During the processing of milk and dairy products, waste water with a heavy load enters the drains and thus also the feed to the waste water treatment plant. Fast changes in the load, particularly high peak loads in the waste water, create major problems for the waste water treatment plant. The risk of an overload and as a result a degradation in the treatment performance is always present. The Spectral Absorption Coefficient(SAC )curve covers a period of 48 hours and includes laboratory results for the COD measured in parallel.

For operational reasons, only random samples or mixed samples can be taken and analysed in the laboratory to determine the COD. However, the continuous measurement of the SAC enables all peak loads to be measured without gaps and without delay. It is possible to react specifically and automatically to results. Using the continuous measurement, for instance, it is possible to control a gate that separates the waste water with a high load from water with only a low load. Water with a high load is stored temporarily in a storage tank.

cz.hach.com/asset-get.download.jsa?id=25593610993 (The SAC in the feed to industrial waste water treatment plant for dairies and milk processing factories...)

The COD test is widely used as a means of measuring the organic strength of effluents. This test allows measurement of waste of a waste in terms  of the total quantity of oxygen required for oxidation to CO2 and H2O. During the determination of COD, organic matter is converted to carbon dioxide and water regardless of the biological assimilability. The dichromate reflux method is preferred over procedures using other oxidants (e.g. potassium permanganate) because of its superior oxidizing ability, applicability to a wide variety of samples and ease of manipulation.

go through attached file may be it would be helpful for you.

Regards

Gupta A.D.

you changed question,if u wanna measure COD ,can use SAC method&if wanna get rid of particles can use Electrocoagulation.Electrocoagulation has many advantages such as simple equipment, easy operation and automation, a short retention time, low sludge production and no chemical requirement. Alum (Aluminum sulfate) is a nontoxic material commonly used in water treatment plants to clarify drinking water. adopted 50 mg Al/l as a safe upper limit for post-treatment dissolved aluminum concentrations. Activated charcoal is very porous and absorbs toxins quickly.

The charcoal is made from carbon and ground into very fine granules, about the size of a dust speck of dust, which work like sponges. Then the material is activated through different processes. Activating the charcoal allows it to absorb anything is comes in contact with. Each pore within the charcoal grain soaks up anything traps and holds organic chemicals, nitrates and toxins.

http://www.sciencedirect.com/science/article/pii/S2212371713000425

try used digestion method process for COD measurement.. make sure u dilute the samples before testing..

try measuring it without centrifuge or filtering. degrade all solids include algea. you can also measure the cod of similar amount of algea in de-ionized water and subtract it from the total value. you can also filter everything and report cod as dissolved cod if it works for you. 

Why not stick to variations of soluble COD by filtering samples with 0.45 um filters? Only soluble organic matters can be directly utilized by algae, isn't it? 

COD is the measuring of organic and inorganic compound that could be degraded chemicaly by oxidizing agent. So you can take your sample with algal cell and digest it and before titration with FAS you can filter it to see the pink color of titration.

Chemical oxygen demand (COD) relies on chemical oxidation with chromic acid (a strong oxidizer). Many organic compounds, including color bodies and fibers, which are not easily biodegradable, along with any inorganic chemicals will show up as chemical oxygen demand but not biochemical oxygen demand (BOD). Some mills have found that filtered COD samples give a better surrogate for the five-day BOD test than the one-day BOD test.       Chemical oxygen demand (COD) is the amount of a specified oxidant that reacts with the sample under controlled conditions. Results are defined as the mg of Oâ‚‚ consumed per liter of sample. The sample is heated for two hours with a strong oxidizing agent, potassium dichromate. Oxidizable organic compounds react reducing the dichromate ion to the green chromic ion. The amount of Crâºâ¶ or Cr⺠³ is measured colorimetrically with a spectrophotometer. Chemical oxygen demand can be used to estimate biochemical oxygen demand (BOD≈ ½ COD) and determine the dilutions needed for the BOD five-day test.

Total COD is run on undiluted samples. For a soluble COD, the samples are filtered through a 0.45 mm filter before analysis to remove biological interference. 2 mL of the sample is pipetted into a COD digestion reagent vial. The vial is then inverted several times to mix (vial will get hot). The vial is placed in the COD reactor at 150 ° C for two hours. The samples then cool and the samples are tested using a spectrophotometer. The chemical oxygen demand value will be read in mg/L for both total COD (tCOD) and soluble COD (sCOD).

For samples with a concentration of 0 to 150 mg/L, use the low range COD vials. For higher concentrations the high range COD vials (0-1500 mg/L) should be used. If the COD exceeds 1500 mg/L, the sample should be diluted to bring the results in range.

Chloride is the primary interference.   Vials with mercuric sulfate can be used to eliminate chloride interference up to 2000 mg/L Cl–. Samples with higher chloride concentrations should be diluted enough to reduce the chloride concentration below this limit. If the sample is diluted the values are adjusted based on the dilution factor. If the COD testing is for permit reporting, the method including vials with mercury is the EPA approved method.