I would suggest a pH neutralization tank (chemical or biological process) followed by extended aeration and if nitrogen is to be removed, then I would add an anoxic tank.

Please define "EC".

How much total nitrogen (Kjeldahl Nitrogen)?

What is the phosphorus concentration? How many m3 of effluent are generated daily?

EC probably means electric conductivity

Hi Hasanali, although it is a relatively high strength wastewater, diary waste is biodegradbale therefore biological treatment can work. Before biological treatment, you need to bring down the pH around 7-8 to allow a healthy microbiological growth. Multiple technologies (i.e., SBR, conventional activated sludge systems, extended aeration systems) and configurations (if nitrogen removal is needed you need to configure your system to achieve nitrogen removal) can be used based on treated flow and treated effluent objectives. I would not suggest MBR unless a very efficient oil and grease seperation is provided as part of preliminary treatment knowing that dairy waste can contain significant amount of fat and grease. The biological treatment is not effective for reducing TDS or EC. The chemical addition for pH neutralization will also increase the TDS content of the wastewater. Therefore, you need to account such increase when evaluating TDS content of the treated water. If the target TDS is say less than 1,000 mg/L, you need to add additional treatment (i.e, NF, RO, EDR) after biological treatment to reduce the TDS.

Before you choose a treatment process, I strongly recommend to check if the cleaning method could be changed. It seems to me that NaOH is overused, which complicates the treatment and raise TDS. Consider a combination of reduced amount of NaOH and other cleaning agents such as bio-degradable surfactants

One of my co author has written the below added article this may be useful to this discussion pl

Conference Paper IMPROVE QUALITY OF BRACKISH WATER THROUGH BIOFILTER SYSTEM C...

I agree with Oded Nir. Many times in industry we fail to segregate effluents as it require additional facilities and try to look at end to pipe technologies alone. you may like to look at the individual stream characteristics to arrive at optimum solution.

Thanks for your answers dear friends.

We have 50 m3/d Wastewater.

We need that EC(electric conductivity) in end of treatment process be less than 2000

Oil and grease are 56 mg/l

We don't need remove nutrient.

We want a very compact package for wastewater treatment.

Best regard.

Influent TDS is 1154 mg/l.

We can't change cleaning process.

Maybe use the fact of high pH and apply ferric coagulant, as it was found to be advantageous in the following study: DOI: 10.1177/0734242X07079876

Correct if I'm wrong, but according to conversions of TDS to EC (according to Lenntech website) 1154 ppm TDS will give 1.80 mS/cm - could you state what values do you want to achieve in effluent 2000 of what?

I would recommend you to combine coagulation with what was proposed by Ufur.

Best,

Krzysztof

The cheapest option would be to separate the waste water from the washing production systems containing NaOH. This segregated waste can then be pre-treated by being neutralized with CO2 before joining the rest of the waste stream for biological treatment.

The wastewater has a significant biodegradable component which means extended aeration can be used, however the unbiodegradable component may require precipitation method to achieve 100mg/L. Heterotrophic Organisms pH inhibition is outside range of 4.5 to 9.5 which means at 12.6 they are inactive that calls for two possible actions to introduce pretreatment of effluent from washing system 50m3 is manageable or if possible to separate treatment trains and employ different treatment methods..

Maybe is possible to construct a system which will not require acid addition and not increase the total solids (TS) or electric conductivity (EC).

If the reported pH of 12.6 is measured in water which hasn’t taken up carbon dioxide from the atmosphere it is equivalent to about 40 mM hydroxide ion.

The total nitrogen is likely about 100 mg/L as estimated from the BOD which will produce about 7 mM acid from nitrification: R-NH3+ + O2 -> NO3- +H+ +H2O.

From biodegradation of 710 mg/L BOD you can make 22 mM carbonic acid in the water without stripping it if you oxygenate by injecting oxygen from an industrial oxygen concentrator (http://en.wikipedia.org/wiki/PSA_oxygen_generator). The process is: {CH2O} + O2 -> H2CO3.

Together these processes can neutralize the water so the biodegradation can occur at neutral pH.

The resulting water will have a high residual alkalinity of about 33 meq./L so the pH will go up to about 10 if the water is brought in equilibrium with atmospheric CO2. I don’t think is wise to apply this water directly for irrigation but if you have other sources of irrigation water with low or neutral pH to mix it with you can make usable irrigation water.

At first you can try to use carbon dioxude CO2 for correcting of pH. Portion of CO2 must be fix by experiment.

Absorption of CO2 increse alakalinity what will be advantage in the nitrification process.

At high pH coagulation process is an efficient method by using polyaluminium chloride (PAC). or you may use ozonation process.

The cheapest method is the application of a pretreatment in the stream of washing water prior the biological treatment. Because of the small volume of wastewater, a well can be used as the pH equilibration tank. For the conductivity reduction by sedimentation, flotation etc in the same well, you must know the composition of TDS. Alternatively, you can dilute the high conductivity treated water by mixing with irrigation water before use.

In this case, I think BOD and COD is not the issue. Air flotation would be my pretreatment suggestion because it can remove TSS, oil and grease. In this unit, PAC can be the coagulant and can bring down the pH a little bit with its acidity-- but I think some acid still be needed. Then the pretreated water can use biotreatment (maybe activated sludge) to reach your BOD/COD goal.

TDS of wastewater is 1153 mg/L, I think probably the conductivity is higher than 2000 mg/L, or very close to 2000 mg/L. Considering EDR or RO in your treatment process should be necessary.

If you have adequate space try biological approach has as constructed wetlands.

i suggests you to try NANO based methods.