Automated Biochar Injection System
|Sponsors||Gregory Möller [UI Clean Water Machine]|
|Team Name||Mean Clean Water Machine|
|Duration||Fall 2018 - Spring 2019|
The goal of the project is to design a mobile BioChar (BC) injection system that will accept and inject BC into pressurized water lines in an accurate, controlled, and recorded manner in tandem with existing systems on the UIdaho Clean Water Machine with minimal adaptation of current systems.
- 1 Problem Definition
- 2 Design Considerations
- 3 Project Learning
- 4 Final Design
- 5 Validation
- 6 Team Members
- 7 Additional Documentation
Extensive algal blooms and phosphorous resource limitations are current problems faced by communities globally, primarily regarding agricultural fertilization and waste products. The University of Idaho Capstone teams in the past have partnered with Nexom and other entities to create the Clean Water Machine, an upward-circulating sand filtration system, to address the algae growth and purify the agricultural wastewater. Current research is being conducted by pumping BioChar (Bio-mass charcoal, created by burning wood products and other organic materials) into the system in an effort to absorb more chemicals (namely phosphorous) from the wastewater. The BioChar is ideally then filtered out, collected, and mixed into the soil in an attempt to recycle some of the lost phosphorous and create a way to fertilize crops without needing to mine a limited resource. Our goal as a team is to create a system that integrates cohesively with the current Clean Water Machine and automates the process of dosing the BioChar into the wastewater flow, so that more experiments and research may be conducted efficiently and effectively in the future. The completed project will be a mobile unit that accepts and injects BioChar into the pressurized water lines in an accurate, controlled, and recorded manner in tandem with the existing Clean Water Machine system with minimal adaptations. Our system will be completed by May 2019 as a fully functional product ready to be integrated into the Clean Water Machine's operations.
Clean Water Machine System
Currently, the biochar is dosed into the Clean Water Machine in batches in the ratio of 6kg per 50 gallons of influent water. This requires an operator to pour the biochar into the tanks, and manually stir. This is inefficient and does not produce consistent dosing. The flow diagram to the right was provided by our client to describe how the biochar can be monitored, dosed systematically, integrated into the current Clean Water Machine design.
Our role is to create an entire system including the interface with the current set up, the biochar storage, biochar condition control, dose metering, flow into the Clean Water Machine water lines, and the signals and controls required to do so.
Our clients identified the pumping mechanism as a significant challenge in moving biochar. Because it is a granular material which does not dissolve in water, it often clogged pumps and the small particles cause pump parts to wear quickly or malfunction. Our initial assumption for this dosing system was that we would need to find the optimal pump type to avoid disruptions in flow. Peristaltic pumps are easily controlled and flow varied, but often have too narrow of tubing which results in significant clogging. Reciprocating and diaphragm pumps also clump and clog solids very easily, resulting in the pump not operating correctly. The current Clean Water Machine team also attempted to use a centrifugal pump. Although this has benefits such as the mixing motion, there are many parts involved, and the team had prior difficulty with this type.
The team also toured the Water Reclamation and Reuse Facility in Moscow, ID, to see how this treatment process dosed powder polymer. This facility used large positive displacement pumps, which was recommended to us to scale down for our project. Both lobe rotary and progressive cavity positive displacement pumps are effective with viscous fluids and can produce a constant flow. Although usually more expensive than other pump types, the team determined that the progressive cavity pump fit our requirements best because it had fewer parts that may wear down, included rotary mixing motion, and was commonly implemented in similar industrial applications.
|Requirement||Test||Test subject||Target Date||Result||recommendation|
|Operating at less than 60dB at full capacity||Use a sound sensor to record a full cycle of the system, and verify signal remains below maximum sound level||Functional prototype||1/18/2019||N/A||N/A|
|15% accuracy dosing||Have BC dump into separate receptical and weigh on a scale to verify accuracy of dosage dispenser||Functional prototype||1/18/2019||N/A||N/A|
|Must account for variability in BC moisture content||Use a high-accuracy moisture sensor to detect moisture of several batches of BC after processing through system, and compare discrepancies||Functional prototype||1/18/2019||N/A||N/A|
|Must account for variability in BC consistency and texture||Manually, visually inspect BC for clumping and inconsistencies in texture; should be no particles larger than 0.25 inches||Functional prototype||1/18/2019||N/A||N/A|
|Must account for variability in BC dose-rate||Run system through 5 different dose rates, have BC dump into separate receptical, and weigh on a scale to verify accuracy of dosage dispenser||Functional prototype||1/18/2019||N/A||N/A|
|Must account for variability in BC temperature||Use a high-accuracy temperature sensor to detect temperature of several batches of BC after processing through system, and compare discrepancies||Functional prototype||1/18/2019||N/A||N/A|
|Dosage must withstand pressure of 20 psig||Use pressure gauge on output pipe to verify it expels BC mixture at desired pressure||Functional prototype||1/18/2019||N/A||N/A|
|Touch-screen must last 24-hours without recharging||Unplug touchscreen and wait 24-hours; intermittently activate screen (once every 8 hours) to simulate use; after total time period, activate screen and verify use||Functional prototype||1/18/2019||N/A||N/A|
|Must operate within conditions ranging from 20-90% Humidity||Design tests in sealed containers or rooms where humidity level can be adjusted and run system to verify function||Functional prototype||1/18/2019||N/A||N/A|
|Refill no more than once every 3-days||Run system for 72 hours straight with maximum dose-rate and verify that the BC supply will last||Functional prototype||1/18/2019||N/A||N/A|
Major: Mechanical Engineering
Major: Biological Engineering
|[[File: |180px|thumb|left]]||Dylan Kirkpatrick
Major: Biological Engineering
|[[File: |180px|thumb|left]]||Phillip Hagen
Major: Electrical Engineering