The average general healthcare waste generation rate per health center ranges from 298.9 kg/day collected at Mwananyamala regional referral hospital to 1554.4 kg/day collected at Muhimbili national hospital (Figure 3) These values resemble the results reported in Middle East, Latin America and India which ranged between 1.0 - 3.0 kg/day [24].

It was revealed that average daily medical general waste generation rate per patient can be arranged in the order 1.87 kg/person/day (Ilala regional hospital) > 1.56 kg/person/day (Temeke hospital) > 1.42 kg/person/day (Mwananyamala hospital) > 1.04 kg/person/day (Muhimbili National Hospital) These values agree with the range of 0.3 - 1.8 kg/day established earlier [25].

The high fluctuation in medical waste at Muhimbili National hospital compared to other regional hospitals can be attributed by the large number and type of surgical procedures conducted on that day as well as a large number of in-patients admissions at Muhimbili hospital.

The variation in total of HCW generation among hospitals may be attributed to a variety of reasons such as the type of healthcare establishment, income level and welfare of patients and visitors and diversity of departments [26]. It has been mentioned earlier that it is risky to make comparisons with medical waste records from other countries, due to the variability in the definitions and classifications of medical waste throughout the world [27].

The fraction of sharps waste was observed to be 1.65% in both hospitals to include any device or object used to puncture or lacerate the skin in patient care. This is lower than the one determined earlier 14% analyzed in two hospitals [28]. According to WHO/UNICEF [29] sharps are used items like syringes and needles, intra-venous (IV) tubing with needles attached, giving sets, scalpel blades, knives, lancets, blades and broken glass, form a class of medical waste known as sharps waste. Sharps waste contains items that can cause cuts or puncture wounds to healthcare workers. Whether sharps are infected or not, are considered highly dangerous and potentially infectious waste, due to their puncture or cutting property [30].

Figure 4 shows the variation of the daily sharps waste incineration rate (in kg/day) recorded. All sharps waste generated are incinerated as the best available option. The overall average sharps waste generation rate was established to range from 8.5 ± 2.7 - 13.9 ± 1.8 kg/day, with Muhimbili National hospital having the highest and Mwananyamala regional hospital having the lowest.

Higher values of sharps waste generated observed at Muhimbili national referral hospital is not surprising due to emergency cases referred to MNH from Temeke, Amana, Mwananyamala and private hospitals located within the city

and from the surrounding districts and other regions of the country. The observed values are lower than the average sharps waste generation rate observed earlier [31], which was established to be 40.8 kg/day with wider daily variations between 10 and 90 kg sharps waste per day. These values are higher than those detected in Ethiopia, where the rate of sharp generation in 10 different hospitals was 0.267 ± 0.107 kg/day [32].

Infectious Waste

Waste which was measured was those items contaminated with blood or other body fluids. Cultures and stocks of infectious agents from laboratory work [31]. Waste from infected patients in isolation wards. Waste contaminated with blood or other body fluids include free-flowing blood, waste pharmaceutical materials (expired chemicals) blood components and other body fluids; dressings, bandages, swabs, gloves, masks, gowns, drapes and other material contaminated with blood or other body fluids; and waste that has been in contact with the blood of patients undergoing haemodialysis (e.g. disposable towels, gowns, aprons, gloves and laboratory coats). Figure 5 shows the quantity of infectious waste collected from different hospitals.

The study analyzed, infectious waste excluding the plastic bottles and pathological waste, occupy about 34.1% of the entire waste materials. Muhimbili hospital has the highest average of 537.8 ± 21.2 kg/day followed by Ilala hospital with 124.4 ± 4.8 kg/day, Temeke hospital 90.1 ± 10.9 kg/day and the lowest detected at Mwananyamala hospital with 84.1 ± 29.0 kg/day. These values are in line with other studies conducted in Lebanon [33], which ranges between 188 kg/day - 490 kg/day. In Tanzania it corresponds to results obtained earlier from Amana Hospital recorded 649 kg/day [27].

Thus, for the first time in Tanzania, this study has provided information on the infectious waste generation excluding the plastic bottles and pathological items, allowing bench-marking between hospitals. The calculated generation rates can serve as a reference for hospitals and controlling authorities. Indeed, in case the generation rate of a hospital is far from the average rate of the category

it belongs to, this could be an alerting sign on its sorting and waste management practices, whether for the hospital’s administrations or the local authorities.

Pathological Waste

Pathological waste is a subcategory of bio-hazardous waste, which originates from surgical procedures or research that involves removal of organs, tissues or body parts like waste from operation theaters will also contain removed body organs (like tonsils, appendices, limbs etc.) which renders the medical waste scary, and nuisance. Figure 6 shows the pathological amount collected in hospitals.

Pathological waste occupies about 8.6% of the total hospital waste collected. Muhimbili hospital register the highest with average of 116.1 kg/day followed by 35.5 kg/day recorded at Mwananyamala hospital, 30.2 kg/day Ilala hospital and the lowest is 28.9 recorded at Temeke hospital. These correspond to values detected earlier [24], who detected 24.6 kg/day of pathological waste.

The amount measured for pathological waste call upon the use biogas technology. This will lead to production of methane by anaerobic digestion helps to reduce the amount of waste that must be disposed of using other methods like incineration or land filling that generally does not have environmental benefits.

Non-Infectious Waste

When we consider the rate of generation of non-infectious waste the order can be arranged as 0.56 kg/bed∙day (Muhimbili National Hospital) < 0.58 kg/bed∙day (Ilala Hospital) < 0.61 kg/bed∙day (Mwananyamala Hospital) < 0.68 kg/bed∙day (Temeke Hospital) These values are extremely lower than the one determined earlier in Amana and Ligula hospital waste generation [27].

The non-infectious waste as indicated under (Figure 7) are mostly generated from the administrative and housekeeping activities of healthcare facility establishments which include waste generated during maintenance of health-care premises or from food preparation and facility surrounding such as Packaging, food remains, scraps, paper, unwanted flowers, empty saline bottles, non-bloody

diapers; non-bloody IV tubing and bags, uncontaminated gowns, gloves, masks, hats and shoe covers, plastic containers, newspapers, magazines, paper, packaging materials for drugs or medicine, food remains plastic water bottles (as described in non-infectious plastics), worn-out clothes, cans, fruits remains etc.

The average ranges from 98.00 ± 7.50 kg/day (Ilala Hospital) to 833.00 ± 10.41 kg/day (Muhimbili National Hospital). These values are in line with the value determined earlier in Dar es Salaam city of average of 739 kg/day [27].

There are several factors to consider when determining the rate of production of general waste in hospitals. One of the factors is the number of beds in hospitals. As the number of beds increases the waste generation per bed becomes high. Another factor is standard of living of people using the respective hospital [25]. As the standard of living becomes low the rate of production of non-infections waste increases.

The analysis also showed generation rate for general waste to be higher compare to other categories of waste such as pathological. This is good news to hospital administrators, as if well segregated, can easily and economically be collected, treated and disposed of using the normal municipal technologies to reduce cost and help hospitals to concentrate with much hazardous waste which are dangerous and costly to handle. The rate of medical waste collection in both hospitals is not very good as some of wastes are left uncollected which call for more effort to be kept in this area as medical waste left uncollected can harm human health and environment.

Plastics Non-Infectious and Infectious Plastic Waste

Plastics are integral part of society and have varied application. Plastics are composed of a network of molecular monomers bound together to form macromolecules. According to another study [34], there are increasing concerns due to non-degradability and generation of toxic gases on combustion during incineration.

Plastic refers to wide range of synthetic or semi-synthetic organic polymeric materials of high molecular weight. They are usually synthetic hence non-degradable and most commonly they are derived from petrochemicals but many cases are partially natural [35]. A polymer may contain other additives like plasticizers, stabilizers, lubricant, UV absorbing material, flame retardants to improve performance. Plastics have permeated every facet of human life such as packaging, agriculture, water transportation, building construction, telecommunication, education, medicine, transportation, defense, consumer durables to name a few. Figure 8, shows levels of non-hazardous plastic materials.

Usually in a hospital setup non plastic waste are mixed with other non-infectious materials. But for the purpose of this study a separate waste bin/container colored green was placed in all waste generation point to collect all plastics materials generated in that particular day. A close supervision was conducted to ensure segregation of waste is done correctly especially for and then at the end of the day weighed and recorded. The noninfectious plastic wastes occupy about 3.6% of the total waste collected. Ilala hospital records the highest value with average of 23.4 kg/day, followed by Temeke Hospital with average of 22.7 kg/day, Mwananyamala hospital 21.9 kg/day and the smallest was detected at Muhimbili hospital 21.7 kg/day.

The development of intravenous (IV) bags and tubing from plastics led to other disposable ubiquitous to healthcare centers. These are frequently used in hospitals for drug-delivery, treat of dehydrated patients through fluid replacement, blood transfuse, and to correct electrolyte imbalances. These IV bags and tubing in hospitals constitute 20% - 25% of hospital waste.

Figure 9 shows the quantity of infectious plastic materials collected in hospitals. For these infectious materials it occupies 4.1% of the entire waste material collected where Muhimbili recorded the highest volume 36.5 ± 3.9 kg/day followed by 22.2 ± 3.6 at Ilala hospital, 21.3 ± 4.2 kg/day Temeke Hospital and the lowest is at Ilala hospital 21.0 ± 4.6 kg/day.

The technology employed is mechanical recycling is based on traditionally

grinding extrusion to obtain granules. Mechanical recycling is the most preferred and widely used method of recycling and it recycles particular type of polymers used in water and soft drink bottles [36]. The use of plastic waste as alternative fuel will help to reduce the energy cost along with reduction in the CO₂ emissions [37]. During co-incineration of plastic waste in blast furnace and cement kilns, it is completely burnt at high temperature and slag which remain as waste, can be further utilized as cement and road construction [34]. However, the emission of toxic gases and heavy metals during incineration it turns down the possibility of incineration as good environmentally friendly technique [38].

Estimation of Healthcare Waste Production in a Year

Accurate information on the quantity and the characteristics of medical waste is necessary to assist in the determination of suitable and appropriate disposal methods [39].

As a result of this practice there is a wide variation of reported medical waste generation rates [40]. In order to more accurately estimate medical waste generation rates with more robust and reliable figures, the total yearly collected number of medical waste in different categories from different hospitals and healthcare institutions were obtained and used in this study. Table 1 shows the estimate of different categories of healthcare waste collected in a year. For convenient 366 days was used to estimate the values presented in tones.

Apart from total waste which records the highest value about 897.9 tonnes, infectious waste followed with about 306.1 tonnes. The value is less high than the values detected earlier 0.098 tonnes [33]. Total sharps are 14.8 tonnes/year which are around 151 times higher than those detected earlier, which they record 0.098 tonnes/year [33].

Since these figures predict continued increasing trends, further studies are necessary to assess the estimated results with the real future waste generation through computerized worked formulars per levels and categories of healthcare facilities. In order to reduce the healthcare waste management load and cost, the

mixing of non-infectious waste with infectious waste materials must be prevented through best practices at hospital setting. The best way to control the impact of medical waste is to produce less of it, and one of the most effective ways to do this is to ensure that only infectious and pathogenic medical waste is sent for treatment, other hospital waste should be treated in the same manner as municipal household waste.