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Core Ideas A subsurface drainage‐fed bioreactor was retrofitted with a supplemental surface water pumping system. Design criteria of the pumping system are presented along with challenges and future recommendations. Pumped bioreactor systems show promise for the treatment of alternative nitrate‐laden sources of water. Pumped bioreactors have the potential to remove nitrate beyond the typical drainage season. 

Cu2TSiS4 (T = Mn and Fe) polycrystalline and single-crystal materials were prepared with high-temperature solid-state and chemical vapor transport methods, respectively. The polar crystal structure (space group Pmn21) consists of chains of corner-sharing and distorted CuS4, Mn/FeS4, and SiS4 tetrahedra, which is confirmed by Rietveld refinement using neutron powder diffraction data, X-ray single-crystal refinement, electron diffraction, energy-dispersive X-ray spectroscopy, and second harmonic generation (SHG) techniques. Magnetic measurements indicate that both compounds order antiferromagnetically at 8 and 14 K, respectively, which is supported by the temperature-dependent (100–2 K) neutron powder diffraction data. Additional magnetic reflections observed at 2 K can be modeled by magnetic propagation vectors k = (1/2,0,1/2) and k = (1/2,1/2,1/2) for Cu2MnSiS4 and Cu2FeSiS4, respectively. The refined antiferromagnetic structure reveals that the Mn/Fe spins are canted away from the ac plane by about 14°, with the total magnetic moments of Mn and Fe being 4.1(1) and 2.9(1) μB, respectively. Both compounds exhibit an SHG response with relatively modest second-order nonlinear susceptibilities. Density functional theory calculations are used to describe the electronic band structures. 

The new, quaternary diamond-like semiconductor (DLS) Cu 4 MnGe 2 S 7 was prepared at high-temperature from a stoichiometric reaction of the elements under vacuum. Single crystal X-ray diffraction data were used to solve and refine the structure in the polar space group Cc. Cu 4 MnGe 2 S 7 features [Ge 2 S 7 ] 6− units and adopts the Cu 5 Si 2 S 7 structure type that can be considered a derivative of the hexagonal diamond structure. The DLS Cu 2 MnGeS 4 with the wurtz-stannite structure was similarly prepared at a lower temperature. The achievement of relatively phase-pure samples, confirmed by X-ray powder diffraction data, was nontrival as differential thermal analysis shows an incongruent melting behaviour for both compounds at relatively high temperature. The dark red Cu 2 MnGeS 4 and Cu 4 MnGe 2 S 7 compounds exhibit direct optical bandgaps of 2.21 and 1.98 eV, respectively. The infrared (IR) spectra indicate potentially wide windows of optical transparency up to 25 μm for both materials. Using the Kurtz–Perry powder method, the second-order nonlinear optical susceptibility, χ (2) , values for Cu 2 MnGeS 4 and Cu 4 MnGe 2 S 7 were estimated to be 16.9 ± 2.0 pm V −1 and 2.33 ± 0.86 pm V −1 , respectively, by comparing with an optical-quality standard reference material, AgGaSe 2 (AGSe). Cu 2 MnGeS 4 was found to be phase matchable at λ = 3100 nm, whereas Cu 4 MnGe 2 S 7 was determined to be non-phase matchable at λ = 1600 nm. The weak SHG response of Cu 4 MnGe 2 S 7 precluded phase-matching studies at longer wavelengths. The laser-induced damage threshold (LIDT) for Cu 2 MnGeS 4 was estimated to be ∼0.1 GW cm −2 at λ = 1064 nm (pulse width: τ = 30 ps), while the LIDT for Cu 4 MnGe 2 S 7 could not be ascertained due to its weak response. The significant variance in NLO properties can be reasoned using the results from electronic structure calculations. 

The new compounds Li₂Mg₂Si₂S₆and Li₂Mg₂Ge₂S₆have been prepared via traditional high‐temperature, solid‐state synthesis. The title compounds crystallize in the polar, noncentrosymmetric, trigonal space groupP31m(No. 157) and adopt a new structure type featuring staggered, ethane‐like (T₂S₆)⁶⁻units, where T=Si or Ge. These (T₂S₆)⁶⁻units are nestled within the holes of magnesium‐sulfide “layers” that are created through the edge‐sharing of MgS₆octahedra. The holes found in the lithium‐sulfide “layers”, created by LiS₆edge‐sharing octahedra, remain vacant, containing no (T₂S₆)⁶⁻anionic group. Through the face sharing of the respective MgS₆and LiS₆octahedra, the magnesium‐sulfide and lithium‐sulfide “layers” are stitched together resulting in an overall three‐dimensional structure. The optical bandgaps of Li₂Mg₂Si₂S₆and Li₂Mg₂Ge₂S₆are 3.24 and 3.18 eV, respectively, as estimated from optical diffuse reflectance UV‐Vis‐NIR spectroscopy. The compounds exhibit second harmonic generation responses of ∼0.24×KDP and ∼2.92×α‐quartz for Li₂Mg₂Si₂S₆and ∼0.17×KDP and ∼2.08×α‐quartz for Li₂Mg₂Ge₂S₆, using a Nd:YAG laser at 1.064 μm. Electronic structure calculations were performed using density functional theory and the linearized augmented plane‐wave approach within the WIEN2k software package. Examination of the electronic band structures shows that these compounds are indirect bandgap semiconductors.