Advanced technologies for the treatment of wastewaters from agro-processing industries and cogeneration of by-products: a case of slaughterhouse, dairy and beverage industries

Abstract

Agro-industrial wastewaters are known by high strength of organic pollutants that cause an adverse effect on the water bodies. Wastewater management becomes a major task, leads environmental regulations to be stricter worldwide. Increased disposal of untreated/partially treated industrial wastewaters are major environmental problems in Ethiopia. In Ethiopia, industries most commonly dispose their untreated wastewater straight into the nearby rivers. Somewhat, constructed wetlands are used by some industries for treatment of wastewaters. The objective of this review paper was to summarize the characteristics and recent research efforts done on anaerobic treatment of some selected agro-industrial wastewaters and innovative technologies used for cogeneration of byproducts. Many developed countries designed cost effective approaches for agro-industrial wastewater management. The fullscale anaerobic treatment system in China generates 40,000 m 3 biogas daily for 20,000 households from agro-industrial wastes. Likewise, the Brewery, Addis Ababa, Ethiopia used full-scale anaerobic treatment technology and produce average methane yield of 487 Nm 3 /day. The estimated maximum methane production potential of Kera, Luna slaughterhouses, and Ada milk factory were 4.5599LCH 4 , 0.1878LCH 4 , and 0.9952LCH 4 , respectively. These indicate that they can be potential sources of biogas production. Limitations of the brewery are burning of the produced energy and some quantified parameters being become above national standards while meat processing and diary industries are discharging their wastewater without treatment into the rivers. We devised the brewery to use the produced energy properly and extend its treatment to achieve the national standards using integrated sequencing batch reactor. Similarly, slaughterhouse and diary industries should install anaerobic-aerobic integrated treatment techniques.

Zeolite as a Potential Medium for Ammonium Recovery and Second Cheese Whey Treatment

“…Agro-industrial development is considered to be major contributor of environmental pollution [1]. Agro-industries (e.g., dairies, olive mills, wineries) produce significant quantities of wastewaters characterized by high organic loads and nutrients [2].…”

Rapid anaerobic digestion of organic solid residuals for biogas production using flocculating bacteria and membrane bioreactors – a critical review

“…Various types of high rate anaerobic digesters: Upflow anaerobic sludge blanket (a); and expanded granular sludge bed (b) (adopted from); anaerobic fluidized bed reactor (adopted from); upflow anaerobic filter process reactor (adopted from).…”

Bioremediation of brewery wastewater using hydroponics planted with vetiver grass in Addis Ababa, Ethiopia

“…Breweries are a widespread industry with an important economic value in the agro-food sector and brewing is intrinsically a water intensive industry (Alayu and Yirgu 2017). Brewery industry is one of the important industries that cause water pollution.…”

“…Hence, breweries produce a substantial effluent stream, rich in organic matter and nutrients originating from the brewing process (Simate 2015). In spite of significant technological improvements, water consumption, wastewater, solid waste, and by-products and emissions to air remain major environmental challenges for the brewing industry (Fillaudeau et al 2006;Pettigrew et al 2015;Alayu and Yirgu 2017).…”

“…The contribution of vetiver grass in the removal process includes: nutrient uptake from the wastewater solution by the root system; release of oxygen by the roots into the root zone (rhizosphere) creates favorable conditions for aerobic decomposition of organic matter and growth of nitrifying bacteria; the root system provides surface area for attached microbial growth which is responsible for microbial degradation processes and the roots exude organic carbon as carbon source for denitrifier bacteria for nitrate removal. Its endproduct has several uses including animal fodder, handicraft, and material for organic farming (Alayu and Yirgu 2017).…”