EPC Week 7

Afroz

This week, I worked on addressing my concerns about the water content expected in the waste that would prevent composting or solid fuel recovery from being feasible. A low-energy way to maintain a reasonable water content is by draining into a leach (evaporative) field. This pursuit resulted in the setting up of a spreadsheet that takes an estimated volume of wastewater that could be generated, local meteorological and evapotranspirative factors to calculate the required area of the leach field. I’m populating the calculator with regional soil (permeability) , weather (reference evapotranspiration rate) and vegetative (species, landscape and microclimate factors) data so that it can be used as a tool to judge the feasibility of composting/solid fuel per case based on land availability. My intent is to set it up in a user-friendly format that can take the basic inputs of number of female and male occupants and the location of the home, to display the land area requirements.

The field would have layers of gravel and top soil (to allow for the plants to take root), and the filtration occurs through evapotranspiration. The 2 feet deep “field” will be housed in a concrete/brick enclosure with a liner to prevent leaching to the soil. The enclosure will be raised, or a mud mound provided to prevent rainwater run-off from creating any contamination.

 

Sonya

This week we took a step back and thought about how to consolidate our findings for the quarter and how to compare different technologies. This led us to the conclusion that the main alternatives to biogas, which deal with waste on a very local, home-centered level, were composting and biochar. Furthermore, we decided to begin considering specific toilet designs as we wrap up our work on the engineering aspect of the project. Both of these alternative technologies have the barrier of excess water (as described in an earlier blogpost), so this week I researched the toilet designs that treat this water. Specifically, I looked at the evapotranspiration trench (and the concept of trenches in general). The leachate water is routed from the toilet, either by being diverted through a third hole or by trickling through the solid waste and draining through a pipe located at the bottom of the tank. This pipe needs to be about half a meter above the leachate trench, in order to properly fill the trench. Then, the trench is filled with layers of sand and gravel; the sand holds water that can evaporate, and water that doesn’t evaporate filters down through the gravel. A layer of topsoil is above these layers and holds plants, which helps the evaporation (often, a geotextile sheet is between the topsoil and the sand/gravel, to keep the soil in place. This sheet also helps draw water up for evaporation.) Typical depths for the trenches are 0.6-0.8 meters; as detailed in Afroz’s post, it is possible to calculate the required area of a trench for a given amount of wastewater.

 

Ariel

As mentioned by Afroz and Sonya, this week we focused on methods of dealing with the leachate that has to be removed in order for either compost or biochar production to be viable.  This week I also looked into kiln designs for creating biochar.  In a previous post I mentioned the design Re:char is using which features a removable container for the feces which is placed in the chimney of the kiln.  This design has the benefit of allowing users to create biochar without interacting with the waste.  However, it has the drawback of only accommodating one container at a time.  A top-lit updraft kiln might be a solution to this problem. For this design a large outer drum is constructed, either out of brick or steel.  The container has air inlets at the bottom that will allow a supply of air for the combustion of the fuel.  Three smaller covered metal containers containing the biomas to be converted into biochar (in this case, feces) are placed inside the outer drum.  Fuel is packed around the containers and a lid is placed on top of the outer drum to limit the supply of oxygen.  A chimney is then added to create an upward draft to sustain the burn.  This design has the benefit of being easy to use and fairly simple to construct.  The most difficult part of construction will likely be obtaining a suitable metal lid and chimney.  The ability to fit more than one container into the kiln at once will make it more feasible to have only one kiln for a community or cluster of houses and will make the process more efficient.

Awareness Week 7

Shannon Hoban:

The awareness team has been working on creating material to leave behind. I have been working on brochure to leave with the clinics that addresses the dangers of open defecation and what can be done to improve the risk of these dangers. In addition, we have been working on what can be done to improve the Parishudh website. We have realized that most donors want to see the direct impact that their money has, so being able to donate to a specific family or project might be an effective marketing strategy. Also, I watched a documentary titled “The Word Toilet Crisis”, that showed many other organizations that are working towards an open defecation free world. The tools they are using could be applied to our awareness campaign. An sanitation promoter in Indonesia targeted the women because they could have the largest impact in changing their children’s behavior. Also, many organizations used CLTS method to raise awareness about the dangers of open defecation. Finally, many of the organizations also preached that there must be a service that goes along with the toilets in order to make the product sustainable.

Brooke Wright:

This week, we have started focusing on effective packaging strategies of all of the information we have gathered to make Parishudh very attractive to grants and other funding. We think that we should focus on the follow up strategies that Parishudh is currently using and our ideas for improvements. We want to focus on the idea that Parishudh wants to follow up with the communities and is in it for the long term! I have specifically been working on a lesson plan to leave behind for teachers or committee members to perform in schools to get children excited about sanitation and create a spark for change in the communities. The lesson will be two hours long and will encompass a general schedule as well as specific activities for the children to do. We are also contacting professors and other knowledgeable sources to get information about what aspects are the most heavily weighted when places like the World Bank are considering funding for NGOs. In this part of our project, we are working closely with the finance team to determine the most effective strategies to secure funding.

Finance week 6

We’re beginning to face difficulty in seeing a viable way to make biogas production sustainable. To produce biogas in large quantities for use beyond the household level requires lots of cattle and a larger centralized plant — this has a high up-front cost and also requires an extensive transportation infrastructure to be developed surrounding human waste. Moreover, the biogas would have to be profitable and in demand near its location to maintain the plant at the very least. So, the alternative is to focus on community-level or household level biogas plants. Community-level plants allow for reasonable biogas production assuming a few families and a cow. It’s less clear though how we would make this sustainable. Biogas can serve as an alternative to LPG use for cooking, but it would be too difficult to bottle the biogas for individual sale. It seems like it would be easier to have a directly piped system from the plant to the point of use. Thus, the idea arose for a communal kitchen. This solution, however, would require both cultural changes and would enable very low biogas yields, so it doesn’t sound doable at first glance. A sustainable option would be to produce biogas plants for those are able and willing to pay for them on an individual basis and encourage them to  purchase the human waste from their community members — this would a) give them greater biogas yields, and b) provide incentives for toilet use in their communities.

Awareness Week 6

Shannon Hoban:

This week the awareness team has been working to create a brochure that can be handed out that will contain information about biogas. We want something that is simple and easy to understand that lays out the benefits and potential of biogas. Explaining what biogas is and what the community can gain from using an anaerobic digester will encourage people to purchase and effectively use a digester. We wanted to emphasize the benefits of clean fuel, the cost and time savings of using biogas over having to purchase or gather other sources of fuel, and the simplicity of the product.
In addition, we are reading about past examples of other organizations implementing biogas. We are trying to discover what the issues were and what we can do differently. We have found information that makes it seem like a digester can really only be effective at a community level. However, we are now considering how we will encourage maintenance and ownership of the product.

Brooke Wright:

As the EPC team narrows down its design options, the awareness team has decided to focus on how we will convey information to the end users. Since we are focusing on creating user guidelines for the biogas design, we have put together our ideas into a brochure and poster. Even if the context is not exactly what Parishudh wants, we hope to provide a template that they can use to convey many different types of information. This is very important because while the NGO has a great deal of information, they are looking for our help in how to present these ideas and facts in a way that the users will respond to. I have been focused on creating a poster that is visually appealing and easy to understand. It consists primarily of pictures that portray the do’s and don’ts of biogas upkeep and maintenance. This poster will be useful to put on the outside or inside of the toilet area and remind users how to properly use the digester for optimal resource recovery. It is important to make sure these digesters are being used properly so that decreased performance due to misuse doesn’t discourage users.

EPC Week 6

Dennis

I have been looking even more on our options for biogas usage. It would seem like an easy task, but in all honesty, because we have so many situations that we have to handle and deal with, it is a lot harder than expected.

So, I will attempt to explain the calculations for how much gas is being produced in this blog post. These are from some numbers that we found in studies that have been posted online, so whether or not they are absolutely precise is unsure.

We have a biogas plant that is meant for 40 people (10 families), where each person produces approximately .02 m^3 of biogas per day. So, per day, the biogas plant produces about .8 m^3. We have a number saying that 1 m^3 of biogas is approximately the same energy value of .45 kg of LPG. From there we figured that we produce the equivalent of .36 kg of LPG per day. Using a 10,000 btu rating for our stove, 1 kg would burn at approximately 5 hours, and therefore, the “.36 kg LPG” equivalent that we produce will burn for about 1.8 hours per day. This is enough for about 1 meal.

 

Using a cost rating of 1000 RS for 14.3 kg LPG, we then saw that for “.36 kg LPG” equivalent would produce about 14 RS per day.

 

The model that we were looking at is to hire a villager to maintain the biogas plant, but give him access to the biogas usage. Subsequently, he can can charge 14 RS per day (420 RS per month) to whichever villager that wants to use it for that day. Otherwise he can use it himself. This would be a part time job, but also give the motivation and incentive to maintain the biogas plant at a high efficiency rate. I will be making a graphical model of some of these numbers, and subsequently we will decide whether or not to run with the idea.

 

Ariel

This week I started looking into methods of turning solid waste into biochar.  Biochar is produced by subjecting biomass to high temperatures in the absence of oxygen and can be used as a soil amendment.  This method of waste disposal also has the benefit of destroying all dangerous pathogens.  An organization called re:char has developed a method of converting human waste into biochar that they have successfully implemented in Kenya.  Their design collects urine and solid waste in two separate containers.  When the solid waste container is full, the owner removes it, seals it, and places it in the top of the chimney of a small community kiln.  The kiln heats the sealed container until the waste has been turned into biochar.  Both the biochar and the urine are used in the fields.  Studies done by re:char showed that the application of biochar to the soil significantly increased crop growth.  This method of waste disposal has the benefit of being cost efficient and simple.  However, the large amounts of water used for cleansing in India could cause difficulties in applying this method.  I will do more research into whether it is possible for water vapor to escape from the container during the heating process.  Even if the water vapor is able to escape, the increased amounts of fuel that would be required to turn the waste to biochar might make this method impractical.  One possible solution to this problem is incorporating a third hole in the bathroom design for cleansing.  However, the cleansing water would then have to be dealt with separately.  Next week I will continue to look into biochar and try to determine if there is a feasible solution to these problems.

Sonya

This week we wrapped up composting and started looking into solid fuel/biochar. As far as composting goes, I decided to do research on examples of composting toilets that have been installed in various locations in India, to see how successful others have been. From this and the conclusions drawn last week there were a few key takeaways. It seems as though the vast majority of sites use a diversion system for the water (either combining it with the urine diversion or having three holes) and then filter the water in an attempt to retain the remaining solids/pathogen-containing-matter in the filters and then drain the water into gardens. However, we also learned when discussing the project with Prof. Davis that changing habits is very difficult, so we are hesitant to use an anal-washing-water-diverting system. Other sites in India simply divert the anal washing water directly to gardens without treatment, which is not an acceptable option. Furthermore, in the only source I could find about a follow-up study a year after having installed the composting toilets, the toilets looked at in Sri Lanka were only half in use; a small percentage had been converted to pour-flush toilets; and the rest were not being used. This may have been due to the lack of an awareness campaign (no information on that) or to the systems being water-diverting (three-hole). We also concluded that for composting we would need to either create a large number of holes for evaporation of the water or remove it, both which involve many problems (for example, removing it would require a two-pile system so as not to remove fresh feces). So, the only way composting is really feasible is to divert wash water, which is likely in practice to be the failure point.

 

Afroz

Biochar was on everyone’s mind this week. As Sonya points out, the significant water content expected in the waste is a huge deterrent to our adoption of solid fuel recovery technology. I’m apprehensive about the amount of energy that will be required to dry the waste and preserve it for future collection and use. Nevertheless, we are exploring options to ensure an exhaustive analysis. Meanwhile, biogas is still reigning tall after composting was resigned from our list of options through careful comparison. Discounting the possible operation and maintenance issues, the biogas units are an excellent choice. We are currently working on developing a community-centric model that would take care of the operations and maintenance technicalities. I’m taking a closer look at prominent village level biogas models used currently. The Biogas Sector Partnership (Nepal) has been very successful in the sustained generation and use of biogas for cooking purposes. The technology used is a fixed dome plant. The digester is built in a pit near the house, and consists of a masonry cylindrical tank topped by a concrete dome. It ranges in size from 4 to 10m3. The key to the success of this project was significant resource devotion to training local construction and support staff to run the program, this might be where our focus should be as well. A post-implementation analysis has also shown significant health improvements as a result of the reduced particulate emissions associated with firewood.  

 

Awareness – Week 5 – Moving Forward

Shannon

This week the awareness team has shifted gears and is starting to work with the EDC team on biogas. We are looking into ways of educating people about how much potential is possible with biogas anaerobic digesters. The case studies we are looking at show that most people do not realize that it is possible to make gas, and also money, from their waste. Many farmers could make a large profit off of the waste from cows. We have gathered material to create a brochure or presentation that can be given to a community that will help inform them of the potential of biogas anaerobic digesters. In addition, we are starting to better understand the digesters and what the major issues with them are so that we can create a user’s manual to go along with the product. 

Brooke

After the midterm presentation, we have received great feedback about the effects of plays and movies on creating behavior change in India. An example was used where a movie was able to convince groups of women to persuade their husbands of certain actions. Furthermore, we we’re told about groups that perform plays with props and actors and travel throughout different areas to convey certain messages. Since the effects of drama and visual displays have been so effective in the past, we plan to look further into this for our future awareness campaigns. Also, as we move forward with developing a manual and presentation for the biogas anaerobic digesters, we need to look into the formation of a service around this particular design. We will work with the EPC and finance team to cater a service to the toilet design and make it financially viable. In creating a service, it is important for the awareness team to make sure that people are educated about the proper use of the toilet and the great potential that energy recovery can bring. We also need to make sure that people can afford these units and know about potential financing to make biogas units affordable.

Finance Week 5 Update

Isaac

This week we are considering revenue-generating financial models for biogas production as a means of wastewater treatment. The major issue is as follows: biogas production is an added cost, so to pay for it along with the toilets themselves, we’ll need to find a model that puts the biogas to use in some sort of value-generating fashion. One thought is to start a dairy farm with a couple hundred cows–the feces of these cows can be combined with the waste from toilets to reach ample levels of biogas production. The biogas can be used to sustain the plant or sold to replace LPG use. The dairy can be sold as well, making the process sustainable. We could have some sort of membership system whereby people who ensured their waste from toilets was delivered would garner benefits such as milk discounts, etc. We’d have to think this through further and talk with people to see if such a scheme sounds at all viable. It’s of course more complicated and elaborate than our other model under consideration, which is to simply market biogas to the household level as a cheaper replacement for LPG’s used for cooking. Larger biogas reactors as well as dairy farms have much higher up-front costs than smaller, community level biogas reactors. Adoption and demand would still have to be gauged in either scenario. We’ll focus on composting next as well.

Aditya

Biogas keeps holding our interest because of the possibility of its consumptive use or revenue generation through its sale. This week we kept exploring more ways of solving this problem. It seems that biogas might not be feasible on a small scale as the payback period for the initial investment comes out to be very large. Secondly, if the output is not significant, the users do not feel the need to expend any effort on the operation and maintenance.

Building community sized plants would be the key to success. This approach creates the possibility of disputes during distribution/sale of gas. Distribution would largely be constrained to areas in the vicinity of the biogas plant.

We also began to look at composting or other service-based models for finding methods of disposing waste while generating revenue at the same time.