BitOwl Application Suit does include a captcha system. It is not recommended for use do to improper testing, and BitOwl does not know how effective it is.
First, you need to open config.php and add the following line...
$_bitowl["master"]["captcha"] = true;
Next, news-comment-form.html uses the following codes {captcha} which is the url to the captcha's image. {captcha-field} fills the input tag for the captcha's input. {captcha-failed-message} will be "Incorrect Code" if the user inputs the wrong code.