February 01, 2012

Composting toilets could reduce sewage costs

As published in The Erin Advocate

Composting toilets could be part of a solution to the sewage problem that has stifled growth in Erin and threatens residents with huge costs.

The Servicing and Settlement Master Plan (SSMP) study is entering a phase this year in which engineers will work out a series of options for the Town to consider, as many of the older household septic systems in Hillsburgh and Erin village will soon need to be repaired or replaced.

One option is to do nothing, but the provincial government will not stand for that. Do we want to create our own solutions, or are we willing to have the Ministry of the Environment force some upon us?

Another option will be a full, traditional sewage system, built in phases over many years, including a large treatment plant in Erin village that would discharge into the Credit River. It would handle sewage pumped down from Hillsburgh, plus all the septage pumped from rural septic tanks. Hook-up in the urban areas would be mandatory.

The SSMP, however, must present the Town with other options. They have to be realistic options, not just some straw ideas that can be easily dismissed, or unproven technologies that are too risky.

The technology of composting toilets has advanced greatly in the last 40 years, so they can now provide efficient breakdown of waste, with no mess, no smell and minimal maintenance. Unlike modern septic systems, they do not require homes to be built on one full acre of valuable land.

The waste does not have to stay in the bathroom, under the toilet. Standard drain plumbing and minimal water can transport it from more than one toilet to a single composting unit on a lower floor or in the basement.

The device is airtight, with venting to the outdoors. Waste goes into a heated drum that rotates, mixing the material and allowing liquid to drain to an evaporation chamber. As the solid material breaks down, it moves to a finishing chamber where a drawer allows the soil-like compost to be removed without any exposure to raw waste. Manufacturer Sun-Mar Corp. says that with a large "bio-drum", most families would only have to remove compost once per year.

A top-of-the-line system costs about $2,000 at Home Depot, plus installation. Replacing a septic system can cost over $30,000, especially on the majority of old village lots, which are now too small for a standard septic tank and drain bed. No one knows what the hook-up charge for a sewer system would be, but Mayor Lou Maieron recently suggested that it could be $20,000 (spread over many years), or maybe a lot more. No one knows the cost of a treatment plant, but it would have been about $25 million in 1995, to serve Erin village only.

The key to mass adoption of a composting toilet strategy would be a communal greywater system. Greywater is the relatively clean drainage from sinks, bathtubs, showers and laundry. The main contaminants are food particles and soap products.

This water may require a system to drain or pump it to small-scale filtering areas, such as constructed wetlands that would service separate neighbourhoods. This would be a lot of trouble, but not nearly as expensive or disruptive as a full sewage system.

Would it be any more trouble than having hundreds of miniature sewage treatment plants buried under our lawns, as we now have with septic beds?

Could an entire subdivision be built without sewers or septic tanks, relying on composting toilets for contaminated waste and a filtering system for greywater?

Would people be willing to buy such houses, if they could save the cost of a $30,000 septic system, or the initial and ongoing costs of sewers? It would not be acceptable for some people, but many others would be proud to be part of such a development.

What if, instead of having to replace your entire septic system, you could extend its useful life by having a composting toilet to handle a significant amount of your waste?

What if downtown businesses could avoid the cost of having a holding tank pumped out regularly, without the massive disruption of sewer construction? (Even if sewers are built, it may be possible to build the system without entirely tearing up Main Street in the business district.)

I am not an expert on any of this stuff, but I have seen enough to know that innovative solutions are possible. Fortunately, we have hired experts for the SSMP who should be able to give us some achievable options. We're into this study for over $300,000 already, so let's make sure it is not wasted. The Town probably couldn't back out of this process even if it wanted to.

It is inevitable that Erin will get some population growth and higher density housing. Let's work to ensure it is done moderately and intelligently. Instead of giving up on the SSMP, let's set our standards high and get as much as we can out of it.