If You Flush, You Pollute – Guest Blog by Dr. Rick Bennett & Friends

Image of the water column from a dive at Keʻei, South Kona. PC to M. Lamson.

Although it may be difficult to admit, for most Kona residents, flushing the toilet will result in groundwater and ocean pollution. The environmental impact is far less for homes on a sewer system in Keauhou and Waikōloa, as the waste nutrients are irrigated and taken up by the golf course grasses. Sewers and water reuse are the directions we should be headed. Instead, we are on track to perpetuate the effects of cesspool pollution with ineffective and expensive septic systems and injection wells.

The problem is human waste. Specifically, urine is the predominant source of nitrogen. About 6 percent of the weight of all the proteins we consume is nitrogen. It gets metabolized and excreted as urea. In the environment, urea is ultimately converted to nitrate. Nitrates are fertilizers that stimulate algae and other aquatic plants in water systems, upsetting the balance of the marine ecosystem. The recent greening of our bays and harbor is visual evidence of excessive nitrogen in the water. Unless we intervene, this trend will worsen as waste flows increase and temperatures rise.

High levels of nitrogen compounds in waterways can cause algae and aquatic plants to bloom. The rapid growth takes up oxygen in the water, killing off fish and other organisms and affecting water clarity. Nitrogen compounds come from several sources, including human and animal waste and commercial fertilizers.

All along the Eastern Seaboard, communities are removing septic systems for centralized sewers or onsite Nutrient Reducing Biosystems (NRB). Sadly, Hawaiʻi seems poised to make the mistakes other communities have made, only to discover that septic systems could pollute almost as severely as cesspools.

To their credit, the State of Florida put nitrogen removal requirements for a septic system into state law after decades of debate and delays.
“In the 108-square mile basin for Blue Spring in Orange City, the (Florida Environmental Protection) department concluded the primary cause of the nitrogen — 54 percent — is coming from human wastewater flowing from more than 23,000 densely clustered septic tank systems in DeLand, DeBary, Deltona, and Orange City.”  — The Dayton Beach News Journal June 2, 2019.

This work in Florida and other Eastern Seaboard States begs the question: why do we propose spending nearly a billion dollars on conventional septic systems that do not solve the nutrient pollution problem? Like Florida, our warm climate lends itself to the success of Nutrient Reducing Biosystems, or “NRB”, also called the “Layer Cake System” by New York’s Stony Brook University scientists. The NRB is applied life science employing the attributes of bacteria that require oxygen to work and other bacteria that thrive in the absence of oxygen in two distinct layers of the leach field. Our Blue Rock and Green Waste Compost make for compelling and lessor-cost systems. Alternative NRBs can be used in neighborhoods or cases of small lot sizes. Test data from New York suggests a 90 percent reduction of Nitrogen and Phosphorus nutrients, and a thousand-fold reduction in bacteria is typical, especially in
warm climates.

Dr. Rick along the Kona coastline.

This above guest blog was shared in March 2023 and is reprinted here by Dr. Rick Bennett with permission.  You can check out his blog with past entries all about water and ocean health (from 2015-2020) at his website: http://www.h2okona.org/

Below is a video shared with us by Dr. Rick about more recent updates on nutrient reduction in wastewater from a Stonybrook University conference from New York (July 2024).