Assessement for management of wastewater quality from a healthcare unit--case study.

Sirbu, Dana ; Curseu, Daniela ; Popa, Monica 等

1. INTRODUCTION

Hospital complexes use for their activities and their hygiene, great volumes of water which are then rejected, fill of micro-organisms of which some are multiple resistant, often toxic and sometimes radioactive chemicals. The hospital is a heavy water consumer, while in medium the consumption of the households is 150 to 200 liters per capita and by day, the average value passes from 500 to 1200 liters/bed/day in the hospitals. Quality and quantity of wastewater produced in every hospital depends on different factors, such as: bed number, accessibility to water, kind of services, number of units/departments, climate situation, people's culture and geographical situation (Sabzali & Shivaii, 2006). All the new technologies which answer progress as regards care (hemodialysis, radiology, laboratories of high technologies, etc), should not compromise the watery ecosystem of our rivers and seas. The harmful effects related to their wastewater should be a subject to consider for all hospitals managers and it is necessary to assess the quality of their hospital effluent.

The aims of this study are: to characterize the effluents from the chemical and microbiological point of view and to compare with the national and international recommendations in order to develop efficient projects to improve the quality of these rejections.

2. MATERIALS AND METHODS

A hospital wastewater from Cluj County, with a capacity of 175 beds, which discharges the total volume of effluents into the urban wastewater network without pre-treatment, has been selected. The investigated hospital has following departments: internal medicine, pediatrics, surgery, psychiatry, gynecology and obstetrics, laboratory and pharmacy. In order to characterize the pollutant composition of the wastewater discharged, a questionnaire concerning susceptible matters of trapping various pollutants, were applied and evaluated.

To define quality parameter, sampling from out coming sewages of the hospital and from the municipal network system, was conducted. The following chemical and microbiologic analyses were carried out: pH, COD (chemical oxygen demand), [BOD.sub.5] (5-day biological oxygen demand), chlorides, TSS (total suspended solids), total phosphorous, MPNTC (most probable number of total coliforms) and MPNFC (most probable number of fecal bacteria). The samples were collected on three days of the week: Monday, Wednesday and Sunday, two samples per day at 10 a.m. and 3 p.m., 4 weeks. All the analyses were carried out in conformity with the national standards. The results were compared with the Romanian and European threshold values, and the Pc/Vt ratio (Pc--pollutant concentration in the hospital effluent, Vt--threshold values) was calculated (RD, 2002; Sirbu et al., 2005).

3. RESULTS AND DISCUSION

Investigation of hospital daily water consumption shows that the average value is 165 [m.sup.3]/day which is equal to 942 L/day/bed. Quantitative amount of daily wastewater production, considering water to wastewater conversion coefficient of 0.8 was estimated at 132[m.sup.3]/day (754 L of wastewater day/bed). On the basis of questionnaire, we found several types of hospital rejections which are shown in Table 1.

COD and BOD5 were determined for the measurement of total organic load. In the hospital effluent sample, COD concentration (535 mg/l), and [BOD.sub.5] (368 mg/l) exceeded the discharge national standards ([P.sub.c]/[V.sub.t]> 1), showing that hospital wastewater were heavily loaded with organic and mineral substances (Table 2).

The biodegradability of organic substances is a measure of the speed and completeness of their degradations by microorganisms and therefore the [BOD.sub.5]/COD ratio could be used to analyze the degree of degradation.

A [BOD.sub.5]/COD ratio 0.5-0.6 could be considered as threshold value to study the biodegradability of organic substances into the hospital wastewater (Seiss et al., 2001). In our study the [BOD.sub.5[/COD ratio in hospital wastewater is 0.68, which indicate that the pollutants would be difficult to degrade, which describes a potential impact on the WWTP (wastewater treatment plant) efficiency. However, COD might give false results in the sample contained organic or inorganic elements that were refractory, i.e., resistant to oxidation. For the accuracy of biochemical knowledge of hospital wastewater, according to biodegradability, it is necessary to introduce in the monitoring of hospital effluents the TOC (total organic carbon) determination and the COD/TOC ratio. TOC degradation rate depends on the chloride concentration of the wastewater. The different organochlorine compounds resulting from disinfections could contribute to high TOC concentrations in the hospital effluents. The results of bacteriological characterization are summarized in Table 3. Accordance with previous studies on microbiological characterization of hospital wastewater the concentrations in germs are weaker in the hospital effluents than in the urban effluents, which is probably related to the higher concentration of the disinfectants and the antibiotics (Kummerer, 2001; Sirbu et al., 2007). The level of contamination is variable according to the hour, the day or the flow at the time of the taking away. The hospital stocks are characterized by their resistance to antibiotics. These results showed that the application of important quantity of disinfectants in hospital can reduce bacteria in wastewater but give rise to toxicity effects on aquatic organisms (Popa et al., 2005). So, the parameters used for the microbiological characterization was also considered in this study like an indirect detection of the massive presence of disinfectants and/or antibiotics. Total/fecal coliform populations of hospital wastewater were affected because chloride values of these effluents are greater than values generally uncounted in domestic wastewater. Many studies conclude that chloride could be used as indicator of the toxicity of hospital wastewater on aquatic organisms when NaOCl was used (Emmanuel et al., 2001). Chloramines and other agents, such as sodium hypochlorite and some iodized substances are responsible for the disinfectant effect. Organic halogen compounds are formed by reaction of chlorine with organic wastewater compounds. An additional AOX in the wastewater will result. The AOX have a bad biodegradability and several toxic effects on aquatic organisms. Hospitals cannot be neglected as contributors to AOX in urban wastewater (Kummerer, 2001). For more accuracy it seams to be important to introduce the determination of AOX (organohalogen compounds absorbable) in hospital wastewater monitoring in our country.

These substances, which are not biodegradable, may finally enter surface water by WWTP effluents, and enter groundwater after the application of sewage sludge as fertilizers (Gartisser et al., 1996). Among other substances, various pharmaceuticals made the object of ecological research, such as: the sex hormone, the radio elements, antibiotics and cytostatic agents (Sirbu et al., 2007).

4. CONCLUSION

The problems of wastewater in health care units have not been monitored in Romania so far. All the results confirm the existence of hazardous substances in the studied hospital effluents, and hence the need for continuing the approach by establishing the ecotoxicological risk assessment of hospital wastewater for the aquatic ecosystems. It should also be noted that the effluent of the hospital undergoes major dilution in the communal sewage system. To align with the European Commission Directives for each medical unit, it would be important to be able to evaluate their effluents and to develop efficient projects of management them.

5. REFERENCES

Emmanuel, E.; Blanchard, J.; Keck, G. & Perrodin, Y. (2001). Caracterisation chimique, biologique et ecotoxicologique des effluents hospitaliers (Chemical, biological and ecotoxicological characterisation of hospital wastewater). Sci. Techn., 22: 31-33.

Gartisser, S.; Brinkler, L., Erbe, T; Kummerer, K & Willmund, R. (1996). Contamination of hospital wastewater with hazardous compounds. Acta Hydrochim, 24: 90-97.

Kummerer, K. (2001). Drugs in the environment: emission of drugs, diagnostic aids and disinfectants into wastewater by hospitals. Chemosphere 45:957-969.

Popa, M.; Curseu, D.; Sirbu, D. & Chakirou, C. (2005) Toxicological Effects of Some Chemicals from Hospital Wastewaters. Proceeding of Sustainability for humanity & environment in the extended connection field Science--Economy-Policy, vol.II, pp. 308-312, ISBN 973-625-206X, Timisoara, febr. 2005, Ed. Politehnica Timisoara.

RD (2002). Guidelines for Wastewater Evacuation in Urban Sewer Network (In Romanian). Romanian Directive 188/2002, Bucharest, Romania.

Sabzali, A. & Shivaii, H. (2006). Hospital wastewater treatment. Adv. Res. Magazine. Tehran, 1:44-50.

Seiss, M.; Gahr, A. & Niessner R. (2001). Improved AOX degradation in UV oxidative wastewater treatment by dialysis with nanofiltration membrabe. Wat. Res., 13:3242-3248.

Sirbu, D.; Curseu, D.; Popa, M. & Popa, M.S. (2007). Approaches on Management for Pharmaceutical and Personal Care Products in Water. Proceedings of the 18th International DAAAM Symposium, Katalinic, B. (Ed.) vol 18, no1, pp. 693-694, ISBN 3-901509-58-5, Zadar, Oct. 2007, Croatia.

Sirbu, D.; Popa, M.; Curseu, D.; Achimas,, A. & Hegediis, L. (2005). Environmental Risk of Hospital Wastewater, Central European Journal of Occupational and Environmental Medicine, vol.11, nr.4, pp.281-287, ISSN 1219-1221.

Tab. 1. General types of hospital rejections

Rejections Types and sources

Rejects of rejections of the kitchens, detergent products,
domestic rejections of the garages and workshops, those of the
nature laundry, and the boiler room

Rejects of Chemical pollutants:
specific --cleaners and disinfectants which are often highly
nature complex products or mixtures of active substances.
 The most often used products are mainly chlorinated
 derivatives, the products containing aldehydes
 (formaldehyde and glutaraldehyde: toxic molecule
 both for man and the environment), the iodized
 compound (betadine).

 --drugs (analgesics, antibiotics, radio elements, and
 cytostatic agents)

 --chemical agents from the laboratories (acids, strong
 bases, solvents)

 --heavy metals such as mercury and the silver
 resulting, for one of breakings of the mercury
 thermometers and for the other of the service of
 radiology.

 Biological pollutants:

 --the pathogenic rejections of germs resulting from
 the people's diseases (Pseudomonas aeruginosa,
 Staphylococcus aureus, E. coli, Streptococcus
 pneumoniae, Klebseilla pneumoniae)

Tab. 2. Comparison of the average concentrations in pollutants
of hospital and urban effluents

 Concentrations in:

 hospital urban Threshold
 Parameters effluents effluents values

Temperature
 ([degrees]C) 26.8 19.8 40
pH (U) 8.7 * 7.5 6.5-8.5
 ([P.sub.c]/[V.sub.t]> 1)
TSS mg/l 335 * 282 300
 ([P.sub.c]/[V.sub.t]> 1)
[BOD.sub.5] mg/l 368 * 280 300
 ([P.sub.c]/[V.sub.t]> 1)
COD mg/l 535 * 498 500
 ([P.sub.c]/[V.sub.t]> 1)
[BOD.sub.5] / COD 0.68 0.56 0.5-0.6
Total Phosphorous 7.6 6 5
mg/l ([P.sub.c]/[V.sub.t]> 1)
Chlorides mg/l 287 60 400

Tab. 3. Microbiological characterization of hospital effluent

 Concentration
 in:

Parameters Threshold Hospital
(average values) values * effluent

MPNTC 4.8 x [10.sup.4]
germs/100 ml

MPNFC 1 x [10.sup.8] 3.9 x [10.sup.4]
germs/100 ml [P.sub.c]/[V.sub.t]< 1

 Concentration
 in:

Parameters Urban
(average values) effluent

MPNTC 3.9 x [10.sup.6]
germs/100 ml

MPNFC 2.8 x [10.sup.6]
germs/100 ml