Dear @Antonio, multi-objective optimization is used in sewer system rehabilitation. Different algorithms were applied. I am aware of one model developed by Serbian researcher Dragan Savic and his colleagues.  Multi-Objective Genetic Algorithm was applied. It is very good conference paper. I have attached a copy of.

The objective function in the optimisation model is the cost minimisation, number of defects...

Stochastic Multiobjective Optimization Models can also be applied...!

http://web.sbe.hw.ac.uk/staffprofiles/bdgsa/11th_International_Conference_on_Urban_Drainage_CD/ICUD08/pdfs/565.pdf

Dear @Antonio, multi-objective optimization is used in sewer system rehabilitation. Different algorithms were applied. I am aware of one model developed by Serbian researcher Dragan Savic and his colleagues.  Multi-Objective Genetic Algorithm was applied. It is very good conference paper. I have attached a copy of.

The objective function in the optimisation model is the cost minimisation, number of defects...

Stochastic Multiobjective Optimization Models can also be applied...!

http://web.sbe.hw.ac.uk/staffprofiles/bdgsa/11th_International_Conference_on_Urban_Drainage_CD/ICUD08/pdfs/565.pdf

In Planning stage

The Plan optimizes the location of land uses based upon an analysis of the proximity to Metro, relationship to major roadways, adjacency to parks and open space, and distance from noise and other environmental hazards. Water, sanitary sewer, and storm water systems are generally in place to serve; however due to aging, need to be relocated with the pattern of ownership and the proposed new developments

https://www.alexandriava.gov/uploadedFiles/planning/info/eisenhowereast-carlyle/EESAP.pdf

The use of “Knee of the Curve” analysis is for reasonable assumption that the assessment and/or the implementation of rehabilitation measures can be directed for the elimination of Non-FOG Spills and also the length of sewers in each Area.

http://dekalbwatershed.com/PDF/PASARP.pdf

Thanks for your excellent contribution, Dear Ljubomir. I began study the research area of cost-benefit analysis of sewer rehabilitation in the decade of 90 (particularly when I was in Exeter University), and I supervised a Master Thesis in sewer rehabilitation, in my Department, that was concluded in 2008. In the sequence of that work, we wrote a conference paper (in Portuguese) about cost-benefit analysis in sewer rehabilitation that was presented in an International Congress in 2011 (available in the RG link below). I found another research paper of Ward and Savic (2013) in this area, but in fact I had not accessed before to these two conference papers that you mentioned, and that, at a first glance, look also very promising. The optimization in this area looks yet perhaps a little bit in an embryonic stage. I am working on this area, so any reference will be extremely well come. Thanks again.

Conference Paper UMA ABORDAGEM GENÉRICA SIMPLES CUSTO-BENEFÍCIO NA REABILITAÇ...

I do not realize why Dragan Savic has not joined this fine thread . Let me bring his link to publications here. He deserves.

https://www.researchgate.net/profile/Dragan_Savic3/contributions

Dear Krishnan: Thanks for your references that effectively point to the phases and important aspects related with sewer systems management. A Project (Planning, Construction and Operation) Phase, with several project stages of a new system or of an expansion of a partially existing network (summarily: conception, design, construction, and operation and maintenance); and a Rehabilitation Phase for old systems (or eventually networks badly constructed?), with basically three phases (according to US EPA Handbook of 1991 entitled “Sewer System Infrastructure Analysis and Rehabilitation”: “Preliminary Survey, Sewer System Analysis, and Rehabilitation”).

In fact, the first priority all over the world has been traditionally the construction of Public Infrastructures, whenever they do not exist, but the good performance of the existing systems is also fundamental in order to guaranty the public health and the preservation of the natural resources.

Thanks, Dear Friend Ljubomir. In fact, Professor Dragan Savic published several papers in this research area of multi-optimization of sewer rehabilitation as you have shown. Perhaps? he (or eventually even any of his co-authors?) may lose a little of his precious time, helping us to develop and maintain at the highest level (as always you do) with his expertise the scientific quality of this discussion.

I have  report in spanish on how to select treatment plants for pre-feasibility studies. If you think this can help you, I can try to put it as one of my publications. In another publication I suggest more than 10 MCDM methods. Check also the author: Mario Tabucanon from AIT.  Yours,   ricardo

Thanks very much for your contribution and references in Multiple-Criteria Decision Analysis, Dear Ricardo (including Professor Mario Tabucanon in Industrial Engineering). I am not sure if I understood when you spoke about Wastewater Treatment Plants. Are you speaking about Optimal Rehabilitation of WWTP? Of course I am interested in knowing any relevant data that you have or that has been developed.

For the Project Phase, I obtained, in the decade of 90, the optimal location of the wastewater treatment plants, or discharges, pumping systems, pipe diameters and installation depths, in three-dimensional optimization of sanitary sewer systems and storm water drainage systems using several optimization techniques, such as a Genetic Algorithm, Simulated Annealing and a multilevel Dynamic Programming model. Later I developed an exponential algorithm for systematic enumeration of all feasible layouts of the systems, that is, all feasible forests (each drainage system in plant is a tree where the WWTP is the root) starting from an undirected planar graph. The purpose was minimizing the global cost of the systems for the design criteria after its complete modeling.

Dear Antonio,

a lot of optimisation algorithms are developed in this field indeed (see earlier answers), however I strongly doubt the value of this type of approach since in practise it turns out that sewer managers have to make decisions in a complex (political) environment. Wouter van Riel published some articles on the topic of decision making in sewer rehabilitation in which this is explained. See e.g. Urban Water Journal 02/2015; DOI:10.1080/1573062X.2015.1011667 and Urban Water Journal 07/2014; 11(6). DOI:10.1080/1573062X.2014.904903 and the files attached. Furthermore the quality of the information (normally cctv footage based info) used in these high end optimisation algorithms is questionable. (see Structure and Infrastructure Engineering 02/2011; 2011(3-iFirst article). DOI:10.1080/15732479.2010.541265). In my view the main problem is sewer asset management is obtaining the correct information and to acknowledge the fact that decisions are made in a complex environment, in doing so I feel you get better decisions than using some algorithm.

best regards

Francois Clemens

Dear Francois: thanks very much for your answer and for the pertinent references. I took a glance on the papers and in fact they present very important aspects on decision making of sewer rehabilitation, particularly from a practical point of view.  Some conceptual issues that the papers (and you) discuss are really very interesting and would lead us for a long, long, long and interesting conversation. Many Civil Engineers are managers or become managers as the profession progresses and necessarily every civil works must functioning (and normally the constructions/productions really work) properly. Optimization, as Engineering, is a trustable area of knowledge. Engineers always used cost-benefit analysis in most of their engineering projects (even before the advent of the current computers and mathematical programming techniques, although many times intuitively or empirically). In this case of sewer rehabilitation optimization, the major difficulties seem to be the modelling of all aspects involved in the engineering decision.

Hi Antonio,

indeed, I've doing a lot of optimisation over the years myself (and still do), however the most important issue in case of sewer systems, in my view is to fully understand the deterioration mechanisms and find manners to obtain information on the current status of objects and systems. I suggest we organise a skype call in the coming week to discuss these matters, and maybe identify area in which we can work together.

enjoy your weekend

Francois

P.S. my skype name is francois.clemens

Thanks Francois for your answer. I agree with you. Deterioration mechanisms, infiltrations and structural condition in sewer networks may be very important issues, particularly in Netherlands (Holland or Royaume des Pays-Bas), due to frequent high ground water levels (?). In my country, municipal authorities are making an intensive effort to obtain the necessary information for evaluation the current state of our existing sewerage systems.

Dear All, I am very glad to share the most recent work developed in this research area by António Freire Diogo (myself), Luís Tiago Barros, Joana Santos, and Jorge Santos Temido– “An effective and comprehensive model for optimal rehabilitation of separate sanitary sewer Systems”. The Abstract is on RG and the Full Text is Available in the link

https://authors.elsevier.com/a/1VgqbB8cccnP3

Article An effective and comprehensive model for optimal rehabilitat...

Intersting!

Thank you for the link to your recent works, dear António. This is not only a very interesting subject to study. Also a quite useful tool for the more healthy development of human societies.

The most recent (Aug.2017, Pgs97-118) issue of National Geographic offers an amazing aricle on the distribution, costs and development of sanitary distribution around the World. 

Dear @Antonio, congratulation for your new article. Have you seen this reference:

Multiobjective Optimal Design of Sewerage Rehabilitation by Using the Nondominated Sorting Genetic Algorithm-II

https://search.proquest.com/openview/aca84e7cf5570d9ec31e7d5c752f14fd/1?pq-origsite=gscholar&cbl=54174

Thanks for introducing a new reference in this discussion that in fact I did not know, Dear good friend Ljubomir. However, previous works of two of these authors are also mentioned in our paper. Perhaps you can see the corresponding paragraphs and also what is written about Genetic algorithms in our paper.   

I have been invited for revising in Journals of Water Resources, but never in multi-objective optimization, at least until now … I never published any paper in such journals. Who knows if I will not publish there in the future?

For me it's impossible to answer the specific question.  However, based on your particular case, constraints (e.g. like backwater effects, control points) you come up with the System Constraints. I have published in these journals since the early 80s.

Thanks for your answer, and, according to your words, congratulations for your success in publishing in Water Resources Journals, Dear Carlos.My scientific area is “Hydraulics, Water Resources and Environment” and is very wide. Most colleagues and/or peers think that my scientific works have been more related with Hydraulics and Environment and not so much with Water Resources, and naturally that I have to respect their opinion. However, when looking to the papers published in these journals and the invitations to revise, this argument seems inconsistent. For a better understanding, see the RG question I performed some time ago.  

Nevertheless, I am very happy and satisfied in researching and publishing in Hydraulics, Environment and related areas, wonderful areas with wonderful persons without ghosts.

https://www.researchgate.net/post/How_should_a_researcher_deal_with_evidence_that_goes_against_the_main_stream_of_the_established_knowledge

Hi,

The main concern is to minimize cost and improve each pipeline condition. We at Concordia University, Construction Automation Lab, have developed robust models in this regard. You can take a look at Khaled Shahata Phd thesis in 2013 (concordia university). In case you are interested in WWTP, you can refer to Altayeb Qasem thesis and papers. He has developed a condition assessment model and life-cycle costing.

Also, my PhD topic is extensively related to sewers. If you need additional info, we can discuss.