I'm just going to throw this into the mix. It may be nothing, I may be suffering from confirmation bias, but the water angle and these bloody 2-planes keeps coming back to me. Consider these:-
2-NYAW - New York American Water?
2-RBTS - Reed Bed Treatment System (used for sewage treatment)?
2-RNWL - A method for assessing the water level in reservoirs?
Reed beds are a not a sewage treatment system on their own, but are used in conjunction with a primary treatment such as a settling or septic tank (which will need emptying periodically). Reed beds only treat liquid effluent - solids will need to be treated elsewhere, either pumped from the septic tank and treated with the mains sewage, or composted. Reed beds are aquatic plant based systems which allow bacteria, fungi and algae to digest the sewage and clean the water. There are two basic types of reed bed - vertical flow and horizontal flow - and the best system often results from combining the two.
Determination of the optimal normal water level of reservoirs (RNWL) was investigated, incorporating environmental ecology as a primary consideration. RNWL constitutes a relatively significant eigen value of any water conservancy project. In the present study, a four-step method based on a mathematical programming model and suitable for RNWL decision making was developed and applied to the water conservancy project of the Songyuan backwater dam in China. System analysis, correlation analysis, significance testing, principal component analysis, sensitivity analysis, and system optimisation theory are used in the solution process. In this study, various factors that impact the economic viability, engineering characteristics, environmental and urban ecology are considered for holistic optimisation. The study shows that the proposed four-step method may provide a feasible quantitative form of support for RNWL decision making.