Low-cost decentralized sanitation system based on vacuum collection and reuse of excreta and kitchen waste (Chinese Academy of Sciences, China)

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Low-cost decentralized sanitation system based on vacuum collection and reuse of excreta and kitchen waste (Chinese Academy of Sciences, China)

Dear all,

As you can see from my signature below, I am a professor in Beijing, China at the Chinese Academy of Sciences.

My grant was entitled:

Low-cost decentralized sanitation system based on vacuum collection and reuse of excreta and kitchen waste
  • Name of lead organisation: Research Center for Eco-environmental Sciences (RCEES), Chinese Academy of Sciences (CAS)
  • Primary contact at lead organization: Bin Fan
  • Grantee location: Beijing, Chian
  • Developing country where the research is being tested: China
The Project Team:



Short description of the project:
After 3 decades of rapid economic increasing, the decision makers of China care for the environment and the elemental well-beings very much more than anytime ago. Among the 0.9-billion population that have not possessed modern sanitation and sewage service, more than a half are unreachable to the centralized wastewater networks. It is estimated that the central and local governments should build decentralized sanitation systems for more than 0.5 billion people in next 20 years.

A question should be answered by the Chinese researchers: need we follow the steps of the westerns to build the traditional wastewater and wastes treatment plants, which consume large quantity of energy, materials and resources just to degrade the remains from what we eat and excrete, or need we seek a more sustainable solution that consume less water and less energy as well as less money while maintain the same sanitary, convenient and organoleptic fit as the traditional ones? This solution must keep the merits such as water-flush and pipe-transportation, since people are not willing to live in the middle ages. We think vacuum sanitary appliances and sewage system as shown in Figure 1 is capable of this Job.


Figure 1: The schematic of the decentralized sanitation system based on the vacuum collection techniques

Helped by the 10,000$ from the Bill & Melinda Gates’ Foundation, we built a demonstrate engineering located in Chentang Village, Changsu City, Jiangsu Province in China. The engineering contains 41 vacuum toilets, 750m-length pipeline, a pump-station with a 24m3 tank for storing the blackwater and has served for 23 families over 2 years. The total engineering cost is 430,000 RMBs (~66,000$), which is not more expensive than the traditional system. A prototype vacuum collector for colleting heavy kitchen wastewaters and wastes was also tested in laboratory. If it being integrated into the vacuum sewage system, 80% of the challenges as well as the costs of the domestic wastes disposal will be saved. Recently cooperated with the villager committee, a 0.5-hectre plantation that only uses organic fertilizer was put into operation near by the pump-station. It was estimated 1267 m3 tap water and 5840 KWh energy was saved per year, comparing with the traditional water flush sanitary and wastewater treatment.

Whether the vacuum sanitation appliances and sewage system can serve for thousands and millions of people is not determined by the engineering cost, since the manufacturing cost of the vacuum appliances and equipments is expected to cut off 2/3 when large-scale use. The vacuum sanitation mode means a novel industrial chain with five links: vacuum manufacturing, engineering service, system maintaining service, organic fertilizer produce and usage. How to chain the five links and get policy support is the main challenge we face to.

Goal(s):
to build up a more affordable and sustainable sanitation mode which bases principally on vacuum collection of domestic wastes (excrements and kitchen wastes) and reused them as fertilizer on the premise of satisfying the people’s demands on convenience and aesthetics.

Objectives (or activities or key research components): Build up a pilot scale verification system and fulfill the preliminary technical and economical feasibility study.

Research questions:
The technical and economical feasibility of the proposed sanitation mode.

Methodology:
(1) Build a demonstration plant;
(2) Operate and maintain the demonstration plant; collect the technical and economical parameters.

Results:
The pilot scale engineering was built at Chentang Village, in Changsu City, Jiangsu Province of China. It contains 41 vacuum toilets, 750m-length pipeline, a pump-station with a 24m3 tank for storing the blackwater. From June 19, 2011 when it being finished installation, the system has been serving for 23 families of villagers.

According to the operation record, from June 19, 2011 to March 20, 2012, the total used times of the vacuum toilets were automatically counted as 82746; the total volume of the black water collected was 70.5 m3, and the average flushing water used up by the vacuum toilets was 0.52 L per time; the total electric power consumption was 535.5KWh, averaged 31KWh per family per year or 0.006 KWh per time of flushing. Each toilet was averagely maintained 2 times in this period, mainly for clearing away clogging resulted by improper use. Most clogging happened in the first 4 months. With the villagers habiting to the correct usage of the vacuum toilet, the clogging happened less and less recently.

The black water was cleared away by a local fecal treatment plant, with the service price of 5.1 US$/m3. Accordingly, the running cost of the pilot system is 526.7 US$/a, equal to 0.015 US$ per villager per day, not including the equipment and pipe-line maintaining cost. The pilot system is expected to save 1267m3 tap water per year comparing with the traditional water flushing toilets. The local tap water price is 0.4 US$/m3, so the pilot system is expected to save ~506.8US$/a of water bill.

We paid 2 times of visit to all the families using the vacuum toilets, and the consensus was “very satisfactory”: clean, convenient, no uncomfortable odors, no noise and water-saving. Before the pilot system was built, some villagers had used traditional water flushing toilets, and others had used latrine pits or closestools. The local groundwater of the village is importable now because of contamination.

The village had ever planned to build a sequencing batch reactor (SBR) for treating the wastewater, which engineering budget was 58,155 US$, and the running cost was estimated as 1462 US$/a. Considering the engineering and running cost of the vacuum source separation technology is promising to be lowered in future, we think it is a truly aspirational “next generation” product that everyone will want to use – in wealthy areas as well as developing areas.


Figure 2 vacuum pipe-line layout of the pilot engineering


Figure 3 process layout of the pilot engineering

Future work:
The pilot plant only partly proved the feasibility of the proposed decentralized sanitation system mode as shown in Figure 1. There are still some challenges to close the loop of the sanitation mode shown in Figure 1. The main technical gaps lie in:
(1) Kitchen wastewater and wastes have not been collected into the vacuum system;
(2) Organic fertilizer manufacturing and utilizing are not realized.

Start and end date: April 20, 2011 through April 19, 2012

Grant type: Grand Challenges Explorations, Round 6 (GCE R6)

Funding for this research currently ongoing: Work on the project is continuing through a corporation plan including a company and the local government.

Research or implementation partners: Bureau of housing and urban-rural development of Changsu city (Jiangsu Province, China); Jiangsu town & village water technology service company.

Current state of affairs:
We have developed a prototype of vacuum washing basin for collecting kitchen wastewater and wastes (Figure 6).


Figure 6 the prototype of vacuum washing basin

As a continuing research plan, we are carrying out a field study aiming to use the black water as fertilizer on-site (see 2 photos below).


Figure 7 the onsite blackwater reuse system


Figure 8 the vegetables fertilized by the digested blackwater

Biggest successes so far:
Partly demonstrate the economical and technical feasibility of the vacuum source-separation sanitation mode in Chinese rural area.

Main challenges / frustration:
(1) the prejudices that think vacuum collection system being too expensive and difficult to operate and maintain.
(2) Lack of enough support from manufacturer. Maybe the biggest challenge is how to construct a closed loop of the industry and business: vacuum equipment manufacturing, system construction and running, organic fertilizer manufacture and organic agriculture. Such a closed loop can only be tested in a larger scale.

We welcome any comments and feedback, and expect to cooperate with people in the same camp to promote the usage of this sanitation mode.

Greetings,

Bin Fan


++++++++++++
Note by moderator (EvM): This is the 52nd grant to be introduced on the forum in this way, out of a total of 83 grants (an overview of all the 83 grants is available here: www.susana.org/lang-en/research/funded-b...nda-gates-foundation ).

+++++++++++

(The pdf file below contains the same information as this post)

Bin Fan
Professor

Research Center for Eco-environmental Sciences (RCEES), Chinese Academy of Sciences (CAS) ( www.rcees.ac.cn )

North research center for rural wastewater treatment technology, ministry of housing and urban-rural development of the people’s republic of China ( www.nrcrwtt.ac.cn/ )

Shuangqing Road 18, Haidian District, Beijing 100085
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Re: Low-cost decentralized sanitation system based on vacuum collection and reuse of excreta and kitchen waste (Chinese Academy of Sciences, China)

Dear Bin Fan,

Thanks a lot for this interesting project description! It is amazing how much you got down in just one year of grant duration. Your grant is by the way the second grant we have on this forum from China (see here for the other one: forum.susana.org/forum/categories/105-pr...ijiazhuang-uni-china ).

And I wonder if you saw a previous discussion we had here on the forum about vacuum sewer systems, maybe you find it interesting: forum.susana.org/forum/categories/39-mis...inking-vacuum-sewers

After reading your grant description and results, I have some easy questions for you:
  1. What is the company that supplied the vacuum toilets? Are they big in China? Have they sold many of them in China already?
  2. Can you explain a bit more what you meant with this sentence?

    The black water was cleared away by a local fecal treatment plant

    Do you mean treated? What kind of fecal treatment plant, which process does it use? How does it reach pathogen kill, or lets say how much pathogen kill did it reach?
  3. When you did the reuse experiments with blackwater, how do you ensure a certain level of hygienic safety? Which vegetables did you use?
For the last question maybe you find this discussion thread useful:
forum.susana.org/forum/categories/35-bio...fertilizer-bioslurry

What are your views about those Chinese technical codes for application of anaerobic digestate fertiliser which were discussed in that thread? Are they good?

Welcome to the forum!

Regards,
Elisabeth

Community manager and chief moderator of this forum via SEI project ( www.susana.org/en/resources/projects/details/127 )

Dr. Elisabeth von Muench
Independent consultant in Brisbane, Australia
This email address is being protected from spambots. You need JavaScript enabled to view it. Twitter: @EvMuench
Sanitation Wikipedia project leader: en.wikipedia.org/wiki/Wikipedia:WikiProject_Sanitation
E-mail me to get involved: This email address is being protected from spambots. You need JavaScript enabled to view it.
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  • fanbin
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  • a researcher in Research Center for Eco-environmental Sciences (RCEES), Chinese Academy of Sciences (CAS). My research interest is how to construct the managment and technology system of the chinese rural sanitation
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Re: Low-cost decentralized sanitation system based on vacuum collection and reuse of excreta and kitchen waste (Chinese Academy of Sciences, China)

I consider the vacuum collection (generally including sanitary appliances, pipe system and vacuum pump station) is the best way to realize the concept of Ecosan. Although the current municipal sewage system based on traditional water-flush has many drawbacks, it has two principal elements should be inherited in any future sanitation modes: (1) use water to clean the sanitary appliance (e.g. toilets) because water is almost the only medium being considered “clean”; (2) remove the ‘dirty’ matters (e.g. excreta) away from dwelling places at once and at a least distance outside seeing and olfaction, so pipeline is almost the exclusive choice. Fortunately, vacuum can satisfy the both with 1/10 water comparing with that used by the traditional water flush. The later is also obligatory because too much water content in the collected slurries would make resource reclamation impossible.
Does vacuum sewage system too expensive or too technical for running? This is a pseudo-preposition. Is the manufacturing and operating difficulty of a vacuum toilet, its pipeline or vacuum pump-station more than a car? Definitely nay! The modern industrial methods can make the vacuum sewage system as inexpensive as the traditional gravity system, if not more cheaper. The key question is how large quantity such a market is. However, scientists as well as entrepreneurs, the citizens and especially the politicians should work together, to promote realization of the new sanitation mode basing on integrated vacuum collection of domestic bio-wastes. The money spent in domestic wastewater and wastes treatment might be much higher than the vacuum system need.
The hope is in China I believe, though I know the most famous manufacturer is currently in Germany (Roediger), Switzerland (EVAC), America (AIRVAC)、Norway (JETS), and etc. There is a huge market of a 500,000,000-population in the next 2 or 3 decades in China, and the Chinese industrialists can make any industrial products the most cheap in the world. I do understand the urgent needs of sanitation of the people who live in other development areas, but sanitation affairs is 90% of the social and politics, and less than 10% of the science and technology!

Bin Fan
Professor

Research Center for Eco-environmental Sciences (RCEES), Chinese Academy of Sciences (CAS) ( www.rcees.ac.cn )

North research center for rural wastewater treatment technology, ministry of housing and urban-rural development of the people’s republic of China ( www.nrcrwtt.ac.cn/ )

Shuangqing Road 18, Haidian District, Beijing 100085
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  • fanbin
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Re: Low-cost decentralized sanitation system based on vacuum collection and reuse of excreta and kitchen waste (Chinese Academy of Sciences, China)

(re-post) Thanks a lot for your interesting in Chinese decentralized sanitation as well as my grant work. I will go visit the posts you suggested. The following is my answer to your questions:

Q1: Things become a little complex when entangled with commerce. However, supports from industry are very wanted. There are several companies being able to provide vacuum equipments in China, most of which come of mobile toilets manufacturing (e.g. those used in high railway). The biggest one can sell 10,000 sets of vacuum toilets per year, however less than 1/10 of which are currently related with municipal sanitation.

Q2: Before the trial farm field was built in the earlier of this year, we had to ask a local fecal treatment plant to provide paid service. The black water was delivered to the fecal treatment plant using a fecal suction truck. Most cities in china has such fecal treatment plants, which usually belong to municipal sanitation management organizations and are used to treat slums of the septic tanks and the fecal of the public toilets outside sewage pipelines. Pathogen is not the question after the fecal being treated in these treatment plants.

Q3: I understand your concerning about the hygienic safety. The black water is not direct contact with the above-ground parts of the vegetables, which include aubergine, tomato and rice. I and my team members have regaled on the aubergines and the tomatoes, and their tastes are very nice! We had to sell them in market because we can’t eat so much. Our Chinese seldom eat raw vegetables. However, hygienic safety has been listed in our research plan.

Bin Fan
Professor

Research Center for Eco-environmental Sciences (RCEES), Chinese Academy of Sciences (CAS) ( www.rcees.ac.cn )

North research center for rural wastewater treatment technology, ministry of housing and urban-rural development of the people’s republic of China ( www.nrcrwtt.ac.cn/ )

Shuangqing Road 18, Haidian District, Beijing 100085
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Re: Low-cost decentralized sanitation system based on vacuum collection and reuse of excreta and kitchen waste (Chinese Academy of Sciences, China)

Definitely a worthwhile line of research. Personally I have since then moved on and are not in research anymore (personal reasons), but I still think it would make a lot of sense to develop a really low cost vacuum sewer system.

I think the original designs from from around 1900 can still give a lot of insights regarding that (most of the original patents are publicly available online). They did for example use common appliances in the house and not those complex and expensive vacuum toilets.

Microbiologist & emergency WASH specialist
WASH news aggregator at: news.watsan.eu
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  • fanbin
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Re: Low-cost decentralized sanitation system based on vacuum collection and reuse of excreta and kitchen waste (Chinese Academy of Sciences, China)

The bottleneck of the vacuum ecosan application is not in technology but in the background government policies and its business model.
The technical system of the vacuum ecosan usually comprises 6 units: (1) indoor appliances, e.g. vacuum toilets and vacuum kitchen waste collectors, (2) outdoor pipelines, (3) vacuum pump-station, (4) onsite establishments for storing and pretreating the heavy waters (e.g.,black water, yellow water and so on), and sometimes even for onsite resource reclamation and reusing, (5) heavy water transferring and organic fertilizer preparing, and (6) agriculture or organic agriculture. From the view of technique, all the unit technology is almost ready at present, even if not so matured. The urgently wanted technique is to integrate the whole system and make every part run soundly, especially the indoor appliances. I don't think such questions cannot be overcome today though I know that the progress in technology is always needed.
Almost all the manufacturers of this field and some investors show high strong interesting in the vacuum ecosan mode. I dream to establish a close loop to serve for 100,000 populations. Only in this scale can each unit technique and the system integration be rounded, and especially the economical advantages, the environmental advantages and the social effects of the vacuum ecosan will be in full play! How much money is needed? Total cost is about 50 million dollars, however 5 million dollars is enough to start and promote such a program. The government, companies and the residents can assume 30, 50, 20 percent of the other investment need respectively.

Bin Fan
Professor

Research Center for Eco-environmental Sciences (RCEES), Chinese Academy of Sciences (CAS) ( www.rcees.ac.cn )

North research center for rural wastewater treatment technology, ministry of housing and urban-rural development of the people’s republic of China ( www.nrcrwtt.ac.cn/ )

Shuangqing Road 18, Haidian District, Beijing 100085
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Re: Low-cost decentralized sanitation system based on vacuum collection and reuse of excreta and kitchen waste (Chinese Academy of Sciences, China)

FYI, see a neutral and balanced science report on the issues involved from Canada: www.iwaponline.com/wst/06412/wst064122417.htm

Economic viability and critical influencing factors assessment of black water and grey water source-separation sanitation system
C. Thibodeau, F. Monette, M. Glaus and C. B. Laflamme

Département de génie de la construction, STEPPE-École de Technologie Supérieure, 1100, Notre-Dame Ouest, Montréal, Québec, Canada H3C 1K3 E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Laboratoire des technologies de l'énergie, Institut de recherche d'Hydro-Québec, 600 avenue de la Montagne, Shawinigan, Québec, Canada G9N 7N5

ABSTRACT

The black water and grey water source-separation sanitation system aims at efficient use of energy (biogas), water and nutrients but currently lacks evidence of economic viability to be considered a credible alternative to the conventional system. This study intends to demonstrate economic viability, identify main cost contributors and assess critical influencing factors. A technico-economic model was built based on a new neighbourhood in a Canadian context. Three implementation scales of source-separation system are defined: 500, 5,000 and 50,000 inhabitants. The results show that the source-separation system is 33% to 118% more costly than the conventional system, with the larger cost differential obtained by lower source-separation system implementation scales. A sensitivity analysis demonstrates that vacuum toilet flow reduction from 1.0 to 0.25 L/flush decreases source-separation system cost between 23 and 27%. It also shows that high resource costs can be beneficial or unfavourable to the source-separation system depending on whether the vacuum toilet flow is low or normal. Therefore, the future of this configuration of the source-separation system lies mainly in vacuum toilet flow reduction or the introduction of new efficient effluent volume reduction processes (e.g. reverse osmosis).

Keywords: anaerobic digestion; black and grey water; cost contributors; economic viability; source-separation sanitation system; vacuum toilets

Regards,
Detlef

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  • fanbin
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Re: Low-cost decentralized sanitation system based on vacuum collection and reuse of excreta and kitchen waste (Chinese Academy of Sciences, China)

Thanks a lot for recommending readings. It’s an excellence work, but the conclusions might be quite different if the application contexts are in China. There are huge amounts of villages (about 250,000,000) and small towns (about 20,000) which have long histories. Most of them haven’t built the minimum modern sewage systems because tap water and modern home sanitary appliances (e.g. shower and water-flush toilet) have just been spread for several years, and most of whose dwellers are not willing to migrate to a new settlement (e.g. of a 50,000 population). In such places decentralized systems, either using source separation mode or using traditional mode, are almost the exclusive choice. So in china, S-50,000 and C-50,000 must means 100 (even more) S-500 and C-500. Will the conclusions be the same as in Canada?
Additionally, except for some other presumptions might also be different between the two country, the model of the source-separation system (see Fig.1 in the article) is also questionable, at least some key technical links, e.g. grey water collection and treatment, can be more optimized. Furthermore, the assessment neglected the negative effects of the chemical fertilizer on environment and food, both of which are serious in China.
However, we thanks again for the authors. They give us many useful elicitations for our research plan. Please continue to pay attention to the vacuum source-separation in China as well as in our works.

Bin Fan
Professor

Research Center for Eco-environmental Sciences (RCEES), Chinese Academy of Sciences (CAS) ( www.rcees.ac.cn )

North research center for rural wastewater treatment technology, ministry of housing and urban-rural development of the people’s republic of China ( www.nrcrwtt.ac.cn/ )

Shuangqing Road 18, Haidian District, Beijing 100085
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