2. 1 Collection of hospital sewage 2. 1. 1 Sewage in hospital wards and non-wards should be separated, and the internal health and safety management system of the hospital should be strictly controlled and separated, and the sewage generated by the hospital should not be discarded and discharged into the sewage system at will. Newly-built, rebuilt and expanded hospitals should separate the sewage that may be contaminated by infectious disease pathogens from other sewage, and existing hospitals should collect the sewage contaminated by infectious disease pathogens from other sewage as far as possible.
2. 1.2 Infectious disease hospitals (including general hospitals with infectious wards) should be equipped with special septic tanks. Infectious pollutants contaminated by infectious disease pathogens, such as feces and other excreta, must be strictly disinfected in accordance with the relevant provisions of China's health and epidemic prevention. Disinfected feces and other excreta should be treated separately or discharged into a special septic tank, and its supernatant will enter the hospital sewage treatment system.
Hospitals without septic tanks should treat disinfected excrement as medical waste.
2. 1.3 All kinds of special drainage in the hospital, such as wastewater containing heavy metals, oily wastewater and printing wastewater, should be collected separately and discharged into the hospital sewage treatment system after taking different pretreatment measures.
2. 1.4 Radioactive wastewater from isotope therapy and diagnosis must be collected and treated separately.
2.2 hospital sewage discharge 2.2. 1 hospital sewage discharge
1, new hospital
The sewage discharge of newly-built hospitals should be designed according to Technical Measures for Design of Civil Building Engineering (J.J. [2003] No.4), so as to clean up and separate the sewage.
2. Existing hospitals
1) Sewage discharge is determined according to the measured data.
2) When there is no measured data, please refer to the following data for calculation.
(1) Large well-equipped hospitals or hospitals with more than 500 beds: the average daily sewage volume is 400-600 L/ bed. D, kd = 2.0-2.2, and kd is the daily variation coefficient of sewage.
(2) Medium-sized hospitals with general equipment or hospitals with 100 ~ 499 beds: the average sewage volume is 300 ~ 400 L/ bed. D, kd = 2.2 ~ 2.5, kd is the daily variation coefficient of sewage.
(3) Small hospitals (below 100 beds): the average sewage volume is 250 ~ 300 L/ bed. D, kd=2.5, kd is the daily variation coefficient of sewage.
2.2.2 Scale classification of hospital sewage treatment facilities
The scale of hospital sewage treatment facilities is divided into 100, 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000 and 1000 or more according to the number of beds.
2.3 Hospital sewage quality
2.3. 1 new hospital
The pollutant discharge of each sickbed can be selected according to the following values:
Bo D5:40-60g/ bed.d, CODcr: 100 ~ 150g/ bed.d, suspended matter: 50 ~ 100g/ bed.d;
Calculate the design water quality of the newly-built hospital according to the pollutant discharge of each hospital bed and the water quantity in 2.2. 1.
2.3.2 Existing hospitals
1) The sewage quality shall be subject to the measured data;
2) When there is no measurement data, refer to Table 2-2.
Table 2-2 Hospital Sewage Quality
2.4 Hospital sewage discharge standard
2.4. 1 existing standards
At present, the Comprehensive Wastewater Discharge Standard (GB8978- 1996) stipulates the corresponding fecal coliforms and residual chlorine standards for hospital sewage according to the different use functions of the receiving water body, and has no special requirements for physical and chemical indicators such as COD and SS, but only meets the standards of other pollutant discharge units with relatively low requirements, and only gives the lower limit of residual chlorine, without the upper limit.
According to the current standards, the existing hospital sewage treatment technology is low, and the main problem is that the concentration of suspended solids is high (1), which affects the disinfection effect; (2) The water quality fluctuates greatly, and the dosage of disinfectant is difficult to control; (3) The amount of disinfection by-products is large, which affects the safety of ecological environment; (4) There is no upper limit for the residual chlorine standard, and excessive residual chlorine endangers ecological safety.
New standard
In order to strengthen hospital sewage treatment and implement the new environmental standard system, the state organized relevant departments and personnel to compile the Discharge Standard of Water Pollutants for Medical Institutions.
1. The new standard comprehensively treats the sewage, waste gas and sludge produced by hospitals, emphasizing the disinfection effect of sewage containing pathogens and taking into account the safety of the ecological environment.
2. In terms of biological indicators, the new standard puts forward different requirements for hospital sewage discharged into sewers and water bodies. The new standard strictly distinguishes the nature of hospitals and divides them into two levels according to the direction of sewage discharge, and puts forward strict control indicators at all levels on the basis of the original standard.
3. The new standard considers disinfection effect and ecological safety. According to different hospitals and sewage destinations, the disinfection time and residual chlorine amount are clearly defined, and the upper limit of residual chlorine standard is strict.
4. In terms of physical and chemical indexes, the indexes such as COD, BOD5, SS, animal and vegetable oils, petroleum and anionic surfactants of hospital sewage discharged into surface water and infectious hospital sewage are strictly controlled on the basis of the original standards, so as to enhance the anti-risk ability of sewage treatment system. Considering that ammonia nitrogen will also consume disinfectants, strict requirements are also put forward for ammonia nitrogen.