We could hardly generate biogas (particularly Methane) in paper mill wastewater treatment via ABR. However it worked efficiently as a pretreatment unit, unfortunately no sign of sustainable biogas was achieved.

Due to inorganic nature of paper mill effluents, biogas production process is not feasible on a large scale.

Sir,

Low concentration of biodegradable COD makes it nonviable for Biomethanation process. However if you can give the BOD:COD ration and/or values, it will be more clear and you will get better answers. 

Unfortunately not on sustainable basis as per my experiences. 

I am sorry to disagree with most of the comments made so far. Pulp & paper (P&P) mill effluent is largely organic even from recycled paper and cardboard. For efficient P&P mills consuming minimal water (and energy), we convert at least 50% of the organics to methane (CH4) such as in our 12000 m³/d case for a new P&P mill in Asia using only recycled paper and cardboard as feedstock. If interested I can send more information via email.

The composition of the effluent is important in this issue. If the effluent contains more of the inorganic chemicals used during the P&P process, then it may not yield a reasonable amount of biogas. I will advise that the effluent be first characterized to determine the amount of organic content in the effluent.

RE: Is paper effluent be useful to generate biogas efficiently ?

Good day Dr. Chhipa,

According to US laws, EPA controls placed on paper effluent are vast, covering measurable guidelines with respect to air, water, chemical, chloroform, sulfur/dioxide and wasted debris such as sulphite pulp, bleaching processes, coloring, etc (EPA. 1998). Canada also regulates paper mill effluent strictly, especially dealing with the Fisheries Act SOR/92-269, claiming it to be "Acutely Lethal, BOD matter, and suspended solids" restricting amounts in depositories at any given time (GC. 2014). Mechanical pulp mills (usually used for news print quality) use less bleaching, toxic chemicals, and lesser effluent waste, though that does not answer your question. According to the US National Library of Medicine & National Institutes of Health, there are strategies reducing effects of colorization and toxins that generate less potential hazards; whereas, the paper effluent may be less harmful for biogas/biomass industrial uses (PM. 2011). If or when development of chloroform removal occurs, we may have a new way of generating energy.

As it is, I cannot find any proven methods available to utilize paper effluent without the risks of further polluting environments due to the chemical processing involved, within economical feasibility, other than that which is derived from mechanical pulp mills. Burning paper effluent through biogas will release (what remains) hazardous plums, now sequestered within lined disposal sites lest new methods are found to isolate those toxins. Perhaps dried effluent could be mixed with certain building materials like cement/block/bricks or with the forestry industries laminated wood products; however, I am sure long-term studies need play their role if we are to use (what is considered) noxious debris in buildings and homes used regularly.

I wish you a lot of hope and luck finding a solution to your question posed.

Peace be with you and yours,

Albert Amorino

EPA. (1998). Effluent Guidelines: Pulp and Paper Rulemaking Actions - Regulatory Information. http://water.epa.gov/scitech/wastetech/guide/pulppaper/reg.cfm

GC. (2014). Pulp and Paper Effluent Regulations (SOR/92-269). http://laws-lois.justice.gc.ca/eng/regulations/sor-92-269/page-1.html#h-2

PM. (2011). Strategies for decolorization and detoxification of pulp and paper mill effluent. PubMed.gov. http://www.ncbi.nlm.nih.gov/pubmed/21432056

http://www.ncbi.nlm.nih.gov/pubmed/21432056

http://laws-lois.justice.gc.ca/eng/regulations/sor-92-269/page-1.html#h-2

http://water.epa.gov/scitech/wastetech/guide/pulppaper/reg.cfm

Pulp and paper wastewater is complex with variable COD content, presence of inhibitors and most cases nutrient deficiency that has strong impact on biodegradability and digestibility of paper and pulp wastewater.

For example chlorine bleaching effluents are not suitable for anaerobic treatment due to their low biodegradability and presence of toxic substances that strongly affect the methanogens. However, a considerable amount of pulp/paper waste is still biodegradable (most of them is slowly biodegradable) and digestable so we can produce biogas with a good design. Co-digesting pulp and paper waste with other waste can improve nutrient content and reduce inhibitory effects. Using pretreatment and hydrolysis techniques could be beneficial for reducing reaction times and project economics.

Several reserach studies showed good COD and VSR reductions along with  raeasonable gas yield in pulp/paper waste applications, especially blending those waste with other substrates. Hope this helps.