About half of New England’s households are on septic systems. That’s the highest proportion in the country.
For decades, most conventional systems have done well removing pollutants and pathogens. But they’re not very good at removing nitrogen, which is in human waste.
Too much nitrogen can wreak havoc on coastal ecosystems, decimating shellfish beds and causing massive fish kills. Recent research at the University of Rhode Island indicates that even the best equipment won’t do the job of removing nitrogen, if the septic systems aren’t monitored.