A free chlorine plant of pulp and paper will be installed near Orinoco River in Venezuela and the effluent has to be reused because it will not be discharged to the river. The expected concentration of BOD will be low but the COD will be around 800 mg/L and the real color will be dark too. The secondary treatment will be an activated sludge process selector type.
Can this water be used for irrigation of fields? What are the risks?
Hello, I have researched Brazilian Laws on COD, and for pulp and mill it is allow up to 300 mg/l regarding this parameter. This legislation comes from Parana State as proposal, but I guess the national records are not so different ( http://www.mma.gov.br/port/conama/processos/EFABF603/Prop.ResolGOV_PR_2oGTLancamentoEfluentes_17e18nov08.pdf). I conclude that it is risky to allow 800 mg/l. Also, you should look at other compounds employed in production process that can improve COD and analyse them together. Best regards.
Dear lenin Herrera, Actually secondary treatment comes in the biological treatment. if we are using MBR system in the secondary effluent treatment step after that we are using filtration sytem then we can re use for irrigation purpose.
I agree that the N P K and sodium content will be high. It could therefore be possibly tried initially on barren soils to test the potential rise in their concentration. This will then throw a clear idea of its impact in zones with sufficient supply of life supportive nutrients. Corrective measures could then facilitate usage with a warning. Alkaline soils normally do not leach heavy metals.
The wastewater will most propably contain a high level of heavy metals.
Wastewater from paper mill has a relative high concentration of carbonates and tendency to precipitate calcium in the soil as CaCO3. It will increase the proportion of sodium to calcium and magnesium and sodium.
Irrigation with paper mill effluent will led to an increased pH. The concentration of N, P, K and Na will be high.
The dark colour prevent the natural photosynthesis process due to absence of sunlight penetration.
The propose wastewater must be analysed and treated accordingly before used to irrigation. Patrick