I've tried the Wowza streaming engine but even at low video quality there's a 3 second delay. Are there any standard way to set this up with minimal delay?
The technology and standards certainly exist. Look at video conferencing: minimal delay, perfect A/V sync and great for changing network condition. Apple's FaceTime is a prime example.
I doubt the delay is in the up-link phone to Wowza - more likely in the transcoding and packaging.
Every re-streamer (Wowza and others) use DASH or HLS to get to the client which makes your video stream look like lot's of little files with a 1-3 second duration. This leverages existing cache and CDN infrastructure but introduces seconds of delay.
If your target delay is below a few 100 milliseconds you have to do something like RTP/RTSP.