Tuesday, January 10, 2012


The water smells good, like a creek. It cascades from one cast-iron bathtub into another, then into a ground level Jacuzzi, aerating along the way. Gambusia devour mosquitoe larva while goldfish and koi eat algae. Papyrus, elephant ear, pickerelweed, duck potato, duckweed--no end to the aquatic weeds useful for remediating not-so-dirty graywater.  Every time we shower ten to twenty gallons of the Colorado River flows into this bathtub waterfall, displacing water to the peach and avacado trees and soaking into the Boggy Creek watershed that feeds back into the Colorado River. Just how big is this backyard living machine? 

To jury rig these plumbing backwaters I severed the tub's drain pipe before it joined the outgoing toilet line for the South Austin Regional Wastewater Treatment Plant. Black plastic tubing delivers tub graywater to the sunken backyard Jacuzzi. I inoculated the new ponds with bacteria-laden sludge from the kitchen wetland. Searching for aquatic plants on Craigslist, I found some floating water hyacinth indigenous to South America and water lettuce native to North Africa to spread across the pond surfaces and kick start remediation. Their feathery roots catch drifting biosolids for bacteria to metabolize, keeping algal blooms in check by eating up nutrients. Invasive elephant ear collected from Town Lake unfurl rhizomes and colonize the tubs.

That winter raccoons who lost their homes when the City buried a neighborhood creek raid the wetland and eat most of the elephant ear tubers. This gives the native arrowroot (pickerelweed) from the Rhizome Collective a chance to spread in the spring. Hummingbirds sip nectar from their arrays of bright blue flowers. Dragonflies dip eggs into the water, and the growing nymphs eat mosquito larva. In the spring, hundreds of tadpoles hatch, and fingernail-size baby toads hop out to all corners of Ephemerata Gardens. At dusk the Gulf Coast toads' trilling sounds overlay bubbling water.

DIY wetlands take form through aesthetic improvisations--hands-on encounters with things that push back and teach as they emerge, laying down patterns and habits in sensory refrains. When Nigel Thrift visited Ephemerata Gardens after giving a talk at UT, he was enthusiastic about our backwaters as a form of hopeful urban resiliance through nonstandardized “underground knowledges” of repair and maintenance.* Improvisation involves ad hoc engineering, making it up as you go along or making due with all kinds of idiomatic solutions. We talked about how the improvisations are not at all limited to what do-it-yourselfers decide to do, but also what plants, animals, and bacteria fiddle around with in the self-emmergent landscape patch. Thrift talked about the wetland as an aesthetic form--something that “generates sensory and emotional gratification” and “shared capacity and commonality”**--the pleasures of being around lively habitats, teaching people about graywater remediation, and sharing water plants by giving them away. I had to remind him that these aesthetic forms are not just all rosy, but risky, subjecting you to abject encounters with rat-tailed maggots and invisible pathogens, or the stress of wondering when the Department of Code Compliance is coming to get you.

Wastewater reuse in wetlands and urban agriculture is slowly becoming accepted by departments of code, as well as a formalized strategy in international development projects. Too many people are tapping wastewater as a more dependable water source than rain for municipalities to realistically police and enforce wastewater use prohibitions. Remediating shower water with decentralized, user-maintained systems may be riskier to public health than the big wastewater treatment plants dealing with poop-laden blackwater. But it is much cheaper, conserves energy and potable water, and delivers nutrient rich water to local crops. Despite prohibitions against using wastewater for agriculture, farmers in the global South have been informally using it for irrigation in urban farms for decades. "Urban agriculture cannot be seen separately from wastewater use."*** Efforts to formalize wastewater use focus on experimental systems that provide a basic level of treatment through screening out solids and allowing sludge to settle in basins.

An experimental constructed wetland in Cameroon treats sewage from a population of 650 people by streaming it through a series of eight lagoons. Seven of these are stocked with water lettuce that can double its biomass within a week (giving it the status of a dangerous invasive species in waterways around the world). The researchers who built the system suggested maximum phytoremediation is only achievable by removing one quarter of the plants every fifteen days. All kinds of beings are waiting to highjack this living water with their aesthetic improvisations: "Emanation of foul odours, mosquitoes and flies proliferation and appearance of aquatic snakes are some of the nuisances recorded. These problems become acute when the system is left unattended to for long periods."**** Such systems require hands-on human labor to manage the labor of plant species; but they do not require electrical energy, endless chemical inputs, machine maintenance, or massive municipal funding to be built in the first place.

A similar experiment in Dakar, Senegal (built for a half million dollars in research monies) institutes a community run and owned sewage treatment plant that uses water lettuce to produce nitrogen-rich water for irrigation of urban agriculture.***** The system utilizes a permaculture model that approaches multiple issues (public health, employment for youth and women, and water and food security) with a single integrated solution. Likewise, a development project in Palestine (built for about 200K USD) treats sewage with duckweed, a tiny floating plant with high protein content and extremely fast growth rate. The duckweed is harvested twice a week and used as feed for chickens, so that the chemical-free sewage treatment plant serves as a stable source of income.****** These experiments seek to demonstrate that probiotic sewage treatment using aquatic plants as remediation technologies--a different kind of solar power--are both epidemiologically safe and economically effective alternatives to conventional sewage infrastructure development.

Imagine floating over a city of these DIY wetlands, a graywater oasis. Self-emergent communities of people and ecological beings are puddling around wastewater. Somewhere out there, an old bathtub is waiting to become your DIY wetland!


*Nigel Thrift, 2005, “But Malice Aforethought: Cities and the Natural History of Hatred.” Transactions of the British Institute of Geographers 30:2 (June 2005), 133–150, p.136.
**Nigel Thrift, 2010, “Understanding the Material Practices of Glamour.” In The Affect Theory Reader Melissa Gregg, Gregory J. Seigworth, eds. Durham, NC: Duke University Press. 289–308, p. 292.
***Mark Redwood, Wastewater Use in Urban Agriculture: Assessing Current Research and Options for Local Governments, International Development Research Centre, Cities Feeding People Reports Series (2004), p.18, http://www.bvsde.paho.org/bvsaar/fulltext/redwood.pdf.
****Fonkou, Théophile, Philip Agendia, Ives Kengne, Amougou Akoa, and Jean Nya. Potentials of water lettuce (Pistia stratiotes) in domestic sewage treatment with macrophytic lagoon systems in Cameroon. Proceedings of International Symposium on Environmental Pollution Control and Waste Management, January 2002, Tunis, 709-714, p.711-12, www.geocities.jp/epcowmjp/EPCOWM2002/709-714Fonkou.pdf.
*****Niang, Seydou. "Wastewater Treatment Using Water Lettuce for Reuse in Market Gardens (Dakar)." International Development Research Centre website, web.idrc.ca/es/ev-6339-201-1-DO_TOPIC.html.
******Al Khateeb, Nader. "Duckweed Wastewater Treatment and Reuse for Fodder (West Bank)." International Development Research Centre website, web.idrc.ca/es/ev-6314-201-1-DO_TOPIC.html.

Note: Parts of this entry were first published in Scott Webel, “Free Water! DIY Wetlands and the Futures of Urban Gray Water,” Anthropology Now 3(1): 13-22.

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