Hospital wastewater treatment
Wastewater discharged from hospitals (especially infectious diseases hospitals) and laboratories in science and engineering colleges must be disinfected or treated harmlessly. Depending on the different conditions of the sewage, the treatment methods are also different. As far as chemical methods are concerned, bleaching powder, "three-in-two" or liquid chlorine treatment are often used. Whether it is a first-section pool, a second-section pool or a third-section pool, the above-mentioned chlorine-containing disinfectants should be put in separately or selectively. Some people are very surprised that bleaching powder is used as an anti-biowarfare disinfectant! In fact, the application standards are firstly effective, and secondly they are cheap, easy to produce and easy to transport. If there is a large demand, the supply can be effectively guaranteed! In the era of "preparing for war and famine for the people", our country once listed "three-in-two" as a war preparation material reserve.
In recent years, hospitals’ methods of treating sewage have changed. Some use ozone, some use sodium hypochlorite, and some use chlorine dioxide, and they are used in on-site production. Why did this change happen? Because the liquid chlorine used undergoes chlorination and chlorination with some organic matter in the waste, by-products such as chlorophenol, chloramine, and chloroform are generated, causing secondary environmental pollution, seriously endangering the survival of aquatic animals, and damaging the ecology. Balance, and chloroform can also cause carcinogens to animals and humans.
Among the new methods of sewage treatment, ozone is the best. The aquaculture water bodies in the domestic "Underwater World" are mainly disinfected by ozone. However, ozone equipment has high cost and high maintenance requirements. Its half-life at 25°C is only 16 minutes, and it cannot be stored and transported. These shortcomings leave room for development of sodium hypochlorite and chlorine dioxide. It is expected that within the next 10 years, hospital wastewater treatment will still be dominated by chlorine dioxide and sodium hypochlorite (NaOCl). The article "Application of Chlorine Dioxide in Water" published in the 6th issue of "Fish Disease Research" magazine in 1996 mainly explains the application of chlorine dioxide in water, tap water; industrial wastewater, environmental wastewater; industrial circulating water; aquaculture water, etc. For example, from the perspective of combat readiness, it is appropriate to reserve sodium chlorate, sodium chlorite or stable chlorine dioxide, etc., and use these precursors of chlorine dioxide as "combat readiness materials." As for the dosage, usage, type of equipment, etc., they should be determined according to the specific conditions of the emissions and pollutants of each unit. For example, acidification reduction with NaClO3 is used to produce chlorine dioxide, and treating wastewater is one of the conventional methods. A few hours before discharge at the end of the pool, add an appropriate amount of bleaching powder [Ca(OCl)2], which can not only measure the residual chlorine in the discharged water, but also correct the pH value; or add NaOH, etc. for sedimentation treatment, and the sludge can also be used Use as fertilizer.
Hospital waste treatment
There are many patents for treating medical waste with chlorine dioxide. Chlorine dioxide devices have been invented abroad to treat medical waste. The method is to first separate the bedding, clothing dressings and non-recyclable dressings, waste paper, etc. to be recycled, and then transport them to a resin sealed container that is resistant to chlorine dioxide corrosion, and inject the chlorine dioxide precursor (NaClO2) into this container. ) and acid, etc., only need to be stirred or crushed at the same time for 10 minutes to achieve thorough disinfection. Glass, plastic, metal utensils and even baby corpses can also be treated with chlorine dioxide, eliminating the need for a cremator, which consumes fuel, trouble, time and pollutes the environment. This method only needs to use resin containers to handle different medical supplies. Its simple method is worthy of reference by various hospitals. In addition, when hospitals wash work clothes and bedding, if they can add chlorine dioxide precursors (such as NaClO2 or S.ClO2 stabilized solution) at the same time, they can not only achieve the purpose of disinfection, but also bleach the fabrics, killing two birds with one stone
Comprehensive conclusion: chlorine dioxide is more effective.