Hospital wastewater treatment program (a)
Hospital wastewater treatment methods and processes are determined according to the object of treatment, the object of its treatment of suspended solids, floating matter, organic matter, radioactive isotopes, pathogens, viruses, acids and bases. Among the more harmful are pathogens, which are described as follows.
(1) suspended solids and floating matter
Generally set up septic tanks at the exit of the ward. Sewage into the septic tank, which has a greater specific gravity of pollutants in the pool precipitation separation, fermentation and digestion. In the process of sedimentation is also mixed with some viruses and germs along with the sedimentation, so the sludge should also be treated accordingly. Septic tank water will still carry some of the floating and mechanical impurities into the disinfection pool, which will affect the sterilization effect of the disinfectant, therefore, the sewage into the disinfection pool should be fully precipitated and simple filtration.
(2) organic pollutants
Hospital wastewater organic matter is generally smaller than municipal wastewater, BOD5 more than 100 mg / liter or so. The self-purification ability of the water body itself can be used to digest it. But if discharged directly into the higher requirements of surface water bodies, scenic areas, etc., the organic matter to be treated, generally more biological treatment.
(3) radioisotopes
Due to the spontaneous metamorphosis of the atomic nucleus produces rays, which exist to make the sewage with radioactive contamination, can not be artificially altered in the sewage radioactive substances in the intensity and performance. Therefore, the only way to reduce or avoid its harm is to dilute or concentrate it. For this kind of sewage can be based on the type of radioactive material, half-life length to determine its treatment method. For elements with short half-life, the storage method or dilution method is used for treatment; for radioactive substances with long half-life, physical, chemical or biological methods can be used to treat them, separating them from the sewage first. According to the survey, the current general hospitals use radioisotopes are short half-life, and the amount of sewage is relatively small, so the storage method is usually used to deal with.
(4) parasites
Parasite eggs from feces, its specific gravity is greater than fecal sewage (about 1.02-1.04), so it can be separated from the sewage by precipitation. The eggs of Ascaris lumbricoides are generally used as a criterion for the death of parasites, i.e., when the eggs of Ascaris lumbricoides are dead, it is assumed that all other eggs are dead. Roundworm eggs can live for 1-5 years in the outside world, but in a fermenting environment the life span is much shorter. In the pile of feces, they can live for 7 days in summer and 21 days in winter. Frequently used septic tanks, sludge emptying cycle in more than three months, parasitic eggs can be completely in the pool precipitation, in the fermentation environment to kill.
(5) viruses
Viruses are a far smaller object than bacteria, they do not have a complete cellular structure, must be in a certain live cells to survive and reproduce. Viruses are responsible for 80% of all infectious diseases in humans. Viruses are generally cold-resistant and heat-resistant (but hepatitis viruses are resistant to heat, drying and freezing, such as hepatitis A heat-resistant 56 ℃, more than 1 hour; B heat-resistant 60 ℃, more than 4 hours), but all viruses are sensitive to high temperature boiling and strong oxidizing agents, and therefore can be injected into a certain concentration of chlorine to make it inactivated.
(6) infectious bacteria
Infectious bacteria are many types, but their activities are similar, generally in the PH value of 5-9.6 range of survival, when the PH value beyond this range of germs that is dead. In the water can live for more than a month, but in the fecal sewage life time is shorter. This is because: a. Fecal sewage contains ammonia generated by its own decomposition, which can play a bactericidal role; b. The decomposition of stool can also produce certain bacteriocins to inactivate bacteria. In addition most pathogens (except tetanus which is anaerobic) are aerobic. The use of this feature, such as the pool sealed with a lid, on the one hand, due to the decomposition of organic matter consumes a lot of oxygen, on the other hand, due to the pool sealing the difficulty of replenishment of oxygen, resulting in a reduction in the dissolved oxygen in the sewage, resulting in the aerobic germs in the lack of oxygen to eliminate themselves.
In addition, there are chromium, mercury and other heavy metals in the laboratory, testing room, available chemical methods to remove.
In summary, hospital sewage is an extremely complex system, so it is difficult to achieve satisfactory results using conventional treatment methods.
Recently developed ozone water treatment technology, widely used in hospital sewage treatment works, received excellent results, this is because the ozone than chlorine, bleach, chlorine dioxide has a stronger oxidizing ability, can be faster than chlorine 600-3000 times faster than the rate of death, including chlorine can not completely kill all bacteria, viruses, etc.; can be oxidized by certain heavy metal ions Pb, Hg, etc. Precipitation of certain heavy metal ions Pb, Hg, etc. to achieve the purpose of separation; in addition, ozone can also reduce the biochemical oxygen consumption (BOD) and chemical oxygen consumption (COD), removal of nitrite and decolorization, deodorization and so on. After this treatment 'hospital sewage, can greatly improve the discharge standards, and can even return to use as non-potable water.
Hospital wastewater treatment program (b)
Weifang Modern Environmental Technology Co., Ltd. share hospital wastewater treatment process: hospital wastewater sources of complex composition, containing pathogenic microorganisms, toxic, harmful physical and chemical pollutants and radioactive pollutants, etc., with spatial contamination, acute contamination and latent contamination, etc., not by Effective treatment will become an important pathway for the proliferation of epidemics and serious pollution source environment. This paper mainly introduces the MBR process to deal with hospital sewage.
First, the characteristics of hospital wastewater
Hospital departments with different functions, facilities and staff composition, the main departments and facilities that produce sewage are: diagnostic and treatment rooms, laboratories, wards, laundries, X-rays, washing and printing, animal rooms, isotope treatment and diagnosis, operating rooms and other drainage; hospital administration and medical staff discharges of domestic sewage, cafeteria, single room, family dormitory drainage. The Different departments and sections of the sewage generated by the composition and volume of water are different, such as heavy metal wastewater, oily wastewater, printing and washing wastewater, radioactive wastewater and so on. And the sewage produced by hospitals of different natures is also very different. The source of hospital sewage is complex, containing pathogenic microorganisms, toxic, harmful physicochemical pollutants and radioactive pollutants, etc., with spatial contamination, acute contamination and latent contamination, etc., without effective treatment will become an important pathway for the proliferation of epidemics and a serious source of pollution of the environment.
Second, the source of hospital sewage, water
(a), the source of hospital sewage
The main departments and facilities of the hospital wastewater discharge: treatment rooms, laboratories, wards, laundries, X-ray printing, isotope treatment and diagnostic rooms, operating rooms, etc.; also contains the hospital administration and medical staff discharges of sewage, cafeteria, dormitory drainage.
(b), the amount of hospital sewage water
More fully equipped large hospitals in the average daily sewage volume of 400-600L / (bed. d), K = 2.0-2.2
General equipment in small and medium-sized hospitals in the average daily sewage volume of 300-400L / (bed. d), K = 2.2-2.5
Small hospitals in the average daily sewage volume of 250-300L / (bed. d), K = 2.2-2.5
Small hospitals in the average daily sewage volume of 250-300L / (bed. d), K = 2.5
K - hourly coefficient of variation
Third, the water quality characteristics of hospital wastewater
The main pollutants of hospital wastewater contains pathogenic micro-organisms, toxic, hazardous, and radioactive pollutants of the three categories.
Pathogenic microorganisms and their control indicators:
Usually the number of coliforms and fecal coliforms as a measure of the biological indicators of fecal contamination of water quality.
Waterborne diseases in hospital sewage and domestic sewage are mainly intestinal diseases, and diseases transmitted by viruses include hepatitis and polio.
Toxic and hazardous substances and water quality indicators:
pH: acid and alkaline sewage in hospitals mainly comes from the use of disinfectants in laboratories, testing laboratories and laundry and radiology, etc., which can cause corrosion of the pipeline or affect the effectiveness of the use of disinfectants.
SS: affects the appearance of the water and chlorination disinfection inactivation effect.
BOD and COD: most from the domestic system drainage, biochemical performance is good, ( ) but hospitals widely used disinfectants are detrimental to biological treatment.
Plant and animal oils: from cafeteria drainage, affecting the dissolved oxygen in the water column and the disinfection of bacterial hospital effluent.
Total mercury: contains organic, inorganic, soluble and suspended mercury, but the body can be systemic poisoning. Mainly from loss of mercury from dentistry, crushing thermometers and certain measuring devices that use mercury.
Radioisotopes used in diagnosis and treatment in medical units produce alpha, beta, and gamma radioactivity during their decay, which can accumulate in the body and cause damage to human health.
The concentration of radioactivity in sewage is expressed in Bq/L. Radioactive liquid waste is divided into different classes according to the level of its radioactive concentration:
Class Ⅰ (low discharge waste liquid): concentration ≤4×106Bq/L.
Class Ⅱ (medium discharge waste liquid): concentration of 4×106Bq/L~4×1010Bq/L.
Class Ⅲ (high-discharge waste liquid): concentration >4×1010Bq/L.
Hospital radioactive liquid waste is divided into different classes.
Hospital radioactive wastewater mainly from the isotope treatment room, should be set for this part of the wastewater separate decay pool treatment, after reaching the standard and then discharged into the comprehensive sewer.
Fourth, the hospital sewage treatment technology analysis
Hospital sewage treatment is mainly based on the size of the hospital, the nature and treatment of sewage discharged to the process selection. Hospital sewage treatment process used must ensure that the treated water meets the standards, the three main processes used are: to strengthen the effect of primary treatment, secondary treatment and simple biochemical treatment.
The selection principles are as follows:
Infectious disease hospitals must use secondary treatment, and the need for pre-disinfection treatment;
Treatment of effluent discharged into a natural body of water in counties and hospitals above the county must be used in the secondary treatment;
Treatment of effluent discharged into the city sewers (downstream of the secondary wastewater treatment plant) of the general hospitals are recommended to use the second-tier treatment, the first-tier treatment process must be strengthened. Treatment process must be strengthened to deal with the effect;
For economically underdeveloped areas of small general hospitals, the conditions do not have the use of simple biochemical treatment as a transitional treatment measures, and then gradually realize the second level of treatment or to strengthen the effect of the first level of treatment. Weifang Modern Environmental Technology Co., Ltd. sales: ***** main products: medical sewage treatment equipment integrated sewage treatment equipment township hospital sewage treatment equipment sanatorium sewage treatment equipment
MBR process for the treatment of pharmaceutical wastewater characteristics:
The use of membrane bioreactor as the main treatment unit, which has a strong resistance to impact, the effluent quality and stability of the treatment structure is placed in the ground, occupying an area of about 1,000 square meters. All the structures are placed underground, covering a small area and reasonable layout, and the PLC cabinet is placed in the control room on the ground, which makes the management simpler.
MBR process due to efficient solid-liquid separation, low concentration of suspended solids in the effluent, bacteria and viruses lose the barrier of attachment or package, easy to be inactivated, can effectively remove SS and bacteria.
The efficient retention effect of the membrane module maintains a high biomass in the reactor, which improves the biological treatment efficiency. Due to the enrichment of microorganisms by the retention effect of the MBR, the nitrifying bacteria with a long generation cycle can be retained and reproduced, which achieves a very good denitrification effect.
Microporous aeration in the reactor not only improves the oxygenation efficiency, but also optimizes the hydraulic conditions of the reactor. Microporous aeration to the biological contact oxidation provides enough dissolved oxygen, aeration system to help the membrane on both sides of the turnover of water, strengthen the gas shear effect on the membrane, is conducive to the gas-liquid two-phase flow between the mass transfer, so that the treatment system for the normal and stable operation.
The residual sludge generated by hospital wastewater treatment contains a large number of bacteria and pathogenic microorganisms, improper treatment will cause secondary pollution. Therefore, maintaining the operation under high sludge concentration conditions can effectively solve the sludge discharge problem.MBR residual sludge production is low, and the residual sludge will be returned to the conditioning tank, so as to achieve the system sludge zero discharge, greatly saving the sludge treatment of financial problems, and is conducive to the management of sludge resources.