BioBarrier Offers New Approach to Treating Wastewater Onsite
By Brent Ehrlich
Treating wastewater for onsite use could take a burden off our aging infrastructure while creating high-quality water that won’t contaminate local watersheds (as septic systems can), but capturing and treating wastewater for reuse is tricky. For example, reusing graywater from bathing and washing clothes requires separating it from blackwater from toilets and kitchen sinks, and to prevent growth of bacteria it has to be chemically treated or used immediately for landscape irrigation. Kansas manufacturer Bio-Microbics has developed a residential wastewater treatment system, BioBarrier, that can process combined household wastewater, including blackwater, into non-potable water clean enough to be reused onsite, even indoors. BioBarrier is currently the only system that meets the ANSI/NSF Standard 350 for Onsite Residential and Commercial Water Reuse Treatment Systems.
BioBarrier is a modular system that treats a household’s wastewater using membrane bioreactors (MBR), simplified versions of technology found in many municipal wastewater treatment systems. It is not a full water reuse system, in that it does not contain water storage or distribution networks; those would have to be purchased and installed separately. BioBarrier units certified to NSF 350 use a two-compartment septic tank, an MBR cartridge, a blower, a pump, and controls. Household wastewater (influent) flows into the first chamber, where solids settle out to be pumped out later, like in other septic systems. The company’s SaniTEE device (essentially a cleanable pre-filter) separates out remaining larger pieces before the water flows into a second chamber.
The second chamber houses the heart of the BioBarrier system, the MBR, which contains a block of filter membrane plates layered vertically together. The cartridge is submerged in the tank and connected to an external, aboveground blower that aerates the water so that it percolates up between the filter membranes. The bubbling action and added oxygen keep the membrane clean and help bacteria break down organic solids and other contaminants. According to James Bell of Bio-Microbics, the MBR uses “a flat sheet membrane that is sort of like a sandwich.” The water is filtered from the outside in: a small, submersible pump triggered by a float switch pulls water through the membrane, into the center, and out of the system for reuse. The company claims the membranes remain clean and have an estimated lifespan of around seven years, but the membrane can be cleaned using a mild chlorine solution. The company provides a two-year maintenance program with service every six months for its units.
NSF 350 is the first robust standard for onsite wastewater reuse and covers commercial- and residential-scale systems. Effluent created by these systems is clean enough that it can be used indoors for toilet flushing or outdoors for fountains, commercial car washing, or subsurface and surface irrigation, including crops (as long as local regulations allow it and the water does not come in contact with food). The BioBarrier MBR system is certified to the residential NSF 350 standard for its units treating 500 gallons per day (gpd) for one to eight people, 1,000 gpd (up to 16 people), and 1,500 gpd (up to 24 people), but the company offers HSMBR (High-Strength MBR) systems for commercial buildings and small communities that can treat up to 9,000 gpd.
NSF data show that BioBarrier residential systems meet the more rigorous commercial standard meant for larger units, but according to Bell, the company has not pursued NSF 350 certification for its larger units. “There is no cookie-cutter regulation that fits all commercial systems,” said Bell, and larger commercial systems are designed and reviewed locally case-by-case, so product certification is less relevant.
Because BioBarrier reduces nitrogen, E. coli, and fecal coliform in the effluent to nearly undetectable levels, water produced by the system is clean enough for most onsite uses and can be released into some environmentally sensitive watersheds, but even these systems may require review since codes vary across the U.S. Local codes, for instance, may not allow effluent to be used indoors or for some irrigation without the addition of chlorine.
Though the company does not release cost data, David Wahrer, owner of H2O Reuse, a licensed seller of BioBarrier, estimates the 500 gpd unit costs about $7,500 including a two-year maintenance program—more expensive than conventional septic systems but comparable to the mound systems required for some soil types. Another downside: BioBarrier’s blowers and pumps consume energy, unlike gravity-fed septic systems (although mound systems often incorporate pumps). NSF testing showed a consumption of 7.85 kWh per day for a 500 gpd treatment system (for context, the most energy-efficient refrigerators are about 1 kWh per day). The company offers electronically commutated motors for its blowers, but systems containing these units have not undergone NSF testing, and the company does not offer them as standard.
BioBarrier’s small footprint and high water quality do provide a clear advantage where conventional septic systems are impractical. Wahrer says using the systems can make smaller lots or those not connected to municipal sewer systems buildable, and they can be installed where soil conditions make drainage a problem or where a separation distance is required between a septic system and a body of water. So although BioBarrier is not a drop-in graywater system or an ideal replacement for every septic or municipal wastewater system, it does provide the cleanest water available from a decentralized wastewater product.
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