Biological Anaerobic – Aerobic Treatment Of Dairy Wastewater In Poland
In 2014, farms across the EU-28 produced approximately 164.8 million tones of milk, of which 159.6 million tones (or 96.8 %) were cows’ milk. Cows’ milk production on farms was the highest in Bretagne (France), Southern and Eastern Ireland and Lombardia (Italy) and Masovia (Poland) (8,3%). Milk processing produces wastewater. In Poland 1 m 3 of processed milk accounts for 3.2 m 3 of wastewater. In 2013 the production of dairy products in Poland generated 26.5 hm 3 of sewage: 14.7 hm 3 of which was treated (9.3 hm 3 biologically and 5.4 hm 3 with increased nutrient removal). The dairy wastewater is primarily generated from the cleaning and washing operations. Its main contaminants are: high BOD and COD concentrations, and it contains fats, nutrients, lactose, as well as detergents and sanitizing agents. Biological treatment is the basic method used for wastewater from food processing. Dairy wastewater in Poland is treated using aerobic biological methods: circulated pond, activated sludge process, sequencing batch reactor, Moving Bed Biofilm Reactor and anaerobic reactors. The two steps anaerobic-aerobic reactors are used in two cases in Poland.
Evaluation of Dairy Wastewater Treatment Systems Using Carbon Footprint Analysis
Modernisation of municipal and industrial wastewater treatment plants (WWTPs) should be carried out, taking into account its impact on global warming, e.g., through carbon footprint (CF) analysis. An important industrial sector in Poland is the dairy industry. In dairy WWTPs, the aerobic sewage sludge stabilisation applied thus far is being replaced by the anaerobic process. This change is positive due to the possibility of energy production, but it is unclear how it affects greenhouse gases (GHG) emissions. The aim of the research was to perform CF analysis for two scenarios of dairy WWTP operation. The analysis was based on the real operating data of the current system (current scenario) and project of its modernisation (alternative scenario). The current scenario consists of mechanical and dissolved air flotation (DAF) treatment, biological treatment in sequence batch reactors (SBRs), aerobic sewage sludge stabilisation and its final farmland usage. The alternative scenario assumes replacing aerobic stabilisation with anaerobic stabilisation and a combined heat and power (CHP) system. The CF calculations were based on empirical models, taking into account different emission input parameters, expressed in CO2 equivalents (CO2e). The total CF of the current scenario was 22 kg CO2e PE−1 year−1, while the alternative was 45 kg CO2e PE−1 year−1. The largest share in the current scenario belongs to emissions from WWTPs and energy use, while in the alternative, there is the addition of emissions from biogas use.
Temperature effects on lily development rate and morphology from the visible bud stage until anthesis.
Day (DT) and night temperatures (NT) influenced Lilium longiflorum Thunb. 'Nellie White' stem elongation and development rate from the visible bud stage (VB) until anthesis. Plant height increase after VB was a function of the difference (DIF) between DT and NT (DT-NT). Plant height increased 90% as DIF increased from - 16 to 16C. A cubic model described bud development rate as a function of temperature from 14 to 30C. A linear model adequately described bud development rate as a function of average daily temperature from 14 to 21C. Based on the linear model, bud development rate increased 0.05 per day for each 1C increase in average daily temperature. The base temperature for bud development, i.e., the temperature at which bud development rate was 0, was calculated as 3.5C. Greenhouse forcing of vernalized Easter lilies is commonly divided into three phases: I) placement of vernalized bulbs in the greenhouse to flower initiation, II) flower initiation to VB, and III) VB to anthesis (De Hertogh and Wilkins, 1971). Plant morphological development differs during each of the forcing phases (De Hertogh and Wilkins, 1971). Growth during phase I is vegetative and consists of stem elongation and leaf expan- sion. Flower initiation, leaf expansion, and stem elongation oc- cur during phase II. Inflorescence expansion and stem elongation occur during phase III. Lily responses to temperature during phase III differed from those during phases I and II (Wang and Roberts, 1983). Lily development rate, quantified as days to unfold a leaf, is a de- creasing linear function of average daily temperature between 14 and 30C during phases I and II (Karlsson et al., 1988). Lily development rate during phase III is a nonlinear function of temperature (Healy and Wilkins, 1984). The effect of temper- ature on the rate of lily development decreases as DT and/or NT increase during phase III (Rob and Wilkins, 1973; Healy and Wilkins, 1984). Easter lily morphological development is thermomorpho- genie. For instance, internode length increases as the DIF be- tween DT and NT increases (Erwin et al., 1989). In addition, leaf orientation, leaf length, and flower length are also influ- enced by diurnal changes in temperature.