Utilization of sugarcane factories’ wastes as inexpensive source of nutrients and CO2 for microalgal biomass production: process coupling and potential evaluation

Abstract

One approach for the viable production of algal biomass is to couple its production with wastewater treatment plants, power and/or industrial plants. This is intended towards the utilization of the nutrients and the CO2 in the wastewater and in the flue gases of the industry respectively by the microalgae during their growth. In the present study microalgal biomass production was conceptually coupled with a sugar factory. The potential of the wastewater and the flue gas of the factory to support the growth of the microalgae was evaluated. Likewise the possible reduction of pollution by the microalgae was studied. The outputs from the coupled process were determined using the material and energy balance approach with a spread sheet. The cultivation model shows that 12 mg of total nitrogen (TN) and 7.4 mg of total phosphorus (TP) per liter of wastewater could be transferred to the algal growth ponds. It was found that there is a nitrogen deficit in the wastewater. With the supply of makeup nutrient, 120.5 tons/year microalgal biomass could be produced from the coupled process. Application of the assumptions resulted in the reduction of chemical oxygen demand (COD) (mg O2/L) from 2200 to 447, biological oxygen demand (BOD5) (mg O2/L) from 1200 to 207, TN (mg/L) from 15 to 0.6 and, TP (mg/L) from 10 to 1.5 in the wastewater. Integration of the sugarcane processing factories with algal biomass production is important for both biomass production and bioremediation.

Sustainable microalgal biomass production in food industry wastewater for low-cost biorefinery products: a review

“… Batch Docosahexaenoic acid (DHA) Lee et al ( 2020 ) Sugar cane wastewater Scenedesmus sp. Batch Biomass and biomass Zewdie et al ( 2021 ) Starch wastewater Chlorella pyrenoidosa Batch Biomass Lipids Tan et al ( 2019 ) Brewery wastewater Chlorella sp. , Scenedesmus sp., Spirulina sp.…”

Biotreatment of discarded fruit juices and simultaneous lipid production using Leptolyngbya sp.

“…20,24 However, research employing microalgae for the treatment of food industry wastewaters mainly concerns liquid residues from fruits and vegetables [26][27][28] 28 or other food wastes that must be initially anaerobically digested or hydrolyzed (to produce liquid extracts) before being used as a growth medium. 29,30 Specifically, most of the above-mentioned research works deal with wastewaters from: different stages of the sugar industry 16,17,[31][32][33] ; dairy products 34,35 ; alcoholic or non-alcoholic beverages; 15,34,[36][37][38][39] and other food processing wastewaters, such as raisin wastewaters. 35,39 Only a few studies refer to the treatment of wastewaters from soft drink industries or fruit juice processing, 14,[40][41][42] and most of these used activated sludge or anaerobic digestion reactors (Supporting Information, Table S1).…”