Biogas toilets and carbon credits

Here’s a thought for IYS2008, prompted by my colleague at Leeds, Professor Ed Stentiford. In Nepal there’s the Biogas Support Program (project design document here) which is registered with the Clean Development Mechanism (CDM) of the United Nations Framework Convention on Climate Change (UNFCCC). Essentially just under 10,000 biogas plants (typically 4−10 m3) are fed with animal excreta and the biogas produced (equivalent to a total of 14.73 MW of electrical energy) is used for domestic cooking, lighting, heating, etc. The resulting certified emission reduction (CER) is estimated at just under 50,000 tonnes of CO2-equivalent per year (based on the emissions from the firewood and/or kerosene that would otherwise be used and taking into account methane leakage from the biogas plants and incomplete combustion during biogas use). As a result the Biogas Support Program can sell this annual carbon credit of 50,000 t CO2 and the current price is EUR 23 per t CO2-equivalent, so it’s worth quite a lot of money. OK, these biogas plants are fed with animal excreta, but they could be fed with a mixture of human and animal excreta, together with kitchen wastes. So biogas toilets could earn carbon credits and thus hard cash. Wouldn’t this be a useful starting point for rural sanitation promotion, at least in some countries or some parts of some countries? [For more info. see Carbon – Making the right choice for waste management in developing countries (Waste Management, 2008).]

EU sanitation policies and practices

I was invited by Women in Europe for a Common Future (WECF), a network of 80 environmental organizations in 30 European countries, to attend the ‘High-Level Policy Dialogue on EU Sanitation Policies and Practices in IYS2008’ in Brussels on 29 January. Water and Sanitation is one of five WECF working groups and its work is mainly centred on the WatSan needs of millions of people in eastern Europe (details here) − hence this meeting in Brussels which had as its objective (in the words the organizers) “to raise awareness and stimulate political will within the European Union on the safe management of wastewater and excreta, a challenge worldwide, including in Europe”. Amazingly “in some of the EU member states still almost 40% of the population do not have access to safe sanitation” and “GWP estimates that a total of 20 million Europeans depend on unsatisfactory sanitary installations such as pit latrines, soak away pits and drains”. The presentations by several ‘high and mighty’ representatives of governments and the European Community showed that they knew little about low-cost sanitation, and this was also generally true of most of those attending the meeting, although ‘dry sanitation’ was constantly mentioned but seemed to refer only to EcoSan. Simplified sewerage appeared to be totally unknown − yet Bulgaria, for example, has plans to sewer many of its smaller communities. Cost is, of course, a major concern, as is political will at both national and EU levels − so there’s a real need for decision-makers to understand what low-cost sanitation systems are really applicable at scale in EU member states with a sanitation crisis. And then this knowledge has to reach municipal level. Quite a challenge!

UK Community of Sanitation Practitioners

I’ve just spent the day at WEDC, University of Loughborough, at the launch meeting of the new Community of Sanitation Practitioners − a UK contribution to IYS2008, but also to find ways of encouraging young professionals to enter and prosper in the field of sanitation (but effectively water and sanitation) in developing countries. We didn’t cover much on the latter point, but we heard from three very good practitioners and researchers who gave presentations on slum sanitation, community-led total sanitation (info. here), and sanitation demand at the household level in rural areas (info. here). Kibera in Nairobi, Africa’s largest slum, was the focus of the talk on slum sanitation, and what was really interesting here was the installation of a SPARC-style community-managed sanitation block (info. here) − so this Indian solution for slum sanitation can work in Africa, which is very good to know. I look forward to the next meeting in May.

Simplified/condominial sewerage − 2

My colleague Professor Cícero de Andrade Neto, of the Universidade Federal do Rio Grande do Norte in northeast Brazil, has kindly sent me up-to-date info. on monthly charges for simplified sewerage. In Rio Grande do Norte (where simplified sewerage was first installed in Natal, the state capital, in the early 1980s) the minimum water tariff is currently BRL 18.10 (USD 10.00) per month and the surcharge for simplified sewerage 35% (it’s 70% for conventional sewerage), so the monthly charge for simplified sewerage is BRL 6.34 (USD 3.50). The minimum wage (what Brazilians call ‘one minimum salary’) is BRL 380 (USD 210), thus the charge for simplified sewerage is only 1.7% of the minimum wage − clearly affordable. For poor households in ‘popular’ housing the charges are lower as they pay a reduced minimum water tariff of BRL 11.51 (USD 6.36), and for very poor households in ‘social’ housing it’s even cheaper: they pay a minimum water tariff of only BRL 3.65 (USD 2.02). [Exchange rate on 23 January from oanda.com]

Good News for IYS2008!

I’ve been searching the literature for papers giving benefit-cost ratios for sanitation (a benefit-cost ratio of x means that every USD 1 invested in providing improved/adequate sanitation produces economic benefits to society of USD x − if x >1, it’s a good investment). Guy Hutton, of the Swiss Tropical Institute (now with WSP East Asia & the Pacific in Phnom Penh), very kindly sent me two excellent reports: Meeting the Water and Sanitation Millennium Development Goal (ERM for DFID, 2005 − not available on-line) and Economic and Health Effects of Increasing Coverage of Low-Cost Water and Sanitation Interventions (a background paper for HDR 2006 by WHO & STI). The first shows that in the 12 countries studied (Ethiopia, Ghana, Nigeria, Uganda, South Africa, Tanzania, Zambia, Bangladesh, China, India, Cambodia and Sri Lanka) the benefit-cost ratios for sanitation investments were in the range 5−23, depending on the country. The second derived benefit-cost ratios for water investments, sanitation investments, and water and sanitation investments, for 15 selected countries (none of which is currently on track to meet the MDG water target and/or sanitation target) for meeting the MDG targets and those for universal coverage (i.e., water and/or sanitation for everyone), as follows:
So the benefit-cost ratios for sanitation investments to meet the MDG sanitation target are 1.6−13, and about the same for those to meet the universal coverage target, and − most importantly − they’re all higher than the corresponding benefit-cost ratio for water. Information like this is very useful to persuade Ministries of Finance/Economic Affairs to provide funds for sanitation. So it’s really excellent to have all this in IYS2008.

Urban EcoSan: what are the costs?

The EcoSanRes programme at the Stockholm Environment Institute says in its Background and vision that its “overall goal is to create a global confidence in ecological sanitation as a trustworthy, affordable and sustainable alternative for design of sanitation systems”. To me the key word here is “affordable”. The EcoSanRes programme is the main European partner in a really ambitious urban EcoSan project in Dongsheng in northern China − details here and video here. However, no indication of costs! Yet someone in Sweden or China must know what the costs are, so why haven’t they been published? We’re promised (here) that, “once in full operation in late 2007 … the performance of the ecosan system will be evaluated and economic and environmental analyses for comparisons with conventional practices will be made”. There’s been a lot of interest in this project, so let’s hope the costs will be made available in IYS2008, and also that any cost comparison includes simplified sewerage!

Sanitation practice: good and poor

OK, we’re in IYS2008 and we’ve hundreds of millions of people needing adequate sanitation by 31 December 2015 (if, that is, we’re serious about meeting the MDG sanitation target). So what sanitation systems are we likely to be using? In rural areas it’s going to be an on-site system such as single-pit VIP latrines, single-pit pour-flush toilets, eThekwini latrines (urine-diverting alternating twin-vault ventilated improved vault latrines, or UD-VIVs for short), biogas toilets (pour-flush toilets discharging into an anaerobic digester with biogas use for cooking or lighting; usually some animal excreta are added to the digester as well), or a simple EcoSan system (an arborloo or a fossa alterna) − all these need a greywater system (a simple soakaway, or using the greywater to irrigate a ‘greywater garden’). Simplified sewerage (with simple treatment in a facultative pond) has been used in villages in the northeastern Brazilian state of Ceará (details here). You have to work with the beneficiary communities so they end up with a system which they’ll like and can afford, which they’ll operate and maintain properly, and which they’ll regard as their own (and not something foisted on them by government). What about periurban areas? For a start we won’t be using conventional sewerage or multiple-sewer EcoSan systems (both much too expensive). If the population density is low enough, then systems like alternating twin-pit VIPs and PFs and eThekwini latrines (all with a greywater system) would be applicable; but you have to remember that simplified sewerage becomes cheaper above a certain population density (in Natal in northeast Brazil this was only 160 persons per ha). If simplified sewerage is too expensive then (given that on-site systems are more expensive) probably the only solution is SPARC-style community-managed sanitation blocks (SPARC is the Society for the Promotion of Area Resource Centres, an Indian NGO) − read Community-designed, built and managed toilet blocks in Indian cities (Environment & Urbanization, 2003) and watch the video. These sanitation blocks are built, managed and owned by the community; they are only used by the community members, so they are in no sense ‘public’ facilities. Further info. on on-site systems here, simplified sewerage here, communal sanitation here and on good and poor sanitation practice here.

EcoSan in periurban areas?

The Stockholm Environment Institute (a very well regarded institute), in its 2005 report Sustainable pathways to attain the Millennium Development Goals − Assessing the role of water, energy and sanitation (Table 4-5, p. 50), reports extraordinarily high costs for urban EcoSan systems (in contrast rural EcoSan costs seem affordable). They range from USD 350 per household in sub-Saharan Africa to USD 1200 per household in West Asia. Without subsidies, who’s likely to be able to afford these costs? Not the periurban poor, that’s for sure. In the paper EU demonstration project for separate discharge and treatment of urine, faeces and greywater – Part II: Cost comparison of different sanitation systems (Water Science and Technology, 2007), basically a cost comparison between urban EcoSan and conventional sewerage, German EcoSan researchers reported that “the multiple sewer systems resulting from the separation of urine, brown [and] greywater are responsible for higher investment costs”. So urban EcoSan costs more than conventional sewerage, at least in this demonstration project in Germany. Personally I can’t imagine it would be much different in developing countries. Multiple sewer systems? Three actually: one for ‘yellow water’ (urine), one for ‘brown water’ (faeces + flush water), and one for ‘greywater’ (all non-toilet wastewater). No wonder it’s more expensive! In developing countries we know that simplified sewerage is much cheaper than conventional sewerage, so it has to be a whole lot cheaper than urban EcoSan with its multiple sewers. In any case simplified sewerage + treatment in waste stabilization ponds (including biogas recovery from anaerobic ponds) + effluent use in aquaculture and/or agriculture is as ‘ecological’ as EcoSan. My view is we should only consider EcoSan in rural areas − horses for courses!

A worthy cause for IYS2008: Stop manual scavenging

India has many tens of millions of Dalits, the so-called ‘untouchables’ or lowest of the low, who do all the dirty work other Indians don’t and won’t do − cleaning other people’s toilets (“manual scavenging”), for example, and removing sewer blockages (several million Dalits do these demeaning jobs every day). It’s absolutely horrific − read the very graphic descriptions in a Special Report in Tehelka magazine (8 Dec. 2007) and in India’s Shame in Frontline magazine (22 Sept. 2006), and watch the 30-minute video Manual scavengers, Victims of caste pyramid (CNN-IBN, 22 July 2007). Of course, nothing like this is meant to happen − the Indian Constitution forbids it − but it does. So wouldn’t getting rid of the wholly inhuman work of manual scavenging be a truly excellent thing for the Government of India and all the state governments to do, or at the very least really start to do, in IYS2008? What a fantastic contribution that would be! [There are many organizations fighting for the Dalits − examples are the Indian National Campaign on Dalit Human Rights (see what it says about manual scavenging), the International Dalit Solidarity Network and Dalit Network Netherlands.]

Periurban sanitation planning

What’s the role of “the community” in periurban sanitation planning? What does “community participation” mean in periurban sanitation practice? But first let’s suppose, just suppose, that conventional sewerage were affordable in poor periurban areas. What would happen then? Well, for a start, there would be little or no discussion – the local water and sewerage agency would simply install conventional sewerage. (This is more or less what was done in the UK, Europe and the USA during 1850−1950.) But to ensure a good rate of connection and proper operation, it would interact with the beneficiary communities to inform them what was going to happen, how they should operate the system (no garbage disposal!), what to do when problems occurred, how much the monthly water bill would increase, and offer low-cost loans (to be repaid through the monthly water bill) to install household toilets – and, of course, no connection fees as these are really anti-poor. Does simplified sewerage, generally the first choice for periurban sanitation, need to be any different? My answer to this question is ‘No’. Of course, the situation is different in rural areas, so more complex forms of community participation are usually necessary (and there are plenty to choose from), but in periurban areas, where high population densities in the absence of adequate sanitation soon lead to a high level of faecal disorder, disease and death, people (especially women and girls) really want affordable sanitation − they know that, as the South Africans say, Water may be Life but Sanitation is Dignity. For those of you who really want more then Section 3 of Effective Strategic Planning for Urban Sanitation Services: Fundamentals of Good Practice (GHK Training & Research, 2002) gives an excellent introduction to the topic.

Rural sanitation: eThekwini latrines

I’m personally more interested in periurban sanitation, but of course rural sanitation is very important as well. Some of the options are pretty well known − VIP latrines and pour-flush toilets, for example. Then there are the various ecological sanitation variants such as the Arborloo and the Fossa Alterna (I may not think much of EcoSan in periurban areas but it’s certainly more than OK in rural areas if that what the users want − if you’re really interested in rural EcoSan, then read the excellent Toilets that make compost: Low-cost, sanitary toilets that produce valuable compost for crops in an African context by Dr Peter Morgan). But there’s another option for rural sanitation that is less well known and this is the “urine-diverting alternating twin-vault ventilated improved vault latrine” − which is more than a mouthful, so I abbreviate it to “UD VIV latrine” or even “eThekwini latrine” after the place in South Africa where it was developed. An excellent description is given in eThekwini's Water & Sanitation Programme (this also includes the highly innovative “ground tank” water supply system developed by eThekwini Water) published by WIN-SA. These latrines are wholly above ground (so they have vaults not pits) but otherwise they operate in rather the same way as alternating twin-pit VIP latrines, except that urine is diverted away from the vault to an adjacent soakaway − so the squat-pan or pedestal seat unit is a standard EcoSan urine-diverting one (but this is the only similarity between eThekwini latrines and EcoSan systems); in these latrines in eThekwini there’s also a urinal which discharges to the soakaway − but this is an optional feature. The point of urine diversion in these latrines is to prevent the vault contents becoming too wet, so that they can dehydrate properly (often some ash or soil is added to the vault in use to aid this process). Then, once a year the owner empties the vault not in use using a long-handled shovel and buries what s/he takes out (it’s much easier to do this than empty the pit of a VIP latrine), and then the vault just emptied is put into use (and the other one starts its 12 months of dehydration and pathogen die-off). And, of course, what comes out of the vault isn’t remotely like what went in! [Actually it’s quite easy to convert these eThekwini latrines to ‘proper’ EcoSan systems if that’s what the users want: the diverted urine is used as a fertilizer, not ‘wasted’ in a soakaway; the dehydrated vault contents are used as a compost/soil conditioner; and any greywater used for irrigation.]

Simplified/condominial sewerage − 1

Simplified/condominial sewerage was first installed in Rocas, a low-income area in the city of Natal in northeast Brazil, in 1982. The installation cost per household was USD 325. CAERN (the local state water and sewerage company) borrowed the money for the whole scheme from the then National Housing Bank and calculated that it could pay back this loan over the 30-year term by surcharging the monthly water bill by only 40% (rather than the usual 100% for households, obviously not poor households, served by conventional sewerage). At that time each household in Rocas had a yard-tap level of water supply service, which was not metered, for which it paid the so-called minimum tariff which was then USD 3.75 per month. So the simplified sewerage charge was (0.4 × 3.75) − i.e., only USD 1.50 per month, which was clearly affordable. Similar installation costs were found in Brasília and the Federal District (1998 costs: USD 170−340, vs. around USD 500−1500 for conventional sewerage). In the mining town of Parauapebas in the state of Pará in north Brazil the cost in 1997 was only USD 56, vs. USD 94 for conventional sewerage. Three other important points are (i) in Natal simplified sewerage was found to be cheaper than on-site sanitation (pour-flush toilets and leach pits) when the population density was above 160 persons per hectare (which is not especially high); (ii) the local water and sewerage agency can accept the system simply because it is sewerage (generally it won’t have anything to do with on-site systems, regarding these to be the responsibility of the municipal environmental health office); and (iii) the periurban residents commonly like it because it is very similar to what the rich have (actually in Brasília rich areas are also served with simplified sewerage). The report The Experience of Condominial Water and Sewerage Systems in Brazil written by José Carlos Melo (who developed the basic concept and has designed many systems including the first one in Rocas) is well worth reading. So, in high-density periurban areas simplified sewerage is almost always the cheapest and the best (certainly, a very good) form of sanitation. Why would you want to choose anything else? [Well, you might if you were an ‘EcoSanologist’, but more on periurban EcoSan later …]

‘Small flows flow better in small pipes’

Quite an important hydraulic dictum! So why do many (most?) sewerage design engineers think 100 mm is too small a diameter for sanitary sewers? Simplified sewerage, also known as condominial sewerage, uses a minimum sewer diameter of 100 mm, but whenever I mention this outside Latin America, people just laugh and say ‘Oh no, it just can’t work, it’ll clog very quickly’. Why do engineers (who understand the fundamentals of fluid mechanics) think like this? I’m not sure really, but I suspect it’s just sloppy thinking, or rather non-thinking. They’ll say they’re just following their national sewerage design code − but why does the code say this and why don’t thinking engineers (yes, there are some out there) try to get the code changed? After all, the Brazilians changed their code way back in 1986!

[More on simplified/condominial sewerage soon …]

'Improved' or 'Adequate'?

We all know that some 2.6 billion people lack access to a toilet or a latrine. Even if you do know this horrific fact, it still shocks − here we are in 2008 and this vast number of people have nowhere decent “to go”. Just appalling. Actually, it’s probably even worse than this. WHO and UNICEF, and their Joint Monitoring Programme, use the term ‘improved’ sanitation, which they take to mean connection to a sewer or septic tank or having a pour-flush toilet or a simple or a ventilated improved pit latrine. A healthy spanner was put in the works by UN-Habitat in its 2003 report ‘Water and sanitation in the world's cities: Local action for global goals’ by claiming that ‘improved’ sanitation was not necessarily ‘adequate’ sanitation, with adequacy of provision being defined as “good quality provision in the home (eg, the toilet), the immediate surrounds (eg, connection to a sewer, pit or septic tank that does not contaminate the groundwater or other people’s water) and the neighbourhood (provision to ensure no human contact with excreta and to make sure that wastewater is removed safely)”. The resulting figures for those without access to adequate sanitation are much, much greater than for those lacking access to improved sanitation, at least in urban/periurban areas. In the year 2000 in Africa, for example, there were reckoned to be around 46 million people without improved sanitation in urban/periurban areas, but some 150−180 millions without adequate sanitation; in Asia the figures are 297 millions vs. 600−800 millions, and in Latin America and the Caribbean 51 millions vs. 100−150 millions. This means that, even if we achieve the sanitation target of the Millennium Development Goals and/or the WHO/UNICEF goal of universal coverage by 2025, many hundreds of millions of people will still not have adequate sanitation. We’ve certainly got our work cut out! And then remember that almost all population growth in the world over the next 50 years or so will be in urban/periurban areas of developing countries!

IYS 2008

Well, here we are in the International Year of Sanitation. This blog will give some fairly maverick views on the topic, promote good ideas, and 'expose' those that are not so good. Watch this space!