Programme on Small Scale Medical Waste Incinerators for Primary Health Care Clinics in South Africa

TABLE OF CONTENTS

  1. OBJECTIVE OF THE PROGRAMME 4
  2. STRUCTURE OF THE PROGRAMME 4
  3. COLLABORATORS INVOLVED IN THE PROGRAMME 4
  4. STAKEHOLDERS INVOLVED IN THE PROGRAMME 4
  5. LABORATORY TRIALS 5
  6. FIELD TRIALS 13

 

 

 

1.     OBJECTIVE OF THE PROGRAMME

 

The objective of the programme is to select technical criteria suitable for tender specification purposes that will enable the South African Department of Health to obtain the services and equipment necessary for the primary health care clinics to carry out small-scale incineration for the disposal of medical waste.

 

2.     STRUCTURE OF THE PROGRAMME

 

The test programme is being carried out in phases, as follows:

Phase 1         A scoping study to decide the responsibility of the different parties and

consensus on the test criteria and boundaries of the laboratory tests. The criteria for accepting an incinerator on trial was approved by all parties involved.

Phase 2         Laboratory tests with a ranking of each incinerator and the selection of the incinerators to be used in the field trials.

Phase 3         Completion of field trials, to assess the effectiveness of each incinerator under field conditions.

Phase 4         Preparation of a tender specification and recommendations to the DoH for the implementation of an ongoing incineration programme.

 

This document provides feedback on phases 2 and 3 of the work.

 

 

 

3.     COLLABORATORS INVOLVED IN THE PROGRAMME

 

SA Collaborative Centre for Cold Chain Management SA National Department of Health

CSIR

Pharmaceutical Society of SA World Health Organisation UNICEF

 

 

 

4.     STAKEHOLDERS INVOLVED IN THE PROGRAMME

 

The following stakeholders participated in the steering committee:

 

  • Dept of Health (National & provincial levels) (DoH)
  • Dept of Occupational Health & Safety (National & provincial levels)
  • Dept of Environmental Affairs & Tourism (National & provincial levels) (DEAT)
  • Dept of Water Affairs & Forestry (National & provincial levels) (DWAF)
  • Dept of Labour (National & provincial levels) (DoL)
  • National Waste Management Strategy Group
  • SA Local Government Association (SALGA)
  • SA National Civics Organisation (SANCO)
  • National Education, Health and Allied Workers Union (NEHAWU)

 

 

  • Democratic Nurses Organisation of SA (DENOSA)
  • Medecins Sans Frontieres
  • SA Association of Community Pharmacists
  • Mamelodi Community Health Committee
  • Pharmaceutical Society of SA
  • CSIR
  • UNICEF
  • WHO
  • SA Federation of Hospital Engineers

 

 

International visitors:

  • Dr Luiz Diaz – WHO Geneva and International Waste Management , USA
  • Mr Joost van den Noortgate – Medecins Sans Frontieres, Belgium

 

 

 

 

5.     LABORATORY TRIALS

 

5.1.   Objective of the laboratory trials

 

  • Rank the performance of submitted units to the following criteria:

y Occupational safety

y Impact on public health from emissions

y The destruction efficiency

y The usability for the available staff

 

  • The panel of experts for the ranking consisted of a:

y Professional nurse; Mrs Dorette Kotze from the SA National Department of Health

y Emission specialist; Dr Dave Rogers from the CSIR

y Combustion Engineer; Mr Brian North from the CSIR

 

5.2.   Incinerators received for evaluation

 

Name used in report Model no. Description Manufacturer
C&S Marketing

incinerator

SafeWaste Model Turbo

2000Vi

Electrically operated fan supplies combustion air

– no auxiliary fuel

C&S Marketing cc.
Molope Gas incinerator Medcin 400 Medical

Waste Incinerator

Gas-fired incinerator Molope Integrated

Waste Management

Molope Auto incinerator Molope Auto Medical

Waste Incinerator

Auto-combust incinerator – uses wood

or coal as additional fuel to facilitate incineration

Molope Integrated

Waste Management

 

Name used in report Model no. Description Manufacturer
PaHuOy

incinerator

Turbo Stove Auto-combust unit,

using no additional fuel or forced air supply

Pa-Hu Oy

 

 

5.3.   Emission testing: laboratory method

 

Sampling of emissions followed the US-EPA Method 5G dilution tunnel method for stove emissions. Adjustments to the design were made to account for flames extending up to 0.5 m above the tip of the incinerator and the drop out of large pieces of ash. Emissions were extracted into a duct for isokinetic sampling of particulate emissions. The sampling arrangement is shown by a schematic in Figure 1. A photograph of the operation over the Molope gas fired incinerator unit is shown in Figure 2.

 

All tests were performed according to specified operating procedures. The instructions provided by the supplier of the equipment were followed in the case of the C&S Marketing Unit. No operating procedures were supplied with the Molope Gas, Molope auto-combustion and PaHuOy units. These procedures were established by the CSIR personnel using their previous experience together with information provided by the supplier.

 

Test facilities were set up at the CSIR and measurements were carried out under an ISO9001 system using standard EPA test procedures or modifications made at the CSIR.

 

 

 

Figure 1. Schematic diagram of the laboratory set-up

 

 

 

 

 

Figure 2:Photograph of air intake sampling hood over Molope gas incinerator

 

 

 

5.4.   RANKING RESULTS OF THE LABORATORY TRIALS

 

Using the criteria listed under section 4.1 above, the incinerators were ranked as followed:

 

  Molope gas-fired

unit

Molope wood-fired

unit

C&S electric

unit

PaHuOy wood-fired

unit

Safety 6.8 4.8 5.5 3.3
Health 5.5 3.5 4.3 2.3
Destruction 9 2 6 1
Usability 2 3 3 5
Average 5.8 3.3 4.7 2.9

 

 

5.5.   EMISSION RESULTS OF THE LABORATORY TRIALS

 

Quantitative measurements were used to rank the units in terms of destruction efficiency and the potential to produce hazardous emissions.

 

Conformance to the South African Department of Environmental Affairs and Tourism’s (DEAT) recommended guidelines on emissions from Large Scale Medical Waste Incinerators is summarized in Table 1. The measurements are listed1 in Table 2.

 

 

 

Table 1: Summary qualitative results

 

Parameter Measured Units Molope

 

Gas-fired

Molope

 

Wood-fired

C&S

 

Electric

PaHuOy

 

Wood-fired

SA DEAT

Guidelines

Stack height m × × × × 3 m above

nearest building

Gas velocity m/s × × × × 10
Residence time s × × × × 2
Minimum combustion

temperature

ºC 4 × × × > 850
Gas combustion

efficiency

% × × × × 99.99
Particulate emissions mg/Nm3 4 × 4 × 180
Cl as HCl mg/Nm3 × 4 4 × < 30
F as HF mg/Nm3 4 4 4 4 < 30
Metals mg/Nm3 4 × × 4 < 0.5 and

< 0.05

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 Emission concentrations are reported in accordance with the South African reporting requirements, ie, normalized to Normal Temperature (0

oC) and Pressure (101.3 kPa) and corrected to a nominal concentration of

8 % of CO2 on a dry gas basis. If a measurement fell below the detection limit for the method is it either reported as the detection limit or as N.D., ie, not detectable.

 

 

Table 2: Detailed quantitative results

 

 

Parameter Measured *

 

Units

 

Molope gas

 

Molope auto

 

C&S

 

PaHuOy

 

SA Process Guide1

 

Comments

 

Stack height

 

m

 

1.8

 

1.8

 

1.9

 

0.3

 

3 m above nearest building

 

None of these unite has a stack. The height of the exhaust vent is taken as the stack height. If it is above the respiration zone of the operator it provides some protection from exposure to smoke.

 

Gas velocity

 

m/s

 

0.8

 

0.5

 

1.1

 

0.5

 

10

 

Gas velocities vary across the stack for the Molope gas, Molope auto-combustion, and the PaHuOy units.

 

Residence time

 

s

 

0.4

 

0.7

 

0.6

 

0.4

 

2

 

Residence time is taken to be the total combustion time, and the maximum achievable

 

Minimum combustion zone temperature

oC  

800 -900

 

400 – 650

 

600 – 800

 

500 – 700

 

> 850

 

Molope auto-combustion temperatures are expected to be higher as the centre of the combustion zone is not expected to be at the measurement location.

 

CO2 at the stack tip

 

% vol

 

2.64

 

3.75

 

4.9

 

3.25

 

8.0

 

Actual emission concentrations are less than the values reported here, which are normalized to 8 % CO2 and Normal temperature and pressure for reporting purposes. They are lower between 4 to 8 times.

 

Gas

 

%

 

99.91-

 

98.8 -98.4

 

99.69-

 

98.9

 

99.99

 

Most accurate measurement in

Combustion 99.70 99.03 the duct where mixing of exhaust
efficiency gases is complete. Results of two

trials.

 

Particulate emissions entrained in exhaust gas

mg/Nm3  

102

 

197

 

130

 

338

 

180

 

The total emissions are the sum of the both entrained and un- entrained particulates. Emissions are lower than expected for such units and this is attributed to the absence of raking which is the major source of particulate emissions from incinerators without an emission control

system.

 

Particulate fall- out

mg/Nm3  

42

 

105

 

n.d.

 

n.d.

 

 

Large pieces of paper and cardboard ash rained out of the emissions. Totalling 0.8 to 2 g over a +/- 2 minute period.

 

Soot in particulates

 

%

 

42.2

 

58.1

 

48.7

 

84.8

 

 

Correlates directly with gas combustion efficiency

 

1 Emission concentrations are reported in accordance with the South African reporting requirements, ie, Normalized to Normal Temperature (0

oC) and Pressure (101.3 kPa) and corrected to a nominal concentration of

8 % of CO2 on a dry gas basis. If a measurement fell below the detection limit for the method is it either reported as the detection limit or as N.D., ie, not detectable.

 

 

Parameter Measured *

 

Units

 

Molope gas

 

Molope auto

 

C&S

 

PaHuOy

 

SA Process Guide1

 

Comments

 

% ash residual from medical waste

 

%

 

14.8

 

12.9

 

15.6

 

21.7

 

 

Measurement of destruction efficiency of the incinerator. Typical commercial units operate at 85-90 % mass reduction. PaHuOy is lower due to the melting and unburnt plastic.

 

Cl as HCl

mg/Nm3  

46

 

13

 

25

 

35 & 542

 

< 30

 

PaHuOy chloride concentrations varied considerably. This is expected due to the variability of the feed composition.

 

F as HF

mg/Nm3  

< 6

 

< 1

 

<2

 

< 1

 

< 30

 

Fluoride not found in this waste.

 

Arsenic (As)

mg/Nm3  

< 0.2

 

< 0.2

 

< 0.2

 

< 0.2

 

0.5

 

Arsenic is not expected as a solid.

 

Lead (Pb)

mg/Nm3  

< 0.4

 

< 0.4

 

< 0.4

 

< 0.4

 

0.5

 

Lead not expected in waste

 

Cadmium (Cd)

mg/Nm3  

< 0.2

 

< 0.2

 

< 0.2

 

< 0.2

 

0.05

 

Sensitivity of the x-ray method is adequate for ranking. Higher sensitivity not sought for this trial.

 

Chromium (Cr)

mg/Nm3  

< 0.1

 

0.7

 

0.7

 

< 0.1.

 

0.5

 

Chromium relative to iron ranges between 12 and 25% which is consistent with stainless steel needles

 

Manganese (Mn)

mg/Nm3  

< 0.1

 

0.3

 

0.3

 

< 0.1

 

0.5

 

Manganese may be a component in the stainless steel needle.

 

Nickel (Ni)

mg/Nm3  

< 0.1

 

0.3

 

< 0.1

 

< 0.1

 

0.5

 

Nickel may be a component in the needle.

 

Antimony (Sb)

mg/Nm3  

< 0.2

 

< 0.2

 

< 0.2

 

< 0.2

 

0.5

 

Not expected in this waste.

 

Barium (Ba)

mg/Nm3  

< 0.5

 

< 0.5

 

< 0.5

 

< 0.5

 

0.5

 

Lower sensitivity due to presence in the filter material

 

Silver (Ag)

mg/Nm3  

< 0.2

 

< 0.2

 

< 0.2

 

< 0.2

 

0.5

 

Not expected in this waste.

 

Cobalt (Co)

mg/Nm3  

< 0.1

 

< 0.1

 

< 0.1

 

< 0.1

 

0.5

 

Cobalt might be present in stainless steel.

 

Copper (Cu)

mg/Nm3  

< 0.5

 

< 0.5

 

< 0.5

 

< 0.5

 

0.5

 

Lower sensitivity due to copper in the sample blanks. May be background in the analytical equipment.

 

Tin (Sn)

mg/Nm3  

< 0.2

 

< 0.2

 

< 0.2

 

< 0.2

 

0.5

 

Tin not expected in this waste.

 

Vanadium (V)

mg/Nm3  

< 0.1

 

< 0.1

 

0.4

 

< 0.1

 

0.5

 

Vanadium might be present in stainless steel.

 

Thallium (Tl)

mg/Nm3  

< 0.4

 

< 0.4

 

< 0.4

 

< 0.4

 

0.05

 

Not expected in this waste. Sensitivity of the x-ray method is adequate for ranking. Higher sensitivity not sought for this trial.

 

 

 

5.6.   MAIN FINDINGS OF THE LABORATORY TRIALS

 

The main conclusions drawn from the trials are as follows:

 

:::          All four units can be used to render medical waste non-infectious, and to destroy syringes or render needles unsuitable for reuse.

:::                           The largest potential health hazard arises from the emissions of smoke and soot.              (the combustion efficiency of all units lies outside the

regulatory standards). The risk to health can be reduced by training operators to avoid the smoke or by installation of a chimney at the site.

:::          The emissions from small scale incinerators are expected to be lower than those from a wood fire, but higher than a conventional fire-brick-

lined multi-chambered incinerator.

:::          Incomplete combustion, and the substantial formation of smoke at low height rendered the PaHuOy unit unacceptable for field trials. Figure 3

below shows this unit during a trial burn. Molten plastic flowed out of

the incinerator, blocked the primary combustion air feed vents, and burnt outside of the unit.

 

 

 

Figure 3: Photo of PaHuOy incinerator during trial burn

 

 

5.7.   COMPARISON OF THE FIELDS TRIALS WITH THE LABORATORY TRIALS

 

The CSIR performed a quantitative trial in the field for gas combustion efficiency, temperature profiles and mass destruction rate on the Molope Auto wood-fired unit at the Mogale Clinic.

 

The results of this trial are compared to the laboratory trial results below:

 

  • Waste loading: Disposable rubber gloves were observed in addition to needles syringes, glass vials, bandages, dressings, and paper w
  • Temperatures and combustion efficiency: The same performance in gas combustion        efficiency   was    obtained    for    wood    .

Temperatures were higher but for a shorter time and this was

correlated with the type of wood available to the clinic. The fuel was burnt out before the medical waste was destroyed completely and this resulted in lower temperatures, lower combustion efficiency and higher emissions while burning the waste.

  • Emissions: Large amounts of black smoke were observed and this was correlated directly to cooling of the unit as the wood fuel was exhausted

prior to full ignition of the waste.

  • Destruction efficiency: The destruction efficiency was similar to that in the laboratory measurem
  • Usability: The unit is difficult to control as the result of the variability of the quality of wood
  • Acceptability: the smoke was not acceptable to the clinic, the community, or the local

 

It was concluded that:

  • The performance with fuel alone indicates that laboratory trial data can be used to predict emissions in the
  • The Molope Auto unit is too difficult to control for the available staff and fuel at the

 

 

 

5.8.   RECOMMENDATIONS FROM THE LABORATORY TRIALS

 

The following recommendations are made as the result of the laboratory trials:

:::     A comprehensive operating manual must be supplied with each unit.

Adequate training in the operation of the units must be provided, especially focussed on safety issues.

:::     It is recommended that the height of the exhaust vent on all units be

addressed.     In order to facilitate the dispersion of emissions and reduce the exposure risk of the operators.

:::     The suppliers of the incinerators must provide instructions for the safe handling and disposal of ash.

 

 

 

5.9.   RECOMMENDATIONS FROM THE STEERING COMMITTEE

 

 

 

After completion of the laboratory trials, the project steering committee recommended that the Molope Gas and C&S Marketing units be submitted for field testing. The Molope Auto was recommended for field testing on the condition that the manufacturer modified the ash grate so as to prevent the spillage of partially burnt needles and syringes.

 

 

 

6.     FIELD TRIALS

 

6.1.   OBJECTIVE OF THE FIELD TRIALS

 

The objective of the field trials was to obtain information in the field and assess the strengths and weaknesses of each of the incinerators during use at primary health care clinics.

 

A participative decision making process was used for the trials. It was based on expert technical evaluation by the CSIR and the National Department of Health as well as participation in the trials by experienced end users and participating advisors. All decisions were made by the Steering Committee, which consisted of representatives of stakeholders in the clinical and medical waste disposal process. These included representatives from the National, Provincial, and Local Government departments of Health, Safety and the Environment, as well as Professional Associations, Unions, NGOs, UNICEF, the WHO and local community representatives.

 

6.2.   CLINIC SELECTION

 

The Provinces in which the trials were done selected clinics for the field trials. The criteria set by the Steering Committee for the selection of the clinics were the following:

 

  • Location must be rural or under-serviced with

y No medical waste removal

y No existing incineration

y No transport

  • It must be in a high-density population area
  • Acceptable environmental conditions must prevail
  • Community acceptance must be obtained
  • Operator skill level to be used must be at a level of illiteracy

 

The clinics that were selected were as follows:

 

  • Steinkopf Clinic – Northern Cape Province – Gas incinerator

 

 

  • Marydale Clinic – Northern Cape Province – Gas incinerator
  • Mogale Clinic – Gauteng Province             – Auto combustion

incinerator, wood-fired.

  • Chwezi Clinic – KwaZulu-Natal Province – Gas incinerator
  • Ethembeni Clinic- KwaZulu-Natal Province – Auto-combustion electrical

incinerator

 

 

 

 

 

 

MAP OF SOUTH AFRICA INDICATING WHERE THE CLINICS ARE SITUATED

 

 

 

 

 

 

 

 

NORTHERN PROVINCE

 

GAUTENG PROVINCE

 

 

 

 

 

NORTH WEST PROVINCE

MPUMALANGA PROVINCE

 

 

 

 

 

 

FREE STATE PROVINCE

 

 

NORTHERN CAPE PROVINCE

 

 

KWAZULU-NATAL PROVINCE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I:/UnitPublic/Valerie/Technet 99/Working papers/Session 3/rogers.doc

 

 

 

EASTERN CAPE PROVINCE

 

 

WESTERN CAPE PROVINCE

 

 

6.3.   COORDINATION OF THE TRIALS

 

The criteria for the ranking of the incinerators in accordance with performance in the field were:

 

  • Safety (occupational and public health)
  • Destruction capability
  • Usability
  • Community acceptability

 

The South African National Department of Health coordinated the field trials.

 

Information regarding the field trials as well as questionnaires were supplied to the coordinators in the participating provinces.

 

The team in the field consisted of the operator, supervisor and inspector (coordinator). The manufacturer of the incinerators did the training of the operators.

 

The questionnaires used during the trials were set so as to obtain information with regard to the criteria set for the ranking of the incinerators in accordance with performance in the field. The questionnaires were received from the clinics at two-weekly intervals.

 

Questions with regard to the criteria were the following:

 

A.  SAFETY (occupational and public health)

 

  • Smoke Emission

y Volume and thickness

y Colour

y Odour

  • Ash Content
  • Are the filled sharps boxes and soiled dressings stored in a locked location while waiting to be incinerated?

 

 

 

B.  DESTRUCTION CAPABILITY

 

  • Destruction Rate

y Complete

y Partial

y Minimal

y Residue content

 

C.  USABILITY (for the available staff)

  • Can the incinerator be used easily?

 

 

  • Is the process of incineration safe?
  • Has training been successful?
  • Is protective clothing such as gloves, goggles, dust masks and safety boots available?

 

D.  COMMUNITY ACCEPTABILITY

 

  • What is the opinion of the following persons on the use of the incinerator?

y Operator

y Nurse

y Head of the clinic

y Local Authority representative

y Community leader

 

During the trials the clinics were visited and the incinerators evaluated by members of the Steering Committee and the CSIR as well as Dr L Diaz from WHO, Mr M Lainejoki from UNICEF and the coordinator from the National Department of Health.

 

6.4.   QUESTIONNAIRE RESULTS

 

6.4.1.      MOGALE CLINIC

 

Type of incinerator at the clinic: Molope Auto-Combustion (Fired with wood)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 4 & 5: Molope Auto wood-fired incinerator during field trials at Mogale clinic

 

 

A.               SAFETY (occupational and public health)

 

  1. The process of incineration with this unit was considered by the operator, supervisor and the inspector as unsafe because there is no protective cage around the During the process the incinerator becomes very hot and this could result in injury to the operator.

 

  1. The smoke emission of this incinerator had a volume and thickness which was heavy and black, with a distinct unpleasant odour, and was considered This could cause a pollution problem.

 

 

 

B.               DESTRUCTION CAPABILITY

 

  1. The needles and vials were not completely destroyed but were rendered unsuitable for re-use.

 

  1. The soft medical waste was completely destroy

 

 

 

C.               USABILITY

 

Difficulty in controlling the operating temperature and avoiding smoke emissions made this incinerator user unfriendly.

 

D.               COMMUNITY ACCEPTABILITY

 

As a result of the heavy, black smoke emission the unit was not acceptable to the community.

 

 

6.4.2.      ETHEMBENI CLINIC:

 

 

Figure 6: C&S Marketing Auto Combust Electrical Incinerator At Ethembeni Clinic

 

 

 

Type Of Incinerator: C&S Auto-Combustion (Uses an electrically actuated fan)

 

 

 

A.               SAFETY (occupational and public health)

 

  1. The operator, supervisor and inspector considered this incinerator easy to operate with no danger to the Removal of the ash from the drum for disposal in a pit is, however, considered difficult, as the drum is heavy. Removal of the incinerator lid before it has been allowed to cool has been identified as a potential danger to the operator.

 

  1. Emission of smoke from this incinerator was not considered ex The volume and thickness was evaluated as moderate with no pollution experienced.

 

 

 

B.               DESTRUCTION CAPABILITY

 

  1. The needles and vials were not completely destroyed but were rendered unsuitable for re-use.
  2. The soft medical waste was completely destroy

 

 

 

C.               USABILITY

 

Considered user friendly by operator, supervisor and inspector.

 

D.               COMMUNITY ACCEPTABILITY

 

The incinerator was accepted by the community and was not considered to be harmful.

 

 

 

6.4.3.      CHWEZI CLINIC, MARYDALE CLINIC AND STEINKOPF CLINIC:

 

Type of incinerator: Molope Gas incinerator

 

Figure 7:       Molope Gas incinerator during field trials at Marydale clinic

 

A.               SAFETY (occupational and public health)

 

  1. The operator, supervisor and inspector considered this incinerator easy to operate with minimal danger to the
  2. Smoke emissions were not excessive and were reported to be minim

 

B.               DESTRUCTION CAPABILITY

 

  1. Sharps not completely destroyed but were rendered unsuitable for re-use.

 

 

  1. Soft medical waste completely destroy

 

C.               USABILITY

 

This incinerator was considered user friendly.

 

 

 

D.               COMMUNITY ACCEPTABILITY

 

 

 

The incinerator was accepted by the community and was not considered to be harmful.

 

 

 

6.5.   RANKING

 

 

INCINERATOR RANKING
Molope Gas 1
C&S Auto-Combustion (Uses electrical fan)  

2

Molope Auto- Combustion (Fired with

wood, coal also an option)

 

3

 

 

 

 

6.6.   OUTCOME OF THE FIELD TRIALS

 

Incinerator Safety Destruction Capability Usability Community Acceptability
Molope Gas Good Good Good Good
C&S Auto- Combustion

(Uses Electricity)

 

Good

 

Good

 

Good

 

Good

Molope Auto-

Combust Incinerator

Un-Acceptable Good Un-Acceptable Un-Acceptable

 

Open chat