We are starting a community sanitation project in schools in South Asia and want to ensure an environmental friendly, sustainable cycle for waste treatment for these community toilets.
The waste water from the sample toilet in one school that we started contains a high amount of nitrate (but natural as students use the toilets mostly to urinate). We need to treat this waste and reduce the nitrate concentration from 20 mg/L to 10 mg/L before we dispose this water back into the ground (where we are building ground water recharge trenches).
We are looking to get some inputs for designing a waste treatment system for this project. We will like to opt for simple biologically systems using bio material etc. Your inputs for selecting or designing the waste treatment systems will be very much helpful for us.
Treatment of Wastewater Coming from Urinals, Basins
Dear Aiden Ogley,
The wastewater coming from Urinals, Wash Basins, Showers and Sinks is considered or termed as "Grey Water", this is called Grey Water as this has low polluting in it as easy to treat or handle as compare to Sewage or Industrial Wastewater.
The EU Sewage Directive concerning urban wastewater treatment stipulates a maximum concentration of 10 – 15 mg N/lit for sensitive areas or a reduction of the nitrogen load by 70 - 80 % (Council of European Communities, 1991a). In the USA, treated sewage contains between 10 - 20 mg N/lit (Metcalf and Eddy INC., 1991). Normal Untreated Domestic Sewage has Nitrates ranging 20 - 80 mg N/lit, this shows your output water is quite good in that sense.
Anyway, your wastewater coming will not only have Nitrates rather having BOD, COD, TSS etc. If you want a simple Biological System then the following schemes will be workable depending upon flow rate etc.
Option 1: Anaerobic Digestion which will reduce Nitrates, BOD, COD TSS.
Option 2: Scheme a proper treatment
Anoxic Tank ---> Aeration Tank ---> Settling Tank---> Output.
Option 3: If this has no other TSS or impurities, then may be you can employ Nitrate Removal Filters which are equipped with Anionic Resins for Nitrate Removals (in case only Nitrate is the main concern nothing else).
Your question still needs some more clarifications which I think will come after this above recommendations.
It would be possible to separate nitrogenous content contributing N -BOD and later can be refined to retrieve as ammonia nitrogen or as TKN . Design the detention time as appropriate to retrieve the contents as nitrate, however the content of urea can be expressed in equivalence of nitrate. Its order of the day On-line sensors for nitrogenous contents are available and one make use of that and to refine the design for separation schemes
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Dear colleague us at this time we are solving this problem, reduction 50mg / the 30mg / what is allowed in our country, and for mouth water, you can help with nustra technology, both disinfection, as in the reduction of amount of nitrates, the most important thing is that we do not produce pollution or use byproducts nigun type, take a look at our website or get in contact with us will be happy to help. Yours truly. Xavier Dolo www.dologroup.com
Hello Aiden, Are you sure about the nitrate (NO3) from urine? As far as I know, the main nitrogen compound in fresh urine is urea (NH2)2CO which rapidly hydrolyzes and decomposes to ammonia (NH3) which is volatile and smells as opposed to nitrate. Ammonia can be oxidized biologically to nitrate (nitrification) but this requires several steps and different bacteria along with a lot of oxygen which are not available in urine and toilet wastewater.