46 ❘ ❘ ❘ 106:11 (2005) T 239 Pulp & Paper Canada The MPC scheme is straightforward regarding the handling of constraint variables in the control problem. By combining the controlled and constraint variables, it is possible to set-up and tune the MPC controller both to control the level to a set point and to have upper and lower limits to ensure the production level, i.e. to keep the chip level ...

Biologically produced methane (CH₄) from anaerobic digesters is a renewable alternative to fossil fuels, but digester failure can be a serious problem. Monitoring the microbial community within the digester could provide valuable information about process stability because this technology is dependent upon the metabolic processes of microorganisms. A healthy methanogenic community is critical f...

An anaerobic digester receiving food waste collected mainly from domestic kitchens was monitored over a period of 426 days. During this time information was gathered on the waste input material, the biogas production, and the digestate characteristics. A mass balance accounted for over 90% of the material entering the plant leaving as gaseous or digestate products. A comprehensive energy balanc...

This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. I...

Co-digestion has drawn much attention because of its potential to increase biogas production among other benefits. Restaurant grease has high energy content and methane production potential and so is a promising substrate for co-digestion with municipal wastewater sludge. Anaerobic co-digestion of municipal wastewater sludge and restaurant grease was investigated at laboratory-scale under mesop...

Digester acclimatization can improve the efficiency of anaerobic digestion (AD), a potentially sustainable process for generating biogas from biological decomposition organic byproducts biodiesel production. This study examined impact rate on production and conversion in laboratory digesters using inocula wastewater treatment plant digester an agro-industrial waste digester. The results showed ...

A habitat-simulating medium was developed for the enumeration and isolation of bacteria from a swine waste digester. A roll tube medium with growth factors for strict anaerobes from previously studied anaerobic ecosystems was used to evaluate the effects of deletion, addition, or level of digester fluid, digester fluid treated with acid or base, rumen fluid, fecal extract, anaerobic pit extract...

The effects of bioaugmenting anaerobic biosolids digestion with a commercial product that contained selected strains of bacteria from genera Bacillus, Pseudomonas, and Actinomycetes, along with ancillary organic compounds containing various micronutrients were evaluated. The main objective of the study was to investigate the effects of bioaugmentation specifically on the performance of methanog...

In this work, we study the coupling of a culture of micro-algae limited by light and an anaerobic digester in a two-tank bioreactor. The model for the reactor combines a periodic day-night light for the culture of microalgae and a classical chemostat model for the digester. We first prove the existence and attraction of periodic solutions of this problem for a one day period. Then we study the ...

AIMS This study evaluated the effect of anaerobic digestion at 22, 38 and 55°C on odour, coliforms and chlortetracycline (CTC) in swine manure or monensin (MON) in cattle manure. METHODS AND RESULTS Swine or cattle were fed the respective growth promotant, manure was collected, and 2-l laboratory methane digesters were established at the various temperatures and sampled over 25 or 28 days. Af...