I think anaerobic fluidized bed reactor

It seems a young landfill site with a very high COD. In that case, the biodiegradability is normally quite good although you don't show BOD. You can think about staring with UASB which can be followed with an aerobic MBR to further decrease BOD, TN. Sometimes, RO is used as a final step to ensure an effluent of high quality.

Thanks Mahmoud Abdel daiem and Yongjun Zhang for your advices

If you are treating leachate water you may consider returning this leachate water back into the landfill using it as an irrigation means for fast growing vegetation (e.g. poplar trees). These trees will evaporate a great deal of water, while the COD will have more time to be degraded … A win-win situation!

First, anaerobic bacteria are much sensitive to the inorganics.. i don't know what kind of a landfill site you have.. but if you have mixed municipal waste in the site.. it means you have many inorganics such as heavy metals.. that is not good for anaerobic treatment!

Recirculation is not good if we are talking about Isfehan, it will freeze at the top of the waste or soil during the winter months and will clog the system.. You need to build a reservoir to collect the leachate during the winter months (approx. 7500 m3) and recirculate it to the waste during spring, summer and may be fall months..

But, If you have enough money, I advice you to get a reverse osmosis system for an exact solution..:)

Thanks Boris Kompare and Gorkem Akinci for your advices.

This leachate produced by a composting site and washing recyclable wastes.

Therefore we can't recirculation it. we have some heavy metals in this leachate then we can't use this for irrigation.

The interesting coincidence is; i studied municipal waste composting leachate treatment during my master thesis.. at that time (1992-1993) i only operated some aerobic reactors.. even though the treatment efficiency was not over 70%, fed-batch aerobic treatment was the best.. the salt content inhibited the bacteria rather than heavy metal concentration.. because the HMs tend to be bounded by the organic matter and are not expected to leach during composting(not the same in a landfill).. I have a question at that moment.. how come you have that much of leachate (40 m3 a day) ?? Probably the composting site is not covered by a roof, or the amount of daily waste was too much.. If the site is not covered, a steel constructed roof can be your solution to minimize the leachate..

one of the best solution is to circulate back to the land fill to enhance the biodegradability inside the landfill it self. Due to the young leachate biodegradability, Aerobic reactor will be efficient. However post treatment is strongly required if you want to meet the standard discharge limit.

I cannot agree that recirculation is a good method. It is not sustainable. What about salinity?

Thanks Mohammed Bashir for your idea.

As I mentioned prior, we can't recirculate leachate

I checked the precipitation in Isfahan, the monthly max. is 21 mm in December.. If we accept that all of it rains in one day, you must be having a composting area of less than 2000 m2. Is that right?

Dear Mr. Mahdieh,

First I would recommend you to characterize the leachate biodegradability (BOD/COD).

First I would recommend you to characterize the leachate biodegradability (BOD/COD).

Antonio Calos Teixeira: BOD/COD ratio is approximately 0.25

Dear Dr. Akinci,

This is right.

Truly you will require a series of techniques as no single technique can lower your COD to 200mg/L from 70000mg/L. I would advice you start with a biological method such as SBR which is robust, will help in lowering the nitrogen in your leachate and biodegradable organics. The biological effluent can be post treated by coagulation flocculation which will not only lower COD further but will remove heavy metals. To remove recalcitrant COD, an AOP technique can be used.

Characterize the leachate for its biodegradability and if it BOD/COD is less than 0.3, first treat it by ozonation or some coupled AOP so as to increase the Biodegradability and than biological treatment will lead to efficient COD removal

Reverse osmosis is quiet exploited for this issue. The concentrate has to be processed in specific WWTP.

Thanks Mr. Di Maria, Rajendiran and Oloibiri for your advices

Since BOD/COD is quiete low, I suggest hot Fenton oxidation process followed by biological treatment and, if necessary, tertiary treatment

In this cast try to conduct a coagulation process using suitable coagulant. Then it is possible to continue using adsorption or biological treatment. Another method is to start with coagulation the an advance oxidation method .

I have done several researches with heavy polluted wastes on the past (like liquid waste from olive oil mill which has COD: 50000-120000 mg/l, liquid waste from paint industries-aniline base with COD: 800000-1200000 mg/l etc). I have implemented chemical oxidation (FENTON), Combination of FENTON with electrochemical oxidation, combination of Fenton-redbeds, coagulants, combination of Fenton and MBRs etc… Chemical Oxidation has the ability to reduced COD from heavy polluted waste. You may find some more details in several papers that I published focuses on that subject like: (1) Antonis A. Zorpas, Costa N. Costa, «Combination of Fenton Oxidation and Composting for the treatment of the olive solid residue and the olive mile wastewater from the olive oil industry in Cyprus», Bioresource Technology, Vol 101 (20), pp 7984-7987, 2010 (2) Antonis A. Zorpas, Irene Voukalli, Pantelitsa Loizia, «Chemical Treatment of Polluted Waste Using Different Coagulants», Desalination and Water Treatment, Vol. 45, pp 291-296, 2012. (3) Antonis A. Zorpas, Vassilis J. Inglezakis, «Intergraded Applied Methodology for the Treatment of Heavy Polluted Waste waters from the olive oil industries», Applied and Environmental Soil Science, Volume 2011 (2011), Article ID 537814, 2011. (4) Antonis A. Zorpas, «Chemical oxidation and MBR reactor for the treatment of household heating wastewater», Desalination and Water Treatment, In Press, 2013, (5) A.G. Vlyssides, M. Loizidou, P.K. Karlis, A.A. Zorpas, «Testing an Electrochemical Methods for Treatment of Textile Dye Wastewater», Waste Management, Vol 20, Νο 7, pp. 569-574, 2000 (6) A. Vlyssides, P. Karlis, M Loizidou, A. Zorpas, D. Arapoglou, «Treatment of Leachate From a Domestic Solid Waste Sanitary Landfill by an Electrolysis System», Environmental Technology, Vol 22, pp. 1467-1474, 2001

Ozone/H2O2 or ozone/activated carbon should help increasing the biodegradability of your leachate. I would test first ozone alone then combined with H2O2 or AC.

Have a look on that paper: Co-digestion of intermediate landfill leachate and sewage sludge as a method of leachate utilization, Bioresource Technology 02/2011; 102(3):2563-71. DOI:10.1016/j.biortech.2010.11.105

You can easily get it at my friends profile: https://www.researchgate.net/publication/49692450_Co-digestion_of_intermediate_landfill_leachate_and_sewage_sludge_as_a_method_of_leachate_utilization?ev=prf_pub

Article Co-digestion of intermediate landfill leachate and sewage sl...

Sea water is about 35,000 ppm salt and up so if you were primarily removing salts RO or MED desalination processes would work. Of course membrane fouling could be a problem with RO, so appropriate pretreatment would be necessary, e.g. MF or UF. You might be able to use a modified MBR system to provide biological reduction and prepare the permeate for later RO. If you want to oxidize the leachate Fenton processes or ozone are possible, or perhaps just peroxide, however, I think ozone plus peroxide to produce advanced oxidation would be too expensive and overkill. Depending upon the molecular weight and molecular size of the material being removed, perhaps nanofiltration is worth a try.

I would characterize the waste stream first. Establish BOD or assimiable organic carbon first. Deepnding upon this characterization, you can go with biological or ozone based AOP or other AOP techniques coupled with biological treatment can work. Since your flow rate is relatively low, implementation of AOP technologies may be affordable.

In general complete treatment (i.e. meeting effluent discharge standards) of high strength leachate can be very costly and resulting in various types of sludge and/or concentrated wastewater (e.g. if membrane technologies are used). In case it is a new landfill yet to be constructed, and a long term solution is pursued, I would consider upstream management of the waste to reduce leachate quantity and quality in contrast to end of pipe treatment. Considering that a leachate like that originates from a high fraction of food waste, Mechanical Biological Treatment (MBT) or partial biodegradation of waste could reduce leachate generation rate quite significantly particularly in arid or semi-arid regions. The rest can be managed through a combination of in-situ and onsite methods...

In my opinion using primary sedimentation tank, anaerobic and then aerobic biological treatment and coagulation process with suitable coagulant, respectively, could reduce the amount of COD less than 200 mg/l.