Life cycle assessment (LCA) of end‐of‐life dairy products (EoL‐DPs) valorization via anaerobic co‐digestion with agro‐industrial wastes for biogas production (original) (raw)

Reuse of expired dairy products and sewage in the production of biogas by anaerobic digestion

Revista Engenharia na Agricultura - REVENG

Dairy industry is a prominent sector of the agro-industry with global production of 906 million tonnes of milk. Several dairy products are wasted due their high perishability. Anaerobic digestion is a sustainable alternative for reducing this waste aiming biogas production. This study evaluated the co-digestion of expired dairy products (EDP) with synthetic sewage from two assays using two types of dairy waste, separately: Assay I (EDP mixture of 80% of milk + 15% of yogurt + 5% of milk cream) and Assay II (industrial raw mixture of EDP). Both assays were composed of 20 g COD L-1 (Chemical Oxygen Demand per Liter) using anaerobic batch reactors (1.0 L) assembled in duplicates with 0.5 L headspace (N2) and working volume of 0.5 L with initial pH 8.2, at 37 °C, in a static mode. The cumulative CH4 productions were 2722.5 NmL in 31 days of operation (Assay I) and 3140.0 NmL in 25 days of operation (Assay II). Equivalent CH4 yields were obtained for the both assays with ~330 NmLCH4 g CO...

Valorization of dairy waste to renewable energy using anaerobic digestion

2017

The present study aimed to valorize the dairy waste to renewable energy such as methane using anaerobic digestion. For that, Biochemical Methane Potential (BMP) of two effluents (Pure Whey (PW) and Loss in Dairy Product (LDP)) generated by a dairy cooperative in Morocco was evaluated. The BMP assay was done according to three substrate/inoculums ratio (3, 1.5 and 0.75).The co-digestion between PW, LDP, Biological (BS) and Physicochemical Sludge (PCS) from the same cooperative were performed. The optimal ratio and the co-substrates in synergy were determined. The BMP assessment at 38 ±1°C showed that the low ratios (0.75 and 1.5) gave the most important CH4 yields for the two substrates in mono and co-digestion (79.1, 25.54 and 62.85mlSTP/gVS), and constituted the optimum ratios. In addition, the synergy between co-substrates (LDP, BS and PCS) and PW was very important, because the yield of CH4was increased 2.5 times (M4) compared to the mono-digestion of PW. While an antagonism betw...

Biogas Production by Pilot-Scale Anaerobic Co-Digestion and Life Cycle Assessment Using a Real Scale Scenario: Independent Parameters and Co-Substrates Influence

Processes, 2021

This study evaluates the performance of different agricultural by-products to identify the potential effect of independent variables, using as the dependent variable the biogas production. A Box–Behnken experimental design was carried out in a pilot-scale plant of four stirred stainless-steel digesters under mesophilic semi-continuous digestion. The results obtained support the creation of a technical framework to scale up the process and further evaluation of the potential environmental impacts through life cycle assessment (LCA) methodology. A stable behaviour was achieved in 12 of the 13 experiments proposed. The highest value of daily biogas production was 2200.15 mL day−1 with a stabilization time of 14 days, an organic loading rate of 4 g VS feed daily, low C/N ratio and a 1:1 relation of nitrogen providers. The concentrations of CH4 remained stable after the production stabilization and an average biogas composition of 60.6% CH4, 40.1% CO2 and 0.3% O2 was obtained for the con...