Some investors are put off by companies that have a negative impact on the environment such as major miners and energy producers including BHP Billiton (ASX: BHP), Rio Tinto Ltd (ASX: RIO) and Woodside Petroleum Limited (ASX: WPL), to list a few.
For environmentally conscious investors, a problem that arises is that finding companies that can have a positive impact on the environment is a bit tricky.
Adding to the problem, sometimes companies which claim to have a positive environmental impact, or at least appear to do so, often cause indirect environmental harm or offer poor returns.
But here's a look at two companies that appear to have an environmentally conscious ethos, or offer environmentally positive products and services, to help with narrowing the search.
Phoslock Water Solutions Limited (ASX: PHK)
The Phoslock Water Solutions share price has gained more than 188 per cent over the past year and its shares are now trading for around 26 cents.
Phoslock Water Solutions provides products and services aimed at cleaning up contaminated water bodies.
The company's best-selling product is Phoslock which was developed by the CSIRO to "significantly reduce excess phosphate safely from the environment".
The company, with a market value of about $125 million, has treated polluted water in China, Australia, the United Kingdom and The Netherlands, to list a few countries.
In financial year (FY) 2017 Phoslock reported revenue of $4.2 million, up 92 per cent on the previous year.
For FY 2018 Phoslock is forecasting revenue of $22 million, which would represent an increase of around 450 per cent on the previous year's figure.
Environmental Clean Technologies Ltd (ASX: ESI)
The Environmental Clean Technologies share price hasn't done so well, shedding almost 50 per cent over the past year.
But that could change.
The Environmental Clean Technologies share price gained 12.5 per cent on Thursday as the company announced it received a research and development tax incentive refund worth around $2 million.
The company, with a market capitalisation of almost $42 million, is engaged in the development of cleaner technologies aimed at reducing environmental damage by companies in the energy and resources sectors.
In FY 2017 Environmental Clean Technologies reported revenue of $111,400, an increase of 33 per cent on the previous year.
But the company's loss for FY 2017 also grew, rising by 2.8 per cent to around $4.3 million.
