Matlab code to generate Figure 3

% calculate staedy state CSTR volume for different substrate, product and
% flow
clear all

flow = [1:50]';
S = [0.5:0.01:0.9]; 

for i=1:length(flow)
    for j=1:length(S)
        P = 5.872-S(j); % 100 mg/l ammonia in feed water
        V(i,j)=steadystate_cstr_volume(flow(i),S(j),P);
    end
end

figure
surf(S,flow,V)
title('Volume of reactor 1 in steady state in [L]','FontSize',14)
xlabel('effluent ammonia concentration in [mmol/L]','FontSize',14)
ylabel('flow in [L/min]','FontSize',14)
zlabel('volume of reactor in [L]')
colorbar