Cost-effective wastewater treatment in a continuous manner by a novel bio-photoelectrolysis cell (BPE) system.

Approaches to improve wastewater treatment by microalgae have objectives of greater culture control, efficient nutrient removal and increased lipid content. This work designed a bio-photoelectrolysis cell (BPE) system to modulate wastewater treatment by electric current. The electric current had the capacity to enrich entrapped cell weight with a 0.72-fold increase, which resulted in high daily nutrient removal, with 6.78 mg/L/d for nitrogen and 2.14 mg/L/d for phosphorus at 0.6 A/m2. As the nutrient removal was mostly dependent on cell growth, the 1.17-fold increase of lipid productivity was achieved. The harvesting at 6 A/m2 required lower energy input of 1.77 KWh/kg. For the recyclability of treatment, BPE system could continuously treat the fresh wastewater for at least three cycles with biomass and lipid productivities of 68.67 and 22.04 mg/L/d, respectively. The nitrogen removal model of Cst = 45.52-5.52exp(0.45 t) and phosphorus removal model of Cst = 12.54-1.48exp(0.45 t) were established to evaluate the stability of BPE system.

Managing Scarce Water Resources in China's Coal Power Industry.

Coal power generation capacity is expanding rapidly in the arid northwest regions in China. Its impact on water resources is attracting growing concerns from policy-makers, researchers, as well as mass media. This paper briefly describes the situation of electricity-water conflict in China and provides a comprehensive review on a variety of water resources management policies in China's coal power industry. These policies range from mandatory regulations to incentive-based instruments, covering water withdrawal standards, technological requirements on water saving, unconventional water resources utilization (such as reclaimed municipal wastewater, seawater, and mine water), water resources fee, and water permit transfer. Implementing these policies jointly is of crucial importance for alleviating the water stress from the expanding coal power industry in China.

Fenton's treatment as an effective treatment for elderberry effluents: economical evaluation.

The utilization of Fenton's oxidation for the depuration of elderberry juice wastewater was studied. The aim was to select the adequate cost-effective operating conditions suitable to lead to an effluent within the legal thresholds to be discharged into the natural water courses. The treatment efficacy was assessed by chemical oxygen demand (COD), colour, phenolic content and total solids removal besides its ability to improve biodegradability (biochemical oxygen demand (BOD5)/COD). Moreover, the costs of the applied reactants were also considered. Fenton's reaction was able to abate at least 70% of COD (corresponding to a final value below 150 mg O2 L(-1)). Besides, total phenolic content degradation was always achieved. Within these conditions, the resulting effluent is able to be directly discharged into the natural hydric channels. Fenton oxidation could be successfully applied as a single treatment method with a reactant cost of 4.38 €â€…m(-3) ([Fe(2+)] = 20 mmol L(-1), [H2O2] = 100 mmol L(-1), pH = 3 and 4 h of oxidation procedure).

Recovery and removal of nutrients from swine wastewater by using a novel integrated reactor for struvite decomposition and recycling.

In the present study, struvite decomposition was performed by air stripping for ammonia release and a novel integrated reactor was designed for the simultaneous removal and recovery of total ammonia-nitrogen (TAN) and total orthophosphate (PT) from swine wastewater by internal struvite recycling. Decomposition of struvite by air stripping was found to be feasible. Without supplementation with additional magnesium and phosphate sources, the removal ratio of TAN from synthetic wastewater was maintained at >80% by recycling of the struvite decomposition product formed under optimal conditions, six times. Continuous operation of the integrated reactor indicated that approximately 91% TAN and 97% PT in the swine wastewater could be removed and recovered by the proposed recycling process with the supplementation of bittern. Economic evaluation of the proposed system showed that struvite precipitation cost can be saved by approximately 54% by adopting the proposed recycling process in comparison with no recycling method.

Global implementation of two shared socioeconomic pathways for future sanitation and wastewater flows.

Households are an important source of nutrient loading to surface water. Sewage systems without or with only primary wastewater treatment are major polluters of surface water. Future emission levels will depend on population growth, urbanisation, increases in income and investments in sanitation, sewage systems and wastewater treatment plants. This study presents the results for two possible shared socioeconomic pathways (SSPs). SSP1 is a scenario that includes improvement of wastewater treatment and SSP3 does not include such improvement, with fewer investments and a higher population growth. The main drivers for the nutrient emission model are population growth, income growth and urbanisation. Under the SSP1 scenario, 5.7 billion people will be connected to a sewage system and for SSP3 this is 5 billion. Nitrogen and phosphorus emissions increase by about 70% under both SSP scenarios, with the largest increase in SSP1. South Asia and Africa have the largest emission increases, in the developed countries decrease the nutrient emissions. The higher emission level poses a risk to ecosystem services.

Performance of the biosorptive activated sludge (BAS) as pre-treatment to UF for decentralized wastewater reuse.

A biosorptive activated sludge (BAS) was operated at lab-scale with diluted and concentrated municipal wastewater to study the efficiency of removal of organics (particulate and soluble COD) and recovery of nutrients (TKN, ammonia, phosphorus). The system performed significantly better with concentrated wastewater, where COD removal efficiency was 80% at organic loading rates between 10 and 20kg m(-3)d(-1). Supplementation of ferrous iron at 20mg L(-1), significantly improved both the removal of particulate, soluble COD and phosphorus. The effluent from the BAS was further treated using an ultrafiltration process with backwashing. The average permeate flux (at constant TMP=0.3bar) increased from 23 to 28 and 34L m(-2)h(-1) when raw sewage, BAS without iron, and iron respectively were tested. The proposed technology is compact, efficient and suitable for decentralized water reuse, while the capital and operational expenses were calculated as 0.64 and 0.43€ m(-3), respectively.

Nutrient removal from agricultural drainage water using algal turf scrubbers and solar power.

The objectives of this study were to determine nutrient removal rates and costs using solar-powered algal turf scrubber (ATS) raceways and water from an agricultural drainage ditch. Algal productivity using daytime-only flow was 3-lower compared to productivity using continuous flow. Results from this and other studies suggest a non-linear relationship between flow rate and nitrogen removal rates. Nitrogen (N) and phosphorus (P) removal rates averaged 125 mg N, 25 mg P m(-2) d(-1) at the highest flow rates. Nutrient removal rates were equivalent to 310 kg N and 33 kg P ha(-1) over a 7 month season. Projected nutrient removal costs ($90-$110 kg(-1) N or $830-$1050 kg(-1) P) are >10-fold higher than previous estimates for ATS units used to treat manure effluents.

Efficiency of advanced wastewater treatment plant system and laboratory-scale micelle-clay filtration for the removal of ibuprofen residues.

The efficiency of Al-Quds Waste Water Treatment Plant (WWTP), which includes sequential elements as activated sludge, ultrafiltration, activated carbon column and reverse osmosis, to remove spiked ibuprofen, a non steroid anti inflammatory drug (NSAID), was investigated. Kinetic studies in pure water and in the activated sludge indicated that the drug was stable during one month of observation. Besides, the overall performance of the integrated plant showed complete removal of ibuprofen from wastewater. Activated carbon column, which was the last element in the sequence before the reverse osmosis system, yielded 95.7% removal of ibuprofen. Batch adsorptions of the drug by using either activated charcoal or composite micelle-clay system were determined at 25°C and well described by Langmuir isotherms. Octadecyltrimethylammonium (ODTMA) bromide and montmorillonite were used to prepare the micelle-clay adsorbent, for which the adsorption kinetics are much faster than activated charcoal. Results suggest that integrating clay-micelle complex filters within the existing WWTP may be promising in improving removal efficiency of the NSAID.