Aerobic thermophilic treatment of farm slurry and food wastes

Linnaeus Eco-Tech, 2019

The use of biological anaerobic treatment for sludge digestion in treatment plants has a Jong operational record. The result is a lower amount of stabilised sludge and a considerable energy output, as heat and possibly also electrical en ergy. In industrial waste water treatment, anaerobic processes have also been used quite a Jong period, especially in food and pulp and paper industries. The an aerobic treatment of organic waste from industries or municipal waste, is a more recent application. The paper presents a summary of used anaerobic technology, with a special case from the Kalmar waste water treatment plant, where the two existing sludge di gesters are upgraded to termophilic anaerobic treatment, one unit t be used for sludge and the other, separately, for organic waste from food industry and ma nure from farms.

Journal of Environmental Engineering, 2000

ÐLaboratory experiments were conducted to investigate two-stage aerobic thermophilic and anaerobic mesophilic treatment of swine waste. The two-stage system included a 1-day sludge retention time (SRT) aerobic thermophilic reactor operating at 628C and with 1.0 mg dissolved oxygen/l, followed by a 5, 9, and 14-day SRT anaerobic mesophilic digester operating at 378C. A single stage anaerobic mesophilic digester operating at 6, 10, and 15-day SRT and 378C was used as the control. Feed swine waste slurry average composition included total solids (TS)=4.3%; volatile solids (VS)=67% of TS; supernatant chemical oxygen demand (COD)=14,330 mg/l; fecal coliform density=7.2 Â 10 8 MPN/g TS; pH=7.1; and alkalinity=2700 mg CaCO 3 /l. Two-stage system operating at 6, 10, and 15-day system SRT reduced VS by 46, 54, and 61%, respectively, and was signi®cantly better than the control at each SRT. Supernatant COD reduction by the two-stage system (56±67%) was signi®cantly better than that obtained in the control (44±60%). Fecal coliform density was reduced to <10 3 MPN/g TS at all SRT by the two-stage system, whereas, the control did not reduce the fecal coliform density below 10 5 MPN/g TS at all SRT. The two-stage system anaerobic digester produced 0.56±0.64 m 3 CH 4 /kg VS destroyed compared to lower levels of 0.47±0.51 m 3 CH 4 /kg VS destroyed by the control, both operating at 6, 10, and 15-day system SRT. The methane gas production by the twostage system of 0.26, 0.32, and 0.39 m 3 /kg VS fed at 6, 10, and 15-day system SRT, respectively, was signi®cantly higher than that by the control system (0.17, 0.22, and 0.25 m 3 /kg VS fed at 6, 10, and 15day SRT, respectively). The biogas produced by the two-stage system anaerobic digester contained 353±387 ppm (v/v) H 2 S content compared to 569±609 ppm (v/v) H 2 S content in the biogas from the control anaerobic digester. The time-to-®lter values of the product sludge from the two-stage system (245, 197, and 158 s at 6, 10, and 15-day system SRT, respectively) were about 50% lower than those of the product sludge from the control (355, 295, and 250 s at 6, 10, and 15-day system SRT, respectively), indicating better dewaterability of the two-stage system product sludge.

Reviews in Environmental Science and Bio/Technology, 2003

Thermophilic aerobic wastewater treatment is reviewed. Thermophilic processes have been studied in laboratory and pilot-scale while full-scale applications are rare. The paper focuses on the microbiology of aerobic thermophiles, performance of the aerobic wastewater treatments, sludge yield, and alternatives to enhance performance of the thermophilic process. Thermophilic processes have been shown to operate under markedly high loading rates (30-180 kg COD m −3 d −1). Reported sludge production values under thermophilic conditions vary between 0.05 and 0.3 kg SS kg COD removed , which are about the same or lower than generally obtained in mesophilic processes. Compared to analogous mesophilic treatment, thermophilic treatment commonly suffers from poorer effluent quality, measured by lower total COD and filtrated (GF-A) COD removals. However, in the removal of soluble (bacterial membrane filtered) COD both mesophilic and thermophilic treatments have produced similar results. Sludge settleability in thermophilic processes have been reported to be better or poorer than in analogous mesophilic processes, although cases with better settling properties are rare. Combining thermophilic with mesophilic treatment or ultrafiltration may in some cases markedly improve effluent quality. * values estimated from the figure in the original article. 1 process operated without polymer dose. 2 process operated with polymer dose.

International Journal of Advanced Engineering Research and Science, 2019

Large amounts of effluents are generated in pulp and paper mills. In general, these effluents present temperatures above 40 ºC, which may preclude biological treatment in mesophilic conditions (35 ºC). For this, the present work aimed to produce aerobic granules in mesophilic conditions and, after their stability, leads them to thermophilic conditions. After the thermophilic granules were obtained, analyzes of their maintenance, treatment efficiency and verification of the production of the extracellular polymeric substances (carbohydrates, proteins and humic acids), present in the granules under these conditions were carried out. It was observed that the granules, generated from the biological sludge and the effluent of a pulp and paper industry, can act up to a temperature of 45 ºC, presenting a removal rate of around 70%, without great loss of efficiency of the proposed treatment compared to that of mesophilic flocculent sludge.

A short-term thermophilic treatment was conducted in order to study the survival of micro-organisms in slurry derived from a cattle farm, at temperatures of 58, 63 and 68 • C for 6 h. The second trial was a biogas production experiment with an anaerobic mesophilic first stage and a thermophilic second stage. The mesophilic treatment was at 38 • C and the second stage was conducted at 55, 58 or 65 • C. The results of first trial showed that survival of micro-organisms was decreased remarkably at higher temperatures in spite of the fact that during the experiment part of slurry was replaced with fresh slurry. Meanwhile, the second trial showed that optimum production of biogas was at 55 • C while the best result for hygienic control was achieved at 65 • C.

2020

Every year a huge amount of sewage sludge is formed at municipal wastewater treatment plants. Sewage sludge contains a sufficient amount of biogenic elements and organic components, which characterizes them as possible raw materials for the production of organic fertilizers. However, direct incorporation of these sediments into the soil is impossible due to the fact that, in addition to useful organic and mineral components, they contain pathogens, viruses and helminth eggs. The aim of the study was to optimise thermal disinfection conditions for preparing of safety sewage sludge fertilizer. Laboratory studies were carried out using sediments from wastewater treatment plants of some cities. During laboratory experiments, the conditions for thermal disinfection of sediments – the thickness of the sediment layer, the air temperature in the disinfection furnace, and the treatment time of the sediment – were determined. When conducting industrial tests of a conveyor-type sediment decont...

Waste Management & Research, 2013

Differences in biodegradability can affect the treatment of slurry before its use in spraying. The objective of this study was to evaluate the effect of the generation and physical-chemical characterization of swine and dairy cattle slurries on different biological treatment technologies. This research involved monthly sampling (number/composition) for 1 year of 24 swine farms (16%), cattle farms (38%), and mixed swine and cattle farms (46%). The results obtained showed differences in feeding (3 l water kg −1 food for cattle and 5 l water kg −1 food for swine) and assimilation (0.6 kg food kg −1 milk produced and 3 kg kg −1 weight gain), which may influence the generation of slurry (57 l animal −1 d −1 in cattle and 31 l animal −1 d −1 in swine) and its composition. In addition, the composition of swine slurry [23 g chemical oxygen demand (COD) l −1 , 3 g total nitrogen (TN) l −1 ] is significantly different (P < 0.01) to cattle slurry (4 g COD l −1 , 0.3 g TN l −1 ). Finally, the composition and the S index applied to swine slurry [COD N −1 = 8, biological oxygen demand (BOD) 5 COD −1 = 0.3, S index > 0] and cattle slurry (COD N −1 = 16, BOD 5 COD −1 = 0.6, S index < 0) show a difference on the biodegradability of both slurries. Suitability of anaerobic and aerobic treatment was assessed based on the findings.

Sludge microbial quality is a major issue to be assessed for the sustainable reuse of sludge in agriculture. Within the ROUTES project innovative solutions for the production of good quality sludge are evaluated and the hygienisation performances of the proposed sludge treatment systems is assessed. The paper describes the efficiency of pathogens and indicator removal by a combination of a disintegration pre-treatment, by thermal hydrolysis, and thermophilic anaerobic digestion and by a combined anaerobic and aerobic digestion process. To better address the fate of pathogens with diverse resistance capacity different indicators microorganism (E.coli, spore of sulphide reducing clostridia SSCR and somatic coliphage SOMCPH) and specific pathogens (Salmonella and enteric viruses) were monitored. An improvement of hygenization was obtained by both investigated processes. Thermal pre-treatment improved the SOMCPH removal of more than one logarithmic unit and efficiently eliminated bacter...

Journal of Ecological Engineering, 2013

Sewage-treatment plants generate sludge which needs to be neutralized for legal, esthetical, and practical reasons. Economical and ecological concerns indicate that sludge, as long as it is possible, should be returned to the natural environment. The article presents the process of autothermal thermophilic aerobic digestion (ATAD) as a measure to produce biomass, which can be naturally utilized. The description of theoretical principles of the process in question is accompanied by presentation of an ATAD installation which has been functioning since 2009 at the municipal sewagetreatment plant in Olecko. Results of microbiological and chemical tests carried out in the years 2010-2012 have been analyzed. Examinations embraced sludge which was the final product of the aforementioned sewage-treatment plant.

BioResources

The objective of this work was to evaluate the physical characteristics of the thermophilic granular aerobic sludge used in the treatment of bleached kraft pulp mill effluents. Four sequential batch reactors (SBRs) were operated with cycles of 12 hours. Reactor (R1-FSR) with flocculent sludge was used as control. The other three reactors (R2-GSR, R3-GSR+100, and R4-GSR+200) were operated with granular aerobic sludge. Concentrations 100 and 200 mg. L-1 of calcium were applied in the R3-GSR+100 and R4-GSR+200, respectively. The pH was maintained in the neutral range in all reactors. The experimental plan was carried out for 490-day period, in 5 phases at different temperatures of 35 °C to 55 ºC. All SBRs showed COD removal efficiency above 60% in all temperature ranges. The granule average diameter in the R2-GSR, R3-GSR+100, and R4-GSR+200 ranged from 5 to 8 mm. The reactor R3-GS+100 showed better stability due to the addition of 100 mg. L-1 of calcium. The granular sludge sedimentati...