Grantee Research Project Results
2017 Progress Report: Electrical Incinerator for HMW Disposal
EPA Grant Number: SU836783Title: Electrical Incinerator for HMW Disposal
Investigators: Rollins, Andrew M
Institution: Case Western Reserve University
EPA Project Officer: Aja, Hayley
Phase: I
Project Period: November 1, 2016 through October 31, 2017 (Extended to October 31, 2018)
Project Period Covered by this Report: November 1, 2016 through October 31,2017
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2016) RFA Text | Recipients Lists
Research Category: Sustainable and Healthy Communities , P3 Awards , P3 Challenge Area - Chemical Safety
Objective:
This project seeks to reduce the risk to people and the environment from unsafe disposal of hypodermic needles used in medical settings in Uganda. Current methods such as open pit burning are dangerous, inefficient, and often ineffective. We conducted a series of site visits to our field site in Luwero, Uganda, where local health care workers (HCWs) identified improper or incomplete disposal of hazardous medical waste (HMW) generally as a significant threat to HCWs and the general public. As regards disposal of needles (sharps), the current practice of open pit burning is not adequate because it does not produce sufficient heat to destroy needles. As a result, sharps remain in the pits and pose ongoing threats to HCWs and others.
Our objective, therefore, is to design a means for HCWs to dispose of sharps safely and completely. To this end, this project seeks to develop an electrically powered, safe, low cost, and sustainable incineration device and sharps segregation canister for the disintegration of biohazardous stainless steel needles. The device will be designed to integrate easily into the workflow of the prospective users for application in a wide array of health centers (HC). The innovativeness derives from the electrically-driven needle separation mechanism that ensures user safety by preventing contact with the sheared needles from time of injection to its reduction into the harmless sterile pellets. This simple, two-part process on a large scale for hypodermic needle incineration does not exist on the current market.
Our second objective is to continue and foster our ongoing interdisciplinary partnership between engineering and social science faculty and students at Case Western Reserve University (CWRU), Makerere University in Kampala, Uganda (MAK), the Ugandan Ministry of Health (MOH), and rural HCs in Luwero District, Uganda. This will be achieved by continued project development, travel to field sites, and ongoing engagement with local stakeholders.
Progress Summary:
In phase 1, we designed and field-tested an initial prototype of a needle canister that allows HCWs to insert a used syringe in and remove the needles, leaving it in a sealed container. In addition, we designed a proof-of-concept incinerator to melt needles into a sterile metal disk that can be safely and inexpensively disposed of.
Needle removal canister: We have modeled and field-tested two prototype needle removal canisters. The initial prototype is a handheld canister. The user inserts the needle into a funnel shaped opening and clips off the needle using a device similar to a fingernail clipper. The needles remain inside the canister until it is attached to the incinerator and emptied. Based on user feedback, two key features are being redesigned. First, the canister must have sufficient capacity to hold all needles used in a day. Second, to eliminate risk of needle-stick, the canister should be operated with one hand.
A second prototype was field tested to address the latter concern. It consisted of a table-mounted canister with a “funnel” to a narrow opening that would hold the needle while the user bent it a few times to break it off. Initial feedback indicated that the table mounting was well received and one-handed operation remained desirable. The method of fatiguing the needle to break it, however, sometimes took too long.
Point-of-use needle incinerator: Our first incinerator prototype employed an arc method to destroy needles. The device consisted of a needle orientation mechanism, a high temperature ceramic incineration chamber, and a circuit to generate small scale electrical arcs in order to melt the needles. The prototype was powered with an 18V sealed lead-acid battery array. In bench top testing and verification, the device was efficacious when processing a small quantity of needles at a time. The byproduct was non-sharp, sterilized, and posed no danger to the user. Challenges observed during testing included inconsistent orientation of the needles, instability of the arc during manual actuation, low throughput, and lack of a simple scheme for slag byproduct removal.
Whereas lab testing demonstrated the potential feasibility of arc heating as a mechanism for needle destruction, we also considered Joule (resistive) heating. In contrast to the arc method, resistive heating calls for low voltage and high current. Mathematical modeling and preliminary testing was employed to identify characteristics that have to be met for Joule heating to improve upon the arc method. Design concepts were then formulated and evaluated based on numerical scoring of the following criteria: ease of use, cost, ease of fabrication, durability, efficacy, safety, capacity, waste removal, and scalability. The selected concept was comprised of a high temperature cylindrical chamber, with a conductive piston-like plunger capable of applying force between the needles and a conducting plate on the bottom of the chamber.
Preliminary test results of the resistive heating approach indicated that while resistive heating was capable of superheating the needles to a point very close to their melting temperature, as needles began to heat, they quickly became malleable, warped, and lost contact with the anode. As the number of needles tested increased, the combined resistance of the system decreased and the heating became slower and less efficient. The test results indicate the potential for improved needle fusion by application of substantive pressure on the needles during melting. These results are preliminary and will require further verification testing.
Currently, our test platform is capable of utilizing both arc and resistive heating so that we may evaluate and compare the two methods. This device is capable of vertically aligning hundreds of needles simultaneously, and maintaining physical contact between the needles and electrodes during Joule heating, even as the needles melt and deform.
Future Activities:
In phase 1 of the project we demonstrated the technical feasibility of a working proof of concept prototype and developed a low cost mechanical and electronic platform for evaluating practical advantages of using resistive heating versus electrical arc discharge. The mechanical aspects of both the capsule and the incinerator devices have already undergone several design iterations. We have received in-depth end user feedback during site visits to Luwero, Uganda and are working to incorporate this feedback into the design.
We have employed scalable theoretical models and verified their accuracy using a single transformer operating on a power budget compatible with readily available motorcycle batteries. Furthermore, our device has demonstrated sufficient energy output to superheat needles and destroy them. A challenging aspect of the current mechanical design platform has been procurement of a low cost yet technically appropriate incineration chamber material. As such we have investigated methods of reducing cost through the application of temperature resistant and insulative ceramic coatings on machined metal surfaces. However before the feasibility can be determined a more thorough investigation must be conducted.
By processing hazardous hypodermic needles in an easy to use manner, our device aims to protect human health and the environment by facilitating safe disposal practices with a greater ease of use. Specifically, it eliminates the danger to people by requiring interface with the incinerator to unlock and dispose needles and safely melting needles in a contained chamber. It protects the environment by ceasing the production of noxious air/land pollutants and eliminating the need of external fuel. The device fosters prosperity as it will require minimal technical expertise for operation/maintenance, is not reliant on external financially burdensome supply chains, and reduces the labor intensiveness of HMW disposal which are crucial to resource constrained health centers. Lastly, this project is a multi-institutional collaboration between Makerere University (Kampala) and Case Western Reserve University social science and biomedical engineering departments aimed at fostering sustainable, health solutions. The continual engagement with the Ugandan health workers and centers for feedback will ensure that the device is designed to successfully last in these settings.
Proposed Phase II Objectives and Strategies
Phase 2 is designed to build on the objectives and goals of Phase 1. Specifically, the study objectives are:
- To reduce the hazardous medical waste (HMW) disposal burden in low-resource regions of Uganda. This will be accomplished by the development of an electrically powered, safe, low cost, and sustainable sharps segregation canister and incineration device for the disposal of biohazardous stainless steel needles. The device will be designed to integrate easily into the workflow of the prospective users and tailored for use in a wide array of health centers (HC).
- To establish lasting engineering and social science focused educational connections, partnerships, and dialogue between Case Western Reserve University (CWRU), Makerere University in Kampala Uganda (MAK), the Ugandan Ministry of Health (MOH), rural HCs and the local communities in which they are embedded.
The activities of Phase 1, as just described, have been necessary steps in achieving these objectives.
Overview of Phase 2 activities: In phase 2, design will proceed with a table-mounted, one-handed canister. First, needle removal alternatives will be tested and evaluated. The objective is to develop a one-handed device which is stable and usable without applying much force. Second, the interface to empty the canister into the incinerator will be refined to be easy to use, reliable, Funding Opportunity Number: EPA-G2016-P3-PHASE2 7 durable and inexpensive. Phase II, therefore, will involve a series of sequential steps employing the current testing platform.
- The merits of arc discharge vs. joule heating will be assessed using our current testing platform, using motorcycle or car batteries as a power supply.
- A mechanism will be developed that allows needles to be inserted into the chamber without risk of exposure while maintaining the seal on the chamber and avoiding jamming the device.
- We plan to add an external frame containing a lever mechanism to aid in compressing needles in the chamber to increase the contact force required for efficient electrical heating.
- We will evaluate different electrode types to find one conducts well and is mechanically strong enough to avoid damage with repeated use under large forces.
- We will develop an external shielding/filtering construct that will protect workers from exposure to potentially damaging gases released during incineration.
- Development of our needle segregation tool will involve developing a table-mounted device that will fit with our current capsule system.
Journal Articles:
No journal articles submitted with this report: View all 6 publications for this projectSupplemental Keywords:
hazardous waste management, hazardous medical waste, HMW, incineration, innovative technology, waste minimization, sharps disposal, human health, engineering, social science, global health, Uganda, community based needs assessment, international partnershipsProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.