercury, arsenic, lead, cadmium, chromium and other heavy metal toxicity is not only strong, and there is accumulation in the human body has.
1.1.2 Biological pollution
Biological contamination, including biological and bio-waste pollution bacterial endotoxin contamination. Laboratory testing of biological specimens with waste, such as blood, urine, faeces, sputum and vomit, etc.; test items, such as laboratory equipment, positive bacterial culture medium and bacterial specimens. Laboratory to carry out biological experiments will produce high concentrations of harmful micro-organisms of culture medium, medium, without the proper sterilization and direct discharge will cause serious consequences. Biological laboratory ventilation design or inadequate personal security vulnerabilities during the experiment, will spread dissemination of biological bacterial toxins, bringing pollution, and even lead to serious adverse consequences. Raging SARS epidemic in 2003, many biological laboratories to strengthen virus research in SAS, followed by reports of SARS infection, mostly researchers in the laboratory study were infected.
1.1.3 Radioactive contaminants
Radioactive waste radioactive markers, such as radioactive standard solution.
1.3 divided by form of pollutants
1.3.1 Wastewater
Laboratory-generated waste, including excess samples, standard curve and residue samples, failure of the storage solution and lotion, a large number of washing water. Almost all of the conventional analysis of the project there are different levels of water pollution problems. These all-inclusive in the composition of wastewater, including the most common organic compounds, heavy metals and harmful micro-organisms such as cyanide and relatively rare, bacterial toxins, a variety of pesticide residues, drug residues, etc.
1.3.2 emissions
Laboratory-generated emissions, including volatile reagents and samples, the analysis process intermediates, leakage and emptying of the standard gas and carrier gas, etc. Usually the laboratory directly toxic and harmful gas experiments are required fume hood, which of course is to ensure indoor air quality, protect the health and safety analysts an effective way, but also directly pollute the air. Laboratory waste, including mist, formaldehyde, benzene, solvents and other common organic pollutants and mercury vapor, gas and other less experienced light pollution.
1.3.3 Solid Waste
Laboratory-generated solid waste, including excess samples, analysis of the product, the experimental items consumed or damaged (such as glass, gauze), residual or failure of chemical reagents. The complex composition of solid waste, covering all kinds of chemical, biological contaminants, especially a lot of expired chemicals, handling the slightest mistake can easily result in serious pollution incidents.
Two pairs of laboratory contamination of the approach
To prevent the spread of laboratory contamination, contamination of the general treatment principles are: separate collection, storage, respectively, to focus on. As far as possible, and recycling of waste solidification, incineration, in practice, select the appropriate method for testing, minimize waste and reduce pollution. Waste emissions should comply with relevant environmental emission standards.
2.1 Chemical type of waste
General toxic gases through a fume hood or ventilation pipes, air-diluted exhaust. A large number of toxic gases and oxygen combustion must be treated prior to emission or absorption.
Waste should be selected based on their chemical characteristics and location of suitable containers, sealed container through the store, not mix storage container label must indicate the type of waste, storage time, regular treatment. General waste by acid-base neutralization, coagulation, sodium hypochlorite oxidized emissions should be based on the nature of organic solvent waste for recycling.
2.1.1 treatment of waste containing mercury
Emission Standard 3: The maximum allowable waste emissions of mercury concentration of 0.05mg / L (in Hg).
Approach: ① sulfide co-precipitation method: first waste mercury salt the pH adjusted to 8-10, and then adding an excess of Na2S, to generate HgS precipitate. Then add FeS04 (co-precipitation agent), and excess S2-generated FeS precipitation, the precipitate suspended in water is difficult to co-precipitation of HgS particles adsorption. Then put it aside, separation, and then by centrifugation and filtration, the filtrate the amount of mercury can be reduced to 0.05mg / L or less. [2]
② Reduction: copper scrap, iron, zinc tablets, sodium borohydride as reducing agent, metallic mercury can be recovered directly.
2.1.2 treatment of waste containing cadmium
① hydroxide precipitation method: cadmium-containing waste water in the lime dosing, adjusted to pH 10.5 and above, stir and placed, so that cadmium ions into insoluble Cd (OH) 2 precipitate. Precipitation separation with dithizone spectrophotometry of Cd ions in the filtrate (reduced to 0.1mg / L or less), the filtrate to pH values of about 7, and then discharged.
② ion-exchange method: the use of water other than the Cd2 + ions and cation ion exchange resin has a stronger binding force, the priority exchange.
2.1.3 Waste treatment of lead
Add lime in the waste, to adjust the pH value is greater than 11, the waste of lead generation Pb (OH) 2 precipitate. Then add Al2 (S04) 3 (coagulant), the pH value fell to 7-8, the Pb (OH) 2 and Al (OH) 3 co-precipitation, precipitation separation, compliance, emissions waste.
2.1.4 treatment of waste containing arsenic
Adding arsenic waste in FeCl3, the Fe / As 50, and then the pH of waste lime will control 8-10. The use of new hydroxide co-precipitation and arsenic compounds, adsorption of arsenic in waste removal. Place the night, separating precipitation, standards, emissions waste.
2.1.5 phenolic wastewater treatment
Phenol is highly toxic cell protoplasmic poisons, processing methods: the low concentration of phenol-containing waste liquid sodium hypochlorite or bleach can be added to cook, so as phenol is decomposed into carbon dioxide and water. If high concentrations of phenol-containing waste can be extracted by butyl acetate, plus a small amount of sodium hydroxide solution stripping by adjusting the pH recovery after distillation. Treated wastewater discharge.
2.1.6 Integrated waste treatment
With acid, alkali waste PH adjusted to 3-4 by adding iron powder, stirring 30min, and then adjusted with alkali about p H 9 and continue stirring 10min, adding aluminum sulfate or aluminum chloride coagulant, the coagulation precipitation, the supernatant can be directly emitted, deposited on the treated waste.
2.2 biological type of waste
Biological type of waste should be based on its pathogenic properties, select the appropriate physical characteristics and location of the container, separate collection of hand disinfection, burn treatment, Nissan Nissin.
Liquid waste and can be added bleaching powder chlorination disinfection. Combustible solid waste collection, processing, burning all in a timely manner. Non-combustible solid waste collection, bleach can be added for chlorination treatment. Made after final disposal to meet the disinfection conditions.
2.2.1 The single-use products such as gloves, hats, work objects, masks, etc. into the dirt bag after use concentrated fire.
2.2.2 reusable equipment, such as glass slides, straw, glass bottles can be 1000-3000mg / L chlorine solution, soaking 2-6h. And then re-use cleaning or disposal.
2.2.3 containing specimens of glass, plastic, enamel containers can be boiled 15min. Or with 1000mg / L chlorine bleach supernatant soak 2-6h, after disinfection with a detergent and water, wash and drain; for microbial culture, with pressure steam sterilization before use.
2.2.4 inoculated microbiological tests over the agar plate should be pressure sterilization 30min, hot pour the agar abandoned treatment.
2.2.5 urine, saliva, blood and other biological samples, add bleaching powder after mixing the role of 2-4h, poured into septic tanks or latrines. Or for incineration.
2.3 Radioactive Waste
Radioactive waste for the general laboratory in the low-level radioactive waste produced during the experiment radioactive waste collected in the special dirt bucket, barrel marked with eye-catching signs outside, according to the length of the half-life radioisotopes were used storage some time to decay and chemical precipitation concentrated buried or burned after the treatment.
2.3.1 The short half-life radioisotopes (such as: iodine 131, phosphorus 32, etc.) of waste, with special container tightly closed, placed in a special storage room, place ten half-life after discharge or incineration.
2.3.2 The longer half-life radioisotopes (such as: iron 59, 60 drilling, etc.) of the waste, the liquid can evaporate, ion exchange, precipitation and other methods of coagulant concentration, concentration of buried radioactive waste into the container pit.
3 Laboratory of Pollution solution
3.1 raise awareness, develop technical specifications
Laboratories at all levels need to further improve laboratory environmental issues, can not be avoided, left unchecked, it should be based on the characteristics of the laboratory work, focus, and actively explore ways to reduce laboratory contamination. National authorities should also carefully study the characteristics and laboratory pollution prevention approach, put forward feasible, simple and practical technical specifications and requirements and the introduction of appropriate assessment methods. Best construction and acceptance into the lab to go to become a part of capacity building, thus contributing to the implementation of the laboratory environment, pollution prevention and control measures.
3.2 The establishment of the laboratory environmental management system [3]
Laboratory capacity building, quality management, we must also establish a complete lab environment management system. According to the ISO14001 environmental management system concepts and requirements, a comprehensive survey of all aspects of laboratory analysis, develop appropriate files, standard laboratory environmental behavior, the full implementation of ISO14001 has always emphasized pollution prevention and continuous improvement of the basic requirements, and strive to reduce each process of environmental impact, so as to continuously improve laboratory management.
3.3 the full implementation of green chemistry, clean experimental
3.3.1 choose less polluting methods of analysis
The premise of ensuring the experimental results, using non-toxic, pollution-free or low-toxic, low-pollution alternative to toxic reagent kit, try to use non-toxic, low-toxicity alternative to highly toxic reagent kit. Use in certain experiments to highly toxic drugs, we must use a closed collection buckets to collect waste.
School education during the experiment, special attention to the role of teaching multi-media play. Teaching Multimedia is the product of the knowledge economy, information society, it is one of the symbols in the experimental teaching, computer-aided teaching chemistry experiment simulations (simulation) is a chemical reagent and instrumentation devices "zero input" and "zero emission of waste "special experimental approach, it is very suitable for the demonstration experiment. Mainly because of the demonstration experiment for students of observation and imitation rather than training for hands-on ability. Some of the toxic chemical experiments can also be larger in this way to learn a little knowledge in order to prevent a high environmental price to pay practices. [4]
3.3.2 to improve the experimental conditions, to carry out experiments to promote micro-[5]
In the experiment to improve the experimental device, is effective to prevent toxic gas oven, an important measure of toxic liquid spills. Some commercially produced experimental devices can greatly reduce the amount of chemical reagents in the experiment.
Experiment refers to micro-miniaturization of instrumentation devices for the experiment, the reagent is a conventional one-tenth the number of experiments to the thousandth. Thus, the creation of mini-experiment, is saving drugs, reduce costs, reduce pollution, convenient way to experiment.
Improve the experimental method can reduce reagent usage. In pesticide analysis in solid-phase extraction to replace the traditional liquid-liquid extraction, acetonitrile, etc. can greatly reduce the use of toxic reagents, reduce pollution.
3.3.3 Reagents scheduling network set up
Expired, invalid handling of chemicals is a worldwide problem. The lab can set up a regional cooperation network reagent scheduling, select the part of the great harm, with less prone to failure of the reagent into the network, the implementation of resource sharing between laboratories, a large number of chemical agents to avoid failure, but also can save experimental costs.
3.3.4 The function of strengthening regional central laboratory
The current management system administrative departments at all levels have their own small and complete laboratory, waste a lot of resources, not conducive to environmental protection. Laboratory should play the role of regional centers, some of the projects focus on social development. To achieve resource sharing, the relative reduction of pollutants emissions laboratory, the laboratory of pollution is relatively conducive to large centralized management.
3.3.5 Experimental behavior of some well-established examples of clean
· Meet the test requirements in the case, due to lower sample volume;
Do not buy a temporary no access to the reagents;
· Make full use of recyclable reagents;
· Use of biodegradable phosphate-free detergent;
· Avoid using alcohol thermometer mercury thermometer mercury pollution potential.
4 status of pollution control laboratory at home and abroad
In other countries, there is a specialized laboratory waste treatment station to focus collection. Centralized processing station laboratory waste management practices, strict, strong safety awareness of environmental protection. Special focus on location, special room, special storage containers, specialized personnel management, and strict partition, classification, centralized waste treatment plant to send a special deal. Classification of waste handed over by the laboratory, the processing station to pay for waste weighing of the information will be stored into the computer, and then classified into the provisions of the local focus. For example, radioactive scrap, waste oil, scrap chemical reagents, chemical synthesis of the "three wastes", Chemical storage of waste containers so classified. [6]
Waste treatment plant design focused on the content carefully, fully equipped advanced security available *. To prevent the concentration of secondary pollution after the underground leakage, ground station design will handle all the whole pouring cement. Hazardous chemicals, radioactive sources stored in a special room, as well as security monitoring, ventilation systems.
Focus on the costs of waste treatment plant funded by the Government's annual budget. On the other hand, after being acquired from recyclable waste funds are used for centralized waste treatment plant for further development.
At present, China's emissions of the laboratory and has no specific provisions, general reference to the company's pollution emission standards. Recognition and acceptance in the construction of the laboratory or laboratory waste will discharge when requested. If the gas in the ventilation experiment done by a special environmentally friendly waste recycling company. As the full range of laboratory contamination, the situation is complex, most of the smaller amount of pollution generated by the project, the lack of appropriate funds to operate there are considerable difficulties, to bring some pollution problems. At present, except a handful of strong sense of environmental protection laboratory, there is no direct discharge of waste, most of the environmental laboratory only on words, waste recycling agreement signed on paper, a lot of waste is still discharged directly.
Since only sporadic laboratory to carry out most projects, the project work between the frequency of non-uniform, the law of waste emissions, pollution dispersion, these are also difficult to monitor the environmental protection department. Some environmental measures do not improve after treatment, such as how to deal with residue tank is full, is a thorny issue.
5 Conclusion
Laboratory there is a clear environmental pollution, national authorities must improve the management system, research solutions, adopt effective measures to prevent pollution of laboratory waste. Government departments should also be given funding, policy support, a comprehensive, systematic treatment program, step by step, using the appropriate way to properly handle the waste, try the ultimate solution.| Updated:2011.11.25 Source: Clicks:1523
