Dear Dennis,

Those points for tender are splendid. I'm sure, many users of this forum, who are working in sewerage works, will find those points useful. I think, many institutions opt for performance-based system. I have also noticed that some people use the term "result-oriented." I'm not sure whether it is same as performance-based.

Regards,

F H Mughal

Hi FH

Noted re "efficient"; but as you also noted, this is in relative terms.

And I would hazard a guess that in most cases where sanitation systems are non-existent or inadequate, "upgrading " to a modern, managed sewered system will result in a Karachi, rather than a Singapore:)

Insofar as what I would have done, if I had been tasked with upgrading the nightsoil system, that would of course have been dependent on the technologies and knowledge available at the time (which I acknowledged).

However, if it was now and Singapore had a similar autocratic leadership as they did then (oh wait they still do:) - I would have prepared an open tender process that dictated a performance based system (rather than a technical or technology specification) that required the below:

• * No (or minimal) mains water usage in system
• * No (or minimal) mains electricity usage in system
• * Minimum technology, minimum complexity
• * No (or minimal) infrastructure capital expenditure
• * Maximum capability to re-use collected waste product nutrients
• * Meets all state-required health management and disease prevention standards, including user contact with the waste etc
• * Simple self-managed collection, storage and processing system (that meets the above standards) and requires little training for users and product handlers
• * Enables small local entrepreneurs and service providers to manufacture, supply, install and service the system components
• * Has the ability to collect the processed nutrients, and extract maximum re-use value by on-selling to agriculture or other industry sectors
• * Includes Community and User Participation, both in system selection and in cost recovery of the system installation and deployment

Now FH, if I were to be presented with that tender, I would be building out a comprehensive end to end UDDT system myself; one where the technology is a vital, but actually fairly minor, part of the solution.

The more important parts are the service models for the various components of the system that are needed to extract maximum re-use value for the minimum input costs.

That's where we need to be clever, because if there is "gold in them thar hills" as it were:), the profit based, market driven thinkers in government and the private sector will always find a way !!

Dear Dennis,

There were 2 reasons for using the word “efficient.” One was the review of their (PUB – Singapore Water National Agency) website. It gives the impression that Singapore has efficient sewerage system.

Second, I meant that term in relative sense – relative in the sense that, we here in Karachi, a mega-city, have a pathetic sewerage system:

• Frequent sewage overflow from manholes;
• Broken sewer pipes, causing contamination of drinking water supply pipelines (which
themselves are in bad shape);
• It would take days for the concerned agency to respond to overflowing manholes
complaints;
• Out of 472 mgd (million gallons per day) of wastewater generated in Karachi, only 30 mgd
is treated, and that also, to a primary-level of treatment. The rest all goes to sea
untreated;
• Significant marine pollution due to raw wastewater discharges;
• Presence of heavy metals in fish;
• No treatment of industrial wastewaters. They flow in municipal sewer system, ultimately
ending in sea;
• Irrigation of vegetables with raw industrial wastewaters; and
• In-sensitization of the concerned agency to the sewerage problems.

When I look at Singapore’s experience, relative to the above Karachi problems, I consider Singapore to be far better-off, in the context of sanitation, relative to Karachi.

While I appreciate your views, I’m asking you a hypothetical question: if you had been incharge of Singapore’s sewerage system, what system would you have suggested?

Dear Anro,

Your point of large-scale availability of chemical fertilizers is interesting. Here, in Pakistan, the cost of the fertilizers was heavily subsidized – so was the cost of pesticides that enabled indiscriminate use of pesticides (which had, in turn, their share of problems). That graphical representation of yours says it all.

The drainage aspect, you have mentioned, is correct. Just the other day, it was mentioned that during recent heavy rains, Karachi was flooded as the stormwater channels are filled with solid waste. In addition, due to bad planning, buildings have been constructed on the right of way, making clean of stormwater drains almost impossible. And, as you rightly said, these drains also carry wastewater.

Regards,

F H Mughal

FH
There are several factors coming into play when cites have moves away from onsite to piped sewage systems. Ability to pay and access to water supply are obviously ones. But the availability of affordable chemical fertilizers was a major factor across the world’s developing cities. Fueling urban agriculture with the fertilizer from night soil systems and sludge changed quickly with the advent of ammonia production using the Haber-Bosch system. Phosphorus and potassium components quietly were exploited in turn to compliment this development. In deed this was the motor behind the green revolution, large scale farming and increased human population growth.

But other factors are coming into play when it comes to the poor cities in Africa and South Asia that continue to have onsite pit latrine and septic tank systems today. Ability to pay for retro-fitting of piped sewerage systems isn’t there. A high priority for cities that receive significant rainfall is drainage and such channels usually become the conveyor of sewage (and solid waste too). The economy of scale in densely populated urban centers will often look cheaper on paper than onsite collection systems but for poor cities that can remain a major challenge. That solid waste is so intimately linked to latrines and drainage systems increases the complexity. Finances surrounding urban biogas production from all the available organic sources can provide an incentive to rethink these systems making source separation cost effective. But then the benefits have to be made obvious to the city dwellers eg in terms of cleaner streets and public transport.
On site systems needn't be primitive and some of the most hygienic practices are seen in Japan.


More on the onsite household Johkasou wastewater treatment system www.jeces.or.jp/en/technology/index.html

FH

"Efficient ... let's discuss that"

I can only imagine that pre-conceived ideas of "modern" sanitation systems (i.e. western style sewered systems) and a lack of knowledge or availability of alternatives at the time, were behind Singapore's conversion from an (albeit manual and not very hygienic) human waste collection and partial re-use system, to a wasteful, water and capital intensive sewered system that just removes the pollution problem from the household and dumps it in the sea (even if it's minimally treated)

Singapore is known primarily for two thing's in its development - 1) is that it has no natural resources, as they are normally understood, and 2) that they use the intellectual capital of their people to drive progress

Therefore to waste the only "natural" resource you have (the nutrients from human waste) - and even worse,to waste a natural resource you have to buy, treat, pump, re-pump, process, re-treat (i.e. water) - is a case, I would suggest, where criminal negligence could be alleged

Do a search on Singapore NeWater to understand just how valuable water is to Singapore and you will see why I think negligence can be proved

Therefore FH, I will challenge your description of what Singapore has as an "efficient" system

Efficient how?

Because it "efficiently" takes the problem somewhere else?

But at a huge system cost, plus the opportunity cost of the wasted resources? How is that efficient?

So while I think it is wrong that sindh and so many places do not have an EFFECTIVE (note the emphasis) sanitation system, I would hope that experienced practitioners in this field do not promote inefficient, wasteful, "not really" solutions to more trusting communities, who are then only to find their solution either stops working, or sends the community bankrupt to keep it working and doesn't solve the problem anyway

And diverts an uncommon natural resource (water) down a pipe, while the family cannot get clean water for cooking

Particularly, practitioners should not burden communities with these types of systems, when there are innovative technologies and user models around that are much more effective, cost beneficial and environmentally safe than "modern" big infra solutions and approaches, which favour corporations and governments (because the money in big infra is in the construction, not the ongoing maintenance and operation) rather than users

Many of the people in need are "off the grid" in many areas of life - we should be offering "off grid " solutions as well

Night-Soil Bucket System of Singapore: What Triggered the Change?

Singapore had the night-soil bucket system, which was introduced in the 1890s by the municipal authorities. At that time, it was the common method of waste disposal in Singapore.

The night-soil bucket system was simple and all manual. The night-soil collectors would come to each house with empty buckets, carried on their shoulders using a pole that were exchanged for the buckets that were already filled. These buckets were then taken by the collectors to the collection centres.

The name – “night-soil” – came about because the work was done at night. The filled buckets were covered with soil to minimize the odors, hence the name “night-soil” (the name is a soft when compared with the term feces). Night-soil was disposed of in channels, while some of it was used as fertilizer.

I got some pictures of the night-soil bucket system from the internet. I tried to paste them here but was not successful. I’m, therefore, sending the images to Elisabeth. Hopefully, she would be able to paste the pictures.




The 100-year old night-soil bucket system came to end in 1987. Singapore has now efficient sewerage system.

The reason, I’m mentioning the Singapore’s night-soil bucket system here, is this: Almost a similar system exist in the rural areas in Sindh (Pakistan). It also exists in some areas of major towns of Sindh. The century-old system still continues to this day in Sindh.

Why it is so that, the night-soil bucket system was discontinued in Singapore in 1987, but, here in Sindh, it continues to this day? While I request my friends on this forum for their views, according to me, I think, it was mainly due to the initiatives of the concerned agency of Singapore (PUB – Singapore’s National Water Agency), that forced the change and gave way to most efficient present-day sewerage system.

F H Mughal

References

E-Source Sanitation News, published by Cor Dietvorst, 29 November 2014

Waste Water Management in Singapore, presentation by Dr. Ramasamy Meiyappan, Director, Public Utilities Board, Singapore, at ADBI's Workshop on Managing Regional Public Goods: Health, Labor Mobility, and Environment

Public Utilities Board (PUB), Singapore’s National Water Agency (www.pub.gov.sg/)

History of Used Water Management in Singapore (www.pub.gov.sg/about/historyfuture/Pages/UsedWater.aspx)