Note 18 - Liquidity	6 Months Ended
Jun. 30, 2021
Notes to Financial Statements
Substantial Doubt about Going Concern [Text Block]	18 Liquidity We continue to monitor our liquidity needs and in response to our continued losses have taken measures to reduce expenses and restructure operations which we feel are necessary to ensure we maintain sufficient working capital and liquidity to operate the business and invest in our future. We have experienced continued declines in revenues and recurring losses historically. As a result, we have evaluated our ongoing business needs, and considered the cash requirements of our base business of Air Pollution Control (APC) and Fuel Chem businesses. This evaluation included consideration of the following: a) customer and revenue trends in our APC and Fuel Chem business segments, b) current operating structure and expenditure levels, c) current availability of working capital, and d) support for our research and development initiatives. We continue to monitor our liquidity needs and have taken measures to reduce expenses and restructure operations which we feel are necessary to ensure we maintain sufficient working capital and liquidity to operate the business and invest in our future. We believe our current cash position and net cash flows expected to be generated from operations are adequate to fund planned operations of the Company for the next 12 months.

Note 18 - Liquidity

6 Months Ended

Jun. 30, 2021

Substantial Doubt about Going Concern [Text Block]

18 Liquidity

We continue to monitor our liquidity needs and in response to our continued losses have taken measures to reduce expenses and restructure operations which we feel are necessary to ensure we maintain sufficient working capital and liquidity to operate the business and invest in our future.

We have experienced continued declines in revenues and recurring losses historically. As a result, we have evaluated our ongoing business needs, and considered the cash requirements of our base business of Air Pollution Control (APC) and Fuel Chem businesses. This evaluation included consideration of the following: a) customer and revenue trends in our APC and Fuel Chem business segments, b) current operating structure and expenditure levels, c) current availability of working capital, and d) support for our research and development initiatives. We continue to monitor our liquidity needs and have taken measures to reduce expenses and restructure operations which we feel are necessary to ensure we maintain sufficient working capital and liquidity to operate the business and invest in our future. We believe our current cash position and net cash flows expected to be generated from operations are adequate to fund planned operations of the Company for the next 12 months.