Higher TSS Research Articles

Total nitrogen removal in two-step biofiltration

A one-year study was carried out on two semi-industrial submerged up-flow biofilters - a pre-denitrification (pre-DN) step followed by a nitrifying (N) step, designed to treat the primary settled municipal wastewater of a full scale plant for both carbon and nitrogen removal. Performances of the pre-DN step have been investigated showing high removal denitrifying capacities – 1 to 1.2 kg NO3−–N removed per m3 of reactor per day–, obtained with high TSS and carbon loading rates, at a water velocity up to 21.5 m3/ m2.h. The complete treatment plant – primary settlement + pre-DN/N loop – has demonstrated a nitrogen removal efficiency ranging from 70% without any additional carbon, up to 85% with methanol. COD and TSS removal rates were 91% and 97% respectively. The above results show that two submerged biofilters in series form a treatment line suitable for nitrogen removal. This technical choice leads to very compact full scale plants such as Ahlen WWTP (Germany, 85 000 PE).

Effect of substrate temperature and depostion profile on evaporated Cu(InGa)Se2 films and devices

This paper addresses the effect of substrate temperature (TSS) and deposition profile for Cu(InGa)Se2 films deposited by multisource elemental evaporation on film structure and solar cell performance. Different temporal Cu flux profiles are utilized to give either a graded deposition incorporating a Cu-rich growth step, with [Cu]>[In]+[Ga], before achieving the final film composition with [Cu]<[In]+[Ga], or a uniform deposition with [Cu]<[In]+[Ga] throughout. The Cu(InGa)Se2 morphology, including quantitative analysis of the grain size distributions, and the performance of completed solar cells are compared at TSS=400 and 550°C. The higher TSS gives larger grains and better device performance with the best devices obtained in this work having efficiencies of 16.4% for 550°C and 14.1% for 400°C. At 550°C, Cu-rich film growth gives bigger grains than a uniform flux process, but there is no difference in the device performance. With TSS=400°C, there is no significant difference in the grain size with the different flux profiles, but the Cu-rich growth is needed for improved devices.

Effect of Water Stress on Fruit Quality and Endogenous Abscisic Acid(ABA) Content in Peach Fruit.

To determine the influence of water stress on fruit quality, ABA content in peach fruit and its quality was investigated under water stress condition. Water stress treatments were carried out from June 20 (70 days after full bloom (DAFB) ) in 1994 by mulching with white porous waterproof sheet, and plastic film covering over trees. Heavier water stress was achieved on the treated trees from July 9 corresponding to fruit maturation. ABA content and total soluble solid content (TSS) in the peach fruit increased under the water stress condition. Similar results were achieved also in 1995. In 1994 higher ABA content in the fruit was detected at the soil water potential of below -0.06 MPa (the pF of above 2.8) which coincided with that recommended for peach tree during fruit maturation. However, the photosynthetic rate was decreased by water stress. These results suggest that an increase of ABA content in fruit caused by water stress enhanced assimilates partitioning into peach fruit and resulted in higher TSS.

Solubilization and methanogenesis of a particulate industrial waste: Impact of solids loading and temperature

Effective anaerobic treatment of particulate wastes requires solubilization and acid formation prior to methanogenesis. In this case study of a particulate waste from a corn-processing industry, the influence of solids loading in solubilization, acid formation and methanogenesis was studied under mesophilic (35°C) and thermophilic (60°C) conditions. The waste was concentrated by centrifugation to initial suspended solids concentrations (TSS i) of 150 to 350 g/L (15% to 35%). Anaerobic batch tests were conducted for 20 days, and significant solubilization of the particulate organic matter occurred in all cases. The thermophilic systems were more effective than the mesophilic systems with respect to solubilization of particulates, volatile solids destruction, acetic acid uptake, and methane generation. Methanogenesis appreared to be a rate-limiting step at higher TSS i values, indicated by accumulation of volatile organic acids in the batch systems. Slower rates of methane production led to identification of the limiting solids loading for both temperature regimes. The results of this study can be used to evaluate the limitations of a single stage system for anaerobic treatment of organic particulate industrial wastes.

Micronutrient addition and its impact on WWTP performance

AbstractThe Hoechst Celanese facility in Narrows, Virginia, treats process wastewater in an aerobic biological wastewater treatment plant (WWTP). Historically, the WWTP has experienced high effluent TSS levels. When the facility's National Pollutant Discharge Elimination System (NPDES) permit is modified, more stringent effluent TSS limits will be incorporated based on the OCPSF effluent guidelines. Without significantly improved effluent quality, effluent filtration will be required. At the historical effluent TSS levels experienced by the WWTP, conventional filters will not provide the reliability needed for permit compliance. In 1990, influent sampling indicated that the poor effluent quality could be the result of nutrient limitations. Nitrogen was identified as a limiting macronutrient, but effluent quality did not substantially improve when only nitrogen additions were increased. After a program was implemented to add micronutrients concurrently, effluent quality significantly improved. It was concluded that micro‐ and macro‐nutrient additions coupled with effluent filtration will be required to meet the future OCPSF TSS limits.

Performance of `Orlando' Tangelo Trees on Ten Rootstocks in Arizona

The influence, of 10 rootstocks on growth, yield, and fruit quality of `Orlando' tangelo (Citrus paradisi Macf. × C. reticulata Blanco) was studied for 7 years under the arid climate of southwestern Arizona. Trees on macrophylla (Alemow) (C. macrophylla Wester) were the most precocious and produced the highest yields 4 years after planting. Seven-year cumulative yields of trees on Carrizo citrange [C. sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf.], Yuma citrange (P. trifoliata × C. sinensis), Volkamer lemon (C. limon Burm f.), rough lemon (C. jambhiri Lush), Taiwanica (C. taiwanica), and macrophylla were similar and higher than those on Savage citrange (P. trifofiata × C. sinensis), Batangas mandarin (C. reticulata Blanco), Ichang pummelo (C. ichangensis hyb.), and Palestine sweet lime (C. limettoides Tan.). Trees on Carrizo citrange had relatively large tree canopies and larger fruit, and fruit from trees on Volkamer lemon and rough lemon was lower in total soluble solids concentration (TSS) and total acids (TA) than fruit from trees on other rootstocks. Fruit from trees on Savage citrange was smallest but had the highest TSS. Considering yield, growth, and/or various quality factors, Volkamer lemon, rough lemon, Yuma citrange, and particularly Carrizo citrange, are suitable for `Orlando' tangelo in the arid regions of the southwestern United States. Trees on macrophylla, Savage citrange, and Ichang pummelo had small canopies and were least productive. `Orlando' tangelo trees on Savage citrange and Ichang pummelo rootstocks, however, might be good choices at a spacing closer than 7 × 7 m because of their high fruit TSS and fruit size, respectively. Trees on Palestine sweet lime declined and had low yields, and those on Batangas mandarin had low yields and poor fruit quality. These rootstocks are not recommended for `Orlando' tangelo under conditions similar to those of this experiment.