Future OF Houston's
Waste Management
The decomposition of organic materials can be broken down into two processes: Anaerobic (without oxygen) Decomposition and Aerobic (with oxygen) Decomposition. We intend to use both of mother nature’s processes to assist with the reduction of Houston’s landfill-generated methane.
Organic Waste Solution
Commercial Food Waste Collection and Waste Water Treatment Plant Upgrades
In anaerobic digestion bacteria consumes organic material in the absence of oxygen. The four phases, hydrolysis, acidogenesis, acetogenesis and methanogenesis, ultimately produce methane and carbon dioxide. At a landfill this methane escapes into the atmosphere or is flared off. We propose retrofitting of one of Houston’s Waste Water Treatment Plants so that it will actively produce methane from a mix of raw sewage and processed food waste. The methane will be captured and put to use generating power at the facility or sold to fund the facility’s continued operation.
Aside from co-generation at the plant or the sale of renewable biogas to energy plants, there are other uses for the collected methane. It could be compressed to power Compressed Natural Gas (CNG) vehicles, conceivably replacing the traditional gas and diesel powered vehicles that currently serve as Houston’s fleet of trash haulers.
To achieve this, the current aerobic digesters will have to be converted into anaerobic digesters. Additionally new mixers, biogas purification equipment and supporting systems will have to be purchased. The upgrade and retrofit will be expensive, but should pay itself off in 8 years.
Aerobic Digesters and sludge thickeners at Houston's 69th Street Waste Water Treatment Plant. Source: Randall Mayhall
There are several different methods of composting, all dependent upon personal preference and geographic location. There are options to construct your own compost bin out of untreated wood, or to purchase a closed composter such as a Green Cone. A Green Cone allows you to virtually compost anything from meat and dairy to vegetables and pizza boxes, while an open compost bin would only allow for fruit and vegetable scraps and grass clippings or you risk a rodent issue.
In order to make composting effective in reducing methane emissions, it needs to be done in large scale. Creating a compost program at elementary schools would accelerate the benefits and increase awareness throughout. Placing a large compost bin on school property would be suitable for not only the cafeteria waste but for residential waste as well from the neighboring homes. Schools should have three sorting bins, one for each: compost, recyclables, and garbage. Introducing this in schools will educate the students at a young age how important it is to nurture the environment rather than ignore it. To further education, the school can create a small garden on the premises and use it as hands on experience with growing their own produce and then using the compost as a natural soil amendment.
Composting Food Waste and Education
In an effort to decrease the impact food waste has on landfills and the environment, it is necessary to reduce the amount that is discarded as pure waste. 90% of the food waste and food-soiled items we throw away can be recycled naturally through the process of composting. Composting is the natural cycle of “rotting” or decomposition of organic matter by microorganisms under controlled conditions. The end result is a rich, nutrient dense soil, which can be used as a supplement to gardens or to enhance landscaping. So, instead of this material winding up useless in a landfill producing methane, it can be regenerated back into the ground to once again provide food on the table.
Resources
Please refer to our Policy Document for far greater detail and a full list of sources.
In order to provide material for processing at the WWTP, measures will need to be taken to establish a consistent and reliable source of food waste. We recommend that the city mandate the collection of food waste at all municipal buildings that have onsite food waste generators, such as cafeterias or restaurants. By itself, this is unlikely to produce enough material to sustain the desired level of biogas production. To further increase the amount of food waste collected, incentives can be offered to large food waste generators (restaurants, grocery stores, etc.) that volunteer to participate in the program.