Lanai over or near cesspool?

[Carey]

Chas, a cesspool does not have a solids tank...so no holding back on the solids...

Some cesspools here do need servicing (all septic tanks should be serviced, but know of ones that do not get serviced & have solids in the leach field) The gross bulk of the cesspool material here does flow into porous rock structures, or straight into lava tubes (which is a gross thought if you really think about it)

If anyone tries to tell you more about where that material goes...back away from this heretic! I have been to enough meetings, read enough papers & talked to enough hydrolysis gurus here (most originally from the mainland) to realise this one point... 'we don't know nothin' yet!' as far as the inner workings of the hydrodynamics of these volcanic islands!

[MarkP]

If the solids from a cesspool were going to tunnel their way down to the water table, so would all manner of other debris from the surface. Since this debris is not evident when cesspools or other holes are dug, it is a pretty safe bet that cesspool solids are not getting anywhere special beyond a few feet. The issue is hotly debated whether Hawaii's uniquely porous ground mitigates the contamination from cesspools through making everything aerobic or whether it just speeds the wastewater on its way. What is different here from the mainland is that there are almost no impermeable layers. My parents in central New York have a well that is only 85' deep. Here that would never happen. If I wanted a well in Eden Roc it would be 1,700' deep before I could hope for water. The water that starts from the surface today takes years to get down there. Even if the nutrients in the wastewater remain I doubt that any specific pathogens dangerous to people remain viable. No matter. Nobody drills wells in Eden Roc. Down by the water is another story. If you get close enough to the shore those cesspools start to contaminate the ocean. It stands to reason that fresh water wells could be contaminated although that close to the ocean they could also be contaminated with salt water. There may be a sweet spot where the treatment and dissipation from a couple hundred feet of rock is sufficient for health and yet the depth of the well is not excessive.

I should state that this is my opinion. I don't have direct knowledge of water quality test results that would make clear the viability of wells. There are many wells in Hawaii so they must work here one way or another. I just know I ain't paying for any 1,700' deep well. Not when I get, on average, 1/2" or more of rain per day dumped on my head.

[Carey]

Mark...There are Aqualudes here which allow the fairly shallow county wells Kaloko mauka, & the clay layers on Mauna Kea and Mauna Loa that allow the bog areas such as around the Waialuku River and up in the Glenwood area, and the impounded lakes...just some of those interesting little exceptions that make the hydrodynamics here sooo interesting...

There are cesspools here that have been used for years that when opened are fairly clean (even know of a church & dayschool that had a cesspool that was known to be a lava tube...sparkling clean when it was changed to septic for the EPA 319 compliance)... the debris IS going somewhere, if a lava tube is present, there is no "sweet spot" porous rock filtration, but a tube carrying the debris to????

[MarkP]

I wish I could get to the bottom of this question which keeps coming up and starting arguments. I personally believe that the solids could not be moving that far or else we would see all kinds of solids from the forest above whenever a hole was dug or a lava tube explored. We don't. Nevertheless all the evidence needs to fit and some of it seems contradictory. For example, septic tanks do get full and need to have solids pumped out so that argues that the solids don't just digest away to nothing. On the other hand my parents have lived in a house with a septic tank and leach field and have only had it serviced once in over 30 years. Pumping it is definitely not a regular thing or it would have failed already many times. The answer may be that for most of those 30 years it has been only them and sometimes myself. I think that there is a tremendous reduction in solids volume over time in both cesspools and septic tanks but septic tanks are stagnant pools of water while the intermittent filling and draining of cesspools pumps air throughout the active zone. Anaerobic reduction is much slower than aerobic even if they both get the same place eventually. In cases like that of my parents the rate of introduction of solids is so low that the anaerobic microbes keep pace. Since there are no rocks in poop it can reduce down to almost nothing given enough time. Still it is a common thing that septic tanks get full of solids while here in Hawaii cesspools don't.

For the record I think that there is a zone perhaps two or three times the dimensions of the cesspool, where all the solids get trapped and eventually degrade away to almost nothing at about the same ratio that wood gets burned down to ash, and that this is possible because the periodic flows of water pump air through this region. I don't think that poop is making it hundreds of feet in any recognizable form except in the case of lava tubes. Even in those cases I suspect that the water drains into cracks and the result from that point is identical to a cesspool. Not that I would want to explore those tubes on foot.

The issue of perched aquifers is similarly intriguing. I understand that the Honolulu Board of Water Supply makes great use of aquifers in the mountains that are far above sea level. I also understand that if I go to a well driller he will tell me to expect to drill down nearly to sea level to get water. I think that the difference is that the BWS has the resources to explore for these sites whereas the homeowner has to just get lucky.

[Chas]

Thanks for all the interesting answers.

Mark, I think you are correct that if the inflow is very low it does not build up. I know that the amount of people living in the house is a consideration. My tank is only 1,000 gallons, and I live alone so I probably could go a lot longer without having it pumped. I just want to be on the safe side. Pumping is much cheaper than replacing!

I've been told not to put organic waste (food scraps, etc.) down the drain because it doesn't decompose in the tank and will cause the solids to build up faster. Yet toilet paper does decompose? Doesn't seem to make sense, but that's what they tell me. I guess it's that aerobic vs. anaerobic thing.

Anyway, again, thanks for all your replies. I'm noting that this seems to be a sensitive subject...

[Tink]

Grew up with a septic system and my dad had it pumped and inspected about every 5 years and never had a problem. This was for a family of 4. All the other neighbors did not pump, and eventually had to replace their whole system. May have been luck, or maybe it was because we never put any raw garbage or food grease down the drain, and mom bought the softer toilet paper that was difficult to use, but broke down fast. Still going after 40 plus years.

Community begins with Aloha

[terracore]

Our livestock, dogs, etc produce WAY more waste than we do and gravity is pulling all of it into the ground regardless if it flushes into a hole or is deposited on top.