Picking up Phosphorus Grenades

It has been shown that the microcystis aeruginosa bacteria that is associated with algal blooms occurring in Lake Lariat (among many other lakes in the U.S.) is responsive to reductions in phosphorus, but not to efforts targeted at nitrogen reduction. Since dog and cat feces contain more than the usual amount of phosphorus (compared to cow manure, for example), and dogs and cats produce manure close to their own body weight every month, there is probably about 20,000 lbs of manure and about 300 lbs of phosphorus being spread by dogs and cats around the "critical area" of Lake Lariat every month, assuming owners are already sending half of their pets' manure to the landfill. That comes close to 2 tons of phosphorus every year. Unlike nitrogen, phosphorus gets consumed slowly in the soil, so it is more likely to end up in the Lake, where it may accumulate to trigger algal blooms.

Photo by Minnesota Pollution Control Agency

One thing to note about picking up dog crap in one's yard is that it should be done frequently, but at least prior to rain events. Letting it dry for a day or so is OK, if no rain is forecast. I like to time my pile pick-up rounds to coincide with rain-barrel draining when a storm is due the next day. As for dog walking, I've learned to take a couple of poop pickup bags and to have a plastic grocery bag to drop those into. The bigger bag gets tied on my belt until I can dump the contents in a trash can. I would consider composting these, but dog poop bags on the market aren't made for compost piles. Even the vegetable-based bags don't break down quickly or thoroughly enough. (Exceptions exist, e.g. Bio Bag)

For cat owners, the eco-opportunity is greater since cats are often given to going in a litter box. The key is finding a compostable litter. The late Gene Logsdon addressed this idea in chapter 3 of Holy Shit: Managing Manure to Save Mankind. A great odor absorbing material to mix into the litter is ground up biochar. It is not going to break down much in the composting process, but it should enhance composting temperature and time. I'm thinking about hosting an Amazon giveaway with Logsdon's book as the prize. It could be a way to get agriculturally oriented people in my community thinking about manure composting.

Clean Yard, Clean Lake

While septic systems are the major contributor to water pollution in this area, we humanure machines also have dogs that contribute in a more distributed fashion. Normally considered an urban problem due to runoff often being quickly shunted to stormwater drains rather than directed onto the landscape for infiltration, it also warrants attention in suburban settings with less impervious surface.

Taking the Maryland fertilizer law single application limit for lawns as a reference point, a dog contributes about 0.75 pounds per day, so every 25 days or so will drop enough manure to exceed the 1,000 square feet nitrogen and phosphorus limits in the fertilizer law. Nobody fertilizes that frequently, so leaving dog waste to decompose in one's yard violates the principle of the fertilizer law (aside from the fact that it makes a mess out of your lawn). However, when a person walks their dog instead of leaving it in a yard all the time, a lot of their pet's droppings get distributed over an area much greater than 1,000 square feet, so it's probably not excessive and needn't be collected, except in urban areas, or where it is clearly destined to be washed into a storm drain, or when required by rules.

If the fertilizer law is valid, nowhere is it more so than in the critical area, to include around inland lakes and streams. I traced out a line 1,000 feet from Lake Lariat on a topographic map and found that my house is inside that self-imposed buffer. Fortunately, I already collect and compost my dog's waste. Using that compost in a project that can demonstrate its efficacy is going to be one way that I gradually accustom others in my area to the idea of humanure compost. I think the project will be a conservation landscape in front of my house.

Part of my campaign could be spent encouraging dog owners in the target area to pick up the dog shit in their yards, especially from November 15th to March 1st when no fertilization of lawns is allowed. Dog poop will tend to wash into runoff more during those months because the ground is less pervious due to freezing.

Lassoing Lake Lariat

It's hard to believe that the tiny floating tufts of vegetation in the photo here are capable of doing the work of about an acre of wetland shoreline in cleaning up pollution in a lake. These are artificial floating islands mimicking those in northern lakes. They actually do a great job in reducing nutrient and other pollution in Lake Lariat, Maryland. Since Lake Lariat covers 90 acres, a 90:1 ratio of wetland buffer to water surface seems like it wouldn't make that much difference, but the lake was significantly less polluted a year after these floating islands were introduced. 

Two small man-made floating islands are just off the point on the left.

The technology for these floating islands is described on the Maryland distributor's website. They employ a proprietary soil mix, which I can't help but wonder if it could be further enhanced by including biochar. Cycling of pollutants is principally through all the slime that accumulates on the plastic fibers and submerged roots of plants growing on the platform. 

The Lake Preservation Committee was interested in getting more of these islands, last I heard. With the latest blue-green algae bloom episode, we need to, but proactive measures to reduce runoff and seepage from septic systems would be necessary to eliminate the problem altogether. If we target a buffer zone of 1000 feet all around the lake, our campaign would probably include that many homes. I think cleaning up a lake is even more vital than cleaning up a major tidal waterbody, such as the Chesapeake Bay. For one thing, this lake flows through a dam into a bay tributary, so it is a point source of pollution. Another thing is that people living and playing in and around the lake are subjected to more risk because pollutants accumulate there, are confined to a much smaller volume, and may seep into aquifers.

Since all of Maryland's 100 lakes are man-made, using man-made islands to bring balance to those ecosystems seems like a natural fit. They can have other purposes, as well, including creating a causeway, artificial shorelines, hunting blinds, and biogas supplies. My own idea is to park them near the waterfront of property owned by anyone who balks at repairing a failed septic system and put warning signs to swimmers and fisherfolk to avoid that part of the lake. I hope it never has to come to that.

The Blue-Green Waters of Lake Lariat

My approach to finding a good inspector for my septic system has resulted in disappointment. In my area, all of the inspectors on the state's list are not in the business anymore, not available at their listed number, or decided to ignore the training they got in order to do their inspections cheaply.

One of the people I called lives in my neighborhood, but never offered inspections. His name got on the list because he used to work for the county in some capacity dealing with sanitation and had taken the inspector training decades ago. It turned out I knew him from some events we had worked together in our community. I also saw him out on his run this morning - not unusual for this geriatric trackster.

Though my friend couldn't inspect my septic system, we continued to converse and he mentioned that the Lake (Lariat) Preservation Committee, which he serves on, had been considering soliciting residents along the lakeshore to have their septic systems inspected for a highly discounted group rate of $180. The inspection company offering the deal has a camera probe which would be one way to properly inspect components downstream of the tank.

Lake Lariat Beach - it's empty for a reason

The Lake Preservation Committee is interested in checking septic systems which could be contributing to a recent blue-green algal bloom of unknown origin. These blooms are associated with a bacteria that can harm the liver, so signs have been posted recently to discourage swimming.

This problem may be my opportunity - not only to tackle it as a part of my Watershed Steward Academy capstone project, but also to hire a well-equipped inspector for my own system. I don't know if the Lake Preservation Committee considered soliciting homeowners not on the lake to join in the deal, but I would open it up to as many homes in the community that want their system tested, with priority to those homes in the "critical area" of the Lake Lariat watershed. At the 14 September Lake Preservation Committee meeting, I will talk this up and try to get them to leverage SepticSmart week as an outreach platform.

Inspector Screening

Flickr: Natty Dread

Septic systems get far less attention than they warrant, considering how severely they affect our watersheds. Maryland delegates much of the monitoring and control of onsite sewage disposal systems (OSDS) to the counties. Calvert County's monitoring and control from the Public Health Department seems to be limited to checking installers, but they don't take measures to ensure or even encourage valid inspections. When I asked them for a list of inspectors, they sent me their list of installers. I called back to see if there was an inspector list and was told that all the installers are tested and are qualified to conduct inspections. I then called a random company on the list and asked about having a septic system inspection performed. The septic guy they referred me to told me that he had never done an inspection and seemed to think that many home inspectors do a decent job by flowing water into the tank and looking for evidence of seepage. That's the type of inspector the University of Maryland extension warns against.

It turns out that the Maryland Department of the Environment (MDE) does keep a list of individuals who have taken a one day course in OSDS inspections. I can use this list in conjunction with the list of installers licensed by the county to pare down the candidates for my inspection. I will look for local inspectors who aren't installers, because I think there could be a conflict of interest that would push an inspector/installer to fail your system in the hope of getting some big ticket repair work.

Either way, the inspector to hire is someone who follows the recommendations of MDE on how to conduct inspections. They should also use a checklist like the one published by MOWPA. Screening on the phone should include finding out whether they dig to uncover the distribution box and drain tiles. It will be interesting to find out how many of the inspectors listed by MDE as trained actually measure up.

September is for Septic Systems

Though I am a septic skeptic, I still depend on my septic system and want to become a responsible system owner even as I wean us off the practice of dumping in our drinking water. I want to encourage others to be responsible septic system owners, too, so I will do what I can to put together an awareness-raising drive with the help of materials in the toolkit provided by the EPA for septic-smart week (Sept. 19 - 23). At least I can put up some posters; maybe do some door-to-door handouts, making initial contact with homeowners who may be good candidates for conversion to humanure composting.

One thing I've never done that the EPA recommends is hire an inspector every three years to see if my septic system is developing problems. Since I have violated several other guidelines over my 11 years of ownership pertaining to protecting the integrity of my system, I may actually have a failed or failing system and not even know it. Most homeowners are probably in the same boat, not even thinking of having an inspection done until it's time to sell. An inspection now may be timely for us in that regard, as well.

Just looking into the topic of septic systems has given me some other useful awareness. I was planning to plant some shrubs over my drain field, and now, having learned better, I'm looking forward to planting self-seeding annual flowers there instead. There might also be a good area near the end of the drain field for my humanure compost bins. If that somehow negatively affects the capacity of the septic system, the reduced load in the tank may be enough to compensate.

The #1 Source of Pollution in Our Watershed

The 7 million or so gallons of sewage that spilled from wastewater treatment plants into a couple of the Chesapeake Bay's tributaries two weeks ago turned my head in a new direction. It redirected me on my capstone project for the Watershed Stewards Academy to focus on humanure in my neighborhood. Septic tanks are the current locus of the problem. Particularly problematic are failed septic systems in which sewage resurfaces and then gets washed by storm runoff into surface water.

The environmental impact of failed septic systems can be estimated using a figure from Purdue University stating that one failed system will discharge 76,650 gallons of sewage to the surface in one year. Extending that to an estimate of the number of homes in the critical area of the Chesapeake Ranch Estates, and applying a factor of 10%, which is the EPA's estimate of the proportion of septic system failures, and the annual amount of sewage flowing overland from this 1,000 foot wide zone stretching about 1 mile along the Chesapeake Bay comes to 3.8 million gallons. It could be double or triple that, depending on the actual failure rate, which has be estimated at over 30% in some states. Project that kind of problem all along the coastline of the bay and its tributaries and the wastewater treatment plants end up smelling like a rose.

Maryland's laws pertaining to poop aren't all that stringent. Farmers are allowed to dump manure on their fields. Homeowners are allowed to spread it on their lawns. If the fertilizer limits on nitrogen are applied to manure (phosphorus is actually the more limiting element), you could legally put 40 pounds of horse manure on a 1,000 sq. ft. lawn in a single application. Not that anyone would, but you could instead apply 20 pounds of humanure to the same lawn and remain under the nitrogen limits. A failed septic system used by a family of four would expel roughly 700 pounds of excrement (assuming toilets outside the home are used 50% of the time) to the land. That amounts to over 35 times the nitrogen limit for lawn fertilization (humanure contains 5% - 7% N). And that's just the poo! There is also a lot of urine and other nasty liquids in the mix with a whole lot more nitrogen.

It is hard to say whether the nutrient-laden runoff or the 100 or so pathogens in the sewage are a greater problem. Research published in 2015 from leading experts in the field of water sustainability shows that pathogens from septic systems make it into surface water much more than what authorities had believed. The pathogens are pretty scary, but to fish and other marine life, nutrient overload can quickly become deadly.

Keep in mind that all septic systems, working or not, tend to pollute the environment. The total amount of nitrogen loading to the Chesapeake Bay watershed from septic systems in Calvert County exceeds that from every other category,

Photo by Jim Barter

which includes agriculture, urban runoff, forests, and wastewater treatment plants. On average, the amount of nitrogen entering the watershed from a septic system is 19 pounds per year, based on calculations using figures from the Calvert County Watershed Implementation Plan. That is equivalent to dumping lawn fertilizer for over twenty 1,000 sq. ft. applications straight into the bay.  Every house.  Every year. The pathogens (including certain bacteria, viruses, protozoa, and other parasites)  in the effluent from working septic systems also make it into groundwater to one degree or another. In areas where septic systems are greatly concentrated, such as the Chesapeake Ranch Estates, both pollutant types will make the surrounding waters inhospitable to man or beast.