A brewery wastewater system can be run manually. But, you will be a much happier brewer if you add controls to automate as much as possible. You want something that works all of the time so you don’t need to worry about it. You will need to provide some attention to any system, but an automated one should take a few minutes a week at most. The downside to automation is cost. Controls get expensive.
For a truly manual system you would have a tank underground somewhere. You’d need a pump down there that you can turn on and off with an extension cord. You would need a way to test the water for pH; strips would work fine. If the pH is outside your discharge limit you would manually add some chemical. You would want to mix the tank somehow. Test the pH again and turn the discharge pump on. Unplug the pump when the tank is empty. This would be a nightmare to operate but it would work. You could even measure discharge volume by the change in tank level.
The other side of the spectrum is full automation. The equipment required would depend on your discharge requirements, but you would at least want floats to turn the pump on and off, high level alarms, and pH measurement. Further equipment could be a data logger, autodialer, flow meter, flow regulating valve, temperature measurement, better level measurement, and a PLC to control it all.
I work with experienced brewery control companies to build the control portion of the systems I design.