High Biosolids Transport Costs and Carbon Footprint

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All the UK utilities transport bio-solids from rural and smaller sites, and some of the larger sites by tankers.

Due to the process, the content is predominately water with some solids, possibly 2-3%.

The cost is enormous in £ and the carbon footprint is extremely high.

These costs of are readily available on the government site and run in multi-millions for them all. 

Why are they not doing more to reduce cost and carbon footprint? What is the biggest obstacle?

Taxonomy

7 Answers

  1. I was looking for the answer that said anaerobic digestion.  Could not find it anywhere.  Some microbiologists schooled before 1950 were taught archaea were anaerobic. Most scientists today having their degrees during 1960 forwards know they are aerobic. Their technical name is microaerophilic Not having a disurnable cell wall they have no attachment sites. Thereby not being capable of being a pathogen, or a toxin. Basic info for high school. College courses get into the quantum mechanics functionality of the archaea and its pinnacle point in all evolution.  

  2. Of course the anaerobic digestion of sewage sludge locally, with the benefit of energy recovery and local disposal of digestate and sludge cake is attractive environmentally. What is unattractive to the Water Utilities is the equipment capital cost, the risk to the Final Effluent quality and the ongoing operation, servicing and maintenance labour and management cost. The issues that arise are numerous:

    1. Dewatering of indigenous sludges on rural STWs to provide a good dry solids % feed stock for an efficient anaerobic digestion process will generate the return of high load liquors to the existing process. If there is no biological treatment headroom or an ammonia consent in place then the works may also need its treatment capacity upgrading to treat the additional load. Or liquors return balancing will also be needed. This applies to mobile dewatering as well, and with the dramatic increase in EA fines for consent failures the risk to the Water Utility is very high. Fines of £300,000 for a rural sub 5 l/s STW have been levied in the recent past.

    2. The land space available at many rural STWs will be constrained to build even micro size AD, CHP and liquor return balancing. Planning permissions will also need to be considered in respect to CHP noise (costly to mitigate) and also CHP emissions levels of NOX & SOX may need EA permitting. The physical area required for composting and the associated materials handling is also affected by these constraints.

    3. The ongoing operation of these distributed plants will need a reverse in the trend of reducing the workforce to drive the Business Plan efficiency submitted to OFWAT in the five year AMP cycle. AD and associated plant and equipment needs regular maintenance and service of the equipment and the process needs to be constantly monitored to ensure it meets the HACCP criteria pathogen reduction so that the waste if the right quality to be put on agricultural land.

    So, I believe the big picture is quite complex, and whilst I agree that the current inter-tankering practices are not the best for the environment, the solution sits outside of the current AMP cycle regulation of the Water Industry. By attempting to solve this in the current framework any Water Utility runs the risk of severely damaging itself by worsening performance in the areas measured by OFWAT. As a business sadly, your shareholders wouldn't see that as good management or governance. A degree of political imagination is required to enable a solution but unfortunately that is also something that is sadly lacking at the moment. The spreadsheet rules alas! 

     

     

  3. A potential solution is to use anaerobic digestion of raw sewage, to maximise energy recovery, as methane-rich biogas,  and minimise sludge production. This would be followed by aerobic treatment for polishing, before returing trhe purified water to the aquatic environment. However, the capital cost of this might be too high to be cost-effective with present technologies.

  4. An option would be to have utility owned or private mobile dewatering units for excess activated sludge for servicing smaller WWTP's. Some types have a pre-thickening function incorporated and can run directly from the return sludge flow. That way you concentrate to 18 - 20% DS and reduce the total weight and volume by a factor 7 to 10 already on site. If regulations allow, this dewatered sludge can be applied in local agriculture. Many farmers will pick it up for free. 

    (We were operating a WWTP where the operator would put his own small trailer below the decanter centrifuge outlet.)

  5.  If you would like you can set up composting operations on location using RNA microbes. RNA eliminates all odor, pathogens, toxic substances.  Either give away free to the farmers or sell it to locals for all purpose use.  Of course if you used the RNA microbes at the beginning of the process you would eliminate the need for chlorine, dumpsite, transport, drivers, trucks, gas and oil, wages, retirement, insurance. On top of this as the bioremediation processes the loose electrons can be collected and used as an energy source. Not to mention the waste water without waste is now potable drinking water. But I recall UK red tape causes modern technologies to wait about 50 years before implementation.

    2 Comments

    1.  Morning Mike:  Step into my office and let us see if we can get you up to speed.

      RNA  is the name given by the late world renown Dr Carl Oppenheimer. He was the "Father of modern microbiology". The name of the species is called Archaea.  They were the first life on earth and any other planet.  What people call Rna inside of a cell is billions of years removed from the original RNA. The common description of the process is still correct. Archaea do control all DNA coding.  In layman's terms they are the only microbes that has the genetic code to reduce organic compounds into their elemental state.

       You misunderstood that one statement. Allow me to explain.  When the waste in waste water has been biodegraded into its elemental form you are left with elements (not visible) and potable drinking.  All pathogens and toxic substances are eliminated.  Heavy metals are chelated into non toxic elements.  This technology has been used for the last 40 years. Monthly state lab report reveal "No pathogens found, and oxygen content increases by a factor of 3."  Currently this microbe and technology is being used for International oil spills, any and all chemical accidents in the US, pig slur pits, waste treatment systems, composting operations, lawn and garden care,, nursery, retail stores, and is the worlds leading probiotic.  Happy to share anything you might need to read or pictures. We hold most world records on crop nutritional density, size, and yield.  Thank you for your comments. Life is a learning process.  If you have a working knowledge of quantum mechanics please let me know. I will be able to explain the actual functions of the Archaea.  

    2. Hi Guy,

      What do you mean by "RNA microbes"?  "RNA" is normally the abbreviation for 'ribo nucleic acid', which is involved in e.g. transcribing DNA and translating it into RNA, for subsequent protein synthesis.

      Also, you cannot describe the product of composting as "waste water without waste" as it is certainly not suitable as "potable drinking water".

      Best wishes,

      Mike

  6. I'm in the US so I can't speak specifically about how the UK handles things, but from what I know the UK has a number of advanced (state of the art) solids treatment facilities, that pretreat sludge using thermal hydrolysis prior to anaerobic digestion. Anaerobic digestion is carbon negative, but building an advanced anaerobic digestion facility costs millions of dollars, and typically isn't financially feasible unless a facility is processing over 10 million gallons of wastewater per day. This could explain at least some of the trucking of sludge from smaller sites by tankers to larger sites. 

    Hope this helps.